s

Cross-Reference

This applica tion claims priority to O.S, Provisional Patent Application Serial Number 62/447772 filed January 18, 2017, incorporated by reference herein, in its. entirety. o Background

Protein biologies are the fastest growing therapeutic modality. These drags are usually protein (i.e., igG) molecules that are administered to patients and alter a specific physiological process involved in disease. Commercial m nufacturing processes, for protein biologies is a long, expensive and arduous process ^■ > This is because most protein biologiesS are manufactured within living cell lines such as bacteria, yeast, insect and mammalian cells, "These cell lines are ty ically genetically engineered to produce and secrete the protein biologic of interest into the extracellular milieu- (fee cell culture supernatant). Once the biologic is secreted, It is harvested and purified fer cojsroereial use,. Bec use of the expensive nature of this process, it is desirable to engineer fee production cell lines so that0 they produce very high levels of the protein of interest

Summary of the Invention

In one aspect are provided methods for determining immunoglobulin gatnma (IgG) antibody isotype concentration from ^' biological samples, comprising;

S (a) in plurality of wells in a .microliter plate _* incubating biological, samples

•containing IgG antibodies with detection reagents, wherein the detection reagents comprise one or more detectaMy labeled target IgG protein isotypes, or fragments thereof, wherein the incubating occurs for a time and under conditions to promote even mixin of the deieetahly labeled target IgG proteins or fragments thereof with the IgG antibodies thereof to produce0 IgG antibody-target IgG protein mixtures in each well of the pl rality of wells

(b) incubating the IgG antibody-target IgG protein mixture in each well of me •plurality- ^' of wells with one or more IgG isotype-speciitc populations of cap ture reagents, wherein each IgG* isotype-speeific population of capture . eagents comprises binding molecules that selectively bind to a different .specific IgG protein, isotype, wherein the

i binding molecules in each IgG isotype-spedfie opulation of capture reagents are bound to a surface, wiiereis the incubating is carried out for a time arid under conditions to promote binding of h one or more detectable - labeled target IgG proteins or fragments thereof add the IgG anybodies to the IgG is type-specific population of capture reagents, to produce IgG isotype-specifie binding complexes; and

(c) detecting signal from the IgG is iype-speeiiie binding complexes to determine the concentration of one or more IgG antibody isotypes present in the biological sample, wherein the amount of IgG antibody isotype present in the biological sample is inversely proportional to .the detected signal from the relevant IgG isotype-spedfie binding complex, In one mb d men , the welfwd frstther comprises-

(d) incubating serial dilations- of a control sample , wherei n each dilution o f tbe .Serial dilutions of the control sample is present in a separate well of a mieroiiter plate, with the detection, reagents to generate control .mixtures, wherein the eonti'ol sample comprises one or more differeni unlabeled IgG protein isotypes, or fragments thereof, that correspond to the one or .more different, deteeiab!y labeled target IgG protein isotypcs of fragments thereof in the detection reagents, wherein the incubation occurs for a time and under conditions to promote mixing of the unlabeled IgG protein isotypes in the control sample and the one or more different, detectably labeled target IgG protein isotypes, or fragments thereof;

(e) incubating the control mixtures with the one or more IgG isotype-specifie populations -of capture reagents, wherein the incubating is carried out for a time and under conditions to promote competitive blading of the one or .more detestably labeled target IgG protei isotypes or fragments thereof and. the -one or more differeni .unlabeled IgG protein, isotype or fragments thereof to the one of more IgG- isotype-specific population of capture- beads, to produce control IgG is rype-speeifie binding complexes; and

(f) generating a standard curve ^' for each IgG protein isotype by analysis of the

^• signal from die IgG- isotype-speeiftc binding complexes,„ wherein the- concentration of the one or more IgG antibody isotypes in each biological sample is measured by reference to the standard curve for each. IgG protein ^' isotype.

in another aspect are provided methods for determining immunoglobulin gamma (IgG) isotype antibody concentration from, biological samples, comprising;

( a) in plurality of wells in a mtero titer plate, incubating a plurality of biological samples expressing IgG antibodies: with one o more IgG isotype-spee-ifle populations of capture reagents, wherein, each IgG isoty pe-specific population of capture reagents comprises binding molecules that selectively bind to- a different .specific IgG protein isotype,. wherein the binding molecules caehlgG isotype-speeific population of capture reagents are bound to a surface; whe*et» the incubating is carried oat for s time and wader -conditions to promote binding of the IgG antibodies to the IgG isotope-specific capture reagents to produce IgG antibody-igG isotype-speeific capture reagent complexes;

(b) incubating the IgG antibody -IgG isoiype-specifie capture reagent complexes with detection reagents,- wherein the detection reagents comprise one or more detectabiy labeled target IgG protein isotypes _s : or fragm nts thereof wherein the incubation occurs for a time and under conditions t promote binding of the .detestably labeled, target IgG protein isotypes, or fragments thereof to -unoccupied, sites on the Ig isotype-speeific capture reagent complexes to produce detectabiy- labeled target IgG protcia-lgG andbody-lgO tsotype- specifie capture reagent complexes; and

(e) detecting signal from the detectabiy labeled target IgG- protein on the detectabiy labeled target IgG proteia-IgG aniibody-lgG isotype-speeific capture reagent complexes to determine the concentration of one or more IgG antibody isotypes, wherein the amount of an. IgG antibody isotype protein present in. the biological sample is inversely roportional to the detected signal.

In one embodiment tiae memods mrther comprise

(d) ine-ubatajg serial dilutions of a control sample, w erein each lution of the serial dilutions of tiie control sample is pteseat in a separate well of a microliter plate, with one of mote IgG isotype-speeific populations of capture reagents, to generate a control mixture, wherein the control sample comprises? one or more different unlabeled IgG protein isotypes, or fragments thereof that correspond to the one or more different, detectabiy labeled target IgG protein isotypes or fragments thereof in the detection reagents, wherein the incubating is carried out for a time and under conditions to promote binding of the one or .more different unlabeled IgG protein isotypes io the IgG isotype-speeific capture reagents produce control -complexes;

(e) inc ibaiing the control complexes with the detection reagents, wherein the incubating is carried out for a time and under conditions to promote ^' binding of one or more detectabi labeled IgG protein isotypes of fragments thereof, to onoecupied sites on the IgG isotype-speeific capture reagents; and.

(f) generating a standard curve for each IgG protein isotype by analysis of the signal from the detectabiy labeled IgG isotype- bound ^' to the IgG isotype-speeific ^' population of capture reagents, wherein, the concentration, of one or more IgG isotypes ia each biological sample is measured by 'reference to the standard carve for each. IgG -protein isotype. hi various embodiments f either aspect, the detection reagents comprise a defined ratio of two, three,, four or more different, deteetably labeled target IgG protein isotypes, or fragments thereof, and the concentration of two, three,, or four or more Ig antibody isotypes is determined in each biological sample.

in a further embodiment, the detection reagent may farther comprise a detectable cell viability -marker, and wherein the -methods further comprise measuring cell viability and/or cell number in each biological sample, in another embodiment, the surface to which the binding molecules are bound may comprise a bead. In one embodiment each population of capture reagents is separately disthiguishable. In a further, embodiment, the binding molecules comprise antibodies, afBmers apianiers, and/or T½ receptors, tn another

-embodiment, the .methods further comprise determining the total IgG antibody concentration in each biological sample. In a further embodiment, the biological samples comprise cell samples, in one embodiment, the biological sample is an undiluted sample. In another ^• embodiment, the methods do not include any wash steps,.

In one embodiment, the biological samples comprises mouse B cells or .mouse cell hybridoma supernatant with or without cells, wherein the different IgG isotypes are selected from the group consisting of mouse IgG 1, IgG2a, 1 0 15, and IgG3. In another embodiment, the biological samples comprise human cells, wherein the different IgG Isotypes are ^■ selected from the grou consisting of human IgG I, IgG2, IgG3, and IgG4. In a further embodiment, the biological samples comprise rat ceils, wherein the different IgG isotypes are selected from the group consisting of rat IgCsi, lgCi¾ IgG2b, IgGle In other embodiments, the biological samples comprise:

(Γ) rabbit cells or sheep cells, wherein the different IgG isotypes are selected from: the grou consi sting of -rabbit or sheep IgG;

(H) goat cells, pig cells, or bovine cells _* wherein the different IgG isotypes are selected from the group consisting of goat, pig, or bovine IgGl and lgG2;

(ill) horse ceils, wherein the different IgG isotypes are selected from the -.group consisting of horse IgGa, IgGb, l.gOt ^* or

(iv) monkey cells, wherein the different IgG isotypes are selected, from the group consisting of monke IgG l , Ig02, IgG3, lgG4.

