FIELD OF THE INVENTION

The invention relates to populations of gamma delta T cells contacted with anti-TCR delta variable 1 (anti-Vb1) antibodies.

BACKGROUND OF THE INVENTION

The growing interest in T cell immunotherapy for cancer has focused on the evident capacity of subsets of CD8+ and CD4+ alpha beta (ab) T cells to recognize cancer cells and to mediate host-protective functional potentials, particularly when de-repressed by clinically mediated antagonism of inhibitory pathways exerted by PD-1 , CTLA-4, and other receptors. However, ab T cells are MHC-restricted which can lead to graft versus host disease.

Gamma delta T cells (gd T cells) represent a subset of T cells that express on their surface a distinct, defining gd T-cell receptor (TCR). This TCR is made up of one gamma (g) and one delta (d) chain, each of which undergoes chain rearrangement but have a limited number of V genes as compared to ab T cells. The main TGRV gene segments encoding ng are TRGV2, TRGV3, TRGV4, TRGV5, TRGV8, TRGV9 and TRGV11 and non-functional genes TRGV10, TRGV11 , TRGVA and TRGVB. The most frequent TRDV gene segments encode Vb1 , V62, and V63, plus several V segments that have both Vb and Va designation (Adams et ai, 296:30-40 (2015) Cell Immunol.). Human gd T cells can be broadly classified based on their TCR chains, as certain g and d types are found on cells more prevalently, though not exclusively, in one or more tissue types. For example, most blood-resident gd T cells express a Vb2 TCR, commonly VY9V62, whereas this is less common among tissue-resident gd T cells such as those in the skin, which more frequently use the Vb1 TCR paired with gamma chains, for example often paired with ng4 in the gut.

To exploit gd T cells for immunotherapy requires either a means to expand the cells in situ or to harvest them and expand them ex vivo prior to re-infusion. The latter approach has previously been described using the addition of exogenous cytokines, for example see WO2017/072367 and WO2018/212808. Methods for expanding a patients’ own gd T cells has been described using pharmacologically modified forms of hydroxy-methyl but-2-enyl pyrophosphate (HMBPP) or clinically-approved aminobisphosphonates. By these approaches, over 250 cancer patients have been treated, seemingly safely, but with only rare incidences of complete remission. However, there is still a need for activating agents that have the proven capacity to expand large numbers of gd T cells. SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided an ex vivo method of modulating V61 T cells comprising administering a human, anti-TCR delta variable 1 (anti-V61) antibody or fragment thereof, which binds to an epitope of a variable delta 1 (V61) chain of a gd T cell receptor (TCR) comprising one or more amino acid residues within amino acid regions:

(i) 3-20 of SEQ ID NO: 1 ; and/or

(ii) 37-77 of SEQ ID NO: 1 to a cell population comprising V61 T cells.

According to a further aspect of the invention, there is provided an ex vivo method of modulating V61 T cells comprising administering an anti-V61 antibody or fragment thereof which comprises one or more of: a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 2-25; a CDR2 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 26-37 and SEQUENCES: A1-A12 (of Table 2); and/or a CDR1 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 38-61 , to a cell population comprising V61 T cells.

According to a further aspect of the invention, there is provided a V61 T cell population obtained by the ex vivo method as defined herein.

According to a further aspect of the invention, there is provided a composition comprising the V61 T cell population as defined herein.

According to a further aspect of the invention, there is provided a pharmaceutical composition comprising the V61 T cell population as defined herein.

According to a further aspect of the invention, there is provided a method of treating a cancer, an infectious disease or an inflammatory disease in a subject in need thereof, comprising administering a therapeutically effective amount of the V61 T cell population or the pharmaceutical composition as defined herein. BRIEF DESCRIPTION OF THE FIGURES

Figure 1: ELISA Detection of Directly Coated Antigen with Anti-V51Ab (REA173,

Miltenyi Biotec). Detection was seen only with those antigens which contain the V51 domain. Leucine zipper (LZ) format seems more potent than Fc format which is consistent with cell-based flow competition assay (data not shown).

Figure 2: Polyclonal phage DELFIA data for DV1 selections. A) Heterodimer selections: heterodimeric LZ TCR format in round 1 and 2, with deselections on heterodimeric LZ TCR in both rounds. B) Homodimer selections: round 1 performed using homodimeric Fc fusion TCR with deselection on human lgG1 Fc followed by round 2 on heterodimeric LZ TCR with deselection on heterodimeric LZ TCR. Each graph contains two bars for each target to represent selections from different libraries.

Figure 3: IgG capture: left) Sensorgrams of interaction of anti-L1 IgG with L1 , right) steady state fits, if available. All experiments were performed at room temperature on MASS-2 instrument. Steady state fitting according to Langmuir 1 :1 binding.

Figure 4: Results of TCR Downregulation Assay for clones 1245_P01_E07, 1252_P01_C08,

1245_P02_G04, 1245_P01_B07 and 1251_P02_C05 (A) or clones 1139_P01_E04,

1245_P02_F07, 1245_P01_G06, 1245_P01_G09, 1138_P01_B09, 1251_P02_G10 and

1252_P01_C08 (B).

Figure 5: Results of T cell degranulation Assay for clones 1245_P01_E07, 1252_P01_C08,

1245_P02_G04, 1245_P01_B07 and 1251_P02_C05 (A) or clones 1139_P01_E04,

1245_P02_F07, 1245_P01_G06, 1245_P01_G09, 1138_P01_B09 and 1251_P02_G10 (B).

Figure 6: Results of Killing Assay (THP-1 flow-based assay) for clones 1245_P01_E07,

1252_P01_C08, 1245_P02_G04, 1245_P01_B07 and 1251_P02_C05 (A) or clones

1139_P01_E04, 1245_P02_F07, 1245_P01_G06, 1245_P01_G09, 1138_P01_B09 and

1251_P02_G10 (B).

Figure 7: Epitope mapping data for 1245_P01_E07. Graphical representation of epitope binding site of 1245_P01_E07 on SEQ ID NO: 1 .

Figure 8: Epitope mapping data for 1252_P01_C08. Graphical representation of epitope binding site of 1252_P01_C08 on SEQ ID NO: 1 . Figure 9: Epitope mapping data for 1245_P02_G04. Graphical representation of epitope binding site of 1245_P02_G04 on SEQ ID NO: 1 .

Figure 10: Epitope mapping data for 1251_P02_C05. Graphical representation of epitope binding site of 1251_P02_C05 on SEQ ID NO: 1 .

Figure 11: Epitope mapping data for 1141_P01_E01. Graphical representation of epitope binding site of 1141_P01_E01 on SEQ ID NO: 1 .

Figure 12: Total cell counts during Experiment 1 of Example 10. Samples were cultured with varying concentration of anti-V61 antibodies described herein and compared to samples cultured with comparator antibodies or controls. Graphs show total cell counts at (A) day 7, (B) day 14 and (C) day 18.

Figure 13: Analysis of V61 T cells during Experiment 1 of Example 10. Graphs show

(A) percentage of V61 T cells, (B) V61 T cell count and (C) V61 fold change in the samples at day 18.

Figure 14: Total cell counts during Experiment 2 of Example 10. Samples were cultured with varying concentration of anti-V61 antibodies described herein and compared to samples cultured with comparator antibodies or controls. Graphs show total cell counts at (A) day 7, (B) day 11, (C) day 14 and (D) day 17.

Figure 15: Analysis of V61 T cells during Experiment 2 of Example 10. Graphs show

(A) percentage of V61 T cells, (B) V61 T cell count and (C) V61 fold change in the samples at day 17.

Figure 16: Cell composition analysis. The cell types present in the samples (including non-V61 cells) were measured on day 17 of Experiment 2. Cells were harvested and analysed by flow cytometry for surface expression of V61, V62 and c^TCR. The percentage values are also provided in Table 6.

Figure 17: SYTOX-flow killing assay results. Cell functionality was tested using the

SYTOX-flow killing assay and results are presented for (A) Experiment 1 at day 14 using cells in a 10:1 Effector-to-Target (E:T) ratio, and (B) Experiment 2 at day 17 (post freeze-thaw) using cells at a 1 : 1 and 10: 1 E:T ratio. Figure 18: Total cell count post freeze-thaw. Graph shows the total cell counts after 7 days of culturing cells post freeze-thaw for cultures contacted with B07, C08, E07, G04 or OKT-3 antibodies prior to freezing.

Figure 19: Monitoring cell expansion. Total cell counts were monitored until day 42 for cells cultured post freeze-thaw.

Figure 20: Anti-V61 antibody conferred modulation and proliferation of tumour- infiltrating-lymphocyte (TILs) in human tumours. Studies on renal cell carcinoma (RCC) +/- antibodies A) Fold-increase in TIL V61+ cells. B) Total numbers of TIL V61+ cells. C) Example gating strategy D) Comparative cell-surface phenotypic profile of TIL V61+ cells. E) Analysis of the TIL V61 -negative gated fraction.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

Unless defined otherwise, all technical and scientific terms used herein have the meaning commonly understood by a person skilled in the art to which this invention belongs. As used herein, the following terms have the meanings ascribed to them below.

Gamma delta (gd) T cells represent a small subset of T cells that express on their surface a distinct, defining T Cell Receptor (TCR). This TCR is made up of one gamma (g) and one delta (d) chain. Each chain contains a variable (V) region, a constant (C) region, a transmembrane region and a cytoplasmic tail. The V region contains an antigen binding site. There are two major sub-types of human gd T cells: one that is dominant in the peripheral blood and one that is dominant in non-haematopoietic tissues. The two sub-types may be defined by the type of d and/or Y present on the cells. For example, gd T cells that are dominant in peripheral blood primarily express the delta variable 2 chain (V62). gd T cells that are dominant in non- haematopoietic tissues (/.e. are tissue-resident) primarily express the delta variable 1 (V61) chain. References to “V61 T cells” refer to gd T cells with a V61 chain, /.e. V61 ⁺ T cells.

References to “delta variable 1” may also referred to as V61 or Vd1, while a nucleotide encoding a TCR chain containing this region may be referred to as “TRDV1”. Antibodies or fragments thereof which interact with the V61 chain of a gd TCR, are all effectively antibodies or fragments thereof which bind to V61 and may referred to as “anti-TCR delta variable 1 antibodies or fragments thereof” or “anti-V61 antibodies or fragments thereof”. Additional references are made herein to other delta chains such as the “delta variable 2” chain. These can be referred to in a similar manner. For example, delta variable 2 chains can be referred to as V62, while a nucleotide encoding a TCR chain containing this region may be referred to as “TRDV2”. In preferred embodiments antibodies or fragments thereof which interact with the V61 chain of a gd TCR, do not interact with other delta chains such as V62

References to ‘gamma variable chains’ are also made herein. These may be referred to as g- chains or ng, while a nucleotide encoding a TCR chain containing this region may be referred to as TRGV. For example, TRGV4 refers to ng4 chain. In a preferred embodiments, antibodies or fragments thereof which interact with the V61 chain of a gd TCR, do not interact with gamma chains such as ng4.

The term “antibody” includes any antibody protein construct comprising at least one antibody variable domain comprising at least one antigen binding site (ABS). Antibodies include, but are not limited to, immunoglobulins of types IgA, IgG, IgE, IgD, IgM (as well as subtypes thereof). The overall structure of Immunoglobulin G (IgG) antibodies assembled from two identical heavy (H)-chain and two identical light (L)-chain polypeptides is well established and highly conserved in mammals (Padlan (1994) Mol. Immunol. 31:169-217).

A conventional antibody or immunoglobulin (Ig) is a protein comprising four polypeptide chains: two heavy (H) chains and two light (L) chains. Each chain is divided into a constant region and a variable domain. The heavy (H) chain variable domains are abbreviated herein as VH, and the light (L) chain variable domains are abbreviated herein as VL. These domains, domains related thereto and domains derived therefrom, may be referred to herein as immunoglobulin chain variable domains. The VH and VL domains (also referred to as VH and VL regions) can be further subdivided into regions, termed “complementarity determining regions” (“CDRs”), interspersed with regions that are more conserved, termed “framework regions” (“FRs”). The framework and complementarity determining regions have been precisely defined (Kabat et al. Sequences of Proteins of Immunological Interest, Fifth Edition U.S. Department of Health and Human Services, (1991) NIH Publication Number 91-3242). There are also alternative numbering conventions for CDR sequences, for example those set out in Chothia et al. (1989) Nature 342: 877-883. In a conventional antibody, each VH and VL is composed of three CDRs and four FRs, arranged from amino-terminus to carboxy-terminus in the following order: FR1, CDR1 , FR2, CDR2, FR3, CDR3, FR4. The conventional antibody tetramer of two heavy immunoglobulin chains and two light immunoglobulin chains is formed with the heavy and the light immunoglobulin chains inter-connected by e.g. disulphide bonds, and the heavy chains similarly connected. The heavy chain constant region includes three domains, CH1, CH2 and CH3. The light chain constant region is comprised of one domain, CL. The variable domain of the heavy chains and the variable domain of the light chains are binding domains that interact with an antigen. The constant regions of the antibodies typically mediate the binding of the antibody to host tissues or factors, including various cells of the immune system (e.g. effector cells) and the first component (C1q) of the classical complement system.

A fragment of the antibody (which may also referred to as “antibody fragment”, “immunoglobulin fragment”, “antigen-binding fragment” or “antigen-binding polypeptide”) as used herein refers to a portion of an antibody (or constructs that contain said portion) that specifically binds to the target, the delta variable 1 (V61) chain of a gd T cell receptor (e.g. a molecule in which one or more immunoglobulin chains is not full length, but which specifically binds to the target). Examples of binding fragments encompassed within the term antibody fragment include:

(i) a Fab fragment (a monovalent fragment consisting of the VL, VH, CL and CH1 domains);

(ii) a F(ab')2 fragment (a bivalent fragment consisting of two Fab fragments linked by a disulphide bridge at the hinge region);

(iii) a Fd fragment (consisting of the VH and CH1 domains);

(iv) a Fv fragment (consisting of the VL and VH domains of a single arm of an antibody);

(v) a single chain variable fragment, scFv (consisting of VL and VH domains joined, using recombinant methods, by a synthetic linker that enables them to be made as a single protein chain in which the VL and VH regions pair to form monovalent molecules);

(vi) a VH (an immunoglobulin chain variable domain consisting of a VH domain);

(vii) a VL (an immunoglobulin chain variable domain consisting of a VL domain);

(viii) a domain antibody (dAb, consisting of either the VH or VL domain);

(ix) a minibody (consisting of a pair of scFv fragments which are linked via CH3 domains); and

(x) a diabody (consisting of a noncovalent dimer of scFv fragments that consist of a VH domain from one antibody connected by a small peptide linker a VL domain from another antibody).

“Human antibody" refers to antibodies having variable and constant regions derived from human germline immunoglobulin sequences. Human subjects administered with said human antibodies do not generate cross-species antibody responses (for example termed HAMA responses - human-anti-mouse antibody) to the primary amino acids contained within said antibodies. Said human antibodies may include amino acid residues not encoded by human germline immunoglobulin sequences (e.g. mutations introduced by random or site-specific mutagenesis or by somatic mutation), for example in the CDRs and in particular CDR3. However, the term is not intended to include antibodies in which CDR sequences derived from the germline of another mammalian species, such as a mouse, have been grafted onto human framework sequences. Human antibodies that are prepared, expressed, created or isolated by recombinant means, such as antibodies expressed using a recombinant expression vector transfected into a host cell, antibodies isolated from a recombinant, combinatorial human antibody library, antibodies isolated from an animal (e.g. a mouse) that is transgenic for human immunoglobulin genes or antibodies prepared, expressed, created or isolated by any other means that involves splicing of human immunoglobulin gene sequences to other DNA sequences, may also be referred to as “recombinant human antibodies”.

Substituting at least one amino acid residue in the framework region of a non-human immunoglobulin variable domain with the corresponding residue from a human variable domain is referred to as “humanisation”. Humanisation of a variable domain may reduce immunogenicity in humans.

“Specificity” refers to the number of different types of antigens or antigenic determinants to which a particular antibody or fragment thereof can bind. The specificity of an antibody is the ability of the antibody to recognise a particular antigen as a unique molecular entity and distinguish it from another. An antibody that “specifically binds” to an antigen or an epitope is a term well understood in the art. A molecule is said to exhibit “specific binding” if it reacts more frequently, more rapidly, with greater duration and/or with greater affinity with a particular target antigen or epitope, than it does with alternative targets. An antibody “specifically binds” to a target antigen or epitope if it binds with greater affinity, avidity, more readily, and/or with greater duration than it binds to other substances.

“Affinity”, represented by the equilibrium constant for the dissociation of an antigen with an antigen-binding polypeptide (KD), is a measure of the binding strength between an antigenic determinant and an antigen-binding site on the antibody (or fragment thereof): the lesser the value of the KD, the stronger the binding strength between an antigenic determinant and the antigen-binding polypeptide. Alternatively, the affinity can also be expressed as the affinity constant (KA), which is 1/KD. Affinity can be determined by known methods, depending on the specific antigen of interest. Any KD value less than 10 ⁶ is considered to indicate binding. Specific binding of an antibody, or fragment thereof, to an antigen or antigenic determinant can be determined in any suitable known manner, including, for example, Scatchard analysis and/or competitive binding assays, such as radioimmunoassays (RIA), enzyme immunoassays (EIA) and sandwich competition assays, equilibrium dialysis, equilibrium binding, gel filtration, ELISA, surface plasmon resonance, or spectroscopy (e.g. using a fluorescence assay) and the different variants thereof known in the art.

“Avidity” is the measure of the strength of binding between an antibody, or fragment thereof, and the pertinent antigen. Avidity is related to both the affinity between an antigenic determinant and its antigen binding site on the antibody and the number of pertinent binding sites present on the antibody.

“Human tissue V61+ cells,” and “haemopoietic and blood V61+ cells” and “tumour infiltrating lymphocyte (TIL) V61+ cells,” are defined as V61+ cells contained in or derived from either human tissue or the haemopoietic blood system or human tumours respectively. All said cell types can be identified by their (i) location or from where they are derived and (ii) their expression of the V61+ TCR.

“Modulating antibodies” are antibodies that confer a measurable change including, but not limited to, a measurable change in cell cycle, and/or in cell number, and/or cell viability, and/or in one or more cell surface markers, and/or in the secretion of one or more secretory molecules (e.g., cytokines, chemokines, leukotrienes, etc.), and/or a function (such as cytotoxicity towards a target cell or diseased cell), upon contacting or binding to a cell expressing the target to which the antibody binds.

A method of “modulating” a cell, or population thereof, refers to a method wherein in at least one measurable change in said cell or cells, or secretion therefrom, is triggered to generate one or more “modulated cells”.

An “immune response” is a measurable change in at least one cell, or one cell-type, or one endocrine pathway, or one exocrine pathway, of the immune system (including but not limited to a cell-mediated response, a humoral response, a cytokine response, a chemokine response) upon addition of a modulating antibody.

An “immune cell” is defined as a cell of the immune system including, but not limited to, CD34+ cells, B-Cells, CD45+ (lymphocyte common antigen) cells, Alpha-Beta T-cells, Cytotoxic T- cells, Helper T-cells, Plasma Cells, Neutrophils, Monocytes, Macrophages, Red Blood Cells, Platelets, Dendritic Cells, Phagocytes, Granulocytes, Innate lymphoid cells, Natural Killer (NK) cells and Gamma Delta T-cells. Typically, immune cells are classified with the aid of combinatorial cell surface molecule analysis (e.g., via flow cytometry) to identify or group or cluster to differentiate immune cells into sub-populations. These can be then still further sub divided with additional analysis. For example, CD45+ lymphocytes can further sub-divided into nd positive populations and nd negative populations.

“Model systems” are biological models or biological representations designed to aid in the understanding of how a medicine such as an antibody or fragment thereof may function as a medicament in the amelioration of a sign or symptom of disease. Such models typically include the use of in vitro, ex vivo, and in vivo diseased cells, non-diseased cells, healthy cells, effector cells, and tissues etc., and in which the performance of said medicaments are studied and compared.

“Diseased cells” exhibit a phenotype associated with the progression of a disease such as a cancer, an infection such as a viral infection, or an inflammatory condition or inflammatory disease. For example, a diseased cell may be a tumour cell, an autoimmune tissue cell or a virally infected cell. Accordingly said diseased cells may be defined as tumorous, or virally infected, or inflammatory.

“Healthy cells” refers to normal cells that are not diseased. They may also be referred to as “normal” or “non-diseased” cells. Non-diseased cells include non-cancerous, or non-infected, or non-inflammatory cells. Said cells are often employed alongside relevant diseased cells to determine the diseased cell specificity conferred by a medicament and/or better understand the therapeutic index of a medicament.

“Diseased-cell-specificity” is a measure of how effective an effector cell or population thereof, (such as, for example, a population of V61+ cells) is at distinguishing and killing diseased cells, such as cancer cells, whilst sparing non-diseased or healthy cells. This potential can be measured in model systems and may involve comparing the propensity of an effector cell, or a population of effector cells, to selectively kill or lyse diseased cells versus the potential of said effector cell/s to kill or lyse non-diseased or healthy cells. Said diseased-cell-specificity can inform the potential therapeutic index of a medicament.

“Enhanced diseased-cell specificity” describes a phenotype of an effector cell such as, for example, a V61+ cell, or population thereof, which has been modulated to further increase its capacity to specifically kill diseased cells. This enhancement can be measured in a variety of ways inclusive of fold-change, or percentage increase, in diseased-cell killing specificity or selectivity.

Suitably, the antibody or fragment thereof (i.e. polypeptide) of the invention is isolated. An “isolated” polypeptide is one that is removed from its original environment. The term “isolated” may be used to refer to an antibody that is substantially free of other antibodies having different antigenic specificities (e.g. an isolated antibody that specifically binds V61, or a fragment thereof, is substantially free of antibodies that specifically bind antigens other than V61). The term “isolated” may also be used to refer to preparations where the isolated antibody is sufficiently pure to be administered therapeutically when formulated as an active ingredient of a pharmaceutical composition, or at least 70-80% (w/w) pure, more preferably, at least 80- 90% (w/w) pure, even more preferably, 90-95% pure; and, most preferably, at least 95%, 96%, 97%, 98%, 99%, or 100% (w/w) pure.

Suitably, the polynucleotides used in the present invention are isolated. An “isolated” polynucleotide is one that is removed from its original environment. For example, a naturally- occurring polynucleotide is isolated if it is separated from some or all of the coexisting materials in the natural system. A polynucleotide is considered to be isolated if, for example, it is cloned into a vector that is not a part of its natural environment or if it is comprised within cDNA.

The antibody or fragment thereof may be a "functionally active variant" which also includes naturally occurring allelic variants, as well as mutants or any other non-naturally occurring variants. As is known in the art, an allelic variant is an alternate form of a (poly)peptide that is characterized as having a substitution, deletion, or addition of one or more amino acids that does essentially not alter the biological function of the polypeptide. By way of non-limiting example, said functionally active variants may still function when the frameworks containing the CDRs are modified, when the CDRs themselves are modified, when said CDRs are grafted to alternate frameworks, or when N- or C-terminal extensions are incorporated. Further, CDR containing binding domains may be paired with differing partner chains such as those shared with another antibody. Upon sharing with so called ‘common’ light or ‘common’ heavy chains, said binding domains may still function. Further, said binding domains may function when multimerized. Further, ‘antibodies or fragments thereof may also comprise functional variants wherein the VH or VL or constant domains have been modified away or towards a different canonical sequence (for example as listed at IMGT.org) and which still function. For the purposes of comparing two closely-related polypeptide sequences, the “% sequence identity” between a first polypeptide sequence and a second polypeptide sequence may be calculated using NCBI BLAST v2.0, using standard settings for polypeptide sequences (BLASTP). For the purposes of comparing two closely-related polynucleotide sequences, the “% sequence identity” between a first nucleotide sequence and a second nucleotide sequence may be calculated using NCBI BLAST v2.0, using standard settings for nucleotide sequences (BLASTN).

Polypeptide or polynucleotide sequences are said to be the same as or “identical” to other polypeptide or polynucleotide sequences, if they share 100% sequence identity over their entire length. Residues in sequences are numbered from left to right, i.e. from N- to C- terminus for polypeptides; from 5’ to 3’ terminus for polynucleotides.

A “difference” between sequences refers to an insertion, deletion or substitution of a single amino acid residue in a position of the second sequence, compared to the first sequence. Two polypeptide sequences can contain one, two or more such amino acid differences. Insertions, deletions or substitutions in a second sequence which is otherwise identical (100% sequence identity) to a first sequence result in reduced % sequence identity. For example, if the identical sequences are 9 amino acid residues long, one substitution in the second sequence results in a sequence identity of 88.9%. If first and second polypeptide sequences are 9 amino acid residues long and share 6 identical residues, the first and second polypeptide sequences share greater than 66% identity (the first and second polypeptide sequences share 66.7% identity).

Alternatively, for the purposes of comparing a first, reference polypeptide sequence to a second, comparison polypeptide sequence, the number of additions, substitutions and/or deletions made to the first sequence to produce the second sequence may be ascertained. An “addition” is the addition of one amino acid residue into the sequence of the first polypeptide (including addition at either terminus of the first polypeptide). A “substitution” is the substitution of one amino acid residue in the sequence of the first polypeptide with one different amino acid residue. Said substitution may be conservative or non-conservative. A “deletion” is the deletion of one amino acid residue from the sequence of the first polypeptide (including deletion at either terminus of the first polypeptide).