In another aspect are provided kits comprising:

(a) a detection reagent,, comprising a defined ratio of two,, three, four, o more different, detectabiy labeled target IgG protein isotypes, or antigenic fragments thereof; and. (b) two, three, four, or more populations of capture reagents, wherein each population o f capture reagents comprises binding molecules that selecti vely brad to a ^■ different IgG antibody isotype, wherein the binding molecules m each population of capture reagents are bound to a surface.

hi one embodiment the surface comprises a bead. In another .embodim t, each population of capture reagents is separately dis tinguishable, ϊη a further embodiment, the binding molecules comprise antibodies, in soother embodiment _s the kits 'further comprise control sample comprising a defined ratio of two or more different unlabeled IgG protein isotypes, or antigenic fragments thereof, that correspond to the two or more .different, detectably labeled target gG protein isotypes, or antigenic fragments thereof in the detection reagents. In one embodiment, the control sample comprising a defined ratio of three or more or four or more different unlabeled. IgG protein isotypes, or antigenic fragments thereof that correspond to the three or more or four or more different, detectably labeled target IgG protein isotypes _* or antigenic fragments thereof in the detection reagents >

In one embodiment, the detection reagent, comprising a defined ratio of 2, 3 _* or 4 different, detectably labeled target mouse IgG protein isotypes seiecied from the group consistin of Gl, %G2a, igG2b _> and lgG3, or antigenic fr gments thereof; and the capture reagent comprises 2, 3, or 4 populations of capture reagents, wherein each population of capture reagents comprises binding molecules that selecti vely hind to a different mouse IgG antibody isotype selected- from the grou consistin of IgG 1, lgG2a, IgG2b, and IgG3. In another embodiment, the detection reagent, comprising a defined ratio of 2, 3, or 4 different, detectably labeled target human IgG protein isotypes selected from the group consisting of IgGl , igG2, IgG3 _s and igG4, or antigenic fragments thereof; and the capture reagent comprises 2 , 3 , or 4 populations of capture reagents, wherein each population of capture reagents comprises binding molecules that selectively hind to a different human IgG antibody isotype selected from the group consisting Of IgG i, lgO¾ IgG3, and IgG4. In a still feather embodiment, the detection reagent comprises a defined ratio of 2, 3, or 4 dit¾rent, detectabl iabeied target rat IgG protein isotypes selected from the group -consisting of IgG 1, IgG2a, igG2b, IgGlc or fragments thereof; and the capmre reagent comprises 2, 3, or 4 populations of capture reagents, wherein each population of capture reagents comprises binding molecules that selectively bind to a different rat IgG antibod isotype selected from the grou consisting of IgG 1, IgGla, %G2b, IgG2c, In various other embodiments,

(A) the detection, reagent comprises a defined ratio of: (ί) 2 different, deteetably labeled target goat, pig, or bovine IgG protein tsorypes selected from the group consisting of IgGl , IgG2 or fragments thereof;

(ii) 2 or 3 different, deteetably labeled target horse IgG protein iso pes selecied from the group consisting- -of IgGaJgGb, IgGt or fragments thereof; or

(iii) 2, 3, or 4 different, deteetably labeled target monkey igG protein isotopes selected from die grou consisting of IgG I, %G2, lgG3, XgG4 or fragments thereof; and

(B) the capture reagent comprises

0) 2 populations of capture reagents, wherein each popul ation of capture reagents eotuprises binding -molecules that selectively bind, to a different target goat, pi , or boviiie IgG protein isotype selected from the group consisting oHgG.I , igG2 or fragments thereof;

(ii) 2 or 3 populations of capture reagents, wherein each. opulation of capture reagents comprises binding molecules thai selectively bind to a different horse IgG protein isotype selected from the group consisting of IgGa, ¾Gb _s IgGt or ftagraents thereof; or

(iii) 2, 3, or 4 po ula ions of capture reagents, wherein each population of capture reagents comprises binding molecules that selectively bind to a different monkey IgG protein isotype selected from the group consisting of IgGl, IgG2, IgGS, lgG4 or fragments thereof.

.In -another aspect are provided methods for analyzing a plurality of ceil samples for iinmimoglobuiin gamma (igG) antibody production, the method comprising:

(a) transferring a plurality of cell samples to an. assay plate having a plurality of sample: wells, wherein each sample well contains a eel! sample that is an undiluted cell culture expressing a target IgG antibody and. .mixing the plnrali tv of ceil samples with analysis .reagents- to generate a pl uralit of analy sis mixtures, wherein the analysis reagents comprise:

ft) a capture bead, wherein the captur bead binds to IgG antibody; and (ii a first detection .molecule comprising (A) a control IgG antibody or fragment thereof, and (B) a first detectable moiety;

(b) incubating the plurality- of analysts mixtures tor a time and under conditions to promote binding of the target IgG antibody and the first detection molecule to the capture bead; and (c) determining the target: IgG antibody concentration in each analysis mixture of the plurality of aaalysts mixtures by flow cytometry analysis,

la one embodiment, the ceil culture is -propagated from s single clone. In another embodiment,, the capture bead is eovaiently ind ed -with Protein G or Proteifi A. in a further embodiment, the capture bead is a magnetic bead or an agarose bead. In another embodiment, the assay plate contains iyophiiized analysis reagents before me plurality of samples are transferred. Ϊ» one embodiment mixing the analysis reagents with me plurality of samples comprises adding the analysis reagents to the cell sample in the w lls. In another

embodiment, the assay plate is eentotuged before readin the plurality of analysis mixtures its the assay plate in a flow eyto eter; in 3 fertber embodiment, the mixin comprises simultaneously mixing the plurality of cell samples and ail of analysis -reagents, wherein the first defection mo ecule competes- with the target IgG antibody for binding io the capture bead; and wherein the amount of the first detection .molecule bound to the capture bead in each ■analysis. -mixture provides a measure of the target IgG antibody concentration in a gi ven analysis mixture, in another embodiment, the mixing comprises stepwise addition of the ^• capture beads and the first detection molecule, wherein the stepwise addition comprises:

first mixing the plurality of cell samples with the capture ^' beads for a time and under conditions to p omote inding of the target IgG anti body to the capture beads to generate a plurality of first mixtures, and then adding the first detection molecules ^' to the pluralit of first mixtures for a time and under conditions to promote binding of the first detection molecules to the capture beads io generate the plurality- of analysis mixtures;

wherein the amount of the first, detection..molecule bound to the capture bead in each analy sis mi xture provides a measure of the target IgG antibody concentration in a given analysis mixture,

In another aspect are provided methods for analy zing a plurality of cell samples for immunoglobulin gamma (IgG) antibody production, the method comprising;

(3) transferring a plurality of cell samples to as assay plate having a pluralit of sample wells, wherein each sample well contains a cell sample that is an undiluted ceil culture expressing a target IgG antibody and mixing the plurality of cell samples with analysis reagents to generate a plurality of analysis mixtures, wherein the analysis reagents comprise:

(i) a capture bead, wherein Hie capture bead, binds to IgG antibody; ^' and

(ii) . a first detection molecule comprising a first detectable moiety; (b) mcubating the plurality o analysis mixtures for a time and trader conditions to promote binding of the target IgG antibody .and the first detection molecule to the capture bead; and

(c) determining the target IgG antibody concentration in each analysis mixture of the plurality of analysis mixtures by flow cytometry analysis.

in one embodiment, the fi st detection molecule tacks immunoglobulin fight chains and is capable of binding to the capture bead, in oher embodiment, the method further comprises contacting the plurality of analysis mixtures with- a second detection molecule for a time and -.under conditions to promote binding of the second detection molecule to die target IgC antibody .bound the capture bead;

wherein the second detection, molecule comprises a deiectahly labeled anti-IgG light chain antibody that is optically distinguishable from the first detection molecule; .and

wherein the amount of the second detection molecule bound to the target IgG antibody in each analysis mixture provides a measure of intact target IgG antibody

concentta.ti.on in a given analysis .mixture..

I» another embodiment the plurality of analysis mixtures ate eenuifuged and subjected to a wash step before the abeled- anti-Eg t chain antibody is added. In a farther embodiment, the analysis reagents further comprises one ox more of a cell viabilit dye, a cell surface hionrarker, of a marker of apoptosts. In various embodiments, the methods farther comprise deteromtrag one o more of;

(i) a number of ceils in each anal ysis mixture;

(a) a percentage of viable cells in each, analysis mixture;

(ii.) a concentration of target IgG antibody per cell in each analy sis .mixture; and/or (in) a coftceatratioa of target IgG antibody- per viable cell i» each analysis mixture, In another aspect are provided kits comprising:

(a) an. assay platt\ and

(b analysis reagents, wherein the analysis reagents comprise:

(i) a capture bead, wherein the capture bead hinds to IgG antibod : and

(ii a first detection molecule comprising a first detectable moiety.

In one embodiment;, the first detection molecule comprises control IgG- antibody or fragment thereof, la another .embodiment the kit further comprises a detectahly labeled anti- light chain antibody that is optically distinguishable from the first detection molecule, in a further embodiment, the analysis reagents further, comprises one or more of a cell viability dye, a eel! surface bioroarker, or a marker of apoptosis. In another embodiment, the capture bead is covalcnii linked with .Protein G or Protein A, in a fetter e bodi ent, the capture bead is s magnetic bead or an agarose bead, In another embodiment, the assay plate contains lyophlhzed. analysis reagents.

S Description of the Figures

Figure I is a d agram of multiplexed competition assay format with 4 capture beads to capture 4 different JgG isotypes.

Figure 2 is a diagram of an -exemplary setup of standard wells in tne nnerotiter plate, 0 Detailed - 'Descri tion

All .references cited are herein incorporated b reference in their entirety. As used hereto, the singular forms "a", "an" and "tlie" include plural referents unless the context clearly dictates otherwise. " rid" as used herein is interchangeably used with ^' "or" unless expressly stated otherwise.

5 All embodiments of any aspect of the invention can be used .in combination, unless the context clearly dictates otherwise.

Unless the context clearly requires otherwise, raroughout: the description and the claims, tfee words comprise', C m rising', mil the li&e are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense: that is to say, in the sense of "taeluding,0 but not limited to". Words using the singular or plural number also include the plural and ■singular number, respectively. Additionally,, the words "herein." "above," and "below ^' " and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of the- application.

The description of embodiments of the disclosure is not intended to be exhaustive orS to limit the disclosure to the precise form- disclosed. While the specific embodiments of, and examples for, the disclosure are described herein, for illustrative purposes, various equivalent modifications. ^' ate possible within the scope of the disclosure, as those skilled in the relevant art will recognize.

In a first aspect are provided methods for determining immunoglobulin gamma (IgG)0 antibody isotype _: concentration fern: biological samples, comprising;

(a) in plurality of wells in a miexotiter plate, incubating biological samples containing IgG antibodies with ^' detection reagents, wherein the detection reagents comprise one or more detestably labeled target IgG protein i.sotypes, or fragments thereof, wherein the incubating occurs for a time and under conditions to promote even mixing of the detcetably labeled target IgG proteins or fra men s thereof fe tie IgG antibodies thereof to produce IgG antibody-target IgG protein mixtures k each well of the plurality of wells

(b) incubating the IgG antibody-target IgG protein mi ure in each well of the phrrality of wells, ith, one or more IgG isotype-specific populations of capture reagents, wherein each IgG isotype-specifie population of ^* capture .reagents comprises binding molecules that selectively bind to a different specific IgG protein isotype, wherein the binding molecules in each IgG isotype-specific .population of capture reagents are bound to a surface, wherein the incubating is carried out for a time and under conditions to promote binding of the one or more deteetably labeled target IgG proteins or fragments thereof and the Ig antibodies to the IgG sotype-speciic population of capture reagents, to jproduee IgG isotype-specifie binding complexes; and

(e) detecting signal from the I G: ssotype-specifie binding complexes to determine the concentration of one or more IgG antibody isotypes present in the biological sample,, wherein the amount of a IgG antibody isotype present in the -biological sample is inversely proportional to the detected signal from the relevant IgG isotype-specific binding complex.

The methods petroit determining the concentration of one or more IgG antibody isotypes present the biological sam le based on the inverse relationship of the IgG antibody Isotype present in the biological sample is inversely proportional, to the detected signal from the relevant Ig isotype-specific binding complex.

Any suitable biological sample that contains IgG antibodies can be used, including but not limited to isolated IgG anybody-secreting cells, populations of Ig antibody-secreting cells, supeffiatanis of such cells, cell extracts thereof, serum, serum extracts, biological fluids (including but not limited- to blood), and biological fluid extracts (including but not limited to blood extracts). In non-limiting embodiments, the biological sample may comprise antibody - secreting S ceils, ftybridoni cells, supematants thereof (i.e., cell culture media in which the cells or hybridomas have been cultured, with or without the cell component), or cell extracts thereof. In certain embodiments, the -bi ©logical sample comprises ceils propagated from a single clone. In other embodiments, the biological sample comprises an. undefined ceil population. In one embodiment, die biological sample is an undiluted sample, such as an undiluted sample from ceii/hybridoma eiilture. The methods of the invention permit quantitation of IgG antibody isotypes without dilution of the eell hybrtdoma culture samples,:, which is not possible using previous antibody concentration detection techniques and greatly simplifies the assay workflow by removing the intermediate sample dilutio ste which may require the subjective guess of the dilation, factor.

The biological sampl may be of say erigia, including bat not ^' limited io harnan, rodent (i.e., .mouse, rat, hamster, etc.), rabbit, pig, goat, monkey, sheep, horse, bovine, etc,

As used herein, the IgG antibodies in the biological sample may be polyclonal or monoclonal antibodies, in a specific embodiment, the IgG antibodies in the biological sample are monoclonal antibodies, fragments thereof, or immunological binding equivalents , thereof. Such antibodies include any type of antibody that a eel! may express or be

engineered to express, including but not limi ted to ..monoclonal antibodies (rrsAbs), humaRized or chimeric antibodies, single chain antibodies (scFvs), Fab a ment, Hsb% .Segments, disulfide-liniked Fvs (sdFv) fragments, anti-idiotypie (anti-Id) antibodies, intra- bodtes, synthetic antibodies, epitope-hinding fragments of any of the above, and fusion protein that includes, a region ee fvaient to the IgG Fc region.

The detection reagents comprise one or more detectably labeled target IgG protein isotypes, or fragments thereof that retain the ability to bind to the corresponding IgG antibod isotype. in various eaabodimeats, the detection reagents comprise 2, 3, 4, 5, or more

detectably labeled target IgG protein isotypes, or frag ents thereof Such IgG proteins are ^■ conunercially available from a number of vendors _* including B& Biosciences, Sigma

Chemical Company, Millipore, add ThermoFisher Scientific. Each target IgG protein isotype, or fragment thereof has the abili ty to bind to a specific I gG antibody isoty pe. In One non- limiting embodiment, the biological samples comprises mouse B cells or mouse cell hybridorrs supernatant (wife or without cells), and the differen t IgG isotypes are selected from the grou consisting of mouse IgGI , IgG 2a, lgG2h, and lgG3. In this embodiment, the detection reagent comprises- 1, 2, 3, or 4 detectably labeled target IgG protein isotypes (i.e.: IgG L igG2a, igG2b, and/or lgG3)„ or fragments thereof, in another non-limiting

embodiment, the biological samples comprise hitman antibody-secreting cells, and the different IgG isotypes are selected .from the group consisting of human IgG 1 , IgG 2 , IgG 3 , and tgG4, In this embodiment, the detection reagent comprises .1 , 2, 3, or 4 detectably labeled target IgG protein isotypes or fragments thereof In. a. further non-limiting

embodiment, the biological samples comprise rat antibody-secreting ceils, and the different Ig isotypes are selected irom the group consisting of rat IgGI, IgG2a, IgG2b, IgG2e. In this embodiment, the detection reagent comprises 1 , 2, 3, or 4 detectably labeled target Ig protein isotypes or fragments thereof In various further cmbodiinen.ts, (i) the biological sam les comprises rabbit or sheep antibody-secreting cells, and t e only IgG isotypes are rabbit or sheep IgO;

(ii) the biological samples comprises goat pig, or bovine antibody-secreting cells,, and the different IgG isotypes are selected from die group consisting of goat, pig, or bovine IgG I and Ig02. In this embodiment, the deieetion reagent comprises 1 or 2 detectabiy labeled target IgG protein isotypes or fragments thereof;

(lit) the biological sample comprises .horse antibody-secreting cells, and the different IgG isotypes are selected from the group -consisting of .horse IgGa, IgGk IgGt. in these embodiment, the detection reagent comprises 1, or 3 detectabiy labeled target IgG protein isotypes or fmg ents thereof or

(iv) the bioiogicai sample comprises antibody-secreting monkey ceils,, and the different I G- isotypes are selected from the group consisting of monkey IgG.! , Ig02, IgG3, IgG4. in this embodiment, the detection reagent comprises 1 , 2, 3, or 4 detectabiy labeled target IgG protein isotypes or fragments thereof.

in various embodiments the detection reagents comprise a defined ratio of 2 _S 3, 4 o more different, detectabiy labeled target IgG protein isotypes of fragments thereof This embodiment permits more rapid quantification o -the concentration of 2, 3 _{$ %} or more IgG antibody isotypes m the biological sample. Any defined ratio of the detectabiy labeled target IgG protein isotypes or fragme ts ^' thereof may be Used, so long as the ratio is known. In one no»4imitio:g embodiment each detectabi labeled target IgG protein isotype or fragment thereof is present in. about the same concentration, in another non-iiinitio embodiment, each detectabiy labeled target IgG protein isotype or fragment thereof is present in about the same amount (i.e.., about 1:1:1 when there are three different detectabiy labeled target IgG protein isotypes or fragments thereof),

.Any .suitable concentration of target IgG protein isotypes or fragments thereof can be used in the assays, hi one non-limiting embodiment, each target IgO protein isotype or fragment thereof in the detection reagent h present at betwee about I sg mi to about 1 CI mg nii. in various other embodiments, each target IgG protein isotype or -fragment thereof in the detection reagent is present at between about 10 ng/ml to about 1 rag/mi, about 100 ng/mi to about 750 ug/mi, about 5Θ ng/ml to about 500 pg/ml, about I. pg/ml to about 25Q pg/ml, or at least J 25 pg? ml.

Any suitable detectable label can be used, including: but not limited to a fluorescent label, hapten* coio.rinietrie iabe!, various radioactive labels, enzymes, prosthetic groups, fluorescent markers, luminescent markers, biolumineseent markers, labeled particles such as silicon, .glass, or racial particles; proteiu-protehi binding pairs, protein-antibody binding pairs and the like. Examples of fluc-rescetu labels include _* but are act liwted to, yellow fiuoreseetrt protein (YFP),. green -fluorescence protein {GFP cyan fluorescence protein (CFP), umbelliferone, fluorescein, fluorescein isothioeyanate, rhodamiue, dicklorotriazhiylarain.e fluorescein, cyasines, dansyl chloride, phycocj'anifl, allophycoeyarihi (APC), brilliant: violet dye, brilliant ultraviolet dye, andphywer dirm. Examples of eiolurninesceni markers include, but are -not limited to, lucifera.se (e.g., bacterial, firefly, click beetle and the like), lueiferin, aequorin and the like. Examples of mmie systems having visually detectable signals include, but are not limited to, galactosidases, glueorinidases, phosphatases, peroxidases, cholisesterases and the like. Detectable labels are commercially available from a . ^■ variety of sources. In certain embodiments tile detection label comprises a flitorophore or fluorescent protein. When the detection reagents comprise 2, 3, or more different, detectably labeled target IgG protein isotypes or fragments thereof, each different population of detectably labeled targe t IgG protein isotypes or fragments thereof may have the same or a

distinguishable label, depending ^' on the intended detection assay.

in a further embodiment, the detection reagent further comprises a detectable cell viability market, and the methods further comprise measuring cell viability and/or ceil manber in each biological sample; An suitable cell viabilit marker can be used. A cell viability dye can allow for the detection non-viable cells in a sample. For example the eell viability dye ca permanently label dead cells allowing them to be excluded from analysis even- when the cell preparation is being analyzed by flow cytometry for intracellular targets (for example Fixable Viability Dye eFloiirS ¹ , Propsdium iodide (PI) is a membrane rmpermeant dye that is generally excluded from viable ceils), A cell viability dye can also label live cells. For example, & non-fluorescent compound freely eaters live cells and intracellular esterases convert it to s .fluorescent dye, hi. such an example, the dye will not be retained n cells afte fixation or permeabiLmition and therefore, is not useful for hiiraceiltilar staining protocols. In some embodiments, the analysis reagents further comprises, a cell surface bio arker or a marker of apoptosis. Those skilled in the art recognized that ceil surface markers are proteins expressed on the surface of cells and can. often conveniently serve as markers of specific cell types. For example, T cell and B cell surface markers identif their lineage and stage in the differentiation process.