A “conservative” amino acid substitution is an amino acid substitution in which an amino acid residue is replaced with another amino acid residue of similar chemical structure and which is expected to have little influence on the function, activity or other biological properties of the polypeptide. Such conservative substitutions suitably are substitutions in which one amino acid within the following groups is substituted by another amino acid residue from within the same group:

Suitably, a hydrophobic amino acid residue is a non-polar amino acid. More suitably, a hydrophobic amino acid residue is selected from V, I, L, M, F, W or C.

As used herein, numbering of polypeptide sequences and definitions of CDRs and FRs are as defined according to the Kabat system (Kabat et ai, 1991, herein incorporated by reference in its entirety). A “corresponding” amino acid residue between a first and second polypeptide sequence is an amino acid residue in a first sequence which shares the same position according to the Kabat system with an amino acid residue in a second sequence, whilst the amino acid residue in the second sequence may differ in identity from the first. Suitably corresponding residues will share the same number (and letter) if the framework and CDRs are the same length according to Kabat definition. Alignment can be achieved manually or by using, for example, a known computer algorithm for sequence alignment such as NCBI BLAST v2.0 (BLASTP or BLASTN) using standard settings. References herein to an “epitope” refer to the portion of the target which is specifically bound by the antibody or fragment thereof. Epitopes may also be referred to as “antigenic determinants”. An antibody binds “essentially the same epitope” as another antibody when they both recognize identical or sterically overlapping epitopes. Commonly used methods to determine whether two antibodies bind to identical or overlapping epitopes are competition assays, which can be configured in a number of different formats (e.g. well plates using radioactive or enzyme labels, or flow cytometry on antigen-expressing cells) using either labelled antigen or labelled antibody.

Epitopes found on protein targets may be defined as “linear epitopes” or “conformational epitopes”. Linear epitopes are formed by a continuous sequence of amino acids in a protein antigen. Conformational epitopes are formed of amino acids that are discontinuous in the protein sequence, but which are brought together upon folding of the protein into its three- dimensional structure.

The term “vector”, as used herein, is intended to refer to a nucleic acid molecule capable of transporting another nucleic acid to which it has been linked. One type of vector is a “plasmid”, which refers to a circular double stranded DNA loop into which additional DNA segments may be ligated. Another type of vector is a viral vector, wherein additional DNA segments may be ligated into the viral genome. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g. , bacterial vectors having a bacterial origin of replication and episomal mammalian and yeast vectors). Other vectors (e.g. non-episomal mammalian vectors) can be integrated into the genome of a host cell upon introduction into the host cell, and thereby are replicated along with the host genome. Moreover, certain vectors are capable of directing the expression of genes to which they are operatively linked. Such vectors are referred to herein as “recombinant expression vectors” (or simply, “expression vectors”). In general, expression vectors of utility in recombinant DNA techniques are often in the form of plasmids. In the present specification, “plasmid” and “vector” may be used interchangeably as the plasmid is the most commonly used form of vector. However, the invention is intended to include such other forms of expression vectors, such as viral vectors (e.g. replication defective retroviruses, adenoviruses and adeno-associated viruses), which serve equivalent functions, and also bacteriophage and phagemid systems. The term “recombinant host cell” (or simply “host cell”), as used herein, is intended to refer to a cell into which a recombinant expression vector has been introduced. Such terms are intended to refer not only to the particular subject cell but to the progeny of such a cell, for example, when said progeny are employed to make a cell line or cell bank which is then optionally stored, provided, sold, transferred, or employed to manufacture an antibody or fragment thereof as described herein. References to “subject”, “patient” or “individual” refer to a subject, in particular a mammalian subject, to be treated. Mammalian subjects include humans, non-human primates, farm animals (such as cows), sports animals, or pet animals, such as dogs, cats, guinea pigs, rabbits, rats or mice. In some embodiment, the subject is a human. In alternative embodiments, the subject is a non-human mammal, such as a mouse.

The term "sufficient amount" means an amount sufficient to produce a desired effect. The term "therapeutically effective amount" is an amount that is effective to ameliorate a symptom of a disease or disorder. A therapeutically effective amount can be a "prophylactically effective amount" as prophylaxis can be considered therapy.

As used herein, the term “about” when used herein includes up to and including 10% greater and up to and including 10% lower than the value specified, suitably up to and including 5% greater and up to and including 5% lower than the value specified, especially the value specified. The term “between”, includes the values of the specified boundaries.

A disease or disorder is “ameliorated” if the severity of a sign or symptom of the disease or disorder, the frequency with which such a sign or symptom is experienced by a subject, or both, is reduced.

As used herein, “treating a disease or disorder” means reducing the frequency and/or severity of at least one sign or symptom of the disease or disorder experienced by a subject.

“Cancer,” as used herein, refers to the abnormal growth or division of cells. Generally, the growth and/or life span of a cancer cell exceeds, and is not coordinated with, that of the normal cells and tissues around it. Cancers may be benign, pre-malignant or malignant. Cancer occurs in a variety of cells and tissues, including the oral cavity (e.g., mouth, tongue, pharynx, etc.), digestive system (e.g., esophagus, stomach, small intestine, colon, rectum, liver, bile duct, gall bladder, pancreas, etc.), respiratory system (e.g., larynx, lung, bronchus, etc.), bones, joints, skin (e.g., basal cell, squamous cell, meningioma, etc.), breast, genital system, (e.g., uterus, ovary, prostate, testis, etc.), urinary system (e.g., bladder, kidney, ureter, etc.), eye, nervous system (e.g., brain, etc.), endocrine system (e.g., thyroid, etc.), and hematopoietic system (e.g., lymphoma, myeloma, leukemia, acute lymphocytic leukemia, chronic lymphocytic leukemia, acute myeloid leukemia, chronic myeloid leukemia, etc.). Methods of modulating gd T cells

According to a first aspect of the invention, there is provided an ex vivo method of modulating delta variable 1 chain (V61) T cells comprising administering an anti-V61 antibody or fragment thereof as defined herein to a cell population comprising V61 T cells. It will be understood that “administering” the antibody or fragment thereof includes “contacting” the V61 T cells.

Modulation of V61 T cells may include:

- expansion of the V61 T cells, e.g. by selectively increasing the number of V61 T cells or promotion of survival of V61 T cells;

- stimulation of the V61 T cells, e.g. by increasing V61 T cell potency, i.e. increasing target cell killing;

- prevention of V61 T cell exhaustion, e.g. by increasing persistence of the V61 T cells;

- degranulation of V61 T cells;

- immunosuppression of the V61 T cells, e.g. by downregulation of V61 TCR cell surface expression, i.e. by causing V61 TCR internalisation or reduced expression of V61 TCR protein, or blocking the V61 TCR from binding;

- reducing V61 T cell number, e.g. by inhibition of V61 T cell proliferation or by inducing V61 T cell death (i.e. killing V61 T cells).

Such modulation of V61 T cells may include, for example, V61 T cell activation or V61 T cell inhibition. In one embodiment, the V61 T cells are activated by administering an anti-V61 antibody or fragment thereof as defined herein. In an alternative embodiment, the V61 T cells are inhibited by administering an anti-V61 antibody or fragment thereof as defined herein. In an alternative embodiment, the V61 T cells are not inhibited upon administration of an anti- V61 antibody or fragment thereof as defined herein to a patient.

In one embodiment, the modulation of V61 T cells comprises administering an anti-TCR delta 1 variable antibody or fragment thereof to V61 T cells in a culture (i.e. in vitro or ex vivo). The V61 T cells may be present in a mixed cell population, e.g. in a cell population comprising other lymphocyte cell types (e.g. ab T cells or NK cells).

In one embodiment, the cell population comprising V61 T cells is isolated (i.e. from a sample as described herein) prior to administration of the anti-V61 antibody or fragment thereof. In a further embodiment, the cell population is enriched for T cells prior to administration of the anti-V61 antibody or fragment thereof. In a yet further embodiment, the cell population is enriched for gd T cells prior to administration of the anti-V61 antibody or fragment thereof. The method may also be performed on a cell population comprising a purified fraction of gd T cells. In such embodiments, the cell population is depleted of cells types other than gd T cells present in the sample, such as ab T cells and/or NK cells, prior to administration of the anti- V61 antibody or fragment thereof. The cell population may additionally, or alternatively, be enriched of cells types which may contain V61 , such as T cells and/or gd cells, prior to administration of the anti-V61 antibody or fragment thereof. For example, prior to culturing the sample, the sample may be enriched for T cells, or enriched for gd T cells, or depleted of ab T cells or depleted of hoh-gd T cells. In one embodiment, the sample is first depleted of ab T cells and then enriched for CD3+ cells. Enrichment or depletion may be achieved using techniques known in the art, such as using magnetic beads coated with antibodies that bind to molecules on the cell surface relevant to the phenotype to be enriched/depleted.

The presence of cell types other than lymphocytes in cell culture, may inhibit V61 cell expansion. Such cells, e.g. stromal, epithelial, tumour and/or feeder cells, may be removed prior to culture. Thus, in one embodiment, the cell population is not in direct contact with stromal cells during culture. Examples of stromal cells include fibroblasts, pericytes, mesenchymal cells, keratinocytes, endothelial cells and non-haematological tumour cells. Preferably, the lymphocytes are not in direct contact with fibroblasts during culture. In one embodiment, the cell population is not in direct contact with epithelial cells during culture. In one embodiment, the cell population is not in direct contact with tumour cells and/or feeder cells during culture.

In one embodiment, the method comprises culturing the V61 T cells in the absence of substantial stromal cell contact. In a further embodiment, the method comprises culturing the V61 T cells in the absence of substantial fibroblast cell contact.

In one embodiment, the method comprises culturing the V61 T cells in media which is substantially free of serum (e.g. serum-free media or media containing a serum-replacement (SR)). Thus, in one embodiment, the method comprises culturing in serum-free media. Such serum free medium may also include serum replacement medium, where the serum replacement is based on chemically defined components to avoid the use of human or animal derived serum. In an alternative embodiment, the method comprises culturing in media which contains serum (e.g. human AB serum or fetal bovine serum (FBS)). In one embodiment, the media contains serum-replacement. In one embodiment, the media contains no animal- derived products. It will be appreciated that a sample cultured in serum-free media has the advantage of avoiding issues with filtration, precipitation, contamination and supply of serum. Furthermore, animal derived products are not favoured for use in clinical grade manufacturing of human therapeutics. Use of serum-free media for the cells, particularly V61 T cells, substantially increases the number of cells obtained from the sample compared to the use of media containing AB serum.

In one embodiment, the anti-V61 antibody or fragment thereof is in a soluble or immobilized form. For example, the antibody or fragment thereof may be administered to the V61 T cells in a soluble form. Alternatively, the antibody or fragment thereof may be administered to the V61 T cells when the antibody or fragment thereof is bound or covalently linked to a surface, such as a bead or plate (i.e. in an immobilized form). In one embodiment, the antibody is immobilized on a surface, such as Fc-coated wells. Alternatively, the antibody or fragment thereof is bound to the surface of a cell (e.g. immobilized on the surface of an antigen presenting cell (APC)). In another embodiment, the antibody is not immobilized on a surface when the cell population is contacted with the antibody.

The cell population contacted by the anti-V61 antibody or fragment thereof may be obtained from a variety of sample types (methods of isolation are further described below). In one embodiment, the sample is a non-haematopoietic tissue sample. References herein to “non- haematopoietic tissues” or “non-haematopoietic tissue sample” include skin (e.g. human skin) and gut (e.g. human gut). Non-haematopoietic tissue is a tissue other than blood, bone marrow, lymphoid tissue, lymph node tissue, or thymus tissue. In one embodiment, the non- haematopoietic tissue sample is skin (e.g. human skin). In some embodiments, the cell population (e.g. gd T cells) is not obtained from particular types of samples of biological fluids, such as blood or synovial fluid. In some embodiments, the cell population (e.g. gd T cells) is obtained from skin (e.g. human skin), which can be obtained by methods known in the art. For example, the cell population may be obtained from the non-haematopoietic tissue sample by culturing the non-haematopoietic tissue sample on a synthetic scaffold configured to facilitate cell egress from the non-haematopoietic tissue sample. Alternatively, the methods can be applied to a cell population (e.g. gd T cells) obtained from the gastrointestinal tract (e.g. colon or gut), mammary gland, lung, prostate, liver, spleen, pancreas, uterus, vagina and other cutaneous, mucosal or serous membranes.

In an alternative embodiment, the sample is a haematopoietic sample or fraction thereof (i.e. the cell population is obtained from a haematopoietic sample or a fraction thereof). References herein to “haematopoietic sample” or “haematopoietic tissue sample” include blood (such as peripheral blood or umbilical cord blood), bone marrow, lymphoid tissue, lymph node tissue, thymus tissue, and fractions or enriched portions thereof. The sample is preferably blood including peripheral blood or umbilical cord blood or fractions thereof, including buffy coat cells, leukapheresis products, peripheral blood mononuclear cells (PBMCs) and low density mononuclear cells (LDMCs). In some embodiments the sample is human blood or a fraction thereof. The cells may be obtained from a sample of blood using techniques known in the art such as density gradient centrifugation. For example, whole blood may be layered onto an equal volume of FICOLL-HYPAQUE followed by centrifugation at 400xg for 15-30 minutes at room temperature. The interface material will contain low density mononuclear cells which can be collected and washed in culture medium and centrifuged at 200xg for 10 minutes at room temperature.

The cell population may be obtained from a cancer tissue sample (i.e. the gd T cells may also be resident in cancer tissue samples), e.g. tumours of the breast or prostate. In some embodiments, the cell population may be from human cancer tissue samples (e.g. solid tumour tissues). In other embodiments, the cell population may be from a sample other than human cancer tissue (e.g. a tissue without a substantial number of tumour cells). For example, the cell population may be from a region of skin (e.g. healthy skin) separate from a nearby or adjacent cancer tissue. Thus, in some embodiments, the cell population is not obtained from cancer tissue (e.g. human cancer tissue).

The cell population may be obtained from human or non-human animal tissue. Therefore, the method may additionally comprise a step of obtaining a cell population from human or non human animal tissue. In one embodiment the sample has been obtained from a human. In an alternative embodiment, the sample has been obtained from a non-human animal subject.

Expansion of nd T cells

In one embodiment, the modulation comprises activation of the V61 T cells, in particular expansion of the V61 T cells. Therefore, according to an aspect of the invention, there is provided an ex vivo method of expanding V61 T cells comprising administering an anti-V61 antibody or fragment thereof as defined herein to a cell population comprising V61 T cells. Such expansion of V61 T cells may be achieved through the selective increase in number of V61 T cells and/or through the promotion of survival of V61 T cells. In one embodiment, the expansion of V61 T cells comprises administering an anti-TCR delta 1 variable antibody or fragment thereof to V61 T cells in a culture (i.e. in vitro or ex vivo). The V61 T cells may be present in a mixed cell population, e.g. in a cell population comprising other lymphocyte cell types (e.g. ab T cells or NK cells).

The invention therefore provides ex vivo methods for producing an enriched gd T cell (e.g. V61 T cell) population. The enriched population can be produced from an isolated mixed cell populations (e.g. obtained from samples taken from patients/donors) by a method comprising contacting the mixed cell population, or a purified fraction thereof, with the antibody or fragment thereof. Said antibody (or fragment thereof) selectively expands V61 T cells by binding to an epitope specific to a V61 chain of a gd TCR.

Also provided is an expanded V61 T cell population obtained according to the method as defined herein. According to this aspect of the invention, it will be appreciated that such an expanded population of V61 T cells may be obtained and/or expanded in vitro or ex vivo. In one aspect, there is provided an expanded V61 population obtained according to the method as defined herein, wherein the V61 population is isolated and expanded in vitro or ex vivo.

Antibodies or fragments thereof as described herein may be used in methods of expanding gd T cells (e.g. V61 T cells). These methods may be carried out in vitro. If the expansion methods are carried out in vitro, the antibodies (or fragments thereof) may be applied to isolated gd T cells (e.g. V61 T cells) obtained as described above. In some embodiments, the gd T cells are expanded from a cell population that has been isolated from a non-haematopoietic tissue sample. In an alternative embodiment, the gd T cells are expanded from a cell population that has been isolated from a haematopoietic tissue sample, such as a blood sample.

Expansion of gd T cells (e.g. V61 T cells) may comprise culturing the sample in the presence of the antibody or fragment thereof as described herein, and a cytokine. Cytokines may include interleukins, lymphokines, interferons, colony stimulating factors and chemokines. In one embodiment, the cytokine is selected from the group consisting of interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-7 (IL-7), interleukin-8 (IL-8), interleukin-9 (IL-9), interleukin-12 (IL-12), interleukin-18 (IL-18), interleukin-21 (IL-21), interleukin-33 (IL- 33), insulin-like growth factor 1 (IGF-1), interleukin-1 b (I L-1 b), interferon-g (IFN-g) and stromal cell-derived factor-1 (SDF-1). It will be understood that references to the cytokines as described herein, may include any compound that has the same activity as said cytokine with respect to its ability to promote similar physiological effects on V61 T cells in culture and includes, but is not limited to, mimetics, or any functional equivalent thereof. In one embodiment, said cytokine is a common cytokine receptor gamma-chain (y _c ) family of cytokines. In a further embodiment, the y _c -cytokine is selected from: IL-2, IL 4, IL-7, IL-9, IL- 12, IL-15, IL-21 or mixtures thereof.

The cytokine (e.g. an interleukin) used may be of human or animal origin, preferably of human origin. It may be a wild-type protein or any biologically active fragment or variant, that is, to say, capable of binding its receptor. Such binding may induce activation of gd T cells in the conditions of a method according to the invention. More preferably, the cytokines may be in soluble form, fused or complexed with another molecule, such as for example a peptide, polypeptide or biologically active protein. Preferably, a human recombinant cytokine is used. More preferably, the range of interleukin concentration could vary between 1-10000 U/ml, even more preferably between 100-1000 U/ml.

In a further embodiment, the cytokine is a chemokine. It will be further appreciated that the chemokine will vary and be selected depending on the sample used to obtain the gd T cells.

In one embodiment, the method comprises culturing the cell population in the presence of IL- 2, IL-9 and/or IL-15. In a further embodiment, the method comprises culturing the cell population in the presence of IL-2 and/or IL-15 (i.e. IL-2, IL-15 or a combination thereof). In an alternative embodiment, the method comprises culturing the cell population in the presence of IL-9 and/or IL-15 (i.e. IL-9, IL-15 or a combination thereof). In one embodiment, the method comprises the cell population in the presence of IL-2, IL-9 and/or IL-15, and an additional growth factor (for example, IL-21). In other embodiments, the method comprises culturing a cell population in a medium devoid of growth factors other than IL-2 and/or IL-15. In alternative embodiments, the method comprises culturing a cell population in a medium devoid of growth factors other than IL-9 and/or IL-15. In a further embodiment, the method comprises culturing a cell population in a medium which consists of a basal medium supplemented with IL-2, IL-9 and/or IL-15. In a further embodiment, the method comprises culturing a cell population in a medium which consists of a basal medium supplemented with IL-2 and/or IL-15.

In one embodiment, the method comprises culturing the cell population in the presence of IL-21.

In one embodiment, the method comprises culturing the cell population in the presence of IL-4. The physiological effects promoted by IL-4 on V61 T cells (as described in WO20 16/198480), include the decrease of NKG2D and NCR expression levels, the inhibition of cytotoxic function and improved selective survival. Furthermore, it has previously been shown that the absence of IL-4 during the later days of culture can change the physiological properties of the cells towards a more appropriate phenotype for use as an anti-tumour or anti viral treatment. Therefore, in one embodiment, the method of expansion comprises further culturing the sample in the absence of growth factors having IL-4-like activity, such as IL-4. In one embodiment, the method of expansion comprises culturing the sample in the absence of IL-4.

In one embodiment, the cytokine is a growth factor having interleukin-15-like activity, i.e. any compound that has the same activity as IL-15 with respect to its ability to promote similar physiological effects on V61 T cells in culture and includes, but is not limited to, IL-15 and IL- 15 mimetics, or any functional equivalent of IL-15, including IL-2 and IL-7. The physiological effects promoted by IL-15, IL-2 and IL-7 on cultured V61 T cells (as described in WO20 16/198480) were essentially equivalent, namely, the induction of cell differentiation towards a more cytotoxic phenotype. Furthermore, it has previously been shown that the absence of IL-2, IL-7 and IL-15 during the initial days of culture contributed to the starvation and apoptosis of contaminant cells (including TCRc^+ T and V62+ T cells), which critically depend on these cytokines for survival. Therefore, in one embodiment, the method of expansion comprises first culturing the sample in the absence of growth factors having IL-15- like activity.

Thus, in one embodiment, the method comprises culturing the cell population in a first culture medium comprising IL-4 and then culturing the cell population in a second culture medium comprising IL-15.

In one embodiment, the first culture medium is in the absence of IL-15, IL-2 and/or IL-7. In one embodiment, the second culture medium is in the absence of IL-4.

Thus, in one embodiment, the method of expansion comprises:

(1) culturing cells in the sample in a first culture medium comprising an antibody or fragment thereof as described herein and IL-4; in the absence of IL-15, IL-2 and IL-7; and

(2) culturing the cells obtained in step (1) in a second culture medium comprising an antibody or fragment thereof as described herein and IL-15, in the absence of IL-4.

As described herein, the culture media, may also contain other growth factors, including cytokines that can further enhance the expansion of V61 T cells. Examples of such cytokines include, but are not limited to: (i) IFN-y and any growth factor having IFN-y-like activity, (ii) IL-21 and any growth factor having IL-21-like activity and (iii) I L-1 b and any growth factor having IL-1 b-like activity. Examples of other growth factors that can be added include co stimulatory molecules such as a human anti-SLAM antibody, any soluble ligand of CD27, or any soluble ligand of CD7. Any combination of these growth factors can be included in the media.

In one embodiment, the first or second culture medium, or both culture media, comprises one or more additional cytokines. The first and/or second culture medium may comprise a second, a third and/or a fourth cytokine. In a further embodiment, the additional cytokines are selected from IL-21, IFN-g and II_-1b.

In one embodiment, the method comprises culturing the cell population in the presence of IL- 15 and a factor selected from the group consisting of IL-2, IL-4, IL-21 , IL-6, IL-7, IL-8, IL-9, IL- 12, IL-18, IL-33, IGF-1, I L- 1 b , IFN-g, human platelet lysate (HPL), and stromal cell-derived factor-1 (SDF-1).

Expansion of gd T cells may comprise culturing the sample in the presence of at least one further T cell mitogen. The term “a T cell mitogen” (which may also be referred to as “a gd TCR agonist”) means any agent that can stimulate T cells through TCR signalling including, but not limited to, plant lectins such as phytohemagglutinin (PHA) and concanavalin A (ConA) and lectins of non-plant origin. In one embodiment, the T cell mitogen is an anti-CD3 monoclonal antibody (mAb). Other mitogens include phorbol 12-myristate- 13-acetate (TPA) and its related compounds, such as mezerein, or bacterial compounds (e.g. Staphylococcal enterotoxin A (SEA) and Streptococcal protein A). The T cell mitogen may be soluble or immobilized and more than one T cell mitogen may be used in the method of expansion.

As used herein, references to “expanded” or “expanded population of gd T cells” includes populations of cells which are larger or contain a larger number of cells than a non-expanded population. Such populations may be large in number, small in number or a mixed population with the expansion of a proportion or particular cell type within the population. It will be appreciated that the term “expansion method” refers to processes which result in expansion or an expanded population. Thus, expansion or an expanded population may be larger in number or contain a larger number of cells compared to a population which has not had an expansion step performed or prior to any expansion step. It will be further appreciated that any numbers indicated herein to indicate expansion (e.g. fold-increase or fold-expansion) are illustrative of an increase in the number or size of a population of cells or the number of cells and are indicative of the amount of expansion. In one embodiment, the method comprises culturing the cell population for at least 5 days {e.g. at least 6 days, at least 7 days, at least 8 days, at least 9 days, at least 10 days, at least 11 days, at least 12 days, at least 13 days, at least 14 days, at least 18 days, at least 21 days, at least 28 days, or longer, e.g. from 5 days to 40 days, from 7 days to 35 days, from 14 days to 28 days, or about 21 days). In a further embodiment, the method comprises culturing the cell population for at least 7 days, such as at least 11 days or at least 14 days.

In further embodiments, method comprises culturing the cell population for a duration (e.g. at least 5 days, at least 6 days, at least 7 days, at least 8 days, at least 9 days, at least 10 days, at least 11 days, at least 12 days, at least 13 days, at least 14 days, at least 18 days, at least 21 days, at least 28 days, or longer, e.g. from 5 days to 40 days, from 7 days to 35 days, from 14 days to 28 days, or about 21 days) in an amount effective to produce an expanded population of gd T cells.

In one embodiment, the cell population is cultured for a period of 5 to 60 days, such as at least 7 to 45 days, 7 to 21 days, or 7 to 18 days. If the method includes an isolation culture period (e.g. of 1 to 40 days, such as 14 to 21 days), the isolation and expansion steps, in some embodiments, can last between 21 and 39 days.

The method may comprise regular addition of the anti-V61 antibody or fragment thereof and/or growth factor during culturing. For example, the anti-V61 antibody or fragment thereof and/or growth factor could be added every 2 to 5 days, more preferably every 3 to 4 days. In one embodiment, the anti-V61 antibody or fragment thereof and/or growth factor is added after 7 days of culture and every 3 to 4 days thereafter.