The incubating occurs for a time and under conditions to promote even mi xing of the detectably labeled target IgG proteins or fragments thereof with, the IgG antibodies thereof to produce IgG antibody -target IgG protein mixtures in each well of the plurality of wells. Any suitable conditions to romote such even mixing may be used, and it is well within the level of those of skill ike art ^' to determine such appropriate conditions as temperature, imtmdity levels, length, of incubation, appiicaiioti of stirring or other mixing forces,, medium to be used, etc.

The method comprises incubating the IgG antibody-target IgG protein mixture in each well of die plurality of wells with one or more IgG isotype-specife populations of capture reagents, wherein each Ig f isotype-speciftc population of capture reagents comprises binding «io.ieaii.es that selectively bind to a different specific IgG protein isotype. Each population of capture reagent is specific for a different specific IgG protein isotype, and thus can be used to segregate the IgG antibody-target IgG- protein mixture based on tie IgG isotype. Any suitable binding molecules can be used that selectively bind to specific IgG protein isotype. In various non-limiting embodiments, the binding .molecules -comprise antil'todies, affimers aptamers, Fc receptors, or other pi'Oteis/sugair/iipid or combination molecules-, in one specific .embodiment, the binding molecules comprise antibodies that selectively bind to IgG protein isotype- Such IgG isotype selective antibodies are commercially available from anumber of vendors, incfudin BD Biosciences^ Sigma Chemical Company, Millipore, and ThermoFishet Scientific.

^' The binding molecules i each IgG. isotype-specifie- opniation of capture reagents are bound to a surface. An suitable surface can be used, including but not limited, to glass, cellulose, poly aery ia tde, nylon, -polystyrene, polyvinyl chloride, polypropylene supports, magnetic or paramagnetic beads, agarose beads, and Ftlnation media such as NHS-activated Sepharose or C Br-aeti vated Sepharose. In. one specific embodiment, the binding molecules in each IgG isotype-specifie population of capture reagents are bound to a bead, such as a magne tic or paramagnetic bead, A magnetic or paramagnetic capture bead is ty pically about I mm in diameter o less _* an is sufficiently small enough In order to prevent sedimentation or clogging. Suitable beads are known, to those of skill in art and can be obtained from different sources (e.g., Bynabeads y-0»e ^'* from lavitroge.u Dyn.al, Morway -or Estapore ftom Merck,. France). Beads can be pre-coupled or coated with binding molecules for passive of active coupling of antibodies or antigens, Irs other embodiments, the capture bead can be an agarose bead. Typically agarose beads are about 20pm to .ISOum. in diameter, in another specific embodiment, the binding molecules in each Ig isotype-specifie population of capture reagents are present in a printed array in the wells of a micro-tiler plate.

Any suitable density o capture reagents can be used in the assay s. In one non* limftnig -embodiment, _, each population of capture reagents are present at a density of bet ween about 0.01 nitllion to -about 1 0 million capture reagents per milliliter. Io various further embodiments, each population of -capture reagents ate present at a density of between about 0,1 million to about 30 million, between about ^' 0.25 million to .about .25 million, between about 0,5 million to about 10 million capture, or between, about 0,75 million to about 5 S .million capture reagents per milliliter.

The incubating is carried out for a rime and under conditions to promote binding of the one or more detectably labeled target IgG proteins or fragments thereof and the IgG antibodies to the IgG Lsotype-speciik population of capture reagents, to produce IgG isotype- specific binding complexes. Any suitable conditions to promote such even mixing may be

$0 used, and it is well within the level : of those o skill, i the art to determine such, appropriate conditions as temperature, humidity levels, length of incubation, application of stirring or other mixing forces, medium to be used* etc.

Signal (i.e.: from the detectably labeled target IgG protein isotypes. or fragments thereof) is detected from the IgG isotype-speciilG binding complexes to determine the

15 concentration, of one or more IgG antibody isotypes present in the biological sample. As this is a competition assay, the -amount of an IgG antibody isotype present in. the biological sample is Inversel proportional to the detected signal ftora the relevant IgG isotype-speeifie binding complex _* Any suitable technique- for detecting signal fr m, the IgG isotype-speeifie binding complexes can be used ^' depending on the detectable label employed, including but

20 not limited to enzyttie- linked immunosorbent assays (EL1SA), flow cytometry, plate reader, Meso Scale Discovery platform, and fluorescent microscopy, In One specific embodiment, the detection involves flow cytometry, by suspending IgG isotype-speei.ffc binding complexes In a stream: of fluid and passing them by an electronic detection apparatus, allowing simultaneous multi-parametric analysis of the physical and chemical characteristics

25 of up to tens of thousands of complexes per second.

In one embodiment, the methods further comprise gerieratirig a standard curve for each IgG protein isotype, wherein the concentration of the one or more IgG antibody Isotypes isi each, biological sample is measured by reference to the standard curve for each IgG protein isotype. In one such embodiment, the method further comprises

30 (d) incubating serial, dilutions of a control sample, wherein each dilution of the serial dilutions f the control sample i present in a separate well of a microriter plate, with the detection reagents to generate control mixtures, wherein the control sample comprises one or more different unlabeled IgG protein isotypes, or fragments thereof, that correspond t the one or more ditlerent, detectably labeled target IgG protein, isotypes or fragments thereof time and under conditions to promote binding of the deiectably l beled target IgG protein Isotypes, or ftagments thereof to unoccupied sites on (fee IgG isorype-spectfic capture reagent complexes to produce deteciably labeled target IgG protekt-IgG antibody-igG isotype- specific capture reagent complexes; and

(c) detecting signal from the detectahly labeled target IgG- protein on. the

defectab!y labeled target IgG proiein gG atuibody-igG isotype-specific capture reagent complexes to determine the concentration of one or more IgG antibody isotypes, wherein the amount of an IgG antibody isotype protein present in the biological sample is inversely proportional to .the detected signal,

la this aspect, the methods follow a preincubation protocol.

For hybridoma culture, mch as mouse hybridoma culture, the foil competition assay protocol may be preferred. This protocol can handle quantitation of IgG range commonly seen irt. mouse hybridoma culture ( l-50ug/mL),

For B cell cultures _* the preincubation assay protocol may be preferred. This protocol is an adjusted competition protocol For low-level IgG sample, pre-incubation of the capture reagents and the biological sample before the addition of the deieetion eompet on reageiit naay better detect the low level of IgG in the sample This protocol can handle better the quantitation of mouse IgG tango commonly seen, in, for example, monse B ceil culture 01.1 - 2ug/mL).

All emb iments of the first aspect of the invention are suitable for use in the- second aspect of the invention, in one embodiment, the methods further comprise generatin a standard curve for each IgG protein ^' isotype, wherein the concentration of the one or rrtore IgG antibody isotypes in each biological sample is measured by reference to die standard curve for each IgG proteia isotype. In one such embodiment, the method further comprises (d) incubating serial dilutions of a control sample, wherein each dilution of the serial dilutions of die control sample is present in a separate well of a microliter -plate, with one or more IgG isotype-specifie populations of capture reagents, io generate a control mixture, wherein the control sample comprises- one or more different unlabeled IgG protein isotypes, or fragments thereof, that correspond to the one or more different, detectahly labeled target IgG protein isotypes or fragments thereof in the detection reagents, wherein the mcuba ^' ftng is carried out for a time and under conditions to promote binding of tire one or more different unlabeled IgG protein isotypes to trie IgG isotype-specifie capture reagents produce control complexes; (e) incubating the control complexes with the detection reagents, wherein the Incubating is carried out for a time and under conditions to promote bkdmg of one or more detestably labeled IgG ^■ . rotein isotypes or fragments thereof, to unoccupied sites on the IgG isotype-specifie capture reagents; and

(f ) generating a standard curve for each IgG protein isotype by analysis of the signal from the defectably labeled IgG isotype bound to the IgG tsotype-specifie population of capture reagents, wherein the concentration of one or more IgG isotypes in each biological sample is measured by reference £0 the standard curve for each IgG protein isotype.

la this embodiment, the one or more deteciahiy labeled target IgG protein Isotypes, or Segments thereof and the one or more different unlabeled IgG protein isotypes, or fragments thereof compete for binding to the IgG isoiype-specifie population of capture reagents. Tire amount of an IgG antibody isotype present in. the biological sample is inversely proportional to the detected signal from the relevant IgG isatype-speeific- binding complex, and can be interpolated from IgG tsotype-specifie standard .curve and be quantitated by the positive qiiantity above the baseline quantity calculated from a control well with a .zero concentration of unlabeled IgG protein isotype or fragments thereof.