Methods of expansion provide an expanded population of gd T cells that is greater in number than a reference population. In some embodiments, the expanded population of gd T cells (e.g. V61 T cells) is greater in number than the isolated population of gd T cells prior to the expansion step (e.g. at least 2-fold in number, at least 5-fold in number, at least 10-fold in number, at least 25-fold in number, at least 50-fold in number, at least 60-fold in number, at least 70-fold in number, at least 80-fold in number, at least 90-fold in number, at least 100-fold in number, at least 200-fold in number, at least 300-fold in number, at least 400-fold in number, at least 500-fold in number, at 600-fold in number, at least 1,000-fold in number, or more relative to the isolated population of gd T cells priorto the expansion step). In one embodiment, the expanded population of gd T cells (e.g. V61 T cells) is greater in number than a population cultured for the same length of time without the presence of the antibody or fragment thereof. In one embodiment, the expanded population of gd T cells (e.g. V61 T cells) is greater in number than a population cultured for the same length of time in the presence of TS8.2 or TS-1.

Methods of expansion provide an expanded population of V61 T cells that has a higher percentage of V61 T cells than a reference population. In some embodiments, the expanded population of V61 T cells contains greater than about 50% V61 T cells, such as greater than about 55%, 60%, 65%, 70%, 75%, 80%, 85%, 87%, 90%, 91%, 92%, 93%, 94% or 95% nd1 T cells. In a further embodiment, the expanded population of V61 T cells contains greater than about 85% V61 T cells, such as greater than about 90% V61 T cells.

In some embodiments, the expanded population of gd T cells (e.g. V61 T cells) contains less than about 10% ab T cells, such as less than about 5%, 4%, 3%, 2%, 1.5%, 1%, 0.5%, 0.2%, 0.1% or 0.05% ab T cells. In a further embodiment, the expanded population of V61 T cells contains less than about 1% ab T cells. T cells with ab receptors are highly reactive, therefore suitable cell populations for administration to patients in the context of the present invention can only contain low levels of ab T cells. The antibodies described herein may be used to selectively expand the V61 T cell population which reduces the need for extensive purification methods after expansion in order to remove ab T cells.

In some embodiments, the expanded population of gd T cells (e.g. V61 T cells) contains less than about 10% V62 T cells, such as less than about 5%, 4%, 3%, 2%, 1.5%, 1%, 0.5%, 0.2%, 0.1% or 0.05% V62 T cells. In a further embodiment, the expanded population of V61 T cells contains less than about 0.5% V62 T cells.

In some embodiments, the expanded population of gd T cells (e.g. V61 T cells) contains less than about 10% Natural Killer (NK) cells (also referred to as CD56+CD3- cells), such as less than about 5%, 4%, 3%, 2.5%, 2%, 1.5% or 1% NK cells. In a further embodiment, the expanded population of V61 T cells contains less than about 2% NK cells.

An increase or decrease in expression of cell surface markers can be additionally or alternatively used to characterize one or more expanded populations of V61 T cells, including CD27, CD69, TIGIT, PD-1 and TIM-3. In some embodiments, the expanded population of V61 T cells expresses a high level of CD27 (CD27 ^hi9h ). For example, more than about 70%, such as more than about 80%, 85%, 90% of the expanded population of V61 T cells expresses CD27 (i.e. CD27+). In some embodiments, the expanded population of V61 T cells has a greater mean expression of CD27, relative to the isolated population of V61 T cells, e.g. prior to expansion. In some embodiments, the expanded population of V61 T cells expresses a low level of CD69, TIGIT, PD-1 and/or TIM-3. For example, less than about 40%, such as less than about 30% of the expanded population of V61 T cells expresses CD69, TIGIT, PD-1 and/or TIM-3. In some embodiments, the expanded population of V61 T cells has a lower mean expression of one or more of the markers selected from the group consisting of CD69, TIGIT, PD-1 and TIM-3, relative to the isolated population of V61 T cells.

Numerous basal culture media suitable for use in the proliferation of gd T cells are available, in particular medium, such as AIM-V, Iscoves medium and RPMI-1640 (Life Technologies), EXVIVO-10, EXVIVO-15 or EXVIVO-20 (Lonza), in the presence of serum or plasma. The medium may be supplemented with other media factors as defined herein, such as serum, serum proteins and selective agents, such as antibiotics. For example, in some embodiments, RPMI-1640 medium containing 2 mM glutamine, 10% FBS, 10 mM HEPES, pH 7.2, 1% penicillin-streptomycin, sodium pyruvate (1 mM; Life Technologies), non-essential amino acids (e.g. 100 mM Gly, Ala, Asn, Asp, Glu, Pro and Ser; 1X MEM non-essential amino acids (Life Technologies)), and 10 pl/L b-mercaptoethanol. In an alternative embodiment, AIM-V medium may be supplemented with CTS Immune serum replacement and amphotericin B. In certain embodiments, the media may be further supplemented with IL-2, IL-4, IL-9 and/or lL-15 as described herein. Conveniently, cells are cultured at 37°C in a humidified atmosphere containing 5% C0 _{2 i} n a suitable culture medium during isolation and/or expansion.

Addition of other factors in the expansion culture of gd T cells may also be used. In one embodiment, such factors are used in the expansion which selectively promote the expansion of gd T cells. For example, expansion may additionally comprise addition of exogenous cytokines to the expansion culture, such as interleukins. Such expansion may comprise culturing the gd T cells in the presence of IL-2 and IL-15. Alternatively, expansion may comprise culturing the gd T cells in the presence of IL-9 and IL-15. It will be appreciated that any expansion step is performed for a duration of time effective to produce an expanded population of gd T cells.

Methods of expanding gd T cells may comprise a population doubling time of less than 5 days (e.g. less than 4.5 days, less than 4.0 days, less than 3.9 days, less than 3.8 days, less than 3.7 days, less than 3.6 days, less than 3.5 days, less than 3.4 days, less than 3.3 days, less than 3.2 days, less than 3.1 days, less than 3.0 days, less than 2.9 days, less than 2.8 days, less than 2.7 days, less than 2.6 days, less than 2.5 days, less than 2.4 days, less than 2.3 days, less than 2.2 days, less than 2.1 days, less than 2.0 days, less than 46 hours, less than 42 hours, less than 38 hours, less than 35 hours, less than 32 hours). Methods of isolating gd T cells

As described herein, antibodies (or fragments thereof) may be applied to gd T cells in culture, i.e. gd T cells, which have been obtained from a sample. In one embodiment, the cell population is isolated from a sample prior to administering the anti-V61 antibody or fragment thereof. Therefore, there is provided a method of modulating (in particular, expanding) V61 T cells comprising administering an anti-V61 antibody or fragment thereof as defined herein to a population of gd T cells (e.g. a cell population comprising V61 T cells) isolated from a sample. gd T cells that are dominant in non-haematopoietic tissues (i.e. are tissue-resident) primarily contain the delta variable 1 chain, therefore anti-V61 antibodies described herein find particular use in gd T cells isolated from non-haematopoietic tissues. Thus, in one embodiment, the sample is a non-haematopoietic tissue sample, such as skin. Alternatively, methods of the invention may be used to expand the population of V61 T cells in a sample which does not primarily contain the V61 chain, e.g. a blood sample. Therefore, the method may be used to increase the number of V61 T cells in a sample.

References herein to “isolation” or “isolating” of cells, in particular of gd T cells, refer to methods or processes wherein cells are removed, separated, purified, enriched or otherwise taken out from a tissue or a pool of cells. It will be appreciated that such references include the terms “separated”, “removed”, “purified”, “enriched” and the like. Isolation of gd T cells includes the isolation or separation of cells from an intact non-haematopoietic tissue sample or from the stromal cells of the non-haematopoietic tissue (e.g. fibroblasts or epithelial cells). Such isolation may alternatively or additionally comprise the isolation or separation of gd T cells from other haematopoietic cells (e.g. ab T cells or other lymphocytes). Isolation may be for a defined period of time, for example starting from the time the tissue explant or biopsy is placed in the isolation culture and ending when the cells are collected from culture, such as by centrifugation or other means for transferring the isolated cell population to expansion culture or used for other purposes, or the original tissue explant or biopsy is removed from the culture. The isolation step may be for at least about 3 days to about 45 days. In one embodiment, the isolation step is for at least about 10 days to at least 28 days. In a further embodiment, the isolation step is for at least 14 days to at least 21 days. The isolation step may therefore be for at least 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, 14 days, 15 days, 16 days, 17 days, 18 days, 19 days, 20 days, 21 days, 22 days, 23 days, 24 days, 25 days, 26 days, 27 days, 28 days, 29 days, 30 days, 31 days, 32 days, about 35 days, about 40 days, or about 45 days. It can be appreciated that although cell proliferation may not be substantial during this isolation step, it is not necessarily absent. Indeed for someone skilled in the art it is recognized that isolated cells may also start to divide to generate a plurality of such cells within the isolation vessel containing the sample.

Thus, references herein to “isolated gd T cells”, “isolated gd T cell population” or “isolated population of gd T cells” will be appreciated to refer to gd cells that have been isolated, separated, removed, purified or enriched from the sample, such as a non-haematopoietic tissue sample of origin, such that the cells are out of substantial contact with cells contained within the intact (non-haematopoietic tissue) sample. References herein to “isolated V61 T cells”, “isolated V61 T cell population”, “isolated population of V61 T cells”, “separated V61 T cells”, “separated V61 T cell population” or “separated population of V61 T cells” will be appreciated to refer to V61 T cells that have been isolated, separated, removed, purified or enriched from the sample, such as a non-haematopoietic tissue sample of origin, such that the cells are out of substantial contact with cells contained within the intact (non- haematopoietic tissue) sample.

The cell population may be obtained by any suitable method that allows isolation of lymphocytes, in particular V61 T cells, from human or non-human animal samples, such as a non-haematopoietic tissue sample. One such method is set out in Clark et al. (2006) J. Invest. Dermatol. 126(5): 1059-70, which describes a three-dimensional skin explant protocol for isolating lymphocytes from human skin. An explant may be adhered to a synthetic scaffold to facilitate lymphocyte egress from the explant onto the scaffold. A synthetic scaffold refers to a non-native three-dimensional structure suitable to support cell growth. Synthetic scaffolds may be constructed from materials such as polymers (e.g. natural or synthetic polymers, e.g. poly vinyl pyrolidones, polymethylmethacrylate, methyl cellulose, polystyrene, polypropylene, polyurethane), ceramics (e.g. tricalcium phosphate, calcium aluminate, calcium hydroxyapatite), or metals (tantalum, titanium, platinum and metals in the same element group as platinum, niobium, hafnium, tungsten, and combinations of alloys thereof). Biological factors (e.g. collagens (e.g. collagen I or collagen II), fibronectins, laminins, integrins, angiogenic factors, anti-inflammatory factors, glycosaminoglycans, vitrogens, antibodies and fragments thereof, cytokines (e.g. IL-2 or IL-15, and combinations thereof) may be coated onto the scaffold surface or encapsulated within the scaffold material to enhance cell adhesion, migration, survival, or proliferation, according to methods known in the art. This and other methods can be used to isolate a cell population from a number of other non-haematopoietic tissue types, e.g. gut, prostate and breast. Other examples of suitable methods of isolation utilise “crawl-out” methods which may include the culturing of the cell population and/or sample in the presence of cytokines and/or chemokines sufficient to induce the isolation or separation of gd T cells, in particular V61 T cells. Isolation of gd T cells from the sample (e.g. non- haematopoietic tissue sample) may comprise culturing the sample in the presence of IL-2 and IL-15.

Non-haematopoietic tissue resident lymphocytes can be harvested and separated from stromal cells, such as dermal fibroblasts, e.g. by firm pipetting. The lymphocyte harvest may further be washed through a 40pm nylon mesh in order to retain fibroblast aggregates that may have become loose during the process. Lymphocytes may also be isolated using fluorescent or magnetic associated cell sorting using, for example, CD45 antibodies.

Alternatively, isolation of gd T cells from the sample (e.g. a haematopoietic tissue sample) may comprise culturing the sample in the presence of a T cell mitogen (e.g. a gd TCR agonist) and a cytokine (in particular a common cytokine receptor gamma-chain ( _c ) family of cytokines), as described in WO2012/156958. As another alternative, isolation of gd T cells from the sample (e.g. a haematopoietic tissue sample) may comprise culturing the sample in the presence of a T cell mitogen and a cytokine as described in WO2016/198480.

Isolation of gd T cells may comprise culturing the sample in the presence of at least one cytokine. For example, the method may comprise culturing the sample in the presence of at least agent, such as a chemokine. It will be further appreciated that chemokines will be selected depending on the gd T cells being isolated. Furthermore, the chemokines will vary and be selected depending on the sample used for isolation of the gd T cells.

Isolation of gd T cells may comprise further culturing the sample in the presence of at least one cytokine. Said cytokine may be different to the cytokine used in the initial culture.

Isolation methods may comprise culturing the sample. References herein to “culturing” include the addition of the sample, including isolated, separated, removed, purified or enriched cells from the sample, to media comprising growth factors and/or essential nutrients required and/or preferred by the cells and/or sample. It will be appreciated that such culture conditions may be adapted according to the cells or cell population to be isolated from the sample or may be adapted according to the cells or cell population to be isolated and expanded from the sample.

In certain embodiments, culturing of the sample is for a duration of time sufficient for the isolation of gd T cells from the sample. In certain embodiments, the duration of culture is at least 14 days. In certain embodiments, the duration of culture is less than 45 days, such as less than 30 days, such as less than 25 days. In a further embodiment, the duration of culture is between 14 days and 35 days, such as between 14 days and 21 days. In a yet further embodiment, the duration of culture is about 21 days.

In particular embodiments, the gd T are collected from the culture after culturing of the sample. Collection of the gd T cells may include the physical collection of gd T cells from the culture, isolation of the gd T cells from other lymphocytes (e.g. ab T cells and/or NK cells) or isolation and/or separation of the gd T cells from other cells present in the sample, e.g. stromal cells such as fibroblasts. In one embodiment, gd T cells are collected by mechanical means (e.g. pipetting). In a further embodiment, gd T cells are collected by means of magnetic separation and/or labelling. In a yet further embodiment, the gd T cells are collected by flow cytometric techniques such as FACS. Thus, in certain embodiments, the gd T cells are collected by means of specific labelling the gd T cells. It will be appreciated that such collection of gd T cells may include the physical removal from the culture of the sample, transfer to a separate culture vessel or to separate or different culture conditions.

It will be appreciated that such collecting of gd T cells is performed after a duration of time sufficient to achieve an isolated population of gd T cells from the sample. In certain embodiments, the gd T cells are collected after at least one week, at least 10 days, at least 11 days, at least 12 days, at least 13 days or at least 14 days of culturing of the sample. Suitably, the gd T cells are collected after 40 days or less, such as 38 days or less, 36 days or less, 34 days or less, 32 days or less, 30 days or less, 28 days or less, 26 days or less or 24 days or less. In one embodiment, the gd T cells are collected after at least 14 days of culturing of the sample. In a further embodiment, the gd T cells are collected after 14 to 21 days of culturing of the sample.

In one embodiment, the sample is cultured in media which is substantially free of serum (e.g. serum-free media or media containing a serum-replacement (SR)). Thus, in one embodiment, the sample is cultured in serum-free media. Such serum free medium may also include serum replacement medium, where the serum replacement is based on chemically defined components to avoid the use of human or animal derived serum. In one embodiment, the media contains no animal-derived products. In an alternative embodiment, the sample is cultured in media which contains serum (e.g. human AB serum or fetal bovine serum (FBS)).

Culture media may additionally include other ingredients that can assist in the growth and expansion of the gd T cells. Examples of other ingredients that may be added, include, but are not limited to, plasma or serum, purified proteins such as albumin, a lipid source such as low density lipoprotein (LDL), vitamins, amino acids, steroids and any other supplements supporting or promoting cell growth and/or survival. gd T cells that are dominant in the blood are primarily V62 T cells, while the gd T cells that are dominant in the non-haematopoietic tissues are primarily V61 T cells, such that V61 T cells comprise about 70-80% of the non-haematopoietic tissue-resident gd T cell population. In one preferred embodiment, the isolated gd T cells comprise a population of V61 T cells.

Antibodies or fragments thereof

Provided herein are antibodies or fragments thereof capable of specifically binding to the delta variable 1 chain (V61) of a gd T Cell Receptor (TCR).

In one embodiment, the antibody or fragment thereof is an scFv, Fab, Fab’, F(ab')2, Fv, variable domain (e.g. VH or VL), diabody, minibody or monoclonal antibody. In a further embodiment, the antibody or fragment thereof is an scFv.

Antibodies described herein can be of any class, e.g. IgG, IgA, IgM, IgE, IgD, or isotypes thereof, and can comprise a kappa or lambda light chain. In one embodiment, the antibody is an IgG antibody, for example, at least one of isotypes, lgG1 , lgG2, lgG3 or lgG4. In a further embodiment, the antibody may be in a format, such as an IgG format, that has been modified to confer desired properties, such as having the Fc mutated to reduce effector function, extend half life, alter ADCC, or improve hinge stability. Such modifications are well known in the art.

In one embodiment, the antibody or fragment thereof is human. Thus, the antibody or fragment thereof may be derived from a human immunoglobulin (Ig) sequence. The CDR, framework and/or constant region of the antibody (or fragment thereof) may be derived from a human Ig sequence, in particular a human IgG sequence. The CDR, framework and/or constant region may be substantially identical for a human Ig sequence, in particular a human IgG sequence. An advantage of using human antibodies is that they are low or non-immunogenic in humans.

An antibody or fragment thereof can also be chimeric, for example a mouse-human antibody chimera.

Alternatively, the antibody or fragment thereof is derived from a non-human species, such as a mouse. Such non-human antibodies can be modified to increase their similarity to antibody variants produced naturally in humans, thus the antibody or fragment thereof can be partially or fully humanised. Therefore, in one embodiment, the antibody or fragment thereof is humanised.

Antibodies targeted to epitopes

Provided herein are antibodies (or fragments thereof) which bind to an epitope of the V61 chain of a gd TCR. Such binding may optionally have an effect on gd TCR activity, such as activation or inhibition.

In one embodiment, the epitope may be an activating epitope of a gd T cell. An “activating” epitope can include, for example, stimulating a TCR function, such as degranulation, TCR downregulation, cytotoxicity, proliferation, mobilisation, increased survival or resistance to exhaustion, intracellular signaling, cytokine or growth factor secretion, phenotypic change, or a change in gene expression. For example, the binding of the activating epitope may stimulate expansion (i.e. proliferation) of the gd T cell population, preferably the V61+ T cell population. Accordingly, these antibodies can be used to modulate gd T cell activation, and, thereby, to modulate the immune response. Therefore, in one embodiment, binding of the activating epitope downregulates the gd TCR. In an additional or alternative embodiment, binding of the activating epitope activates degranulation of the gd T cell. In a further additional or alternative embodiment, binding of the activating epitope activates gd T cell killing.

Alternatively, the antibodies (or fragments thereof) may have a blocking effect by prevention of the binding or interaction of another antibody or molecule. In one embodiment, the present invention provides isolated antibodies or fragments thereof that block V61 and prevent TCR binding (e.g. through steric hinderance). By blocking V61 , the antibody may prevent TCR activation and/or signalling. The epitope may be an inhibitory epitope of a gd T cell. An “inhibitory” epitope can include, for example, blocking TCR function, thereby inhibiting TCR activation.

The epitope is preferably comprised of at least one extracellular, soluble, hydrophillic, external or cytoplasmic portion of the V61 chain of a gd TCR.

In particular, the epitope does not comprise an epitope found in a hypervariable region of the V61 chain of the gd TCR, in particular CDR3 of the V61 chain. In a preferred embodiment, the epitope is within the non-variable region of the V61 chain of the gd TCR. It will be appreciated that such binding allows for the unique recognition of the V61 chain without the restriction to the sequences of the TCR which are highly variable (in particular CDR3). Various gd TCR complexes which recognise MHC-like peptides or antigen may be recognised in this way, solely by presence of the V61 chain. As such, it will be appreciated that any V61 chain comprising gd TCR may be recognised using the antibodies or fragments thereof as defined herein, irrespective of the specificity of the gd TCR. In one embodiment, the epitope comprises one or more amino acid residues within amino acid regions 1-24 and/or 35-90 of SEQ ID NO: 1, e.g. the portions of the V61 chain which are not part of the CDR1 and/or CDR3 sequences. In one embodiment, the epitope does not comprise amino acid residues within amino acid region 91-105 (CDR3) of SEQ ID NO: 1.

In a similar manner to the well characterised ab T cells, gd T cells utilize a distinct set of somatically rearranged variable (V), diversity (D), joining (J), and constant (C) genes, although gd T cells contain fewer V, D, and J segments than ab T cells. In one embodiment, the epitope bound by the antibodies (or fragments thereof) does not comprise an epitope found in the J region of the V61 chain (e.g. one of the four J regions encoded in the human delta one chain germline: SEQ ID NO: 131 (J 1 *0) or 132 (J2*0) or 133 (J3*0) or 134 (J4*0)). In one embodiment, the epitope bound by the antibodies (or fragments thereof) does not comprise an epitope found in the C-region of the V61 chain (e.g. SEQ ID NO: 135 (C1*0) which contains the C-terminal juxtamembrane/transmembrane regions). In one embodiment, the epitope bound by the antibodies (or fragments thereof) does not comprise an epitope found in the N- terminal leader sequence of the V61 chain (e.g. SEQ ID NO:129). The antibody or fragment may therefore only bind in the V region of the V61 chain (e.g. SEQ ID NO: 130). Thus, in one embodiment, the epitope consists of an epitope in the V region of the gd TCR (e.g. amino acid residues 1-90 of SEQ ID NO: 1).

Reference to the epitope are made in relation to the V61 sequence derived from the sequence described in Luoma et al. (2013) Immunity 39: 1032-1042, and RCSB Protein Data Bank entries: 4MNH and 30MZ, shown as SEQ ID NO: 1:

AQKVTQAQSSVSMPVRKAVTLNCLYETSWWSYYIFWYKQLPSKEMIFLIRQGSDEQN AKS GRYSVNFKKAAKSVALTISALQLEDSAKYFCALGESLTRADKLIFGKGTRVTVEPNIQNP DPA VYQLRDSKSSDKSVCLFTDFDSQTNVSQSKDSDVYITDKTVLDMRSMDFKSNSAVAWSNK SDFACANAFNNSIIPEDTFFPSPESS (SEQ ID NO: 1)

SEQ ID NO: 1 represents a soluble TCR comprising a V region (also referred to as the variable domain), a D region, a J region and a TCR constant region. The V region comprises amino acid residues 1-90, the D region comprises amino acid residues 91-104, the J region comprises amino acid residues 105-115 and the constant region comprises amino acid residues 116-209. Within the V region, CDR1 is defined as amino acid residues 25-34 of SEQ ID NO: 1 , CDR2 is defined as amino acid residues 50-54 of SEQ ID NO: 1 , and CDR3 is defined as amino acid residues 93-104 of SEQ ID NO: 1 (Xu et al., PNAS USA 108(6):2414- 2419 (2011)).

Therefore, in one embodiment, the isolated antibody or fragment thereof binds to an epitope of a variable delta 1 (V61) chain of a gd T cell receptor (TOR) comprising one or more amino acid residues within amino acid regions:

(i) 3-20 of SEQ ID NO: 1 ; and/or

(ii) 37-77 of SEQ ID NO: 1.

In a further embodiment, antibodies or fragments thereof additionally recognize the polymorphic V region comprising amino acid residues 1-90 epitope of SEQ ID NO:128. Hence, amino acids 1-90 of SEQ ID NO:1 and the polymorphic germline variant sequence (amino acids 1-90 SEQ ID NO: 128) may be considered interchangeable when defining epitopes described herein. Antibodies of the invention can recognize both variants of this germline sequence. By way of example, where it is stated that antibodies or fragments thereof as defined herein recognize epitopes comprising one or more amino acid residues within amino acid regions 1-24 and/or 35-90 of SEQ ID NO:1 this also refers to the same regions of SEQ ID NO:128; specifically amino acid regions 1-24 and/or 35-90 of SEQ ID NO:128.

In one embodiment, antibodies or fragments thereof recognize one or more amino acid residues within amino acid regions 1-90 of SEQ ID NO:1 and the equivalently located amino acids of regions 1-90 in SEQ ID NO: 128. More specifically, in one embodiment antibodies or fragments thereof as defined herein recognize a human germline epitope wherein said germline encodes either an alanine (A) or valine (V) at position 71 of SEQ ID NO:1.

In one embodiment, the epitope comprises one or more, such as two, three, four, five, six, seven, eight, nine, ten or more amino acid residues within the described regions.

In a further embodiment, the epitope comprises one or more (such as 5 or more, such as 10 or more) amino acid residues within amino acid region 3-20 of SEQ ID NO: 1. In an alternative embodiment, the epitope comprises one or more (such as 5 or more, such as 10 or more) amino acid residues within amino acid region 37-77 of SEQ ID NO: 1 (such as amino acid region 50-54). In a yet further embodiment, the epitope comprises one or more (such as 5 or more, such as 10 or more) amino acid residues within amino acid region 3-20 (such as 5-20 or 3-17) and one or more (such as 5 or more, such as 10 or more) amino acid residues within amino acid region 37-77 (such as 62-77 or 62-69) of SEQ ID NO: 1.

It will be further understood that said antibody (or fragment thereof) does not need to bind to all amino acids within the defined range. Such epitopes may be referred to as linear epitopes. For example, an antibody which binds to an epitope comprising amino acid residues within amino acid region 5-20 of SEQ ID NO: 1 , may only bind with one or more of the amino acid residues in said range, e.g. the amino acid residues at each end of the range (i.e. amino acids 5 and 20), optionally including amino acids within the range (i.e. amino acids 5, 9, 16 and 20).

In one embodiment, the epitope comprises at least one of amino acid residues 3, 5, 9, 10, 12, 16, 17, 20, 37, 42, 50, 53, 59, 62, 64, 68, 69, 72 or 77 of SEQ ID NO: 1. In further embodiments, the epitope comprises one, two, three, four, five, six, seven, eight, nine, ten, eleven or twelve amino acids selected from amino acid residues 3, 5, 9, 10, 12, 16, 17, 20, 37, 42, 50, 53, 59, 62, 64, 68, 69, 72 or 77 of SEQ ID NO: 1.

In one embodiment, the epitope comprises one or more amino acid residues within the following amino acid regions of SEQ ID NO: 1 (or SEQ ID NO:128, as described above):

(i) 3-17;

(ii) 5-20;

(iii) 37-53;

(iv) 50-64;

(v) 59-72;

(vi) 59-77;

(vii) 62-69; and/or

(viii) 62-77.

In a further embodiment, the epitope comprises one or more amino acid residues within amino acid regions: 5-20 and 62-77; 50-64; 37-53 and 59-72; 59-77; or 3-17 and 62-69, of SEQ ID NO: 1. In a further embodiment, the epitope consists of one or more amino acid residues within amino acid regions: 5-20 and 62-77; 50-64; 37-53 and 59-72; 59-77; or 3-17 and 62-69, of SEQ ID NO: 1.

In a further embodiment, the epitope comprises amino acid residues: 3, 5, 9, 10, 12, 16, 17, 62, 64, 68 and 69 of SEQ ID NO: 1 , or suitably consists of amino acid residues: 3, 5, 9, 10, 12, 16, 17, 62, 64, 68 and 69 of SEQ ID NO: 1. In a further embodiment, the epitope comprises amino acid residues: 5, 9, 16, 20, 62, 64, 72 and 77 of SEQ ID NO: 1, or suitably consists of amino acid residues: 5, 9, 16, 20, 62, 64, 72 and 77 of SEQ ID NO: 1. In yet further embodiment, the epitope comprises the amino acid residues: 37, 42, 50, 53, 59, 64, 68, 69, 72, 73 and 77 of SEQ ID NO: 1 , or suitably consists of amino acid residues: 37, 42, 50, 53, 59, 64, 68, 69, 72, 73 and 77 of SEQ ID NO: 1. In a further embodiment, the epitope comprises the amino acid residues: 50, 53, 59, 62 and 64 of SEQ ID NO: 1 , or suitably consists of amino acid residues: 50, 53, 59, 62 and 64 of SEQ ID NO: 1. In a further embodiment, the epitope comprises amino acid residues: 59, 60, 68 and 72 of SEQ ID NO: 1 , or suitably consists of amino acid residues: 59, 60, 68 and 72 of SEQ ID NO: 1.

In one embodiment, the epitope comprises one or more amino acid residues within amino acid regions 5-20 and/or 62-77 of SEQ ID NO: 1. In a further embodiment, the epitope consists of one or more amino acid residues within amino acid regions 5-20 and 62-77 of SEQ ID NO: 1. In an alternative further embodiment, the epitope comprises one or more amino acid residues within amino acid regions 5-20 or 62-77 of SEQ ID NO: 1. Antibodies or fragments thereof having such epitopes may have some or all of the sequences of 1245_P01_E07, or such antibodies or fragments thereof may be derived from 1245_P01_E07. For example, antibodies or fragments thereof having one or more CDR sequences of 1245_P01_E07 or one or both of the VH and VL sequences of 1245_P01_E07 may bind such epitopes.

In one embodiment, the epitope comprises one or more amino acid residues within amino acid region 50-64 of SEQ ID NO: 1. In a further embodiment, the epitope consists of one or more amino acid residues within amino acid region 50-64 of SEQ ID NO: 1. Antibodies or fragments thereof having such epitopes may have some or all of the sequences of 1252_P01_C08, or such antibodies or fragments thereof may be derived from 1252_P01_C08. For example, antibodies or fragments thereof having one or more CDR sequences of 1252_P01_C08 or one or both of the VH and VL sequences of 1252_P01_C08 may bind such epitopes.

In one embodiment, the epitope comprises one or more amino acid residues within amino acid regions 37-53 and/or 59-77 of SEQ ID NO: 1. In a further embodiment, the epitope consists of one or more amino acid residues within amino acid regions 37-53 and 59-77 of SEQ ID NO: 1. In an alternative further embodiment, the epitope comprises one or more amino acid residues within amino acid regions 37-53 or 59-77 of SEQ ID NO: 1. Antibodies or fragments thereof having such epitopes may have some or all of the sequences of 1245_P02_G04, or such antibodies or fragments thereof may be derived from 1245_P02_G04. For example, antibodies or fragments thereof having one or more CDR sequences of 1245_P02_G04 or one or both of the VH and VL sequences of 1245_P02_G04 may bind such epitopes. In one embodiment, the epitope comprises one or more amino acid residues within amino acid region 59-72 of SEQ ID NO: 1. In a further embodiment, the epitope consists of one or more amino acid residues within amino acid region 59-72 of SEQ ID NO: 1. Antibodies or fragments thereof having such epitopes may have some or all of the sequences of 1251_P02_C05, or such antibodies or fragments thereof may be derived from 1251_P02_C05. For example, antibodies or fragments thereof having one or more CDR sequences of 1251_P02_C05 or one or both of the VH and VL sequences of 1251_P02_C05 may bind such epitopes.

In one embodiment, the epitope does not comprise amino acid residues within amino acid region 11-21 of SEQ ID NO: 1. In one embodiment, the epitope does not comprise amino acid residues within amino acid region 21-28 of SEQ ID NO: 1. In one embodiment, the epitope does not comprise amino acid residues within the amino acid region 59 and 60 of SEQ ID NO: 1. In one embodiment, the epitope does not comprise amino acid residues within the amino acid region 67-82 of SEQ ID NO: 1.

In one embodiment, the epitope is not the same epitope bound by a commercially available anti-V61 antibody, such as TS-1 or TS8.2. As described in WO2017197347, binding of TS-1 and TS8.2 to soluble TCRs was detected when the d1 chain included V61 J1 and V61 J2 sequences but not to the V61 J3 chain, indicating that the binding of TS-1 and TS8.2 involved critical residues in the delta J1 and delta J2 region.

References to “within” herein include the extremities of the define range. For example, “within amino acid regions 5-20” refers to all of amino acid resides from and including residue 5 up to and including residue 20.

Various techniques are known in the art to establish which epitope is bound by an antibody. Exemplary techniques include, for example, routine cross-blocking assays, alanine scanning mutational analysis, peptide blot analysis, peptide cleavage analysis crystallographic studies and NMR analysis. In addition, methods such as epitope excision, epitope extraction and chemical modification of antigens can be employed. Another method that can be used to identify the amino acids within a polypeptide with which an antibody interacts is hydrogen/deuterium exchange detected by mass spectrometry (as described in Example 9). In general terms, the hydrogen/deuterium exchange method involves deuterium-labelling the protein of interest, followed by binding the antibody to the deuterium-labelled protein. Next, the protein/antibody complex is transferred to water and exchangeable protons within amino acids that are protected by the antibody complex undergo deuterium-to-hydrogen back- exchange at a slower rate than exchangeable protons within amino acids that are not part of the interface. As a result, amino acids that form part of the protein/antibody interface may retain deuterium and therefore exhibit relatively higher mass compared to amino acids not included in the interface. After dissociation of the antibody, the target protein is subjected to protease cleavage and mass spectrometry analysis, thereby revealing the deuterium-labelled residues which correspond to the specific amino acids with which the antibody interacts.

Antibody sequences

The isolated anti-V61 antibodies, or fragments thereof, may be described with reference to their CDR sequences.

In one embodiment, the anti-V61 antibody or fragment thereof comprises one or more of: a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 2-25; a CDR2 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 26-37 and SEQUENCES: A1-A12; and/or a CDR1 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 38-61.

In one embodiment, the isolated anti-V61 antibody or fragment thereof comprises a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 2-25. In one embodiment, the antibody or fragment thereof comprises a CDR2 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 26-37 and SEQUENCES: A1-A12 (of Table 2). In one embodiment, the antibody or fragment thereof comprises a CDR1 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 38-61.

In one embodiment, the antibody or fragment thereof comprises a CDR3 comprising a sequence having at least 85%, 90%, 95%, 97%, 98% or 99% sequence identity with any one of SEQ ID NOs: 2-25. In one embodiment, the antibody or fragment thereof comprises a CDR2 comprising a sequence having at least 85%, 90%, 95%, 97%, 98% or 99% sequence identity with any one of SEQ ID NOs: 26-37 and SEQUENCES: A1-A12 (of Table 2). In one embodiment, the antibody or fragment thereof comprises a CDR1 comprising a sequence having at least 85%, 90%, 95%, 97%, 98% or 99% sequence identity with any one of SEQ ID NOs: 38-61. In one embodiment, the antibody or fragment thereof comprises a CDR3 consisting of a sequence having at least 85%, 90%, 95%, 97%, 98% or 99% sequence identity with any one of SEQ ID NOs: 2-25. In one embodiment, the antibody or fragment thereof comprises a CDR2 consisting of a sequence having at least 85%, 90%, 95%, 97%, 98% or 99% sequence identity with any one of SEQ ID NOs: 26-37 and SEQUENCES: A1-A12 (of Table 2). In one embodiment, the antibody or fragment thereof comprises a CDR1 consisting of a sequence having at least 85%, 90%, 95%, 97%, 98% or 99% sequence identity with any one of SEQ ID NOs: 38-61.

In one embodiment the antibody or fragment thereof comprises a VH region comprising a CDR3 sequence sharing at least 80% sequence identity with any one of SEQ ID NOs: 2-13 and/or a VL region comprising a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 14-25. In one embodiment, the antibody or fragment thereof comprises a VH region comprising a CDR3 consisting of a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 2-13 and/or a VL region comprising a CDR3 consisting of a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 14-25.

In one embodiment, the antibody or fragment thereof comprises a VH region comprising a CDR3 comprising a sequence having at least 90% sequence identity with any one of SEQ ID NOs: 2-13 and/or a VL region comprising a CDR3 comprising a sequence having at least 90% sequence identity with any one of SEQ ID NOs: 14-25. In one embodiment, the antibody or fragment thereof comprises a VH region comprising a CDR3 consisting of a sequence having at least 90% sequence identity with any one of SEQ ID NOs: 2-13 and/or a VL region comprising a CDR3 consisting of a sequence having at least 90% sequence identity with any one of SEQ ID NOs: 14-25.

In one embodiment, the antibody or fragment thereof comprises a VH region comprising a CDR3 comprising a sequence having at least 95% sequence identity with any one of SEQ ID NOs: 2-13 and/or a VL region comprising a CDR3 comprising a sequence having at least 95% sequence identity with any one of SEQ ID NOs: 14-25. In one embodiment, the antibody or fragment thereof comprises a VH region comprising a CDR3 consisting of a sequence having at least 95% sequence identity with any one of SEQ ID NOs: 2-13 and/or a VL region comprising a CDR3 consisting of a sequence having at least 95% sequence identity with any one of SEQ ID NOs: 14-25. In one embodiment, the antibody or fragment thereof comprises a VH region comprising a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 2-13 and a VL region comprising a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 14-25. In one embodiment, the antibody or fragment thereof comprises a VH region comprising a CDR3 consisting of a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 2-13 and a VL region comprising a CDR3 consisting of a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 14-25.

In one embodiment, the antibody or fragment thereof, which comprises a VH region comprising a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 2-7, in particular 2-6, such as 2, 3 or 4 and a VL region comprising a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 14-19, in particular 14-18, such as 14, 15 or 16. In one embodiment, the antibody or fragment thereof, which comprises a VH region comprising a CDR3 consisting of a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 2-7, in particular 2-6, such as 2, 3 or 4 and a VL region comprising a CDR3 consisting of a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 14-19, in particular 14-18, such as 14, 15 or 16.

In one embodiment, the antibody or fragment thereof, which comprises a VH region comprising a CDR3 comprising a sequence having at least 90% sequence identity with any one of SEQ ID NOs: 2-7, in particular 2-6, such as 2, 3 or 4 and/or a VL region comprising a CDR3 comprising a sequence having at least 90% sequence identity with any one of SEQ ID NOs: 14-19, in particular 14-18, such as 14, 15 or 16. In one embodiment, the antibody or fragment thereof, which comprises a VH region comprising a CDR3 consisting of a sequence having at least 90% sequence identity with any one of SEQ ID NOs: 2-7, in particular 2-6, such as 2, 3 or 4 and/or a VL region comprising a CDR3 consisting of a sequence having at least 90% sequence identity with any one of SEQ ID NOs: 14-19, in particular 14-18, such as 14, 15 or 16.

In one embodiment, the antibody or fragment thereof, which comprises a VH region comprising a CDR3 comprising a sequence having at least 95% sequence identity with any one of SEQ ID NOs: 2-7, in particular 2-6, such as 2, 3 or 4 and/or a VL region comprising a CDR3 comprising a sequence having at least 95% sequence identity with any one of SEQ ID NOs: 14-19, in particular 14-18, such as 14, 15 or 16. In one embodiment, the antibody or fragment thereof, which comprises a VH region comprising a CDR3 consisting of a sequence having at least 95% sequence identity with any one of SEQ ID NOs: 2-7, in particular 2-6, such as 2, 3 or 4 and/or a VL region comprising a CDR3 consisting of a sequence having at least 95% sequence identity with any one of SEQ ID NOs: 14-19, in particular 14-18, such as 14, 15 or 16.

In one embodiment, the antibody or fragment thereof, which comprises a VH region comprising a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 8-13, in particular 8, 9, 10 or 11 and/or a VL region comprising a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 20-25, in particular 20, 21, 22 or 23. In one embodiment, the antibody or fragment thereof, which comprises a VH region comprising a CDR3 consisting of a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 8-13, in particular 8, 9, 10 or 11 and/or a VL region comprising a CDR3 consisting of a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 20-25, in particular 20, 21 , 22 or 23.

In one embodiment, the antibody or fragment thereof, which comprises a VH region comprising a CDR3 comprising a sequence having at least 90% sequence identity with any one of SEQ ID NOs: 8-13, in particular 8, 9, 10 or 11 and/or a VL region comprising a CDR3 comprising a sequence having at least 90% sequence identity with any one of SEQ ID NOs: 20-25, in particular 20, 21, 22 or 23. In one embodiment, the antibody or fragment thereof, which comprises a VH region comprising a CDR3 consisting of a sequence having at least 90% sequence identity with any one of SEQ ID NOs: 8-13, in particular 8, 9, 10 or 11 and/or a VL region comprising a CDR3 consisting of a sequence having at least 90% sequence identity with any one of SEQ ID NOs: 20-25, in particular 20, 21 , 22 or 23.

In one embodiment, the antibody or fragment thereof, which comprises a VH region comprising a CDR3 comprising a sequence having at least 95% sequence identity with any one of SEQ ID NOs: 8-13, in particular 8, 9, 10 or 11 and/or a VL region comprising a CDR3 comprising a sequence having at least 95% sequence identity with any one of SEQ ID NOs: 20-25, in particular 20, 21, 22 or 23. In one embodiment, the antibody or fragment thereof, which comprises a VH region comprising a CDR3 consisting of a sequence having at least 95% sequence identity with any one of SEQ ID NOs: 8-13, in particular 8, 9, 10 or 11 and/or a VL region comprising a CDR3 consisting of a sequence having at least 95% sequence identity with any one of SEQ ID NOs: 20-25, in particular 20, 21 , 22 or 23.

Embodiments which refer herein to “at least 80%” or “80% or greater”, will be understood to include all values equal to or greater than 80%, such as 85%, 90%, 95%, 97%, 98%, 99% or 100% sequence identity. In one embodiment, the antibody or fragment thereof comprises at least 85%, such as at least 90%, at least 95%, at least 97%, at least 98% or at least 99% sequence identity to the specified sequence.

Instead of percentage sequence identity, the embodiments may also be defined with one or more amino acid changes, for examples one or more additions, substitutions and/or deletions. In one embodiment, the sequence may comprise up to five amino acid changes, such as up to three amino acid changes, in particular up to two amino acid changes. In a further embodiment, the sequence may comprise up to five amino acid substitutions, such as up to three amino acid substitutions, in particular up to one or two amino acid substitutions. For example, CDR3 of the antibody or fragment thereof comprises or more suitably consists of a sequence having no more than 2, more suitably no more than 1 substitution(s) compared to any one of SEQ ID NOs: 2-25.

Suitably any residues of CDR1, CDR2 or CDR3 differing from their corresponding residues in SEQ ID NO: 2-61 and SEQUENCES: A1-A12 are conservative substitutions with respect to their corresponding residues. For example, any residues of CDR3 differing from their corresponding residues in SEQ ID NOs: 2-25 are conservative substitutions with respect to their corresponding residues.

In one embodiment, the antibody or fragment thereof comprises:

(i) a VH region comprising a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 2-13;

(ii) a VH region comprising a CDR2 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 26-37;

(iii) a VH region comprising a CDR1 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 38-49;

(iv) a VL region comprising a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 14-25;

(v) a VL region comprising a CDR2 comprising a sequence having at least 80% sequence identity with any one of SEQUENCES: A1-A12; and/or

(vi) a VL region comprising a CDR1 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 50-61.

In one embodiment, the antibody or fragment thereof comprises a heavy chain with:

(i) a VH region comprising a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 2-13; (ii) a VH region comprising a CDR2 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 26-37; and

(iii) a VH region comprising a CDR1 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 38-49.

In one embodiment, the antibody or fragment thereof comprises a light chain with:

(i) a VL region comprising a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 14-25;

(ii) a VL region comprising a CDR2 comprising a sequence having at least 80% sequence identity with any one of SEQUENCES: A1-A12; and

(iii) a VL region comprising a CDR1 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 50-61.

In one embodiment, the antibody or fragment thereof comprises (or consists of) a VH region comprising a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 2, 3, 4, 5 or 6, such as 2, 3, 4 or 5, in particular 2, 3 or 4. In one embodiment, the antibody or fragment thereof comprises (or consists of) a VH region comprising a CDR2 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 26, 27, 28, 29 or 30, such as 26, 27, 28 or 29, in particular 26, 27 or 28. In one embodiment, the antibody or fragment thereof comprises (or consists of) a VH region comprising a CDR1 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs:38, 39, 40, 41 or 42, such as 38, 39, 40 or 41 , in particular 38, 39 or 40.

In one embodiment, the antibody or fragment thereof comprises (or consists of) a VH region comprising a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 8, 9, 10 or 11. In one embodiment, the antibody or fragment thereof comprises (or consists of) a VH region comprising a CDR2 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 32, 33, 34 or 35. In one embodiment, the antibody or fragment thereof comprises (or consists of) a VH region comprising a CDR1 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 44, 45, 46 or 47.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO: 2, a CDR2 comprising a sequence of SEQ ID NO: 26, and a CDR1 comprising a sequence of SEQ ID NO: 38. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 2, the CDR2 consists of a sequence of SEQ ID NO: 26, and the CDR1 consists of a sequence of SEQ ID NO: 38. In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

3, a CDR2 comprising a sequence of SEQ ID NO: 27, and a CDR1 comprising a sequence of SEQ ID NO: 39. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 3, the CDR2 consists of a sequence of SEQ ID NO: 27, and the CDR1 consists of a sequence of SEQ ID NO: 39.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

4, a CDR2 comprising a sequence of SEQ ID NO: 28, and a CDR1 comprising a sequence of SEQ ID NO: 40. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 4, the CDR2 consists of a sequence of SEQ ID NO: 28, and the CDR1 consists of a sequence of SEQ ID NO: 40.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

5, a CDR2 comprising a sequence of SEQ ID NO: 29, and a CDR1 comprising a sequence of SEQ ID NO: 41. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 5, the CDR2 consists of a sequence of SEQ ID NO: 29, and the CDR1 consists of a sequence of SEQ ID NO: 41.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

6, a CDR2 comprising a sequence of SEQ ID NO: 30, and a CDR1 comprising a sequence of SEQ ID NO: 42. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 6, the CDR2 consists of a sequence of SEQ ID NO: 30, and the CDR1 consists of a sequence of SEQ ID NO: 42.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

8, a CDR2 comprising a sequence of SEQ ID NO: 32, and a CDR1 comprising a sequence of SEQ ID NO: 44. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 8, the CDR2 consists of a sequence of SEQ ID NO: 32, and the CDR1 consists of a sequence of SEQ ID NO: 44.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

9, a CDR2 comprising a sequence of SEQ ID NO: 33, and a CDR1 comprising a sequence of SEQ ID NO: 45. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 9, the CDR2 consists of a sequence of SEQ ID NO: 33, and the CDR1 consists of a sequence of SEQ ID NO: 45. In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

10, a CDR2 sequence of SEQ ID NO: 34, and a CDR1 sequence of SEQ ID NO: 46. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 10, the CDR2 consists of a sequence of SEQ ID NO: 34, and the CDR1 consists of a sequence of SEQ ID NO: 46.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

11, a CDR2 sequence of SEQ ID NO: 35, and a CDR1 sequence of SEQ ID NO: 47. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 11, the CDR2 consists of a sequence of SEQ ID NO: 35, and the CDR1 consists of a sequence of SEQ ID NO: 47.

In one embodiment, the antibody or fragment thereof comprises (or consists of) a VL region comprising a CDR3 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 14-25, such as SEQ ID NOs: 14, 15, 16, 17 or 18 such as 14, 15, 16 or 17, in particular 14, 15 or 16. In one embodiment, the antibody or fragment thereof comprises (or consists of) a VL region comprising a CDR2 comprising a sequence having at least 80% sequence identity with any one of SEQUENCES: A1-A12 (of Table 2), such as SEQUENCES: A1 , A2, A3, A4 or A5, such as A1 , A2, A3 or A4, in particular A1 , A2 or A3. In one embodiment, the antibody or fragment thereof comprises (or consists of) a VL region comprising a CDR1 comprising a sequence having at least 80% sequence identity with any one of SEQ ID NOs: 50-61 , such as SEQ ID NOs: 50, 51 , 52, 53 or 54, such as 50, 51 , 52 or 53, in particular 50, 51 or 52.

In one embodiment, the VL region comprises a CDR3 comprising a sequence of SEQ ID NO:

14, a CDR2 comprising a sequence of SEQUENCE: A1, and a CDR1 comprising a sequence of SEQ ID NO: 50. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 14, the CDR2 consists of a sequence of SEQUENCE: A1 , and the CDR1 consists of a sequence of SEQ ID NO: 50.

In one embodiment, the VL region comprises a CDR3 comprising a sequence of SEQ ID NO:

15, a CDR2 comprising a sequence of SEQUENCE: A2, and a CDR1 comprising a sequence of SEQ ID NO: 51. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 15, the CDR2 consists of a sequence of SEQUENCE: A2, and the CDR1 consists of a sequence of SEQ ID NO: 51.

In one embodiment, the VL region comprises a CDR3 comprising a sequence of SEQ ID NO:

16, a CDR2 comprising a sequence of SEQUENCE: A3, and a CDR1 comprising a sequence of SEQ ID NO: 52. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 16, the CDR2 consists of a sequence of SEQUENCE: A3, and the CDR1 consists of a sequence of SEQ ID NO: 52.

In one embodiment, the VL region comprises a CDR3 comprising a sequence of SEQ ID NO:

17, a CDR2 comprising a sequence of SEQUENCE: A4, and a CDR1 comprising a sequence of SEQ ID NO: 53. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 17, the CDR2 consists of a sequence of SEQUENCE: A4, and the CDR1 consists of a sequence of SEQ ID NO: 53.

In one embodiment, the VL region comprises a CDR3 comprising a sequence of SEQ ID NO:

18, a CDR2 comprising a sequence of SEQUENCE: A5, and a CDR1 comprising a sequence of SEQ ID NO: 54. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 18, the CDR2 consists of a sequence of SEQUENCE: A5, and the CDR1 consists of a sequence of SEQ ID NO: 54.

In one embodiment, the VL region comprises a CDR3 comprising a sequence of SEQ ID NO:

20, a CDR2 comprising a sequence of SEQUENCE: A7, and a CDR1 comprising a sequence of SEQ ID NO: 56. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 20, the CDR2 consists of a sequence of SEQUENCE: A7, and the CDR1 consists of a sequence of SEQ ID NO: 56.

In one embodiment, the VL region comprises a CDR3 comprising a sequence of SEQ ID NO:

21 , a CDR2 comprising a sequence of SEQUENCE: A8, and a CDR1 comprising a sequence of SEQ ID NO: 57. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 21 , the CDR2 consists of a sequence of SEQUENCE: A8, and the CDR1 consists of a sequence of SEQ ID NO: 57.

In one embodiment, the VL region comprises a CDR3 comprising a sequence of SEQ ID NO:

22, a CDR2 comprising a sequence of SEQUENCE: A9, and a CDR1 comprising a sequence of SEQ ID NO: 58. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 22, the CDR2 consists of a sequence of SEQUENCE: A9, and the CDR1 consists of a sequence of SEQ ID NO: 58.