In one embodiment -of the first or second aspects of the. invention, the method ftirther comprises determining the total IgG antibody concentration in each biological sample. Any suitable method for determining the total IgG antibod concentration ca be used, in embodiments where the amount of each IgG isotype present in the biological sample is determined, this embodiment m simply require adding the amount of each individual IgG isotype concentration to arrive at. the total IgG antibody concentration.

in another embodiment of the first or second, aspects of the invention, the methods do not include any wash steps, which removes the labor-intensive handling time and improves the data integrity by decreasing the wash-related readout variation such as the counts of ceils, beads or both.

in a third aspect, the disclosure provides a method for analyzing a pluralit of cell sampies for ^' immunoglobulin gamma (IgG) ^■ antibody production, the method comprising: (a) transferring a p!urali ty of cell samples to an assay plate having; a. pl urality of sample wells,, wherein each sample well contains a cell sample that is an- undiluted cell culture expressing a target IgG antibody and -mixing the pluralit of ceil samples with analysis reagents to generate a plurality of analysis mixtures, wherein tire analysis reagents comprise: (t ) a capture bead, wherein the capture- bead binds to IgG antibody: and. (¾) a first detectioji molecule comprising (A) a control IgG antibody or fragment thereof, and .(B) a first detectable moiety; f b) incubating the phrra!i ty of analysis mixtures- for a time and under conditions to promote binding of the target IgG antibody and the first detection molecule to the capture bead; and (c) determining the target IgG antibody concentration in each analysis mixture of tire piuraiity of analysis .mixtures by flow c tometry analysis. In some embodiments, the mixing of the analysis reagents with the plurality of samples comprises adding the analysis reagents to the cell sample in the wells, in other embodiments, tiie mixing comprises simultaneously mixing the piuraiity of cell samples and ail of analysis reagents, wherein the first detection molecule competes with the target IgG antibody for binding to the capture bead; and wherein the .amount of the first detection molecule bound to the capture bead i each analysis mixture provides a measure Of the target IgG antibody concentration i a given analysis mixture. In yet another embodiment, the method comprises- mixing comprises stepwise addition of the capture beads and the first detection molecule, wherein the stepwise addition comprises; first mi ing- the piuraiity -of cell- samples with the capture heads for -a time and under conditions to promote binding of the target IgG antibody to the capture heads to generate a plurality of first mixtures, and. then adding the first detection molecules to the plurality of first mixtures for a time and under conditions to promote binding of the first detection molecules to the capture beads to generate the plurality of analysis mixtures; ^' wherein -the amount of the fir st detect ion -molecule bound, to the capture bead m each analysis mixt re provides a- measure of the target IgG antibody concentration in a gi ven analysis mixture.

fa ce tain embodiments, the ceil culture is propagated from a single clone. In other embodiments, the cei l population is undefined. Typically, a gene of interest, is introduced into a population of candidate producer cells. Chromosomal integration into host

-chromosomes is a rare event, thus stably-traasfeeted ceils usually have to be selected, and cultured in various ways. For example, for the- selection of stably-transfected cells, a selection marker is co-expressed with the gene of interest. A variety of systems for selecting transfeeted cell exists, including resistance to antibiotics such as neomycin

phosphotransferase, conferring resistance to CM IB, dih drofolate reductase (DHFR), or ghrtamme synthetase. Such systems are well known to those of skill in. arts. After gene transfer, ceils are cultivated- in medium containing the selective agent. Only those cells which have integrated the plasmid survi ve, containing the drug resistant gene. The population of cells integrated wi th die gene of interest are diluted and distributed in wells of a multiwei! "nitcrotiter" plate so that only one cell is deposited in each well. The methods for .doing this are well described in the art and know to a person, o skill in the art. One cell per we ^' ll is practically a difficult goal to achieve; although, most wells contain one celt, there are many wells which have zero cells, and many wells which contain multiple ceils, la general it Is necessary to screen hundreds of thousands of wells to find a small number of eel! lines that secre te high levels Of protein.

As used in this third aspect, the term "capture bead" refers to any molecule that is capable of providing a support for binding to an IgG molecule or protein of interest. In certain enAoditnents, the capture bead is covalentiy linked with a molecul that specifically binds to an IgG molecule or protein of interest. For example, Protein G and Protein A selectively bind antibodies through the Fab and Fc regions, proiein G or Protein A or other hlimunog bifiin-bi ding ^■' bacterial proteins such as Protein .A/G-attd Protein L can be used to blnd detect immunoglobuUns. In other ^' embodiments, the -capture bead can be covaientry linked with an.- antibody that specifically recognizes an IgG- antibody or a molecule: that is .specifically bound by a target antibody. In some embodiments, the capture bead is a

magnetic bead or an agarose bead, A magnetic or paramagnetic capture bead is typically about 1 mm i diameter or less, and is sufficiently small enough in orde to prevent

sedimentation or clogging. Suitable microbeads are known t those of skill in art: and can be obtained from different sources (e.g.., Dynabeads My-One from mvitrogen ynaJ, ^' Norway- or Estapore from Merck, France}. As noted above, beads can be pre-eonp!ed (with a specific afiimty reagent snch as Protein 0} or coated with different molecules for passive or active coupling of antibodies Or antigens, la other embodiments, the capture bead can fee an agarose bead. Typically agarose beads are about 35 ⁽ )g to 20μ»ι in diameter.

As used in. this third aspect, the term "detection molecule" refers to any molecule that allows for the detection of a target IgG molecule or protein of interest, in certain

-embodiments the detection molecule comprises a detectable moiet such as a fiuorophore or fluorescent protein, A detectable moiety, can be used to label the detection molecule, A detectable moiety can include, for example _* a -fluorescent moiety, hapten, eolorimetric moiety, various radioactive moieties, enzymes, prosthetic- groups, fluorescent markers, luminescent markers, bioInrranesCent markers, metal particles, protein-protein binding pairs, proteia- sfttibod.y binding pair and the like. Examples of fluorescent moieties include, but are not limited, to, yellow fluorescent protein (YIP), green, fluorescence protei (GFP), cyan fluorescence protein (€FP), umbelliferone, fluorescein, fluorescein isothiocvanate,

^■ riiodatnine, dichloroiria-iinylanjme fluorescein, cyaaines, dansyl. chloride, phyeocyanio, ^• phyecerythrin. -Examples of hiolummeseent markers include, but are not limited to, lueifease (e.g., bacterial, . firefly, ^' eiicjk beetle and the like}, luciferin, aequorin and the ike; Examples of enayme systems having visually detectable signals include, but ate not limited to, gal etosidases, glueoriuidases, phosphatases, peroxidases, eholinesterases and the like. Detectable moieties are commercially available from a variety of sources.

hi certain embodiments, the assay plate contains lyophitized analysis reagents.

Lyopliilisation is the creation of a stable preparation of a substattee by rapid freezing and dehy ration of the frozen product raider high vacuum. A iyophilize bio logical material should be both, intact and active, and also has the advantages of rapid dissolution .and ^' ideally suited to laboratory process automation, as well as a. long shelf-life at ambient temperature which is desirable for warehousing, transport and en d-user storage of the pr oduct .

In a f urth aspect, the disclosure provides a method tor analysing a pluralit of eeU samples for imraifnoglobul iu garoraa (IgG) ti body production, the method comprising: (a) transferring a pluralit of cell samples to an assay pl ate having a plurali ty of sample wells, wherein each sampl well contains a cell sample that is art undiluted ceil, culture expressin a target IgG antibody and mixing the plurality of cell samples w th analysis reagents to

.generate a plurality of analysis mixtures, wherein trie-analysis reagents comprise: (i) a capture bead, wherein the capture bead binds to IgG antibody; and (ii) a first detection molecule com risi g a first detectable moiety; (b) incubating the plurality of analysis mixtures for a time and under conditions to promote binding of the target IgG antibody and the first;

detection molecule to the capture bead; and (c) determining the target IgG antibody concentration in each analysis mixture of the plurality of analysis mixtures by flow cytometry analysis. In certain embodiments, the first -detection molecule lacks insnunogldbu!in light chains and is capable of binding to the capture bead. In some erabodinients, the further comprises contacting the plurality of analysis mixtures with a second detection molecule for a time and under conditions to promote binding of the second detection molecule to the target IgG antibody hound to the capture bead; wherein the second detection molecule comprises a deteetab!y labeled antt-lgG light chain antibody that is optically distinguishable from the first detection molecule; and. wherein the amount of the second detec tion molecule bound to the target IgG antibod in each analysis mixture provides a measure of intact target IgG antibody ^■ concentration, in a given analysis mixture. In. certain embodiments, the plurality Of/analysis mixtures are centrifuged and s bjected- to a wash step before the labeled anti-light chain antibody is added.

In some embodiments, the analysis reagents further comprises one or more of a cell viability dye, a cell surface blotuarker, or a marker of apoptosis, A cell viability dye can allow for the detection .non-viable cells in a sample. For example . ^' the- eel! viability dye can permanently label dead cells allowing them to he excluded, from analysis evert when, the cell preparation is being analyzed by flow cytometry for intracellular targets (for exam le Ftxable Viability Dye eFtourt Propidkra iodide (PI) is a membrane i petffieaat dye feat is generally excluded from viable eelis). A ceil viability dye cafe also label live cells. For example, a non-fluorescent compoun freely enters live ceils and intracelliilar esterases convert it to a fluorescent dye. In such aft example, die dye will ftoi be retained in ceils afte fixation or permeabilization and therefore, is not useful for intracellular staining protocols, in some embodiments, the analysis reagents forther comprises a cell surface biouiarker or a marker of apoptosis. Those skilled in the art recognized that eeii surface markers are proteins expressed on the surface of cells and can often conveniently serve as markers of specific cell types. For example, T ceil and B cell surface markets Identify their lineage and stage in the ^■ differentiation process, la certain e bodiineots, the method further comprises deterniinia one or aiore of; a number of cells m each analysis mixture; a percentage of viable cells in each analy sis mixture; a concentration, of target IgG antibody per cell in each analysis mixture-; and/or a

concentration of target IgG antibody per viable cell in each analysis mixture, is some embodiments, method can involve analysis software that plots concentration curves from

.known, user defined standards and uses those plo ts to deteranne the concentration, of the secreted protein, la other embodiments, the number of producer cells present: in the sample is deimamed. The software automatically determines ike ratio of secreted protein to cell number, calculates the secreted protein concentration- on a per ceil basis, and. tden&fies the wells which have the highest secreted protein per ceil values. f the high throughput So cytometry system is. used in conjunction with a cell sorter, the software also controls- the system to sort individual cells from high secretor wells to ^' further purify- a desired cell line.