In one embodiment, the VL region comprises a CDR3 comprising a sequence of SEQ ID NO:

23, a CDR2 comprising a sequence of SEQUENCE: A10, and a CDR1 comprising a sequence of SEQ ID NO: 59. In one embodiment, the CDR3 consists of a sequence of SEQ ID NO: 23, the CDR2 consists of a sequence of SEQUENCE: A10, and the CDR1 consists of a sequence of SEQ ID NO: 59.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

2, a CDR2 comprising a sequence of SEQ ID NO: 26, a CDR1 comprising a sequence of SEQ ID NO: 38, and the VL region comprises a CDR3 comprising a sequence of SEQ ID NO: 14, a CDR2 comprising a sequence of SEQUENCE: A1 , and a CDR1 comprising a sequence of SEQ ID NO: 50. In one embodiment, the HCDR3 consists of a sequence of SEQ ID NO: 2, the HCDR2 consists of a sequence of SEQ ID NO: 26, the HCDR1 consists of a sequence of SEQ ID NO: 38, the LCDR3 consists of a sequence of SEQ ID NO: 14, the LCDR2 consists of a sequence of SEQUENCE: A1 , and the LCDR1 consists of a sequence of SEQ ID NO: 50.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

3, a CDR2 comprising a sequence of SEQ ID NO: 27, a CDR1 comprising a sequence of SEQ ID NO: 39, and the VL region comprises a CDR3 comprising a sequence of SEQ ID NO: 15, a CDR2 comprising a sequence of SEQUENCE: A2, and a CDR1 comprising a sequence of SEQ ID NO: 51. In one embodiment, the HCDR3 consists of a sequence of SEQ ID NO: 3, the HCDR2 consists of a sequence of SEQ ID NO: 27, the HCDR1 consists of a sequence of SEQ ID NO: 39, the LCDR3 consists of a sequence of SEQ ID NO: 15, the LCDR2 consists of a sequence of SEQUENCE: A2, and the LCDR1 consists of a sequence of SEQ ID NO: 51.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

4, a CDR2 comprising a sequence of SEQ ID NO: 28, a CDR1 comprising a sequence of SEQ ID NO: 40, and the VL region comprises a CDR3 comprising a sequence of SEQ ID NO: 16, a CDR2 comprising a sequence of SEQUENCE: A3, and a CDR1 comprising a sequence of SEQ ID NO: 52. In one embodiment, the HCDR3 consists of a sequence of SEQ ID NO: 4, the HCDR2 consists of a sequence of SEQ ID NO: 28, the HCDR1 consists of a sequence of SEQ ID NO: 40, the LCDR3 consists of a sequence of SEQ ID NO: 16, the LCDR2 consists of a sequence of SEQUENCE: A3, and the LCDR1 consists of a sequence of SEQ ID NO: 52.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

5, a CDR2 comprising a sequence of SEQ ID NO: 29, a CDR1 comprising a sequence of SEQ ID NO: 41 , and the VL region comprises a CDR3 comprising a sequence of SEQ ID NO: 17, a CDR2 comprising a sequence of SEQUENCE: A4, and a CDR1 comprising a sequence of SEQ ID NO: 53. In one embodiment, the HCDR3 consists of a sequence of SEQ ID NO: 5, the HCDR2 consists of a sequence of SEQ ID NO: 29, the HCDR1 consists of a sequence of SEQ ID NO: 41 , the LCDR3 consists of a sequence of SEQ ID NO: 17, the LCDR2 consists of a sequence of SEQUENCE: A4, and the LCDR1 consists of a sequence of SEQ ID NO: 53.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

6, a CDR2 comprising a sequence of SEQ ID NO: 30, a CDR1 comprising a sequence of SEQ ID NO: 42, and the VL region comprises a CDR3 comprising a sequence of SEQ ID NO: 18, a CDR2 comprising a sequence of SEQUENCE: A5, and a CDR1 comprising a sequence of SEQ ID NO: 54. In one embodiment, the HCDR3 consists of a sequence of SEQ ID NO: 6, the HCDR2 consists of a sequence of SEQ ID NO: 30, the HCDR1 consists of a sequence of SEQ ID NO: 42, the LCDR3 consists of a sequence of SEQ ID NO: 18, the LCDR2 consists of a sequence of SEQUENCE: A5, and the LCDR1 consists of a sequence of SEQ ID NO: 54.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

7, a CDR2 comprising a sequence of SEQ ID NO: 31 , a CDR1 comprising a sequence of SEQ ID NO: 43, and the VL region comprises a CDR3 comprising a sequence of SEQ ID NO: 19, a CDR2 comprising a sequence of SEQUENCE: A6, and a CDR1 comprising a sequence of SEQ ID NO: 55. In one embodiment, the HCDR3 consists of a sequence of SEQ ID NO: 7, the HCDR2 consists of a sequence of SEQ ID NO: 31 , the HCDR1 consists of a sequence of SEQ ID NO: 43, the LCDR3 consists of a sequence of SEQ ID NO: 19, the LCDR2 consists of a sequence of SEQUENCE: A6, and the LCDR1 consists of a sequence of SEQ ID NO: 55.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

8, a CDR2 comprising a sequence of SEQ ID NO: 32, a CDR1 comprising a sequence of SEQ ID NO: 44, and the VL region comprises a CDR3 comprising a sequence of SEQ ID NO: 20, a CDR2 comprising a sequence of SEQUENCE: A7, and a CDR1 comprising a sequence of SEQ ID NO: 56. In one embodiment, the HCDR3 consists of a sequence of SEQ ID NO: 8, the HCDR2 consists of a sequence of SEQ ID NO: 32, the HCDR1 consists of a sequence of SEQ ID NO: 44, the LCDR3 consists of a sequence of SEQ ID NO: 20, the LCDR2 consists of a sequence of SEQUENCE: A7, and the LCDR1 consists of a sequence of SEQ ID NO: 56.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

9, a CDR2 comprising a sequence of SEQ ID NO: 33, a CDR1 comprising a sequence of SEQ ID NO: 45, and the VL region comprises a CDR3 comprising a sequence of SEQ ID NO: 21, a CDR2 comprising a sequence of SEQUENCE: A8, and a CDR1 comprising a sequence of SEQ ID NO: 57. In one embodiment, the HCDR3 consists of a sequence of SEQ ID NO: 9, the HCDR2 consists of a sequence of SEQ ID NO: 33, the HCDR1 consists of a sequence of SEQ ID NO: 45, the LCDR3 consists of a sequence of SEQ ID NO: 21 , the LCDR2 consists of a sequence of SEQUENCE: A8, and the LCDR1 consists of a sequence of SEQ ID NO: 57.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO: 10, a CDR2 comprising a sequence of SEQ ID NO: 34, a CDR1 comprising a sequence of SEQ ID NO: 46, and the VL region comprises a CDR3 comprising a sequence of SEQ ID NO:

22, a CDR2 comprising a sequence of SEQUENCE: A9, and a CDR1 comprising a sequence of SEQ ID NO: 58. In one embodiment, the HCDR3 consists of a sequence of SEQ ID NO:

10, the HCDR2 consists of a sequence of SEQ ID NO: 34, the HCDR1 consists of a sequence of SEQ ID NO: 46, the LCDR3 consists of a sequence of SEQ ID NO: 22, the LCDR2 consists of a sequence of SEQUENCE: A9, and the LCDR1 consists of a sequence of SEQ ID NO: 58.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

11, a CDR2 comprising a sequence of SEQ ID NO: 35, a CDR1 comprising a sequence of SEQ ID NO: 47, and the VL region comprises a CDR3 comprising a sequence of SEQ ID NO:

23, a CDR2 comprising a sequence of SEQUENCE: A10, and a CDR1 comprising a sequence of SEQ ID NO: 59. In one embodiment, the HCDR3 consists of a sequence of SEQ ID NO:

11 , the HCDR2 consists of a sequence of SEQ ID NO: 35, the HCDR1 consists of a sequence of SEQ ID NO: 47, the LCDR3 consists of a sequence of SEQ ID NO: 23, the LCDR2 consists of a sequence of SEQUENCE: A10, and the LCDR1 consists of a sequence of SEQ ID NO:

59.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

12, a CDR2 comprising a sequence of SEQ ID NO: 36, a CDR1 comprising a sequence of SEQ ID NO: 48, and the VL region comprises a CDR3 comprising a sequence of SEQ ID NO:

24, a CDR2 comprising a sequence of SEQUENCE: A11 , and a CDR1 comprising a sequence of SEQ ID NO: 60. In one embodiment, the HCDR3 consists of a sequence of SEQ ID NO:

12, the HCDR2 consists of a sequence of SEQ ID NO: 36, the HCDR1 consists of a sequence of SEQ ID NO: 48, the LCDR3 consists of a sequence of SEQ ID NO: 24, the LCDR2 consists of a sequence of SEQUENCE: A11 , and the LCDR1 consists of a sequence of SEQ ID NO:

60.

In one embodiment, the VH region comprises a CDR3 comprising a sequence of SEQ ID NO:

13, a CDR2 comprising a sequence of SEQ ID NO: 37, a CDR1 comprising a sequence of SEQ ID NO: 49, and the VL region comprises a CDR3 comprising a sequence of SEQ ID NO:

25, a CDR2 comprising a sequence of SEQUENCE: A12, and a CDR1 comprising a sequence of SEQ ID NO: 61. In one embodiment, the HCDR3 consists of a sequence of SEQ ID NO: 13, the HCDR2 consists of a sequence of SEQ ID NO: 37, the HCDR1 consists of a sequence of SEQ ID NO: 49, the LCDR3 consists of a sequence of SEQ ID NO: 25, the LCDR2 consists of a sequence of SEQUENCE: A12, and the LCDR1 consists of a sequence of SEQ ID NO: 61.

In one embodiment, the antibody or fragment thereof comprises one or more CDR sequences as described in Table 2. In a further embodiment, the antibody or fragment thereof comprises one or more (such as all) CDR sequences of clone 1252_P01_C08 as described in Table 2. In an alternative embodiment, the antibody or fragment thereof comprises one or more (such as all) CDR sequences of clone 1245_P01_E07 as described in Table 2. In an alternative embodiment, the antibody or fragment thereof comprises one or more (such as all) CDR sequences of clone 1245_P02_G04 as described in Table 2. In an alternative embodiment, the antibody or fragment thereof comprises one or more (such as all) CDR sequences of clone 1245_P02_B07 as described in Table 2. In an alternative embodiment, the antibody or fragment thereof comprises one or more (such as all) CDR sequences of clone

1251_P02_C05 as described in Table 2. In an alternative embodiment, the antibody or fragment thereof comprises one or more (such as all) CDR sequences of clone

1139_P01_E04 as described in Table 2. In an alternative embodiment, the antibody or fragment thereof comprises one or more (such as all) CDR sequences of clone

1245_P02_F07 as described in Table 2. In an alternative embodiment, the antibody or fragment thereof comprises one or more (such as all) CDR sequences of clone

1245_P01_G06 as described in Table 2. In an alternative embodiment, the antibody or fragment thereof comprises one or more (such as all) CDR sequences of clone

1245_P01_G09 as described in Table 2. In an alternative embodiment, the antibody or fragment thereof comprises one or more (such as all) CDR sequences of clone

1138_P01_B09 as described in Table 2. In an alternative embodiment, the antibody or fragment thereof comprises one or more (such as all) CDR sequences of clone

1251_P02_G10 as described in Table 2.

Suitably the VH and VL regions recited above each comprise four framework regions (FR1- FR4). In one embodiment, the antibody or fragment thereof comprises a framework region (e.g. FR1, FR2, FR3 and/or FR4) comprising a sequence having at least 80% sequence identity with the framework region in any one of SEQ ID NOs: 62-85. In one embodiment, the antibody or fragment thereof comprises a framework region (e.g. FR1, FR2, FR3 and/or FR4) comprising a sequence having at least 90%, such as at least 95%, 97% or 99% sequence identity with the framework region in any one of SEQ ID NOs: 62-85. In one embodiment, the antibody or fragment thereof comprises a framework region (e.g. FR1, FR2, FR3 and/or FR4) comprising a sequence in any one of SEQ ID NOs: 62-85. In one embodiment, the antibody or fragment thereof comprises a framework region (e.g. FR1 , FR2, FR3 and/or FR4) consisting of a sequence in any one of SEQ ID NOs: 62-85.

The antibodies described herein may be defined by their full light chain and/or heavy chain variable sequences. In one embodiment the antibody or fragment thereof comprises an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 62-85. In one embodiment the antibody or fragment thereof consists of an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 62-85.

In one embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 62- 73. In one embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 62-73. In a further embodiment, the VH region comprises an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 62, 63, 64, 65 or 66, such as 62, 63, 64 or 65, in particular 62, 63 or 64. In a further embodiment, the VH region consists of an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 62, 63, 64, 65 or 66, such as 62, 63, 64 or 65, in particular 62, 63 or 64. In a further embodiment, the VH region comprises an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 68, 69, 70, 71, 72 or 73, such as 68, 69, 70 or 71. In a further embodiment, the VH region consists of an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 68, 69, 70, 71 , 72 or 73, such as 68, 69, 70 or 71.

In one embodiment, the antibody or fragment thereof comprises a VL region comprising an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 74- 85. In one embodiment, the antibody or fragment thereof comprises a VL region consisting of an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 74-85. In a further embodiment, the VL region comprises an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 74, 75, 76, 77 or 78, such as 74, 75, 76 or 77, in particular 74, 75, or 76. In a further embodiment, the VL region consists of an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 74, 75, 76, 77 or 78, such as 74, 75, 76 or 77, in particular 74, 75, or 76. In a further embodiment, the VL region comprises an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 80, 81, 82, 83, 84 or 85, such as 80, 81, 82 or 83. In a further embodiment, the VL region consists of an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 80, 81 , 82, 83, 84 or 85, such as 80, 81 , 82 or 83. In a further embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 62-73 and a VL region comprising an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 74-85. In a further embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 62-73 and a VL region consisting of an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 74-85.

In one embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence of SEQ ID NO: 63 (1252_P01_C08). In an alternative embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence of SEQ ID NO: 62 (1245_P01_E07). In an alternative embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence of SEQ ID NO: 64 (1245_P02_G04). In an alternative embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence of SEQ ID NO: 68 (1139_P01_E04). In an alternative embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence of SEQ ID NO: 69 (1245_P02_F07). In an alternative embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence of SEQ ID NO: 70 (1245_P01_G06). In an alternative embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence of SEQ ID NO: 71 (1245_P01_G09).

In one embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence of SEQ ID NO: 63 (1252_P01_C08). In an alternative embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence of SEQ ID NO: 62 (1245_P01_E07). In an alternative embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence of SEQ ID NO: 64 (1245_P02_G04). In an alternative embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence of SEQ ID NO: 68 (1139_P01_E04). In an alternative embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence of SEQ ID NO: 69 (1245_P02_F07). In an alternative embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence of SEQ ID NO: 70 (1245_P01_G06). In an alternative embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence of SEQ ID NO: 71 (1245_P01_G09). In one embodiment, the antibody or fragment thereof comprises a VL region comprising an amino acid sequence of SEQ ID NO: 75 (1252_P01_C08). In an alternative embodiment, the antibody or fragment thereof comprises a VL region comprising an amino acid sequence of SEQ ID NO: 74 (1245_P01_E07). In an alternative embodiment, the antibody or fragment thereof comprises a VL region comprising an amino acid sequence of SEQ ID NO: 76 (1245_P02_G04). In an alternative embodiment, the antibody or fragment thereof comprises a VL region comprising an amino acid sequence of SEQ ID NO: 80 (1139_P01_E04). In an alternative embodiment, the antibody or fragment thereof comprises a VL region comprising an amino acid sequence of SEQ ID NO: 81 (1245_P02_F07). In an alternative embodiment, the antibody or fragment thereof comprises a VL region comprising an amino acid sequence of SEQ ID NO: 82 (1245_P01_G06). In an alternative embodiment, the antibody or fragment thereof comprises a VL region comprising an amino acid sequence of SEQ ID NO: 83 (1245_P01_G09).

In one embodiment, the antibody or fragment thereof comprises a VL region consisting of an amino acid sequence of SEQ ID NO: 75 (1252_P01_C08). In an alternative embodiment, the antibody or fragment thereof comprises a VL region consisting of an amino acid sequence of SEQ ID NO: 74 (1245_P01_E07). In an alternative embodiment, the antibody or fragment thereof comprises a VL region consisting of an amino acid sequence of SEQ ID NO: 76 (1245_P02_G04). In an alternative embodiment, the antibody or fragment thereof comprises a VL region consisting of an amino acid sequence of SEQ ID NO: 80 (1139_P01_E04). In an alternative embodiment, the antibody or fragment thereof comprises a VL region consisting of an amino acid sequence of SEQ ID NO: 81 (1245_P02_F07). In an alternative embodiment, the antibody or fragment thereof comprises a VL region consisting of an amino acid sequence of SEQ ID NO: 82 (1245_P01_G06). In an alternative embodiment, the antibody or fragment thereof comprises a VL region consisting of an amino acid sequence of SEQ ID NO: 83 (1245_P01_G09).

In one embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence of SEQ ID NO: 63 (1252_P01_C08) and a VL region comprising an amino acid sequence of SEQ ID NO: 75 (1252_P01_C08). In an alternative embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence of SEQ ID NO: 62 (1245_P01_E07) and a VL region comprising an amino acid sequence of SEQ ID NO: 74 (1245_P01_E07). In an alternative embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence of SEQ ID NO: 64 (1245_P02_G04) and a VL region comprising an amino acid sequence of SEQ ID NO: 76 (1245_P02_G04). In an alternative embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence of SEQ ID NO: 68 (1139_P01_E04) and a VL region comprising an amino acid sequence of SEQ ID NO: 80 (1139_P01_E04). In an alternative embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence of SEQ ID NO: 69 (1245_P02_F07) and a VL region comprising an amino acid sequence of SEQ ID NO: 81 (1245_P02_F07). In an alternative embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence of SEQ ID NO: 70 (1245_P01_G06) and a VL region comprising an amino acid sequence of SEQ ID NO: 82 (1245_P01_G06). In an alternative embodiment, the antibody or fragment thereof comprises a VH region comprising an amino acid sequence of SEQ ID NO: 71 (1245_P01_G06) and a VL region comprising an amino acid sequence of SEQ ID NO: 83 (1245_P01_G09).

In one embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence of SEQ ID NO: 63 (1252_P01_C08) and a VL region consisting of an amino acid sequence of SEQ ID NO: 75 (1252_P01_C08). In an alternative embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence of SEQ ID NO: 62 (1245_P01_E07) and a VL region consisting of an amino acid sequence of SEQ ID NO: 74 (1245_P01_E07). In an alternative embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence of SEQ ID NO: 64 (1245_P02_G04) and a VL region consisting of an amino acid sequence of SEQ ID NO: 76 (1245_P02_G04). In an alternative embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence of SEQ ID NO: 68 (1139_P01_E04) and a VL region consisting of an amino acid sequence of SEQ ID NO: 80 (1139_P01_E04). In an alternative embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence of SEQ ID NO: 69 (1245_P02_F07) and a VL region consisting of an amino acid sequence of SEQ ID NO: 81 (1245_P02_F07). In an alternative embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence of SEQ ID NO: 70 (1245_P01_G06) and a VL region consisting of an amino acid sequence of SEQ ID NO: 82 (1245_P01_G06). In an alternative embodiment, the antibody or fragment thereof comprises a VH region consisting of an amino acid sequence of SEQ ID NO: 71 (1245_P01_G09) and a VL region consisting of an amino acid sequence of SEQ ID NO: 83 (1245_P01_G09).

For fragments comprising both the VH and VL regions, these may be associated either covalently (e.g. via disulphide bonds or a linker) or non-covalently. The antibody fragment described herein may comprise an scFv, i.e. a fragment comprising a VH region and a VL region joined by a linker. In one embodiment, the VH and VL region are joined by a (e.g. synthetic) polypeptide linker. The polypeptide linker may comprise a (Gly4Ser) _n linker, where n = from 1 to 8, e.g. 2, 3, 4, 5 or 7. The polypeptide linker may comprise a [(Gly4Ser) _n (Gly3AlaSer) _m ]p linker, where n = from 1 to 8, e.g. 2, 3, 4, 5 or 7, m = from 1 to 8, e.g. 0, 1 , 2 or 3, and p = from 1 to 8, e.g. 1, 2 or 3. In a further embodiment, the linker comprises SEQ ID NO: 98. In a further embodiment, the linker consists of SEQ ID NO: 98.

In one embodiment, the antibody or fragment thereof comprises an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs:86-97. In a further embodiment, the antibody or fragment thereof comprises an amino acid sequence of any one of SEQ ID NOs: 86-97. In a yet further embodiment, the antibody or fragment thereof comprises an amino acid sequence of SEQ ID NO: 87 (1252_P01_C08). In an alternative embodiment, the antibody or fragment thereof comprises an amino acid sequence of SEQ ID NO: 86 (1245_P01_E07). In an alternative embodiment, the antibody or fragment thereof comprises an amino acid sequence of SEQ ID NO: 88 (1245_P02_G04). In an alternative embodiment, the antibody or fragment thereof comprises an amino acid sequence of SEQ ID NO: 92 (1139_P01_E04). In an alternative embodiment, the antibody or fragment thereof comprises an amino acid sequence of SEQ ID NO: 93 (1245_P02_F07). In an alternative embodiment, the antibody or fragment thereof comprises an amino acid sequence of SEQ ID NO: 94 (1245_P01_G06). In an alternative embodiment, the antibody or fragment thereof comprises an amino acid sequence of SEQ ID NO: 95 (1245_P01_G09).

In one embodiment, the antibody or fragment thereof consists of an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 86-97. In a further embodiment, the antibody or fragment thereof consists of an amino acid sequence of any one of SEQ ID NOs: 86-97. In a yet further embodiment, the antibody or fragment thereof consists of an amino acid sequence of SEQ ID NO: 87 (1252_P01_C08). In an alternative embodiment, the antibody or fragment thereof consists of an amino acid sequence of SEQ ID NO: 86 (1245_P01_E07). In an alternative embodiment, the antibody or fragment thereof consists of an amino acid sequence of SEQ ID NO: 88 (1245_P02_G04). In an alternative embodiment, the antibody or fragment thereof consists of an amino acid sequence of SEQ ID NO: 92 (1139_P01_E04). In an alternative embodiment, the antibody or fragment thereof consists of an amino acid sequence of SEQ ID NO: 93 (1245_P02_F07). In an alternative embodiment, the antibody or fragment thereof consists of an amino acid sequence of SEQ ID NO: 94 (1245_P01_G06). In an alternative embodiment, the antibody or fragment thereof consists of an amino acid sequence of SEQ ID NO: 95 (1245_P01_G09). It will be understood by a person skilled in the art that scFv constructs may be designed and made inclusive of N-terminal and C-terminal modifications to aid with translation, purification and detection. For example, at the N-terminus of an scFv sequence, an additional methionine and/or alanine amino acid residue may be included ahead of the canonical VH sequences (e.g. starting QVQ or EVQ). At the C-terminus (i.e. C-terminal to the canonical VL domain sequence ending as per the IMGT definition), additional sequences may be included such as (i) a partial sequence of the constant domain and/or (ii) additional synthetic sequences inclusive of tags, such as His-tags and Flag-tags, to aid with purification and detection. In one embodiment, SEQ ID NO: 124 is added to the C-terminus of any one of SEQ ID NOs: 86, 88- 90, 92-97. In one embodiment, SEQ ID NO: 125 is added to the C-terminus of any one of SEQ ID NOs: 86, 88-90, 92-97. In one embodiment, SEQ ID NO: 126 is added to the C-terminus of any one of SEQ ID NOs: 87 or 91. In one embodiment, SEQ ID NO: 127 is added to the C- terminus of any one of SEQ ID NOs: 87 or 91. It is well understood that said scFv N- or C- terminal sequences are optional and can be removed, modified or substituted if alternate scFv design, translation, purification or detection strategies are adopted.

As described herein, the antibodies may be in any format. In a preferred embodiment, the antibody is in an lgG1 format. Therefore, in one embodiment, the antibody or fragment thereof comprises an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 111-122. In a further embodiment, the antibody or fragment thereof comprises an amino acid sequence of any one of SEQ ID NOs: 111-122. In a yet further embodiment, the antibody or fragment thereof comprises an amino acid sequence of SEQ ID NOs: H I- 116, such as SEQ ID NOs: 111-113 and 116. In a yet further embodiment, the antibody or fragment thereof comprises an amino acid sequence of SEQ ID NOs: 117-122, such as SEQ ID NOs: 117-120. In a yet further embodiment, the antibody or fragment thereof comprises an amino acid sequence of SEQ ID NOs: 111 , 112, 116-120, such as SEQ ID NOs: 111 , 112 or 116, or SEQ ID NOs: 117-120.

In one embodiment, the antibody or fragment thereof consists of an amino acid sequence having at least 80% sequence identity with any one of SEQ ID NOs: 111-122. In a further embodiment, the antibody or fragment thereof consists of an amino acid sequence of any one of SEQ ID NOs: 111-122. In a yet further embodiment, the antibody or fragment thereof consists of an amino acid sequence of SEQ ID NOs: 111-116, such as SEQ ID NOs: 111-113 and 116. In a yet further embodiment, the antibody or fragment thereof consists of an amino acid sequence of SEQ ID NOs: 117-122, such as SEQ ID NOs: 117-120. In a yet further embodiment, the antibody or fragment thereof consists of an amino acid sequence of SEQ ID NOs: 111 , 112, 116-120, such as SEQ ID NOs: 111, 112 or 116, or SEQ ID NOs: 117-120. In one embodiment, the antibody binds to the same, or essentially the same, epitope as, or competes with, an antibody or fragment thereof as defined herein. One can easily determine whether an antibody binds to the same epitope as, or competes for binding with, a reference anti-V61 antibody by using routine methods known in the art. For example, to determine if a test antibody binds to the same epitope as a reference anti-V61 antibody, the reference antibody is allowed to bind to a V61 protein or peptide under saturating conditions. Next, the ability of a test antibody to bind to the V61 chain is assessed. If the test antibody is able to bind to V61 following saturation binding with the reference anti-V61 antibody, it can be concluded that the test antibody binds to a different epitope than the reference anti-V61 antibody. On the other hand, if the test antibody is not able to bind to the V61 chain following saturation binding with the reference anti-V61 antibody, then the test antibody may bind to the same epitope as the epitope bound by the reference anti-V61 antibody.