In certain, embodiments;, the methods of the disclosed herei rely on flow cytometry analysis. In some embodiments the sample for flow cytometry is undiluted. In other

examples, the sample is ttnditoted and does not undergo a wash step. In certain embodiments; the sample ears be washed before analyzed with a glow cytometer. Flow cytometry can be employed in ceil counting, cell sorting,, biomarker detection and protein engineering, by SKspeiidiag cells in a stream of fluid and passing them by an electronic detection: apparatus.

la. a fourth aspect, the in.veatioa provides kits comprising:

(a) a defection reagent, comprising a defined ratio of two or more different, detectably labeled target IgG protein isotypes _y or antigenic fragments thereof j and (b) two or mors populations of capture reagents, wherein each population of capture reagents comprises binding .molecules that selectively brad to a different IgG antibody isotype, wherein the binding molecules in each _. population of capture reagents are bound to a surface,

The kits of this aspect can be used, for example, to carry out ike methods described herein. All embodiments of the detection reagents and capture reagents of the first and second aspects can be used in kits of this aspect The detection reagents comprise two or more different, deteetably labeled, target IgG protein isotypes, or fragments thereof that retain the ability to bind to the eorresporKbng IgG antibody isotype. In various embodiments, the detection reagents .comprise. 3, ,.5, or m re deteetabl labeled target IgG protein isotypes, or .fragments thereof. Each target I G- protein isotype, or fragme t thereof lias the ability to bin to a specific IgG- antibody isotype. The detection reagent -comprises a defined rati of 2, 3, 4 r more different, deteetably labeled target IgG protein isotypes of -fragments (hereof. This embodiment permits more rapid quantificatio of the concentration of 2, 3, , or more IgG antibod isotypes in a biological sample. Any defined ratio of the deteetably labeled target IgG protein isotypes or fragments thereof may be used, so long as the ratio is known. In one non-limiting embodiment, each different, deteetably labeled target IgG protein isotype or fragment thereof is present in about the same concentration, In another non-limiting embodiment, each deteetably labeled target IgG protein isotype or f agment thereof Is present In about the same amount (t.e.. about 1: 1 :1 when there are three different, deteetabl labeled target IgG protein isotypes or fragments thereof). Any .suitable concentration of target IgG protein isotypes o fragments thereof can be present in the detection reagent. In one fton- limiting embodiment, each target IgG protein isotype or fragment thereof hi the detection reagent is present at between about 1 ng 'ml to about 10 mg ml In various other

embodiments, each target IgG protein isotype or fragment thereof In the detection reagent is present at betwee about .36 ng/ftr! to about I mg/ml, about 100 ng ml to about .750 g ml, about -500 ng ml to about 500 pg/niL abou 1 ug/ral to about 2:50 ug/uil, or at least 125 pg/ni!. An suitable detectable label can be used, including ^' but not limited to a fluorescent label,, hapten, colorimeirie label, various radioactive labels, e z mes, prosthetic groups,, fluorescent markers, luminescent markers, bioiuminescent markers, metal particles, protein-protein binding pairs, protein-antibody binding pairs and the like. Examples of fluorescent labels include, but are not limited to, yellow fluorescent protein (YFP), green fluorescence protein (GPP), cyan fluorescence protein (CPP), itmbclliferone, fluorescein, fluorescein,

tsothiocyanate, rhoda ine, dichlorotriadrryiamine fluorescein, e anines, dansyl chloride. phycocyaian phycoefj-'tera. Exam les of bioluminesceftt markers include, but are not limited to, lueifcse (e.g., bacterial, firefly, click beetle and the like), lucsferin, aequorin and the like. Examples of enzyme systems having visually detectable signals include, but are sot limited to, galaotosidases. glacoiisidases, phosphatases, peroxidases,, choiinesterases and the like. Detectable labels are commercially available from a variety of sources. In. certain embodiments the detection label comprises a tluorophore or fluorescent protein. Each different population of detcetahiy labeled target IgG protein isoiypes or fragments thereof may have the same or a distitigjjishaWe label, de ending on the intended detection assay.

Each population of .capture reagent is specific for a different specific IgG protein isotype nd thus can be used to segregate fhe IgG antibody-target IgG protein mixture based on the IgG isotype. Any suitable binding molecules ean. be used that selectively bind to a specific igCi protein, isotype. In various nott- ^' Umitihg embodiments, the binding molecule comprise antibodies, affimers aptamers, Fe receptors, or other protein/sugar/Hpid or ^■ combination molecules. In one specific embodiment the binding molecules comprise antibodies that selectively bind to an IgG protein isotype.

The binding molecnles In each IgG isotype-speeific population of capture reagents axe bound to s surface. Any suitable surface can be used, including bat not limited to glass, cellulose, po!yaery lamide, nylon, polystyrene, -polyvinyl chloride, polypropylene supports _* magnetic or paramagnetic beads, agarose beads, and filtration media such as NHS-aeiivated Sephaxose or CNBr-activ&ted SepharOse. In one specific embodiment, the binding molecules in each IgG isotype-speeific populatio of capture reagents are hound to a bead., such as a magnetic or paramagnetic bead. A magnetic or paramagnetic capture bead is typically about 1. mm in diameter o less, and is sufficiently small enough in order t prevent sedimentation or clogging. Suitable beads are known to those of skill in art. and can be obtained from different sources (e.g., Dynabeads My-0he ^1M from Invitrogen JDynal _* Norway or Estapore from Merck, France). Beads can be pre-eohpled or coated with, binding molecules for passive or acti ve coupling- f antibodies or antigens. In other ^■ embodiments, the capture bead can be mi agarose bead. Typically agarose beads are about 350pm to 20pm in diameter. In another specific embodiment, the binding molecules in each IgG isotype-speeific population of capture reagents are present in a printed array in. the -wells of a micro-titer plate.

Any suitable density of capture .reagents can be present in the kits, in one non- limiting embodiment, each population of capture reagents are present at a density of between about.0.01 million to about 1.00 million capture reagents per milliliter. In various further embodiments, each -population of capture reagents are present: at a density of between about 0.1 million to about SO m i between about 0.25 million to about 25 million, between about 0.5 million to- about 10 million -capture, or Between about 0.75 minimi to about 5

-million -capture reagents per milliliter. in one emi odira^ni, the number of different, detectafa-!y labeled target IgG protein isotypes, or antigenic fragments (hereof is die same as the number of capture reagents .

in one specific embodiment, the detection reagent comprises -a defined ratio of 2, 3, ^• or 4 different, deteetabiy la eled target mouse IgG protein isoto es selected, from the roup consisting of gG 1 , JgG¾ lgG2h, and lgG3 -, of antigenic fragments thereof; and the capture reagent comprises 2, 3, or 4 populations of capture ..reagents, wherein each population of capture reagents -comprises Binding molecules thai selecti vely bind to a different mouse IgG antibody isotype selected from the group consisting of IgG I, igG2a, IgG2b _> and igG3.

hi another specific embodiment, die detection reagent, comprises a defined ratio of 2, 3, of 4 different, deteetably labeled target human IgG protein isotypes selected from the .group consisting of gGl , lg02, igG3, and IgG4, or antigenic- fragments thereof; and the capture reagent -comprises % 3, or 4 papulations of capture reagents, wherein each .population of capture reagents comprises binding molecules that selectively bind to a different human IgG antibody isotype -selected from the grou consisting of IgGl, lgG2, IgG3, and . G4.

la a thither specific e-mBodiment, the detection reagent comprises & defined ratio of 2, 3, or 4 different, deteetably labeled target rat IgG protein isotypes selected from the grou consisting of IgG i, IgG2a, IgG2b, %G2c or fragments thereof; an the capture reagent comprises ^' 2, 3, or 4 populations of capture reagents, wherein each population of capture reagents comprises binding molecules that, selectively bind to a different rat IgG- antibody isotype selected from the group consisting of IgGl. IgG2a, IgG2b, IgG 2c.

In various further specific embodiments;, (A) the detection reagent comprises a defined .ratio of:

(ϊ) 2 different, deteetably labeled, target .goat, pig, or bovine IgG protein isotypes selected from the grou consisting of IgG l, IgG2 or fiagmenis thereof

(ii) 2 or 3 different, deteetabiy labeled, target horse IgG protein isotypes selected from the group consisting of.lgGa, igGb, IgGi - o fragments thereof; or

Ciii) 2, 3. or 4 different, deteetably labeled target monkey IgG protein isotypes ^■ selected from the .group consisting of IgGl, IgG2, igG3, lgG4 or fragments thereof; and

(8) the .capture reagent comprises (ί) 2 populations of capture reagents, wherein each population of eapt u re reagents comprises binding molecules that -selectively hind to a <&ffere»t target goat, fig, or bovine .igG protein isotype selected from the group consisting of IgGl , igG2 or fragments thereof;

(ii) 2 or 3 populations of capture reagents, wherein each population of capture reagents comprises binding molecules that selectively bind to a different horse IgG protein isotype selecied from the grou ^' consisting of IgGa, IgG ^' b, IgGt or fragments thereof; or

(Hi) 2, 3, or 4 populations of capture reagents, wherein each po ulati n of capture reagents -comprises binding molecules that selectively hind to a different monkey. IgG protein isotype selected fern the group consisting of IgG 1, IgG2, ig 3, Ig04 or fragments thereof. I» these embodiments, the capture reagents -comprise- binding rnoleeuks thai bind to the species of IgG protein isoty es esen in the detection reagents,

M another embodiment the kits further comprise a control sample comprising a defined, ra tio of two or more (2, 3, or more) different unlabeled IgG prote in isotypes, or antigenic fragments thereof, that correspond to the two o more different, detectabl labeled target IgG protein isotypes, or antigenic fragments tfeereoftii the detection reagents. All embodiments of the control as disclosed in. the first and second aspects can be used in the kits of this aspect.

The kits may further comprise any addi tional components as appropriate for an intended use. in one embodiment-, the kits further comprise a detectable cell viability .marker.

In a fifth, aspect kits are provided, comprising:

(a) an assay plate, and

(b) analysis reagents, wherein the analysis reagents comprise;

(i) a capture bead, wherein the capture bead binds to IgG antibody; and

(ii) a first detection niolec tile comprising a first detectable moiety.

All embodiments disclosed in. the third aspect can be used .in this fifth aspect hi some -embodiments, the first detection molecule comprises a control. IgG antibody o fragment thereof. ^' In other embodiments, the kit further comprises a detectably labeled anti-light chain antibody that is optically distinguishable from the first detection molecule.-: The kit can als farther comprise one or more of a cell liability dye, a cell sarfaee biomarker, or a .marker of apoptosis, in one embodiment, the capture bead is covalentJ linked with Protein G or Protein A. Ϊ» another embodiment, the capture bead is a magnetic bead or an agarose bead, la tertain aspects, the kit comprises an assa plate containing lyophiiize analysts ^' reagents.