The present invention also includes anti-V61 antibodies that compete for binding to V61 with an antibody or fragment thereof as defined herein, or an antibody having the CDR sequences of any of the exemplary antibodies described herein. For example, competitive assays can be performed with the antibody in order to determine what proteins, antibodies, and other antagonists compete for binding to the V61 chain with the antibody and/or share the epitope. These assays are readily known to those of skill in the art; they evaluate competition between antagonists or ligands for a limited number of binding sites on a protein, e.g., V61. The antibody (or fragment thereof) is immobilized or insolubilized before or after the competition and the sample bound to the V61 chain is separated from the unbound sample, for example, by decanting (where the antibody was pre-insolubilized) or by centrifuging (where the antibody was precipitated after the competitive reaction). Also, the competitive binding may be determined by whether the function is altered by the binding or lack of binding of the antibody to the protein, e.g. whether the antibody molecule inhibits or potentiates the enzymatic activity of, for example, a label. ELISA and other functional assays may be used, as known in the art and described herein.

Two antibodies bind to the same or overlapping epitope if each competitively inhibits (blocks) binding of the other to the target antigen. That is, a 1 -, 5-, 10-, 20- or 100-fold excess of one antibody inhibits binding of the other by at least 50% but preferably 75%, 90% or even 99% as measured in a competitive binding assay. Alternatively, two antibodies have the same epitope if essentially all amino acid mutations in the target antigen that reduce or eliminate binding of one antibody reduce or eliminate binding of the other. Additional routine experimentation ( e.g . peptide mutation and binding analyses) can then be carried out to confirm whether the observed lack of binding of the test antibody is in fact due to binding to the same epitope as the reference antibody or if steric blocking (or another phenomenon) is responsible for the lack of observed binding. Experiments of this sort can be performed using ELISA, RIA, surface plasmon resonance, flow cytometry or any other quantitative or qualitative antibody-binding assay available in the art.

In some embodiments, the antibody or fragment thereof contains a modified effector function through alteration to the sugars linked to Asn 297 (EU numbering scheme). In a further said modification, Asn 297 is not fucosylated or exhibits reduced fucosylation (i.e., a defucosylated antibody or a non-fucosylated antibody). Fucosylation includes the addition of the sugar fucose to a molecule, for example, the attachment of fucose to N-glycans, O-glycans and glycolipids. Accordingly, in a defucosylated antibody, fucose is not attached to the carbohydrate chains of the constant region. The antibody may be modified to prevent or inhibit fucosylation of the antibody. Typically, glycosylation modifications involve expressing said antibody or fragment thereof in a host cell containing alternate glycosylation processing capabilities either through targeted engineering or through targeted or serendipitous host or clone selection (e.g. see Example 13). These and other effector modifications are discussed further in recent reviews such as by Xinhua Wang et al. (2018) Protein & Cell 9: 63-73 and by Pereira et al. (2018) mAbs 10(5): 693-711 and which are hereby incorporated.

Antibody sequence modifications

The antibodies and fragments thereof may be modified using known methods. Sequence modifications to antibody molecules described herein can be readily incorporate by those skilled in the art. The following examples are non-limiting.

During antibody discovery and sequence recovery from phage libraries, desired antibody variable domains may be re-formatted into full length IgG by sub-cloning. To accelerate the process, variable domains are often transferred using restriction enzymes. These unique restriction sites may introduce additional/alternate amino acids and away from the canonical sequence (such canonical sequences may be found, for example, in the international ImMunoGeneTics [IMGT] information system, see http://www.imgt.org). These may be introduced as kappa or lambda light chain sequence modifications.

Kappa light chain modifications

The variable kappa light chain variable sequences may be cloned using restriction sites (e.g. Nhe1-Not1) during re-formatting into full length IgG. More specifically, at the kappa light chain N-terminus, an additional Ala-Ser sequence was introduced to support cloning. Preferably, this additional AS sequence is then removed during further development such to generate the canonical N-terminal sequence. Hence, in one embodiment, kappa light chain containing antibodies described herein do not contain an AS sequence at their N-termini, i.e. SEQ ID NOs: 74, 76-78 and 80-85 do not comprise the initial AS sequence. In a further embodiment, SEQ ID NOs: 74 and 76-78 do not comprise the initial AS sequence. It will be understood that this embodiment also applies to other sequences included herein which contain this sequence (e.g. SEQ ID NOs: 86, 88-90 and 92-97).

Additional amino acid changes may be made to support cloning. For example, for the antibodies described herein, at the kappa light-chain variable-domain/constant domain border a valine-to-alanine change was introduced to support cloning. This resulted in a kappa constant domain modification. Specifically, this results in the constant domain beginning RTAAAPS (from a Notl restriction site). Preferably, this sequence can be modified during further development to generate the canonical kappa light-chain constant regions which start with RTVAAPS. Hence, in one embodiment kappa light chain containing antibodies described herein contain a constant domain stating with the sequence RTV. Therefore, in one embodiment, sequence RTAAAPS of SEQ ID NOs: 111-114 and 117-122 is replaced with sequence RTVAAPS.

Lambda light chain modifications

Similar to the kappa example above, the lambda light chain variable domains may also be cloned by introducing restriction sites (e.g. Nhe1-Not1) during re-formatting into full length IgG. More specifically, at the lambda light chain N-terminus, an additional Ala-Ser sequence may be introduced to support cloning. Preferably, this additional AS sequence is then removed during further development such to generate the canonical N-terminal sequence. Hence, in one embodiment, lambda light chain containing antibodies described herein do not contain an AS sequence at their N-termini i.e. SEQ ID NOs: 75 and 79 do not comprise the initial AS sequence. It will be understood that this embodiment also applies to other sequences included herein which contain this sequence (e.g. SEQ ID NOs: 87, 91 , 115 and 116). In one embodiment, SEQ ID NO: 75 does not contain the initial six residues, i.e. the ASSYEL sequence is removed.

As another example, for the antibodies described herein at the lambda light-chain variable- domain/constant domain border a lysine-to-alanine sequence change was introduced to support cloning. This resulted in a lambda constant domain modification. Specifically, this results in the constant domain beginning with GQPAAAPS (from a Notl restriction site). Preferably, this sequence can be modified during further development such to generate the canonical lambda light constant region which starts GQPKAAPS. Hence, in one embodiment, lambda light chain containing antibodies described herein contain a constant domain starting with the sequence GQPK. Therefore, in one embodiment, sequence GQPAAAPS of SEQ ID NO: 115 or 116 is replaced with sequence GQPKAAPS.

Heavy chain modifications

Typically, human variable heavy chain sequences start with either the basic glutamine (Q) or acidic glutamate (E). However, both such sequences are then known to convert to the acidic amino acid residue, pyro-glutamate (pE). The Q to pE conversion results in a charge change to the antibody, whilst an E to pE conversion does not change the charge of the antibody. Hence to avoid a variable charge-change over time one option is to modify a starting heavy chain sequence from Q to E in the first instance. Hence, in one embodiment, the heavy chain of antibody described herein contains a Q to E modification at the N-terminus. In particular, the initial residue of SEQ ID NOs: 62, 64 and/or 67-71 may be modified from Q to E. It will be understood that this embodiment also applies to other sequences included herein which contain this sequence (e.g. SEQ ID NOs: 86, 88, 91-97 and 111, 112, 115, 117-120).

Furthermore, the C-terminus of the lgG1 constant domain ends with PGK. However, the terminal basic lysine (K) is then often cleaved during expression (e.g. in CHO cells). This in turn results in charge change to the antibody through varied loss of the C-terminal lysine residue. Therefore, one option is to remove the lysine in the first instance resulting in a uniform and consistent heavy chain C-terminus sequence ending in PG. Hence, in one embodiment, the heavy chain of an antibody described herein has the terminal K removed from its C- terminus. In particular, the antibody of the invention may comprise any one of SEQ ID NOs: 111-122 where the terminal lysine residue has been removed.

Optional allotype modifications

During antibody discovery, specific human allotypes may be employed. Optionally, the antibodies can be switched to differing human allotypes during development. By way of non limiting example, for the kappa chain there are three human allotypes designated Km1 , Km1 ,2 and Km3 which define three Km alleles (using allotype numbering): Km1 correlates with valine 153 (IMGT V45.1) and leucine 191 (IMGT L101); Km1,2 correlates with alanine 153 (IMGT A45.1) and leucine 191 (IMGT L101); and Km3 correlates with alanine 153 (IMGT A45.1) and valine 191 (IMGT V101). Optionally, one can therefore modify a sequence from one allotype to another by standard cloning approaches. For example, a L191V (IMGT L101V) change will convert a Km 1,2 allotype to a Km3 allotype. For further reference on such allotypes see Jefferis and Lefranc (2009) MAbs 1(4):332-8, which is herein incorporated by reference.

Hence in one embodiment an antibody described herein contains amino acid substitutions derived from another human allotype of the same gene. In a further embodiment, the antibody contains a L191V (IMGT L101V) substitution to the kappa chain to convert the c-domain from a km 1,2 to a km3 allotype.

Antibody binding

The antibody or fragment thereof may bind to the V61 chain of a gd TCR with a binding affinity (KD) as measured by surface plasmon resonance of less than 1.5 x 10 ⁷ M (i.e. 150 nM). In a preferred embodiment, the KD is less than 1.5 x 10 ⁷ M (i.e. 150 nM). In a further embodiment, the KD is 1.3 x 10 ⁷ M (i.e. 130 nM) or less, such as 1.0 x 10 ⁷ M (i.e. 100 nM) or less. In a yet further embodiment, the KD is less than 5.0 x 10 ⁸ M (i.e. 50 nM), such as less than 4.0 x 10 ⁸ M (i.e. 40 nM), less than 3.0 x 10 ⁸ M (i.e. 30 nM) or less than 2.0 x 10 ⁸ M (i.e. 20 nM). For example, according to one aspect, there is provided a human anti-V61 antibody which binds to the V61 chain of a gd TCR with a binding affinity (KD) as measured by surface plasmon resonance of less than 1.5 x 10 ⁷ M (i.e. 150 nM).

In one embodiment, the antibody or fragment thereof binds to the V61 chain of a gd TCR with a binding affinity (KD) as measured by surface plasmon resonance of less than 4.0 x 10 ⁸ M (i.e. 40 nM), less than 3.0 x 10 ⁸ M (i.e. 30 nM) or less than 2.0 x 10 ⁸ M (i.e. 20 nM).

In one embodiment, the binding affinity of the antibody or fragment thereof is established by coating the antibody or fragment thereof directly or indirectly (e.g. by capture with an anti human IgG Fc) onto the surface of a sensor (e.g. an amine high capacity chip or equivalent), wherein the target bound by the antibody or fragment thereof (i.e. the V61 chain of a gd TCR) is flowed over the chip to detect binding. Suitably, a MASS-2 instrument (which may also be referred to as Sierra SPR-32) is used at 25 °C in PBS + 0.02 % Tween 20 running buffer at 30 pl/min.

Described herein are other assays which may be used to define antibody function. For example, the antibody or fragment thereof described herein may be assessed by gd TCR engagement, e.g. measuring downregulation of the gd TCR upon antibody binding. Surface expression of the gd TCR following application of the antibody or fragment thereof (optionally presented on the surface of a cell) can be measured, e.g. by flow cytometry. The antibody or fragment thereof described herein may also be assessed by measuring gd T cell degranulation. For example, expression of CD107a, a marker for cell degranulation, can be measured following application of the antibody or fragment thereof (optionally presented on the surface of a cell) to gd T cells, e.g. by flow cytometry. The antibody or fragment thereof described herein may also be assessed by measuring gd T cell killing activity (to test if the antibody has an effect on the killing activity of the gd T cell). For example, target cells may be incubated with gd T cells in the presence of the antibody or fragment thereof (optionally presented on the surface of a cell). Following incubation, the culture may be stained with a cell viability dye to distinguish between live and dead target cells. The proportion of dead cells can then be measured, e.g. by flow cytometry.

As described herein, the antibodies or fragments thereof used in the assays may be presented on a surface, for example the surface of a cell, such as a cell comprising an Fc receptor. For example, the antibodies or fragments thereof may be presented on the surface of THP-1 cells, such as TIB-202™ cells (available from American Type Culture Collection (ATCC)). Alternatively, the antibodies or fragments thereof may be used directly in the assays.

In such functional assays, output may be measured by calculating the half maximal concentration, also referred to as “EC50” or “effective concentration at 50 percent”. The term "IC50" refers to the inhibitory concentration. Both EC50 and IC50 may be measured using methods known in the art, such as flow cytometry methods. For the avoidance of doubt, the values of EC50 in the present application are provided using lgG1 formatted antibody. Such values can be easily converted based on the molecular weight of the antibody format for equivalent values as follows:

(pg/ml) / (MW in kDa) = mM

The EC50 for downregulation of the gd TCR upon antibody (or fragment) binding may be less than 0.50 mg/ml, such as less than 0.40 mg/ml, 0.30 mg/ml, 0.20 mg/ml, 0.15 mg/ml, 0.10 mg/ml or 0.05 mg/ml. In a preferred embodiment, the EC50 for downregulation of the gd TCR upon antibody (or fragment) binding is less than 0.10 pg/ml. In particular, the EC50 for downregulation of the gd TCR upon antibody (or fragment) binding may be less than 0.06 pg/ml, such as less than 0.05 pg/ml, 0.04 pg/ml or 0.03 pg/ml. In particular, said EC50 values are when the antibody is measured in an lgG1 format. For example, the EC50 gd TCR downregulation value can be measured using flow cytometry (e.g. as described in the assay of Example 6). The EC50 for gd T cell degranulation upon antibody (or fragment) binding may be less than 0.050 pg/ml, such as less than 0.040 pg/ml, 0.030 pg/ml, 0.020 pg/ml, 0.015 pg/ml, 0.010 pg/ml or 0.008 pg/ml. In particular, the EC50 for gd T cell degranulation upon antibody (or fragment) binding may be less than 0.005 pg/ml, such as less than 0.002 pg/ml. In a preferred embodiment, the EC50 ίqGgd T cell degranulation upon antibody (or fragment) binding is less than 0.007 pg/ml. In particular, said EC50 values are when the antibody is measured in an lgG1 format. For example, the gd T cell degranulation EC50 value can be measured by detecting CD107a expression (i.e. a marker of cell degranulation) using flow cytometry (e.g. as described in the assay of Example 7). In one embodiment, CD107a expression is measured using an anti-CD107a antibody, such as anti-human CD107a BV421 (clone H4A3) (BD Biosciences).

The EC50 for gd T cell killing upon the antibody (or fragment) binding may be less than 0.50 pg/ml, such as less than 0.40 pg/ml, 0.30 pg/ml, 0.20 pg/ml, 0.15 pg/ml, 0.10 pg/ml or 0.07 pg/ml. In a preferred embodiment, the EOdO ίqGgdT cell killing upon the antibody (or fragment) binding is less than 0.10 pg/ml. In particular, the EC50 for gd T cell killing upon the antibody (or fragment) binding may be less than 0.060 pg/ml, such as less than 0.055 pg/ml, in particular less than 0.020 pg/ml or 0.010 pg/ml. In particular, said EC50 values are when the antibody is measured in an lgG1 format. For example, the EC50 gd T cell killing value can be measured by detecting proportion of dead cells (i.e. using a cell viability dye) using flow cytometry following incubation of the antibody, gd T cell and target cells (e.g. as described in the assay of Example 8). In one embodiment, death of the target cell is measured using a cell viability dye is Viability Dye eFIuor™ 520 (ThermoFisher).

In the assays described in these aspects, the antibody or fragment thereof may be presented on the surface of a cell, such as a THP-1 cell, for example TIB-202™ (ATCC). The THP-1 cells are optionally labelled with a dye, such as CellTracker™ Orange CMTMR (ThermoFisher).

Antibodies (or fragments) can be obtained and manipulated using the techniques disclosed for example in Green and Sambrook, Molecular Cloning: A Laboratory Manual (2012) 4th Edition Cold Spring Harbour Laboratory Press.

Monoclonal antibodies can be produced using hybridoma technology, by fusing a specific antibody-producing B cell with a myeloma (B cell cancer) cell that is selected for its ability to grow in tissue culture and for an absence of antibody chain synthesis. A monoclonal antibody directed against a determined antigen can, for example, be obtained by: a) immortalizing lymphocytes obtained from the peripheral blood of an animal previously immunized with a determined antigen, with an immortal cell and preferably with myeloma cells, in order to form a hybridoma, b) culturing the immortalized cells (hybridoma) formed and recovering the cells producing the antibodies having the desired specificity.

Alternatively, the use of a hybridoma cell is not required. Antibodies capable of binding to the target antigens as described herein may be isolated from a suitable antibody library via routine practice, for example, using the phage display, yeast display, ribosomal display, or mammalian display technology known in the art. Accordingly, monoclonal antibodies can be obtained, for example, by a process comprising the steps of: a) cloning into vectors, especially into phages and more particularly filamentous bacteriophages, DNA or cDNA sequences obtained from lymphocytes especially peripheral blood lymphocytes of an animal (suitably previously immunized with determined antigens), b) transforming prokaryotic cells with the above vectors in conditions allowing the production of the antibodies, c) selecting the antibodies by subjecting them to antigen-affinity selection, d) recovering the antibodies having the desired specificity.

Pharmaceutical compositions

According to a further aspect of the invention, there is provided a composition comprising the V61 T cell population obtained by a method as defined herein. In one embodiment the V61 T cell population is the expanded V61 T cell population. In such embodiments, the composition may comprise the cells, optionally in combination with other excipients. Also included are compositions comprising one or more additional active agents (e.g. active agents suitable for treating the diseases mentioned herein).

Pharmaceutical compositions may include V61 T cells, in particular expanded V61 T cells, as described herein in combination with one or more pharmaceutically or physiologically acceptable carrier, diluents, or excipients. Such compositions may include buffers such as neutral buffered saline, phosphate buffered saline and the like; carbohydrates such as glucose, mannose, sucrose or dextrans, mannitol; proteins; polypeptides or amino acids such as glycine; antioxidants; chelating agents such as EDTA or glutathione; adjuvants (e.g., aluminium hydroxide); and preservatives. Cryopreservation solutions which may be used in the pharmaceutical compositions of the invention include, for example, DMSO. Compositions can be formulated, e.g., for intravenous administration.

In one embodiment, the pharmaceutical composition is substantially free of, e.g., there are no detectable levels of a contaminant, e.g., of endotoxin or mycoplasma.

The preferred mode of administration is parenteral (e.g., intravenous, subcutaneous, intraperitoneal, intramuscular, intrathecal). In a preferred embodiment, the composition is administered by intravenous infusion or injection. In another preferred embodiment, the composition is administered by intramuscular or subcutaneous injection.

It is within the scope of the invention to use the pharmaceutical composition of the invention in therapeutic methods for the treatment of diseases as described herein as an adjunct to, or in conjunction with, other established therapies normally used in the treatment of such diseases.

In a further aspect of the invention, the cell population, composition or pharmaceutical composition is administered sequentially, simultaneously or separately with at least one active agent.

Treatment methods using cell populations

According to a further aspect of the invention, there is provided the cell population obtained by a method as defined herein for use as a medicament. According to a further aspect of the invention, there is provided the expanded cell population as defined herein for use as a medicament. References herein to a cell population “for use” as a medicament or in therapy are limited to administration of the cell population to a subject. Such uses do not include administration of the antibody or fragment thereof direct to a patient i.e. wherein said antibody is used as the therapeutic.

In one embodiment, the cell population is for use in the treatment of cancer, an infectious disease or an inflammatory disease. In a further embodiment, the cell population is for use in the treatment of cancer.

In one embodiment, the cell population for use as a medicament comprises more than 50% V61 T cells, such as more than 60%, more than 70%, more than 80%, more than 90%, more than 95% or more than 99% V61 T cells. In a further embodiment, the cell population for use as a medicament consists of V61 T cells. In one embodiment, the cell population for use as a medicament comprises less than 10% ab T cells, such as less than 8%, less than 7%, less than 6%, less than 5%, less than 4% or less than 3% ab T cells. In one embodiment, the cell population for use as a medicament comprises less than 10% V62 T cells, such as less than 8%, less than 7%, less than 6%, less than 5%, less than 4% or less than 3% V62 T cells. In one embodiment, the cell population for use as a medicament comprises less than 50% NK cells, such as less than 40%, less than 30%, less than 20%, less than 10% or less than 5% NK cells. In one embodiment, less than 50% of the cells present in the cell population for use as a medicament express CD56, such as less than 40%, less than 30%, less than 20%, less than 10% or less than 5% express CD56.

According to a further aspect of the invention, there is provided the pharmaceutical composition comprising the cell population as defined herein for use as a medicament. In one embodiment, the pharmaceutical composition comprising the cell population is for use in the treatment of cancer, an infectious disease or an inflammatory disease. In a further embodiment, the pharmaceutical composition comprising the cell population is for use in the treatment of cancer.

According to a further aspect of the invention, there is provided a method of modulating an immune response in a subject in need thereof comprising administering a therapeutically effective amount of the cell population as defined herein.

According to a further aspect of the invention, there is provided a method of treating a cancer, an infectious disease or an inflammatory disease in a subject in need thereof, comprising administering a therapeutically effective amount of the cell population as defined herein. Alternatively, a therapeutically effective amount of the pharmaceutical composition comprising the cell population is administered.

According to further aspects of the invention, there is provided the use of the cell population as defined herein for the manufacture of a medicament, for example in the treatment of cancer, an infectious disease or an inflammatory disease.

Adoptive T cell therapy

Gamma delta T cells obtained by the expansion methods of the invention may be used as a medicament, for example for adoptive T cell therapy. This involves the transfer of gd T cells into a patient. The therapy may be autologous, i.e. the gd T cells may be transferred back into the same patient from which they were obtained, or the therapy may be allogeneic, i.e. the gd T cells from one person may be transferred into a different patient. In instances involving allogeneic transfer, the gd T cells may be substantially free of ab T cells. For example, ab T cells may be depleted from the gd T cell population, e.g., after expansion, using any suitable means known in the art (e.g., by negative selection, e.g., using magnetic beads). A method of treatment may include: providing a sample (e.g. a non-haematopoietic tissue sample) obtained from a donor individual; culturing gd T cells obtained from the sample as described herein, e.g. to produce an expanded population; and administering the population of gd T cells to a recipient individual.

The patient or subject to be treated is preferably a human cancer patient (e.g. , a human cancer patient being treated for a solid tumour) or a virus-infected patient (e.g., a CMV-infected or HIV infected patient). In some instances, the patient has and/or is being treated for a solid tumour. Because they are normally resident in non-haematopoietic tissues, tissue-resident V61 T are also more likely to home to and be retained within tumour masses than their systemic blood-resident counterparts and adoptive transfer of these cells is likely to be more effective at targeting solid tumours and potentially other non-haematopoietic tissue-associated immunopathologies.

As gd T cells are non-MHC restricted, they do not recognize a host into which they are transferred as foreign, which means that they are less likely to cause graft-versus-host disease. This means that they can be used “off the shelf” and transferred into any recipient, e.g., for allogeneic adoptive T cell therapy. gd T cells obtained by methods described herein may express NKG2D and respond to a NKG2D ligand (e.g. MICA), which is strongly associated with malignancy. They may also express a cytotoxic profile in the absence of any activation and are therefore likely to be effective at killing tumour cells. For example, the gd T cells obtained as described herein may express one or more, preferably all of IFN-g, TNF-a, GM-CSF, CCL4, IL-13, Granulysin, Granzyme A and B, and Perforin in the absence of any activation. IL-17A may not be expressed.

In some embodiments, a method of treatment of an individual with a tumour may include; providing a sample of said tumour obtained from a donor individual, culturing the gd T cells obtained from the sample as described above, and; administering the population of gd T cells to the individual with the tumour. In a further embodiment, a method of treatment of an individual with a tumour in a non-haematopoietic tissue may include; providing a sample of said non-haematopoietic tissue obtained from a donor individual, culturing the gd T cells obtained from the sample as described above, and; administering the population of gd T cells to the individual with the tumour.

In some instances, a therapeutically effective amount of gd T cells obtained by the any of the methods described above can be administered in a therapeutically effective amount to a subject (e.g., for treatment of cancer, e.g. for treatment of a solid tumour). In some cases, the therapeutically effective amount of gd T cells (e.g., skin-derived gd T cells and/or V61 T cells) is less than 10 x 10 ¹² cells per dose (e.g., less than 9 x 10 ¹² cells per dose, less than 8 x 10 ¹² cells per dose, less than 7 x 10 ¹² cells per dose, less than 6 x 10 ¹² cells per dose, less than 5 x 10 ¹² cells per dose, less than 4 x 10 ¹² cells per dose, less than 3 x 10 ¹² cells per dose, less than 2 x 10 ¹² cells per dose, less than 1 x 10 ¹² cells per dose, less than 9 x 10 ¹¹ cells per dose, less than 8 x 10 ¹¹ cells per dose, less than 7 x 10 ¹¹ cells per dose, less than 6 x 10 ¹¹ cells per dose, less than 5 x 10 ¹¹ cells per dose, less than 4 x 10 ¹¹ cells per dose, less than 3 x 10 ¹¹ cells per dose, less than 2 x 10 ¹¹ cells per dose, less than 1 x 10 ¹¹ cells per dose, less than 9 x 10 ¹⁰ cells per dose, less than 7.5 x 10 ¹⁰ cells per dose, less than 5 x 10 ¹⁰ cells per dose, less than 2.5 x 10 ¹⁰ cells per dose, less than 1 x 10 ¹⁰ cells per dose, less than 7.5 x 10 ⁹ cells per dose, less than 5 x 10 ⁹ cells per dose, less than 2.5 x 10 ⁹ cells per dose, less than 1 x 10 ⁹ cells per dose, less than 7.5 x 10 ⁸ cells per dose, less than 5 x 10 ⁸ cells per dose, less than

2.5 x 10 ⁸ cells per dose, less than 1 x 10 ⁸ cells per dose, less than 7.5 x 10 ⁷ cells per dose, less than 5 x 10 ⁷ cells per dose, less than 2,5 x 10 ⁷ cells per dose, less than 1 x 10 ⁷ cells per dose, less than 7.5 x 10 ⁶ cells per dose, less than 5 x 10 ⁶ cells per dose, less than 2,5 x 10 ⁶ cells per dose, less than 1 x 10 ⁶ cells per dose, less than 7.5 x 10 ⁵ cells per dose, less than 5 x 10 ⁵ cells per dose, less than 2,5 x 10 ⁵ cells per dose, or less than 1 x 10 ⁵ cells per dose).

In some embodiments, the therapeutically effective amount of gd T cells (e.g., skin-derived gd T cells and/or V61 T cells) is less than 10 x 10 ¹² cells over the course of treatment (e.g., less than 9 x 10 ¹² cells, less than 8 x 10 ¹² cells, less than 7 x 10 ¹² cells, less than 6 x 10 ¹² cells, less than 5 x 10 ¹² cells, less than 4 x 10 ¹² cells, less than 3x 10 ¹² cells, less than 2 x 10 ¹² cells, less than 1 x 10 ¹² cells, less than 9 x 10 ¹¹ cells, less than 8x 10 ¹¹ cells, less than 7 x 10 ¹¹ cells, less than 6 x 10 ¹¹ cells, less than 5 x 10 ¹¹ cells, less than 4 x 10 ¹¹ cells, less than 3 x 10 ¹¹ cells, less than 2 x 10 ¹¹ cells, less than 1 x 10 ¹¹ cells, less than 9 x 10 ¹⁰ cells, less than 7.5 x 10 ¹⁰ cells, less than 5 x 10 ¹⁰ cells, less than 2.5 x 10 ¹⁰ cells, less than 1 x 10 ¹⁰ cells, less than 7.5 x 10 ⁹ cells, less than 5 x 10 ⁹ cells, less than 2.5 x 10 ⁹ cells, less than 1 x 10 ⁹ cells, less than

7.5 x 10 ⁸ cells, less than 5 x 10 ⁸ cells, less than 2.5 x 10 ⁸ cells, less than 1 x 10 ⁸ cells, less than 7.5 x 10 ⁷ cells, less than 5 x 10 ⁷ cells, less than 2.5 x 10 ⁷ cells, less than 1 x 10 ⁷ cells, less than 7.5 x 10 ⁶ cells, less than 5 x 10 ⁶ cells, less than 2.5 x 10 ⁶ cells, less than 1 x 10 ⁶ cells, less than 7.5 x 10 ⁵ cells, less than 5 x 10 ⁵ cells, less than 2.5 x 10 ⁵ cells, or less than 1 x 10 ⁵ cells over the course of treatment).

In some embodiments, a dose of gd T cells ( e.g ., skin-derived gd T cells and/or V61 T cells) as described herein comprises about 1 x 10 ⁶ , 1.1 x 10 ⁶ , 2 x 10 ⁶ , 3.6 x 10 ⁶ , 5 x 10 ⁶ , 1 x 10 ⁷ , 1.8 x 10 ⁷ , 2 x 10 ⁷ , 5 x 10 ⁷ , 1 x 10 ⁸ , 2 x 10 ⁸ , or 5 x 10 ⁸ cells/kg. In some embodiments, a dose of gd T cells (e.g., skin-derived gd T cells and/or V61 T cells) comprises up to about 1 x 10 ⁶ , 1.1 x 10 ⁶ , 2 x 10 ⁶ , 3.6 x 10 ⁶ , 5 x 10 ⁶ , 1 x 10 ⁷ , 1.8 x 10 ⁷ , 2 x 10 ⁷ , 5 x 10 ⁷ , 1 x 10 ⁸ , 2 x 10 ⁸ , or 5 x 10 ⁸ cells/kg. In some embodiments, a dose of gd T cells (e.g., skin-derived gd T cells and/or V61 T cells) comprises about 1.1 x 10 ⁶ - 1.8 x 10 ⁷ cells/kg. In some embodiments, a dose of gd T cells (e.g., skin-derived gd T cells and/or V61 T cells) comprises about 1 x 10 ⁷ , 2 x 10 ⁷ , 5 x 10 ⁷ , 1 x 10 ⁸ , 2 x 10 ⁸ , 5 x 10 ⁸ , 1 x 10 ⁹ , 2 x 10 ⁹ , or 5 x 10 ⁹ cells. In some embodiments, a dose of gd T cells (e.g., skin-derived gd T cells and/or V61 T cells) comprises at least about 1 x 10 ⁷ , 2 x 10 ⁷ , 5x 10 ⁷ , 1 x 10 ⁸ , 2 x 10 ⁸ , 5x 10 ⁸ , 1 x 10 ⁹ , 2 x 10 ⁹ , or 5 x 10 ⁹ cells. In some embodiments, a dose of gd T cells (e.g., skin-derived gd T cells and/or V61 T cells) comprises up to about 1 x 10 ⁷ , 2 x 10 ⁷ , 5 x 10 ⁷ , 1 x 10 ⁸ , 2 x 10 ⁸ , 5 x 10 ⁸ , 1 x 10 ^® , 2 x 10 ^® , or 5 x 10 ^® cells.

In one embodiment, the subject is administered 10 ⁴ to 10 ⁶ gd T cells (e.g., skin-derived gd T cells and/or V61 T cells) per kg body weight of the subject. In one embodiment, the subject receives an initial administration of a population of gd T cells (e.g., an initial administration of 10 ⁴ to 10 ⁶ gd T cells per kg body weight of the subject, e.g., 10 ⁴ to 10 ⁵ gd T cells per kg body weight of the subject), and one or more (e.g., 2, 3, 4, or 5) subsequent administrations of gd T cells (e.g. , one or more subsequent administration of 10 ⁴ to 10 ⁶ gd T cells per kg body weight of the subject, e.g., 10 ⁴ to 10 ⁵ gd T cells per kg body weight of the subject). In one embodiment, the one or more subsequent administrations are administered less than 15 days, e.g., 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, or 2 days after the previous administration, e.g., less than 4, 3, or 2 days after the previous administration. In one embodiment, the subject receives a total of about 10 ⁶ gd T cells per kg body weight of the subject over the course of at least three administrations of a population of gd T cells, e.g., the subject receives an initial dose of 1 x 10 ⁵ gd T cells, a second administration of 3 x 10 ⁵ gd T cells, and a third administration of 6 x 10 ⁵ gd T cells, and, e.g., each administration is administered less than 4, 3, or 2 days after the previous administration.

In some embodiments, one or more additional therapeutic agents can be administered to the subject. The additional therapeutic agent may be selected from the group consisting of an immunotherapeutic agent, a cytotoxic agent, a growth inhibitory agent, a radiation therapy agent, an anti-angiogenic agent, or a combination of two or more agents thereof. The additional therapeutic agent may be administered concurrently with, prior to, or after administration of the gd T cells. The additional therapeutic agent may be an immunotherapeutic agent, which may act on a target within the subject’s body (e.g., the subject’s own immune system) and/or on the transferred gd T cells.

The administration of the compositions may be carried out in any convenient manner. The compositions described herein may be administered to a patient transarterially, subcutaneously, intradermally, intratumorally, intranodally, intramedullary, intramuscularly, by intravenous injection, or intraperitoneally, e.g., by intradermal or subcutaneous injection. The compositions of gd T cells may be injected directly into a tumour, lymph node, or site of infection.

Gene Engineering

The gd T cells obtained by the method of the invention may also be gene engineered for enhanced therapeutic properties, such as for Chimeric Antigen Receptor T cell (CAR-T) therapy. This involves the generation of engineered T cell receptors (TCRs) to re-program the T cell with a new specificity, e.g. the specificity of a monoclonal antibody. The engineered TCR may make the T cells specific for malignant cells and therefore useful for cancer immunotherapy. For example, the T cells may recognize cancer cells expressing a tumour antigen, such as a tumour associated antigen that is not expressed by normal somatic cells from the subject tissue. Thus, the CAR-modified T cells may be used for adoptive T cell therapy of, for example, cancer patients.

Other uses of the antibodies or fragments thereof

According to a further aspect of the invention, there is provided the use of an anti-V61 antibody or fragment thereof as described herein to study antigen recognition, activation, signal transduction or function of gd T cells (in particular V61 T cells). As described herein, the antibodies have been shown to be active in assays which can be used to investigate gd T cell function. Such antibodies may also be useful for inducing the proliferation of gd T cells, therefore may be used in methods of expanding gd T cells (such as V61 T cells).

Antibodies which bind to the V61 chain can be used to detect gd T cells (i.e. as a label). Preferably, antibodies used as a label will not stimulate cell proliferation so that the target V61 T cell is not affected upon antibody binding. For example, the antibody may be labelled with a detectable label or reporter molecule or used as a capture ligand to selectively detect and/or isolate nd1 T cells in a sample. Labelled antibodies find use in many methods known in the art, for example immunohistochemistry and ELISA.

The detectable label or reporter molecule can be a radioisotope, such as ³ H, ¹⁴ C, ³² P, ³⁵ S, or ¹²⁵ l; a fluorescent or chemiluminescent moiety such as fluorescein isothiocyanate, or rhodamine; or an enzyme such as alkaline phosphatase, b-galactosidase, horseradish peroxidase, or luciferase. Fluorescent labels applied to antibodies of the invention may then be used in fluorescence-activated cell sorting (FACS) methods.

Polynucleotides and expression vectors

Also provided are polynucleotides encoding the anti-V61 antibody or fragments of the invention. In one embodiment, the anti-V61 antibody or fragment is encoded by a polynucleotide which comprises or consists of a sequence having at least 70%, such as at least 80%, such as at least 90%, such as at least 95%, such as at least 99% sequence identity with SEQ ID NO: 99-110. In one embodiment, the anti-V61 antibody or fragment is encoded by an expression vector which comprises the VH region of SEQ ID NO: 99-110. In another embodiment, the anti-V61 antibody or fragment is encoded by an expression vector which comprises the VL region of SEQ ID NO: 99-110. In a further embodiment the polynucleotide comprises or consists of SEQ ID NO: 99-110. In a further aspect there is provided a cDNA comprising said polynucleotide.

In one embodiment, the polynucleotide comprises or consists of a sequence having at least 70%, such as at least 80%, such as at least 90%, such as at least 95%, such as at least 99% sequence identity with SEQ ID NO: 99-110. In one embodiment, the expression vector comprises the VH region of SEQ ID NO: 99-110. In another embodiment, the expression vector comprises the VL region of SEQ ID NO: 99-110. In a further embodiment the polynucleotide comprises or consists of SEQ ID NO: 99-110. In a further aspect there is provided a cDNA comprising said polynucleotide.

In one embodiment, the polynucleotide comprises or consists of a sequence having at least 70%, such as at least 80%, such as at least 90%, such as at least 95%, such as at least 99% sequence identity with SEQ ID NO: 99-101 or 105-108. In one embodiment, the expression vector comprises the VH region of SEQ ID NO: 99-101 or 105-108. In another embodiment, the expression vector comprises the VL region of SEQ ID NO: 99-101 or 105-108. In a further embodiment the polynucleotide comprises or consists of SEQ ID NO: 99-101 or 105-108. In a further aspect there is provided a cDNA comprising said polynucleotide. In one embodiment, the polynucleotide comprises or consists of a sequence having at least 70%, such as at least 80%, such as at least 90%, such as at least 95%, such as at least 99% sequence identity with SEQ ID NO: 99-101. In one embodiment, the expression vector comprises the VH region of SEQ ID NO: 99-101. In another embodiment, the expression vector comprises the VL region of SEQ ID NO: 99-101. In a further embodiment the polynucleotide comprises or consists of SEQ ID NO: 99-101. In a further aspect there is provided a cDNA comprising said polynucleotide.

In one embodiment, the polynucleotide comprises or consists of a sequence having at least 70%, such as at least 80%, such as at least 90%, such as at least 95%, such as at least 99% sequence identity with any one of the portions of SEQ ID NO: 99-110 which encodes CDR1 , CDR2 and/or CDR3 of the encoded immunoglobulin chain variable domain. In one embodiment, the polynucleotide comprises or consists of a sequence having at least 70%, such as at least 80%, such as at least 90%, such as at least 95%, such as at least 99% sequence identity with any one of the portions of SEQ ID NO: 99-101 or 105-108 which encodes CDR1, CDR2 and/or CDR3 of the encoded immunoglobulin chain variable domain. In one embodiment, the polynucleotide comprises or consists of a sequence having at least 70%, such as at least 80%, such as at least 90%, such as at least 95%, such as at least 99% sequence identity with any one of the portions of SEQ ID NO: 99-101 which encodes CDR1 , CDR2 and/or CDR3 of the encoded immunoglobulin chain variable domain.

In one embodiment, the polynucleotide comprises or consists of a sequence having at least 70%, such as at least 80%, such as at least 90%, such as at least 95%, such as at least 99% sequence identity with any one of the portions of SEQ ID NO: 99-110 which encodes FR1, FR2, FR3 and/or FR4 of the encoded immunoglobulin chain variable domain. In one embodiment, the polynucleotide comprises or consists of a sequence having at least 70%, such as at least 80%, such as at least 90%, such as at least 95%, such as at least 99% sequence identity with any one of the portions of SEQ ID NO: 99-101 or 105-108 which encodes FR1 , FR2, FR3 and/or FR4 of the encoded immunoglobulin chain variable domain. In one embodiment, the polynucleotide comprises or consists of a sequence having at least 70%, such as at least 80%, such as at least 90%, such as at least 95%, such as at least 99% sequence identity with any one of the portions of SEQ ID NO: 99-101 which encodes FR1, FR2, FR3 and/or FR4 of the encoded immunoglobulin chain variable domain.

The polynucleotides and expression vectors of the invention may also be described in reference to the amino acid sequence encoded. Therefore, in one embodiment, the polynucleotide comprises or consists of a sequence encoding the amino acid sequence of any one of SEQ ID NOs: 62 to 85. In one embodiment, the expression vector comprises a sequence encoding the amino acid sequence of any one of SEQ ID NOs: 62 to 73. In another embodiment, the expression vector comprises a sequence encoding the amino acid sequence of any one of SEQ ID NOs: 74 to 85.

T o express the antibodies, or fragments thereof, polynucleotides encoding partial or full-length light and heavy chains, as described herein, are inserted into expression vectors such that the genes are operatively linked to transcriptional and translational control sequences. Therefore, in one aspect of the invention there is provided an expression vector comprising the polynucleotide sequence as defined herein. In one embodiment, the expression vector comprises the VH region of SEQ ID NO: 99-110, such as SEQ ID NO: 99, 100, 101 , 105, 106, 107 or 108. In another embodiment, the expression vector comprises the VL region of SEQ ID NO: 99-110, such as SEQ ID NO: 99, 100, 101 , 105, 106, 107 or 108.

It will be understood that the nucleotide sequences described herein comprise additional sequences encoding amino acid residues to aid with translation, purification and detection, however alternative sequences may be used depending upon the expression system used. For example, the initial (5’-end) nine nucleotides of SEQ ID NOs: 99-110 and the final (3’-end) 36 nucleotides of SEQ ID NOs: 99-100, 102-103, 105-110, or the final (3’-end) 39 nucleotides of SEQ ID NOs: 101 and 104 are optional sequences. These optional sequences can be removed, modified or substituted if alternate design, translation, purification or detection strategies are adopted.

Mutations can be made to the DNA or cDNA that encode polypeptides which are silent as to the amino acid sequence of the polypeptide, but which provide preferred codons for translation in a particular host. The preferred codons for translation of a nucleic acid in, e.g., E. coli and S. cerevisiae, as well as mammalian, specifically human, are known.

Mutation of polypeptides can be achieved for example by substitutions, additions or deletions to a nucleic acid encoding the polypeptide. The substitutions, additions or deletions to a nucleic acid encoding the polypeptide can be introduced by many methods, including for example error-prone PCR, shuffling, oligonucleotide-directed mutagenesis, assembly PCR, PCR mutagenesis, in vivo mutagenesis, cassette mutagenesis, recursive ensemble mutagenesis, exponential ensemble mutagenesis, site-specific mutagenesis, gene reassembly, artificial gene synthesis, Gene Site Saturation Mutagenesis (GSSM), synthetic ligation reassembly (SLR) or a combination of these methods. The modifications, additions or deletions to a nucleic acid can also be introduced by a method comprising recombination, recursive sequence recombination, phosphothioate-modified DNA mutagenesis, uracil- containing template mutagenesis, gapped duplex mutagenesis, point mismatch repair mutagenesis, repair-deficient host strain mutagenesis, chemical mutagenesis, radiogenic mutagenesis, deletion mutagenesis, restriction-selection mutagenesis, restriction-purification mutagenesis, ensemble mutagenesis, chimeric nucleic acid multimer creation, or a combination thereof.

In particular, artificial gene synthesis may be used. A gene encoding a polypeptide of the invention can be synthetically produced by, for example, solid-phase DNA synthesis. Entire genes may be synthesized de novo, without the need for precursor template DNA. To obtain the desired oligonucleotide, the building blocks are sequentially coupled to the growing oligonucleotide chain in the order required by the sequence of the product. Upon the completion of the chain assembly, the product is released from the solid phase to solution, deprotected, and collected. Products can be isolated by high-performance liquid chromatography (HPLC) to obtain the desired oligonucleotides in high purity.

Expression vectors include, for example, plasmids, retroviruses, cosmids, yeast artificial chromosomes (YACs) and Epstein-Barr virus (EBV) derived episomes. The polynucleotide is ligated into a vector such that transcriptional and translational control sequences within the vector serve their intended function of regulating the transcription and translation of the polynucleotide. Expression and/or control sequences can include promoters, enhancers, transcription terminators, a start codon (i.e. ATG) 5' to the coding sequence, splicing signals for introns and stop codons. The expression vector and expression control sequences are chosen to be compatible with the expression host cell used. SEQ ID NOs: 99-110 comprise the nucleotide sequences encoding single chain variable fragments of the invention, comprising a VH region and a VL region joined by a synthetic linker (e.g. encoding SEQ ID NO: 98). It will be understood that polynucleotides or expression vectors of the invention may comprise the VH region, the VL region or both (optionally including the linker). Therefore, polynucleotides encoding the VH and VL regions can be inserted into separate vectors, alternatively sequences encoding both regions are inserted into the same expression vector. The polynucleotide(s) are inserted into the expression vector by standard methods (e.g., ligation of complementary restriction sites on the polynucleotide and vector, or blunt end ligation if no restriction sites are present).

A convenient vector is one that encodes a functionally complete human CH or CL immunoglobulin sequence, with appropriate restriction sites engineered so that any VH or VL sequence can be easily inserted and expressed, as described herein. The expression vector can also encode a signal peptide that facilitates secretion of the antibody (or fragment thereof) from a host cell. The polynucleotide may be cloned into the vector such that the signal peptide is linked in-frame to the amino terminus of the antibody. The signal peptide can be an immunoglobulin signal peptide or a heterologous signal peptide (i.e., a signal peptide from a non-immunoglobulin protein).

A host cell may comprise a first vector encoding the light chain of the antibody or fragment thereof, and a second vector encoding the heavy chain of the antibody or fragment thereof. Alternatively, the heavy and light chains both encoded on the same expression vector introduced into the host cell. In one embodiment, the polynucleotide or expression vector encodes a membrane anchor or transmembrane domain fused to the antibody or fragment thereof, wherein the antibody or fragment thereof is presented on an extracellular surface of the host cell.

Transformation can be by any known method for introducing polynucleotides into a host cell. Methods for introduction of heterologous polynucleotides into mammalian cells are well known in the art and include dextran-mediated transfection, calcium phosphate precipitation, polybrene-mediated transfection, protoplast fusion, electroporation, encapsulation of the polynucleotide(s) in liposomes, biolistic injection and direct microinjection of the DNA into nuclei. In addition, nucleic acid molecules may be introduced into mammalian cells by viral vectors.

Mammalian cell lines available as hosts for expression are well known in the art and include many immortalized cell lines available from the American Type Culture Collection (ATCC). These include, inter alia, Chinese hamster ovary (CHO) cells, NSO, SP2 cells, HeLa cells, baby hamster kidney (BHK) cells, monkey kidney cells (COS), human hepatocellular carcinoma cells (e.g., Hep G2), A549 cells, 3T3 cells, and a number of other cell lines. Mammalian host cells include human, mouse, rat, dog, monkey, pig, goat, bovine, horse and hamster cells. Cell lines of particular preference are selected through determining which cell lines have high expression levels. Other cell lines that may be used are insect cell lines, such as Sf9 cells, amphibian cells, bacterial cells, plant cells and fungal cells. Antigen-binding fragments of antibodies such as the scFv and Fv fragments can be isolated and expressed in E. coli using methods known in the art.

The antibodies are produced by culturing the host cells for a period of time sufficient to allow for expression of the antibody in the host cells or, more preferably, secretion of the antibody into the culture medium in which the host cells are grown. Antibodies can be recovered from the culture medium using standard protein purification methods.

Antibodies (or fragments) of the invention can be obtained and manipulated using the techniques disclosed for example in Green and Sambrook, Molecular Cloning: A Laboratory Manual (2012) 4th Edition Cold Spring Harbour Laboratory Press.

Monoclonal antibodies can be produced using hybridoma technology, by fusing a specific antibody-producing B cell with a myeloma (B cell cancer) cell that is selected for its ability to grow in tissue culture and for an absence of antibody chain synthesis.

A monoclonal antibody directed against a determined antigen can, for example, be obtained by: a) immortalizing lymphocytes obtained from the peripheral blood of an animal previously immunized with a determined antigen, with an immortal cell and preferably with myeloma cells, in order to form a hybridoma, b) culturing the immortalized cells (hybridoma) formed and recovering the cells producing the antibodies having the desired specificity.

Alternatively, the use of a hybridoma cell is not required. Antibodies capable of binding to the target antigens as described herein may be isolated from a suitable antibody library via routine practice, for example, using the phage display, yeast display, ribosomal display, or mammalian display technology known in the art. Accordingly, monoclonal antibodies can be obtained, for example, by a process comprising the steps of: a) cloning into vectors, especially into phages and more particularly filamentous bacteriophages, DNA or cDNA sequences obtained from lymphocytes especially peripheral blood lymphocytes of an animal (suitably previously immunized with determined antigens), b) transforming prokaryotic cells with the above vectors in conditions allowing the production of the antibodies, c) selecting the antibodies by subjecting them to antigen-affinity selection, d) recovering the antibodies having the desired specificity.

It will be understood that all embodiments described herein may be applied to all aspects of the invention.

Other features and advantages of the present invention will be apparent from the description provided herein. It should be understood, however, that the description and the specific examples while indicating preferred embodiments of the invention are given by way of illustration only, since various changes and modifications will become apparent to those skilled in the art. The invention will now be described using the following, non-limiting examples:

EXAMPLES

EXAMPLE 1. Materials and Methods

Human Antibody Discovery

Human phage display was employed to generate the human anti-human variable Vb1 + domain antibodies as described herein. The library was constructed as described in Schofield et al ( Genome biology 2007, 8(11): R254) and comprised a single chain fragment variable (scFv) displaying library of ~40 billion human clones. This library was screened using antigens, methods, selections, deselection, screening, and characterization strategies as described herein.

Antigen preparation

The design of the soluble yb TCR heterodimers comprising the TCRa and TCR b constant regions used in the below Examples were generated according to Xu etal. (2011) PNAS 108: 2414-2419. Vy or Vb domains were fused in-frame to a TCRa or constant region lacking the transmembrane domain, followed by a leucine zipper sequence or an Fc sequence, and a histidine tag/linker.

The expression construct was transiently transfected in mammalian EXPI HEK293 suspension cells (either as single or co-transfections for heterodimer). Secreted recombinant proteins were recovered and purified from culture supernatant by affinity chromatography. To ensure good recovery of monomer antigen, samples were further purified using preparative size exclusion chromatography (SEC). Purified antigens were analysed for purity by SDS-PAGE and aggregation state by analytical SEC.

Antigen functional validation

The specificity of the antigens containing delta variable 1 (Vb1) chain was confirmed in DELFIA immunoassay (Perkin Elmer) and in flow-based assay in competition with yb T cells using REA173-Miltenyi Biotec anti-Vb1 antibody.

Dissociation-enhanced lanthanide fluorescence immunoassay (DELFIA) For the confirmation of antigen’s specificity, DELFIA immunoassay was performed with the antigen directly coated to the plate (3 pg/mL of antigen in 50 pl_ PBS at 4 °C overnight (Nunc #437111) and serial dilution of primary antibodies starting at 300nM. For detection DELFIA Eu-N1 Anti-Human IgG (Perkin Elmer # 1244-330) was used as secondary antibody at 1/500 dilution in 50 pL of 3 % of MPBS (PBS + 3 % (w/V) skimmed milk powder). Development was with 50 pL of DELFIA enhancement solution (Perkin Elmer #4001-0010).

Affinity ranking of antibody of interest were performed using DELFIA immunoassay in which antibodies were captured via protein G coated on the plate and soluble biotinylated L1 (DV1- GV4) antigen was added at 5nM in 50 pL (3MPBS). For detection 50 pL of streptavidin-Eu (1 :500 in assay buffer, Perkin Elmer) was used and signal was developed with DELFIA enhancement solution. D1.3 hlgG1 (described in England etal. (1999) J. Immunol. 162: 2129- 2136) was used as a negative control.