Example methods and systems are described tierehi it should be understood that the words "example," ''exemplary " and "Illustrative" are used herein to mean "serving as -as example, instance, or illustration." Any embodiment or feature described herein as being aft "example," being "exemplar or being "illustrative ^' ' ⁴ is not necessarily to be construed as preferred or advantageous over other embodiments or .features. The example embodiments deseribed herein are not meant to be .limiting. It will be readily understood that the aspects of the present disclosure, as generally deseribed herein, and illustrated in the figures, can be arranged, substituted: combined, separated, arid designed in a wide variety of different conjurations, all of which are explicitly contemplated herein.

2) Mouse IgG Standard Mixture Prepa ation: Prepare a vial of pre-mtxed mouse IgG standard stock: h¾o a same vial, add and mix unlabeled mouse Ig I, JEg62a _* igG2b and IgG.3 proteins. Each isotype may have, for example, 20 )ug mL ecmcenixation in the mixture. A serial titration, of the pre-tmxed mouse IgG may be perfortued with the fresh ceil culture media (the sam media being used in the culture plate or flask where the biological samples come from). These serially diluted standards may b used later in the assa setu to generate standard curves ( 1 standard curve for each mouse IgG isotype),

3} Capture Rea^ut Mix a .same tube/reservoir, add and mi mouse IgG ! capture- head, mouse lgG2a capture head, mouse lgG2b capture bead, and mouse IgG 3 capture beads into enough volume of 0 J% BSA is PBS, The final densit of mouse IgG capture bead is I million, per IHL for each isotype .(IgG I, ¾G2a, IgG2b, and 1§G3) capture bead.

A user may now follow, for example, either the full competition protocol or the preincubation protocol to run the mous IgG qmt)iitatioft%oiypiag assay,

Assay Setup for Fail Competition Protocol:

This assay xaay use a no-wash workflow and provide results in. terms of IgG

concentration (e,g„ pg/m ^' L It involves preparing a serial dilution of a refereii.ee protein mixture to generate 4 standard curves that are used to determine the concentration for 4 mouse IgG isotypes. The FITC detection signal on capture beads lias an. inverse ^' relationship, with mouse IgG concentration 4 capture beads may be used in the assay with each bead- specific for a. single mouse IgG isotype. Total ^' mouse IgG concentration may be calculated in each well by ForeCyl' ^M (hitellieyt) software by adding up 4 mouse IgG' isotype

concentrations. Ceil number and cefl viability may also be analyzed if samples have ceil in addition to mouse IgG supernatant

In one exemplary protocol:

1 , Add Detection Reagent Mixture (Mouse FI C-igG and FL4 Membrane Integrity Dye), 5 pL/ ell of a microliter late;-

2, Add IgG Sa p!s/lgG Standard, 20 jit/weli; Quick Spin (S9i¾ 5 seconds). Mix (2,000 rpn 20 seconds).

3, Add Prepared 4-plex Capture Beads, 5 uL welS; Quick Spin ,(50%, 5 seconds). Mix (2 _* 000 rpni _* 20 seconds), ET 60 rotas.

The plate is now ready for signal detection, such as by sampling on an iQae' ^M Sereener flow cytometry platform,

re-iBcaba^^

Assay . Setup, im Fre-ί ne¾jb¾ti on Protocol

This assay may use a no-wash workflow and provides results in terms -of IgG concentration- (e.g., pg/niL). It may involve- preparing a serial dilution of a reference protein mixture to generate standard curves that are used ^' --determine the concentration for 4 mouse Ig isotypes. The FJTC detection signal on. capture beads has an inverse relationship with mouse IgG concentration. 4 capture beads ma be used in the assay with each head

IS specific for it single oase IgG tsotype. Total mouse IgG concentration may be be calculated: eacSi well,, for e ample by ForeCyt ^1M software, by adding up 4 mouse IgG isotype

concentrations. Ceil number and cell viabilit wa also be analy sed if samples ha*e ceils in addition, to mouse IgG supernatant.

In one e empkr> ^! protocol :

1. Add Prepared 4-plex Capture Beads, 5 uL ell;

2. Add IgG Sample/IgG Standard, 20 L/well; Quick Spin (50Qg, 5 seconds). Mix (¾000 rpn\ 20 seconds).. RT 30mins.

3. Add Detection Reagent Mixture (Mouse FIT -IgG and FL4 Membrane Integrity

Dye), 5 pL/well; Quick Spin .(50%, 5 seconds). Mix (2,000 rpm, 20 seconds). RT 60 mins without light.

The p ate is now ready for signal detection, such, as by sampling on an iQue' ^:

Screertef flow cytometry platform.

Multiplexed 4 capture beads with, one capture bead type to specifically capture a specific mouse IgG tsotype will. -solve the inconsistent quantitation in traditional singleplex capture beads coated with general anti-ruousc IgCi antibody. 4 different mouse Ig isotype nave slight different protein structure w ic caused slight different binding affinit to th general anti-mouse- IgG coated oa beads, in a mouse hyoridoma or B ceil -culture screening late, different wells may have one. of the 4 isotypes. If singkp!ex -anti-mouse IgG capture beads were used to capture mouse IgG in each well, of the plate, the same amount of mouse IgG but with different isotype in different welts may general different binding signal on beads, due to IgG isoiype-dependent binding affinity difference, and. the quantitation based on standard curve with a purified mouse IgG as standard (a natural mixture of 4 isotypes) will extrapolate different mouse IgG quantity- ¾ts will introduce imprecise quantity. A

'multiplexed assay with 4 different -capture beads (one for each isotype) will solve this issue. For example, if A.1 well in die microliter plate ^' has mouse IgG i, it will only be captured o mouse IgG 1 capture beads in the mixed 4 capture beads. The fluorescent signal will be extrapolated to mouse IgG I quantity by using £he mouse IgG ! standard curve, if A2 well has mouse %G2a, it will only be captiired on mouse lgG2a capture beads in the mixed 4 capture beads, and the fluorescent signal on. mouse IgG2a capture beads will: be extrapolated to mouse IgG2a quantity by using, the mouse igG2a standard curve.

Here we have established a multiplexed -competition assay format with 4 capture beads to capture 4 different isotypes, and wi th 4 FITC-mouse IgG isotypes in the reaction (see Figure 1). When the unknown isotype sample with or without cells is added into the reaction at the correct sequence, unknow and unlabeled mouse IgG isotype will compete one of the 4 FH ^' C -mouse IgG isotype to only one of the 4 capture beads. It seems there is no any assay like this in nieasuruig mouse Ig isotype and quantity. The assay does not need wash and dilution and _. can measure Blouse IgG quaniity/isotype from liyhridoma supernatant which normally lias mouse IgG concentration 1-50 ug/niL,

The assays may also allow users to measure the cell count and cell viability in the same multiplex assay, A user can either use the sample supernatant or the sample with cells inside. For the latter, the cell count and ceil viability, and as well as the multiplexed beads, will be measured simultaneously in th high throughput flow cytometry,

The assays can be expanded/modified to measure the same endpoints (IgG isotype,

I G quantity for each isotype, celi number and cell health.) for different species in. addition to mouse species b -modifying the isotype-specifie capture antibody on the capture heads and the detection, reagents and -standard proteins from mouse species to othe species such as ^' uman or rat sic.

Figure 2 shows an exemplary setup of standard wells in. the mierohter plate. Here an exetnplary design of the IgG Standard wells in 96-well Biieroliter plate is shown. Each specific well has 4 isotype proteins with the same amount of each .mouse IgG isotype (mouse IgG I _* 2a, 2b, and.3). Top concentration wells (duplicate wells) on the right (AI2 and B12) have the highest concentration S¾g/n¾L for each isotype. 1 :2 serial titration was applied from the right to the left. For example, Well A i 1 and B 1 1 will have 25ug/n¾L for each isotype. Well .4.1 and 81 are used as negative control with fresh blank media but without any moose IgG protein standard. A. user has the flexibilit to determine the new top concentration or dilution- factor or how many dilution steps. For example, a user can use 1.60ug/niL per isotype for the to concentration, and use 1 :3 serial titration., and use 6 dilution steps rather titan 3 1 dilution, steps as shown in the standard design in Figure 2. A user can use the same standard design on o ther plate types such as 384-weli plate. For the same plate wi thout standards, fo e am le^ row OH in Figured, a user can tun the unknown mouse IgG samples with or without ceils.

In one exemplary technique, cells and beads can be detected via separation in.2D scatter plots, based on size -.(Forward scatter, FSC) and/or granularity (Side scatter, SSC), Singlet beads but not .doublet beads can be gated by using a 2D plot (FSC-Height vs, FSC- Area). Singlet heads will he the right population at the 45 degrees in 2D plot (FSC-Hetght vs. FSC-Area). Doublet or aggregates will, be on the left. Singlet heads can be further separated into 4 capture bead population i n a 2D plot (ted fluorescence channel RL .1 -Height vs . FSC-

The top concentration tested in tli standard carve was .100 itgfttiL per isotypc. Higher than 100 ujg/mL was not tested in the assay. Standards were diluted in DMEM culture media with 10% fetal bovine serum, t9-point 1 :2 serial titration was run in the test.

For curve fitting: PoreCyt ^m software (Inteiiieyt) with: a. PL fitting method with t/Y square for fit weight was used, . ^' which automatically detected the linear range and provided the linear range. The linear range is that range of input or output values for which an elect onic amplifier produced output signal that was a direct, linear function of the input signal,. That is, the output can be represented by the equation; Output - Input * Gain. The linear range provides a precise/sensitive quantitation when the signal of unknown samples fails into this range. The detection range used iiieaas the range between the low-cud detection limit

(minimal concentration with the signal that is 3 * standard deviation of the -blank wi th 0 g m ^' L IgG, and the high-end detection limit (maximal concentration with the signal th t is 3* standard deviation of the saturation signal determined by Fe.re€yt ^!M software). If the standard curve does not reach saturation, die highest tested concentration (here is 100 iig/niL) is used.

For samples from hyhridoma culture, full competition protocol may be recommended; for samples from .mouse B ceil culture, pr >incubatjon protocol, may be recommended.

Example 2

Be-low are descri bed exemplary protocols of die assays of certain aspects, to identify cells that produce high levels of a secreted protein or IgG antibody.

1. Candidate producer cells are diluted and distributed in wells of a -multiwell ''microttier" plate so that Only one cell is deposited in each well. he methods for doing this are well described in the art. One cell per well is practically a difSculi goal to achieve; although tnost welts contain o e cell, there are .many wells which, have zero cells, and many wells which contain multiple cells,, to. general it is necessary to screen himdreds of thousands of wells to find, a small number of cell lines that secrets high levels of protein.

2. The cells are allowed, t proliferate to increase the oumbers of cells In each well, Because proliferation is occurring through mitosi s, the -daughter cells i each well will he exac copies of the original ceU(s) that was (were) deposited in the well.

3. As the cells proliferate, they produce the protein biologic tie.., IgG antibody) and secrete ri into the c k re supernatant,

4. An undiluted aliquot of each well, containing a representative amount of secreted protein and. producer cells is transferred to a new well in a lyophiliged assay plate. Each well of the iyophih ^' zed assay plate contains lyop.hil.ized reagents that arc used to quantitate the amount of secreted protein presen t .and, simultaneousl can be used to assay the number of producer cells present in the sample; Quantitatio reagents prepared in noa-!yophiiized form from a reagent kit could also be used for the analysis. The lyophilized assay plates or the reagent kit contains can the following items". a. A capture bead - for ex mple, fluorescent microspheres coated with a molecule which binds t a specific site oa the secreted proteia and captures the secreted .proteins onto the surface of the microspheres.

b. Detection molecules which a e labeled with a fluorescent probe- and wfeieh bind to a different region on the secreted proteia which, has beers captured oato the microsphere- surface. The iatensky of the fluorescence associated wi th each

microsphere is then directl correlated to the numbe of secreted, captured protein molecules present in the sample,

5. After an. incubation OSHC, the samples are analyzed by high throughpot flow cytometr , One example of -a high ^' throughput flow Cytometr system i the HyperCyt™ HTFC System in. combinatio with a flow -cytometer which can analyze of thousands of samples ia minutes.

6, The high throughput flow c tometry' detection, system is set up to report the fluorescent ^' intensity of the bead-associated detection molecule, which is used to calculate the secreted proteia concentration from a standard curve, in addition, the number of producer cells present in the sample can. be determined- simultaneously, A proprietary software analysis package .automatically determines the ratio of secreted protein to cell number, and calculates the secreted protein concentration oa a per cell basis. If the high throughput flow cytometr system is used in conjunction with a cell sorter, the software also controls the system to sort individual cells from high secretor wells to further purify a .desired ceil line.

3 ^s * Protocol— IgG Quaut Assity-Stepwise Protocol (exemplary):

I . Vortex, the protein G-coated beads (6-Siim size, 0.5% v/v) . Do J : 15 dilution of beads in 0.1 % bovine serum albumin (BSA) in phosphate buffer saline (PBS). Mix the diluted beads, aad add SuUwe!-l beads ioto each, well of a tfticro-titer assay plate (either 9 -weli plate or 384«weii plate);

2. I each well of the assay p e, add 2 u.L IgG sample (either IgG standard to generate IgG standard curve or suspension CMC) cell eulture/seefeted IgG mixture or just the IgG supernatant from me suspension CHO ceil culture).

3. Briefly spin the assay plate to bring down the sample to tire well bottom (500g x 8

seconds). Mix samples In the plate on a plate shaker (200 ⁽ 1 rpm x 20 seconds).

-4. Incubate the assay plate at room temperature for 30 -minutes. Protect the plate from light. 5. Prepare the combined detection reagent: make 20ugftttL FITC-Fc fr ent (Jackson taaautto esearc Laboratory- lac.) and 20t FL4 membrane integrity dye (i elliCyt Coloration) is 0,1% BSA in PBS in the same tube.

6. Add 5»L combined detection reagent ia each wed of the assay plate.

7. Briefiy spin the assay plate to bring down the sample to the well bottom (50% x 8 ^' seconds . Mix samples in the plate on a plate shaker (2000 ipm x 20 seconds),

:. incubate the assay plate at room temperature for 30.minutes. Protect the plate from light.

9, Acquire die samples from, the assay plate by high throughput flow cytorfteter such as hitelHCyt iQue™ Seteener platform.,

Example 2: 2 ^HiS Protocol— IgG Qiiant Assay-SMniilianeous Protocol;

1. Prepare the combined ^' detection reagent: make 2<h*g/mL FIT -Fe fragment (Jackson JmmunoResearch Laboratory inc.) and 20nM FL4 membrane integrity dye (InteliiCyt Corporation) in Θ J % BSA in PBS in. the same tube,

2, Add 5tiL combined detection reagent in each well of a. raicrotiter assa plate (either 96- wetl plate or 384-weii plate).

3. In each well of the assay plate, add 20uL IgG sample (either IgG stand rd to generate IgG standard curve or suspension CHQ cell cuiture/¾ecreted IgG nuxture or just flic IgG Supernatant from the suspension CHO cell culture).:

4, Briefly spin the assay plate to bring down the sample and the combined detection reagent mixture: to the well bottom (50Qg % 8 seconds). ^' Mix samples ia the plate on a plate shaker (2000 i x. 20 seconds).

5. Vortex the protein G-coated beads (i -Sr«« size, 0.3% \fy). Do 1 :15 dilution of beads in 0, \¾ bovine serum l umin (BSA) in phosphate beffer saline (PBS). Mix the diluted beads, and add Suli ell beads into each well of the assa plate with the sample/detection mixture.

i . Briefiy spin, the assay plate to bring down the liquid to the wed bottom (590g χ 8

seconds). Mix samples in. the plate on a plate shaker (2000 rpni x 20 seconds).

7. Incubate the assay plate at room temperature for 60 minutes. Protect the plate from light 8. Ac uire the samples from the assay plate by high through ut flo cytorftetcr such as ioielljCyt iQie ^{i M} :Screener platform.

3 ^!l! Ft ^* etoc«l« gG Quant & Light m Detection Assay-Siepwise Protocol (exemplary):

S L Vortex the protein Ocoated. beads (6~8um.size _s 0,5% y/v). Do h i 5 dilution of beads in 0,1% bovine serum albumin (BSA) in phosphate buffer salme (PBS). Mix. the dilated beads, and add 5oL well beads into each well of a niieto-titer assay plate (either 6- eii plate or 384-weli plate);

2. I» each well of the assay plate, add 20uL IgG- sample (either igG standard to generate IgG0 standard curve or suspension CEO eel! culture/secreted IgG mixture or just the IgG

Supernatant from the suspension CHO eel! culture).

3. Briefly spin the assay plate to bring down the sample to the well bottom (500g x 8

Seconds}, Mix. samples in the plate on a plate shaker (2000 rpm x 20 seconds)..

4. Incubate the assay plat at room temperature fo 30 miiK!tes. Protect the piste from light,5 5. Prepare the combined detection reagent: make 2(hig niL FITC-Fc fragment (Jackson

ImmunoResearch Laborator Inc.), and iOug rnL PB-F(ab')2 anti-human Ig kappa light chain (ThcrmoFisher), and 20n . PL4 membrane integrity dye (InteiliCyt Corporation) in 0, 1% ^' BSA in. PBS in the same tube.

6. Add 5uL combined detection reagent in each well of the assay piate.

0 7, Briefly spin the assay piate to bring down the sample to the well bottom: (5O0g x.8

seconds). Mix samples in the piate on a plate shaker (2000 r rn s.20 seconds),

8 , Incubate the assay plate at room temperature for 30 minutes, Protect the plate from light.

9. Acquire the samples fro the assay plate by high throughput flow eyiorneter such as

InteiliCyt iQue Screener platform.

S

Example 4: 4* Protocol— IgG Quant and Light Cbaiii Detection Assay-Sinnilfantous Protocol

I , Prepare the combined detection reagent: make 20ug mL FITC-Fe fragment (Jackson

IfflmunoResearch Laborator inc.), and lOng mL PE ⁱ (ah }2 anti-hnman Ig kappa light as chain ^' (ThmttoFishesf), and 20nM FL4 membrane integrity dye (IntelHCyt Coloration) in 0-1% BSA ta PBS in the: same tube.

2. Add 5«L combined detection rea ent in each well of a microti ter assay plate (eit er 96- well plate or 384-wd! plate).

3, In each weii of he assay plate, add 20uL IgG sample (either igG standard to generate IgG standard curve or suspension CH0 cell ilmreAeereted igG im tuce or just the igG supernatant from die suspgnstdn CHO cel culture}.

4. Briefly spin the assay plate to bring down the sample and the combined detection reagent: mixture to the well bottom (500g x: 8 seconds). Mix: samp es in the plate on a plate shaker (2000 rpm x 20 seconds).

5. Vortex the protein G~coated heads (6-8ura size, 0.5% v v.}. Do 1:15 dilution of ^' beads in 0.1% bovine serum albumin (BSA) in phosphate buffer saline (PBS). Mix the diluted beads, and add 5«L w¾li beads into each well of the assay plate with the sample/detection mi ture.

6, Briefly spin the assay plate to bring down the liquid to the well bottom (SOOg x 8

seconds). Mix samples in the plate on a plate shaker (2000 tpm x 20 seconds).

7, ^•' incubate the assay plate at roo temperature for 60 minutes. Protect the plate Horn light,

8. Acquire the sample from the assay plate by hig throughput flow eytometer suc as httelliCyt iQee Screefter platform.