Phage display selection outputs were subcloned into the scFv expression vector pSANGIO (Martin et al. (2006) BMC Biotechnol. 6: 46). Soluble scFv were expressed and screened for binding in DELFIA on directly immobilised targets. Hits were defined as a DELFIA signal above 3000 fluorescence units.

Antibody preparation

Selected scFvs were subcloned into lgG1 frameworks using commercially available plasmids. expi293F suspension cells were transfected with said plasmids for antibody expression. For convenience, unless otherwise noted, the antibodies characterised in these Examples refer to lgG1 formatted antibodies selected from phage display as scFv. However, the antibodies of the invention may be in any antibody format as previously discussed.

Antibody purification

IgG antibodies were batch purified from supernatants using protein A chromatography. Concentrated protein A eluates were then purified using Size Exclusion Chromatography (SEC). Quality of purified IgG was analysed using ELISA, SDS-PAGE and SEC-HPLC. nd T cell preparation

Populations of enriched gd T cells were prepared according to the methods described in WO20 16/198480 (i.e. blood-derived gd T cells) or W02020/095059 (i.e. skin-derived gd T cells). Briefly, for blood-derived gd T cells PBMCs were obtained from blood and subjected to magnetic depletion of ab T cells. The ab-depleted PBMCs were then cultured in CTS OpTmiser media (ThermoFisher) in the presence of OKT-3 (or respective anti-V61 antibody), IL-4, IFN-g, IL-21 and I L-1 b for 7 days. At day 7 of culture, the media was supplemented with OKT-3 (or respective anti-V61 antibody), IL-21 and IL-15 for a further 4 days. At day 11 of culture, the media was supplemented with OKT-3 (or respective anti-V61 antibody) and IL-15 for a further 3 days. At day 14 of culture, half of the media was replaced with fresh complete OpTmiser and supplemented with OKT-3 (or respective anti-V61 antibody), IL-15 and IFN-g. From day 17 of culture onwards, the culture was supplemented with OKT-3 (or respective anti- V61 antibody) and IL-15 every 3 to 4 days; half of the media was replaced with fresh media every 7 days.

For skin-derived gd T cells, skin samples were prepared by removing subcutaneous fat and a 3mm biopsy punch is used to make multiple punches. Punches were placed on carbon matrix grids and placed in the well of a G-REX6 (Wilson Wolf). Each well was filled with complete isolation medium containing AIM-V media (Gibco, Life Technologies), CTS Immune Serum Replacement (Life Technologies), IL-2 and IL-15. For the first 7 days of culture, complete isolation medium containing Amphotericin B (Life Technologies) was used (“+AMP”). Media was changed every 7 days by gently aspirating the upper media and replacing with 2X complete isolation medium (without AMP), trying not to disturb the cells at the bottom of the plate or bioreactor. Beyond three weeks in culture, the resulting egressed cells were then passaged into fresh tissue culture vessels and fresh media (e.g. AIM-V media or TexMAX media (Miltenyi)) plus recombinant IL-2, IL-4, IL-15 and IL-21 before harvest. Optionally, ab T cells also present within the culture are then removed with aid of ab T cell depletion kits and associated protocols, such as those provided by Miltenyi. For further reference see W02020/095059. nd T cell binding assay

The binding of antibodies to gd T cells was tested by incubating a fixed concentration of purified antibodies with 250000 gd T cells. This incubation was performed under blocking conditions to prevent unspecific binding of antibodies via the Fc receptor. Detection was performed by addition of a secondary, fluorescent dye-conjugated antibody against human lgG1. For negative controls, cells were prepared with a) an isotype antibody only (recombinant human IgG), b) the fluorescent dye-conjugated anti-human IgG antibody only and c) a combination of a) and b). A control well of completely unstained cells was also prepared and analysed. As positive controls, a purified murine monoclonal lgG2 anti-human CD3 antibody and a purified murine monoclonal lgG1 anti-human TCR V61 antibody were used in two different concentrations and stained with a fluorescent dye-conjugated goat anti-mouse secondary antibody. The assay was accepted if the lower concentration positive controls’ mean fluorescence intensity in the FITC channel was at least tenfold as high as the highest negative control.

SPR Analysis A MASS-2 instrument with an amine high capacity chip (both from Sierra Sensors, Germany) was used to perform SPR analysis. 15 nM IgG were captured via protein G to an amine high capacity chip (100 nM for TS8.2). L1 (DV1-GV4) antigen was flown over the cell at a 1:2 dilution series from 2000 nM to 15.625 nM with the following parameters: 180 s association, 600 s dissociation, flowrate 30 pL/min, running buffer PBS + 0.02 % Tween 20. All experiments were performed at room temperature on MASS-2 instrument. Steady state fitting was determined according to Langmuir 1:1 binding using software Sierra Analyzer 3.2.

Comparator antibodies

Antibodies were compared to commercially available antibodies in test assays as described. nd TCR downregulation and degranulation assay

THP-1 (TIB-202™, ATCC) target cells loaded or not with test antibodies were labelled with CellTracker™ Orange CMTMR (ThermoFisher, C2927) and incubated with gd T cells at 2:1 ratio in the presence of CD107a antibody (Anti-human CD107a BV421 (clone H4A3) BD Biosciences 562623). After 2 hours of incubation, the surface expression of gd TCR (to measure TCR downregulation) and expression of CD107a (to measure degranulation) on gd T cells was evaluated using flow cytometry.

Killing assay

Gamma delta T cell killing activity and effect of test antibodies on the killing activity of gd T cells was accessed by flow cytometry. After 4 hours of in vitro co-culture at 20:1 ratio of gd T cells and CellTracker™ Orange CMTMR (ThermoFisher, C2927) labelled THP-1 cells (loaded or not with the antibody) were stained with Viability Dye eFIuor™ 520 (ThermoFisher, 52065- 0867-14) to distinguish between live and dead target THP-1 cells. During sample acquisition, target cells were gated on the CellTracker™ Orange CMTMR positivity and examined for cell death based on the uptake of Viability Dye. CMTMR and eFIuor™ 520 double positive cells were recognized as the dead target cells. The killing activity of gd T cells was presented as a % of the dead target cells.

Epitope mapping

All protein samples (antigen L1 (DV1-GV4) and antibodies 1245_P01_E07, 1245_P02_G04, 1252_P01_C08, 1251_P02_C05 and 1141_P01_E01) used for epitope mapping were analyzed for protein integrity and aggregation level using a high-mass MALDI.

In order to determine the epitope of L1(DV1-GV4)/1245_P01_E07, L1(DV1-

GV4)/1245_P02_G04, L1(DV1-GV4)/1252_P01_C08, L1(DV1-GV4)/1251_P02_C05, and L1(DV1-GV4)/1141_P01_E01 complexes with high resolution, the protein complexes were incubated with deuterated cross-linkers and subjected to multi-enzymatic proteolysis using trypsin, chymotrypsin, Asp-N, elastase and thermolysin. After enrichment of the cross-linked peptides, the samples were analyzed by high resolution mass spectrometry (nLC-LTQ- Orbitrap MS) and the data generated were analyzed using XQuest and Stavrox software.

SYTOX-flow killing assay

The SYTOX assay allows the quantification of T cell mediated cytolysis of target cells using flow cytometry. Dead/dying cells are detected by a dead cell stain (SYTOX® AADvanced™, Life Technologies, S10274) which only penetrates into cells with compromised plasma membranes but cannot not cross intact cell membranes of healthy cells. NALM-6 target cells were labelled with CTV dye (Cell Trace Violet™, Life Technologies, C34557) and were thus distinguishable from the unlabelled effector T cells. Dead/dying target cells are identified through double staining of the dead cell dye and the cell trace dye. After 16 hours in vitro co-culture of effector and CTV labelled target cells at indicated Effector- to-Target ratios (E:T, 1 :1 or 10:1) the cells were stained with SYTOX® AADvanced™ and acquired on a FACSLyric™ (BD). The killing results are presented as % target cell reduction which is calculated by taking into account the number of live target cells (sample counts) in the test samples over the live target cells in the control wells without added effector cells (maximum counts):

% target reduction = 100

EXAMPLE 2. Antigen design

Gamma delta (gd) T cells are polyclonal with CDR3 polyclonality. In order to avoid a situation where generated antibodies would be selected against the CDR3 sequence (as the CDR3 sequence will differ from TCR clone to TCR clone), the antigen design involved maintaining a consistent CDR3 in different formats. This design aimed to generate antibodies recognising a sequence within the variable domain, which is germline encoded and therefore the same in all clones, thus providing antibodies which recognise a wider subset of gd T cells.

Another important aspect of the antigen preparation process was to design antigens which are suitable for expression as a protein. The gd TCR is a complex protein involving a heterodimer with inter-chain and intra-chain disulphide bonds. A leucine zipper (LZ) format and Fc format were used to generate soluble TCR antigens to be used in the phage display selections. Both the LZ and Fc formats expressed well and successfully displayed the TCR (particularly heterodimeric TCRs, e.g. nd1\/g4).

It was found that the CDR3 sequence from a public database entry for the gd TCR expressed well as proteins (RCSB Protein Data Bank entries: 30MZ). This was therefore selected for antigen preparation.

Antigens containing the delta variable 1 chain were expressed in LZ formats as a heterodimer (i.e. in combination with different gamma variable chains - “L1”, “L2”, “L3”) and in Fc format either as a heterodimer (“F1”, “F2”, “F3”) or as a homodimer (i.e. in combination with another delta variable 1 chain - “Fc1/1”). All delta variable 1 chains of the antigens contained the 30MZ CDR3. Another series of gd TCR antigens using similar formats were designed containing different delta variable chains (such as delta variable 2 and delta variable 3) and used to deselect antibodies with non-specific or off target binding (“L4”, “F9”, “Fc4/4”, “Fc8/8”). These antigens were also designed to include the 30MZ CDR3 to ensure that antibodies binding in the CDR3 region were also deselected. Antigen functional validation was performed to confirm that the designed antigens would be suitable to generate anti-TRDV1 (TCR delta variable 1) antibodies. Detection was seen only with antigens containing the d1 domain (Figure 1).

EXAMPLE 3. Phage Display

Phage display selections were performed against libraries of human scFvs using either heterodimeric LZ TCR format in round 1 and 2, with deselections on heterodimeric LZ TCR in both rounds. Or round 1 was performed using homodimeric Fc fusion TCR with deselection on human lgG1 Fc followed by round 2 on heterodimeric LZ TCR with deselection on heterodimeric LZ TCR (see Table 1).

Table 1. Overview phage display selections bt = biotin.

Selections were performed in solution phase using 100 nM biotinylated proteins. Deselections were performed using 1 mM non-biotinylated proteins.

Success of the phage display selections was analysed by polyclonal phage ELISA (DELFIA). All DV1 selection outputs showed the desired binding to the targets Fc 1/1, L1 , L2, L3, F1 and F3. Varying degrees of binding to non-targets L4, F9, Fc 4/4, Fc 8/8 and Fc were detected (see Figure 2A and B).

EXAMPLE 4. Antibody selection

Hits obtained in Example 3 were sequenced (using standard methods known in the art). 130 unique clones were identified, which showed a unique combination of VH and VL CDR3. Of these 130 unique clones, 125 showed a unique VH CDR3 and 109 showed a unique VL CDR3.

Unique clones were re-arrayed and specificity was analysed by ELISA (DELFIA). A panel of 94 unique human scFv binders which bind TRDV1 (L1, L2, L3, F1, F2, F3) but not TRDV2 (L4), were identified from the selections. Affinity ranking of the selected binders was included to aid the choice of clones going forward. A large number of binders showed affinities in the nanomolar range, reacting with 25 to 100 nM biotinylated antigen. A handful of binders showed a strong reaction with 5 nM antigen, indicating possible single digit nanomolar affinities. Some binders showed no reaction with 100 nM antigen, indicating affinities in the micromolar range.

For the selection of clones to proceed with to IgG conversion, the aim was to include as many germline lineages and as many different CDR3s as possible. Further, sequence liabilities like glycosylation, integrin binding sites, CD11c/CD18 binding sites, unpaired cysteines were avoided. In addition, a variety of affinities was included.

Selected clones were screened for binding to natural, cell-surface expressed ybTCR using skin derived gd T cells obtained from different donors. The clones chosen to be converted to IgG are shown in Table 2.

Table 2. DV1 binders for IgG conversion

EXAMPLE 5: Antibody SPR analysis

Prepared IgG antibodies were passed through a gd cell binding assay, and the 5 best binders were selected for further functional and biophysical characterization. SPR analysis was performed to determine the equilibrium dissociation constants (KD). Sensorgrams of the interaction of the tested antibody with the analyte, along with steady state fits (if available), are presented in Figure 3. No binding was detected for TS8.2 with 80 RU of IgG captured on the chip. Results are summarised in Table 3.

Table 3. Results of IgG capture *Binding of 1252_P02_C05 did not reach saturation, therefore data was extrapolated

EXAMPLE 6: TCR engagement assay

The inventors designed several assays to be used for functional characterization of the selected antibodies. The first assay assessed gd TCR engagement by measuring downregulation of the gd TCR upon antibody binding. Selected antibodies were tested against commercial anti-CD3 and anti-V61 antibodies which were used as positive controls or against 1252_P01_C08 as a positive control (for 1139_P01_E04, 1245_P02_F07, 1245_P01_G06 and 1245_P01_G09). Commercial anti-panY6 was used as a negative control because it is a rqhgd antibody, recognising all gd T cells irrespective of variable chain, and therefore is likely to have a different mode of action. The assay was performed using skin-derived gd T cells obtained from three different donor samples (samples with 94%, 80% and 57% purity). Results are shown in Figure 4. EC50 values are summarised in Table 4, below.

EXAMPLE 7: T cell degranulation assay

A second assay assessed the degranulation of gd T cell. It is thought gd T cells may mediate target cell killing by perforin-granzyme-mediated activation of apoptosis. Lytic granules within the cytoplasm of the gd T cell may be released toward the target cell upon T cell activation. Therefore, labelling target cells with antibodies to CD 107a and measuring the expression by flow cytometry can be used to identify degranulating gd T cells.

As for Example 6, selected antibodies were tested against commercial anti-CD3 and anti-V61 antibodies as positive controls or against 1252_P01_C08 as a positive control (for 1139_P01_E04, 1245_P02_F07, 1245_P01_G06 and 1245_P01_G09). lgG2a, lgG1 and D1.3 antibodies were used as negative controls. The assay was performed using skin-derived gd T cells obtained from three different donor samples (samples with 94%, 80% and 57% purity). Results are shown in Figure 5. EC50 values are summarised in Table 4, below.

EXAMPLE 8: Killing assay

A third assay assessed the ability of gd T cells activated with the selected antibodies to kill target cells.

As for Example 6, selected antibodies were tested against commercial anti-CD3 and anti-V61 antibodies as positive controls or against 1252_P01_C08 as a positive control (for 1139_P01_E04, 1245_P02_F07, 1245_P01_G06 and 1245_P01_G09) and anti-panYb as a negative control. lgG2a, lgG1 and D1.3 antibodies were also used as isotype controls. The assay was performed using skin-derived gd T cells obtained from two donors (94% and 80% purity) and the results are shown in Figure 6.

Results from the three functional assays tested in Examples 6-8 are summarised in Table 4.

Table 4. Summary of results obtained from functional assays

N/D: could not be determined; N/D*: could not be determined, titration curve did not reach plateau; N/D**: Reduced killing profile, EC50 not established.

EXAMPLE 9: Epitope mapping In order to determine the epitope of antigen/antibody complexes with high resolution, the protein complexes were incubated with deuterated cross-linkers and subjected to multi- enzymatic cleavage. After enrichment of the cross-linked peptides, the samples were analysed by high resolution mass spectrometry (nLC-LTQ-Orbitrap MS) and the data generated were analysed using XQuest (version 2.0) and Stavrox (version 3.6) software.

After trypsin, chymotrypsin, Asp-N, elastase and thermolysin proteolysis of the protein complex L1(DV1-GV4)/1245_P01_E07 with deuterated d0d12, the nLC-orbitrap MS/MS analysis detected 13 cross-linked peptides between L1(DV1-GV4) and the antibody 1245_P01_E07. Results are presented in Figure 7.

After trypsin, chymotrypsin, Asp-N, elastase and thermolysin proteolysis of the protein complex L1(DV1-GV4)/1252_P01_C08 with deuterated d0d12, the nLC-orbitrap MS/MS analysis detected 5 cross-linked peptides between L1(DV1-GV4) and the antibody 1252_P01_C08. Results are presented in Figure 8. After trypsin, chymotrypsin, Asp-N, elastase and thermolysin proteolysis of the protein complex L1(DV1-GV4)/1245_P02_G04 with deuterated d0d12, the nLC-orbitrap MS/MS analysis detected 20 cross-linked peptides between L1(DV1-GV4) and the antibody 1245_P02_G04. Results are presented in Figure 9.

After trypsin, chymotrypsin, Asp-N, elastase and thermolysin proteolysis of the protein complex L1(DV1-GV4)/1251_P02_C05 with deuterated d0d12, the nLC-orbitrap MS/MS analysis detected 5 cross-linked peptides between L1(DV1-GV4) and the antibody 1251_P02_C05. Results are presented in Figure 10.

Epitope binding with another antibody, Clone ID 1141_P01_E01, was also tested. After trypsin, chymotrypsin, Asp-N, elastase and thermolysin proteolysis of the protein complex L1(DV1-GV4)/1141_P01_E01 with deuterated d0d12, the nLC-orbitrap MS/MS analysis detected 20 cross-linked peptides between L1(DV1-GV4) and the antibody 1141_P01_E01. Results are presented in Figure 11.

A summary of the epitope mapping results is presented in Table 5.

Table 5. Results of epitope mapping for antigen/antibody complexes

EXAMPLE 10: Expansion of V61 T cells

Expansion of isolated gd T cells was investigated in the presence of selected antibodies and comparator antibodies. Comparator antibodies were selected from: OKT3 anti-CD3 antibody as a positive control, no antibody as a negative control or lgG1 antibody as an isotype control. Commercially available anti-V61 antibodies, TS-1 and TS8.2 were also tested for comparison.

Experiment 1:

An initial investigation was conducted by seeding 70,000 cells/well with Complete Optimizer and cytokines as described in the “gd T cell preparation” for blood-derived gd T cells of Example 1. Selected and comparator antibodies were tested at various concentrations ranging from 4.2 ng/ml to 420 ng/ml. This experiment was conducted using tissue culture plates which allow the binding/immobilisation of the antibodies to the plastic.

Cells were harvested on days 7, 14 and 18 and the total cell count was determined using a cell counter (NC250, ChemoMetec). The results are shown in Figure 12. Cell viability of V61 T cells was also measured on each harvest and all antibodies were shown to maintain cell viability throughout the experiments (data not shown). On day 18, the percentage, cell count and fold change of V61 T cells was also analysed. The results are shown in Figure 13.

As can be seen in Figure 12, the total number of cells produced in cultures with antibodies increased steadily throughout the culture and were comparable or better than the commercial anti-V61 antibodies. At day 18, the proportion of V61 positive cells in the presence of 1245_P02_G04 (“G04”), 1245_P01_E07 (Έ07”), 1245_P01_B07 (“B07”) and 1252_P01_C08 (“C08”) antibodies at most concentrations tested was greater than in cultures where OKT3, TS-1 or TS8.2 control antibodies were present (see Figure 13A).

Experiment 2:

A subsequent experiment was performed on isolated cells in a culture vessel with cytokines as described in the “gd T cell preparation” of Example 1. Compared to Experiment 1 , a different culture vessel was used whose surface does not facilitate antibody binding/immobilisation. Selected and comparator antibodies were tested at various concentrations ranging from 42 pg/ml to 42 ng/ml. During Experiment 2, results were obtained from experiments run in triplicates.

Cells were harvested on days 7, 11 , 14 and 17 and the total cell count was determined using a cell counter as before. The results are shown in Figure 14. On day 17, the percentage, cell count and fold change of V61 T cells was also analysed. The results are shown in Figure 15.

The cell composition, including non-V61 cells, were also measured during Experiment 2. Day 17 cells were harvested and analysed by flow cytometry for surface expression of V61 , V62 and c^TCR. The proportions of each cell type in each culture are shown graphically in Figure 16 and the percentage values are provided in Table 6. Table 6. Cell composition at day 17 - Percentage of live cells of each subset

As can be seen from these results, the proportion of V61 positive cells is greater in cultures with B07, C08, E07 and G04 present compared to OKT3, TS-1 or TS8.2 controls. Therefore, the tested antibodies produce and expand V61 positive cells more efficiently than commercially available antibodies, even when present at low concentrations in culture. Cells from day 17 of Experiment 2 were also analysed for additional cell markers, including CD3-CD56+ to identify the presence of Natural Killer (NK) cells and V61 T cells which express CD27 (i.e. CD27+). The results are summarised in Table 7. Table 7. Cell composition at day 17 - Percentage of NK and CD27+ cells

SEM: Standard error of the mean EXAMPLE 11 : Functionality of V61 T cells

V61 T cells expanded in the presence of the selected antibodies retained a polyclonal repertoire of CDR3 regions and were also tested for functionality using the SYTOX-flow killing assay. The results are presented for cells obtained during Experiment 1 at day 14 using cells in a 10:1 Effector-to-Target (E:T) ratio (Figure 17A) and for cells obtained during Experiment 2 at day 17 (post freeze-thaw) using cells at a 1:1 and 10:1 E:T ratio (Figure 17B).

As can be seen in Figure 17, V61 positive cells expanded in the presence of all antibodies effectively lysed target cells, indicating that they are functional even after freezing and thawing the cells.

EXAMPLE 12: Functionality of cells after storage

The functionality of cells after a storage step of freezing and then thawing was also investigated. A portion of cells was removed from culture at day 17 of Experiment 2 and frozen. Cells were then thawed and further expanded in culture with IL-15. Figure 18 shows the total cell counts after 7 days of culturing cells post freeze-thaw for cultures contacted with B07, C08, E07, G04 or OKT-3 antibodies prior to freezing. All cultures showed the ability to proliferate after storage. Culturing was continued until day 42 and total cell counts were monitored during this period (results shown in Figure 19). Total cell numbers were maintained or increased in the cultures previously exposed to selected antibodies.

EXAMPLE 13: Anti-V61 antibody conferred modulation and proliferation of immune cells in TILs

Studies were undertaken to explore anti-V61 antibody conferred modulation and proliferation of human tumour infiltrating lymphocytes (TILs). For these studies, human renal cell carcinoma (RCC) tumour biopsies were shipped fresh and processed upon receipt. Specifically, the tissue was chopped into ~2mm ² . Up to 1g of tissue was placed into each Miltenyi C tube along with 4.7mL RPMI and enzymes from Miltenyi’s Tumour Dissociation Kit at concentrations recommended by the manufacturer aside from Enzyme R which was used at 0.2 x concentration to prevent cleavage of pertinent cell surface molecules. C-Tubes were placed on the gentleMACS™ Octo Dissociator with Heaters. Program 37C_h_TDK_1 for the dissociation of soft tumours was selected. The digest was then filtered through a 70mM filter to generate a single cell suspension. RPMI containing 10% FBS was added to the digest to quench enzymatic activity. The cells are washed 2 x with RPMI/10%FBS and resuspended for counting. Derived cells were then seeded in TC wells (24-well G-REX, Wilson Wolf) at 2.5x10e6 per well. Cells were then incubated without or without cytokines and with or without antibodies for 18 days. Antibodies included in the study are outlined in Figure 20. These include OKT3 (to 50ng/ml) and 1252_P01_C08 aka “C08” herein (to 500ng/ml). When included, bolus additions of these antibodies were added on day 0, 7, 11 and 14. During said incubation, media was replaced with fresh media on days 11 and day 14. Flow cytometry analysis was performed on day 0 and day 18 to determine the lymphocyte phenotype as well as fold change in cell number. Cells were first gated on live CD45+ cells and then as indicated. In arms where recombinant cytokines were included these were added as follows. Day 0: IL- 4, IFN-g, IL-21, I L- 1 b . Additional IL-15 was included on day 7, 11 , 14. Additional IL-21 and IFN-g were included on day 7 and day 14 respectively. Figure 20 (A) shows the fold-increase in TIL V61+ cells following 18 days culture in the presence of C08 or OKT3 with and without cytokine support (CK) where indicated. These results show substantial fold increases in TIL V61+ cells with the application of either the C08 or comparator OKT3 antibody in the presence of cytokines, as compared to antibody or cytokines alone. Figure 20 (B) shows increases in total V61 cell number at harvest following . These results show substantial increases in TIL V61 + cell number following culture with C08 or comparator OKT3 antibody in the presence of cytokines, as compared to antibody or cytokines alone. Figure 20 (C) presents an example gating strategy used in the flow cytometric analysis of the cells. From the live CD45+ cell population cells were gated on lymphocytes based on their forward and side scatter properties (not shown), gd T cells were then separated from ab T cells by staining for the T cell receptors. Finally, the proportion of V61 cells within the total gd T cell population was determined. Example data for day 18 is shown for 2 conditions as indicated (+/-1252_P01_C08): 64.3% cells were CD45+, of those CD45% cells, 53.1% were gd+, and of the gd cells, 89.7 were nd1+. Figure 20 (D) presents a cell-surface phenotypic profile of TIL V61+ cells at harvest. Higher levels of CD69 were observed following culture with the C08 antibody. Figure 20 (E) presents analysis of the TIL gd-negative, CD8-positive lymphocyte fraction within the live CD45-positive gate at harvest. In summary, the combined results highlight the modulatory effects conferred by anti-V61 antibody of the invention described herein on TIL populations.