SYMPTOMS IN PIGS

SEQUENCE LISTING

Tins application c ntains a sequence listing in paper formal and in computer readable format, the teachings and content of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

FickS of the Invention

The presen t invention relates to the use of an immunogenic composition comprising a porcine circovirus type 2 (PCV2) antigen for treatment of several clinical manifestations (diseases). Preferably, those clinical manifestations are associated with a PCV2 infection. More particularly, the present invention is concerned with art immunological composition effective for providing an immune response that reduces., or lessens the severity, of the clinical symptoms associated with PCV2 infection. Preferably, the immunological composition comprises a recombinant!)- ^' produced antigen of PCV2. More preferably, the PCV ^' 2 antigen is a recombinantly produced protein encoded by one of the open reading frames (ORFs) in (he PCV2 genome. Still mote preferably, the antigen is PCV2 0R.F2 protein. Most particularly , the present invention is concerned with an immunological composition effective for treatment of clinical s pmtoms associated with PCV2 infections in swine receiving the immunological composition, and wherein the composition comprises the protein expressed by ORF2 of PCV2, Another aspect of the present invention is the use of any of the compositions provided herewith as a medicament, preferably as a veterinary medicament, even more preferably as a vaccine. Moreover, the present invention also relates to the use of any of the compositions described herein, for the preparation of a medicament for reducing or lessening the severity of clinical symptoms associated with PC V2 infection. Preferably, the medicament is for die prevention of a PCV2 infection, even more preferably in swine. A further aspect of She present invention relates to a process for the production of a medicament comprising an immunogenic composition of PCV2 for the treatment of several clinical manifestations.

Description of the Prior Art

Porcine cireovirus type 2 (PCV2) is a small (17 -22 inn in diameter), icosahedral, non-enveloped D A virus, which contains a single-stranded circular genome. PCV2 shares approximately 80% sequence identity with porcine cireovirus type i. (PC VI). However, in contrast with PCVl , which is generally non-virulent, swine infected with PCV2 exhibit a syndrome commonly referred to as Post-weaning Muitisysiemic Wasting Syndrome (PM ^' WS). PMWS is cii.njca.tly characterized by wasting, paleness of the skin, unthriftmess, respiratory distress, diarrhea, icterus, and jaundice. In some affected swine, a combination of all symptoms will be apparent while other affected swine will only have one or two of these symptoms. During necropsy, microscopic and macroscopic lesions also appear on multiple tissues and organs, with lymphoid organs being the most common site for lesions. A strong con-elation has been observed between the amount of PCV2 nucleic acid or antigen and the severity of microscopic lymphoid lesions. Mortality rates for swine infected with PCV2 can approach 80%. in addition to PMWS, PCV2 has been associated with several other infections including pseudorabies, porcine reproductive and respiratory syndrome (P ^' RRS), Glasser's disease, streptococcal meningitis, salmonellosis, postweaning coiibacillosis, dietetic hepatosis, and suppurative bronchopneumonia. However, research thus far has not confirmed whether any of these clinical symptoms are in fact, the direct result of a PCV2 infection. Moreover, a is not yet known whether any of these clinical symptoms can be effectively reduced or cured by an active agent directed against PCV2,

Current approaches to treat. PCV2 infections include DNA-based vaccines, such as those described in U.S. Patent No. 6,703,023. However, such vaccines have been ineffective at conferring protective immunity against. PCV ^' 2 infection or reducing, lessening the severity of, or curing any clinical symptoms associated therewith. Moreover, vaccines described in the prior art were focused solely on tile prevention of PCV2 infections in swine, but did not consider any farther medical use.

Accordingly, what is needed in the art is an immunogenic composition for the treatment, of several eiinieai manifestations. Further, what is needed in the art is an immunological composition which confers protective immunity against PCV2 infection but which can also be used to treat existing ciinical symptoms associated with PC V2 infection.

The present invention overcomes the problems inherent in the prior art and provides a distinct advance in the state of the art. The present invention provides a medicinal use(s) of immunogenic composition^) comprising . PC V2 antigen.

in general no adverse events or injection site reactions were noted for any of the PCV2 antigen immunogenic compositions as used herein. Thus, the immunogenic compositions used herein appear to be safe when administered to young pigs, preferably to pigs not older than 15 weeks of age, more preferably not older titan 6 weeks of age, even more preferably not older than 3 weeks, most preferably not older than 2 weeks. Alternatively, it is preferred that the administration of the immunogenic compositions of the present invention occur within at least 2 and preferably within at least 3 weeks of exposure to virulent PCV. According to a further embodiment, the immunogenic compositions used herein for any medicinal use described herein, is adrmnstered LO pigs of 3 weeks of age or older, preferably of 2 weeks of age or older, most preferably but not oicler than i 5 weeks of age.

Unexpectedly, it was found that the therapeutic use of the immunogenic compositions described below, is effective for lessening the severity of various clinical symptoms in swine, in particular, it was discovered that the therapeutic use of the immunogenic compositions of (he present invention, and specifically compositions comprising PCV2. ORF2 antigen, is effective for reducing or lessening h mphadenopathy. lymphoid depletion and/or multintickated'giant histiocytes in swine infected with PCV2. Moreover, the therapeutic use of an antigenic composition, as provided herewith, and that comprises PC antigen, preferably ORF2 antigen, reduces the overall cireovirus load and its immunosuppressive impact, thereby resulting: in a higher level of genera! disease resistance and a reduced incidence of PCV-2 associated diseases and symptoms.

Thus one aspect of the present invention relates to the use of an immunogenic composition comprising PCV2 antigen, preferably recombinant PCV2 antigen, and more preferably PCV2 ORF2 protein as provided herewith, for the preparation of a medicament for the prevention, lessening and/or reduction of lymphadenopath , lymphoid depletion and/or nmltinucleated giant histiocytes in swine. Preferably, said medicament is effective for the prevention, lessenin and/or reduction of lymphadenopathy, lymphoid depletion and/or multinucieated'giant histiocytes associated with PCV2 infections in swine. Still more preferably, said medicament is effective for the prevention, lessening and/or reduction of lymphadenopathy. lymphoid depletion and/or multinucleated/giant histiocytes associated with PCV2 infections in pigs, when administered to pigs not older than .15 weeks of age. more preferably not older than 6 weeks of age, even more preferably not older than 3 weeks, and most preferably not older than 2 weeks. Alternatively, it is preferred that the administration of the immunogenic compositions of die present invention occur within at least 2 and preferably within at least 3 weeks of exposure to virulent PC V.

Another aspect of the present invention relates to a method for She treatment of iynrphadenopalhy. lymphoid depletion and/or multinucleated giant histiocytes in swine, comprising the administration of an immunogenic composition as provided herewith, to a pig, said immunogenic composition comprisin a PCV2 antigen, preferably a recombinant PCV2 antigen, and raorepreferably PCV2 ORF2 protein. In yet another aspect, the present invention provides a method fo she treatment of lymphadenopath . lymphoid depletion and/or multinucleated/giant histiocytes associated with a PCV2 infection in swine, comprising the administration of an immunogenic composition as provided herewith, to a pig, said immunogenic composition comprising a .PCV2 antigen, preferably a recombinant PCV2 antigen and more preferabiv PCV2 ORF2 protein. Preferably , said treatment results in the lessening, reduction, prevention, and/or cure of the lymphadenopathy, lymphoid depletion and or multimiclealed giant histiocytes in swine receiving said immunogenic composition. According to a farther aspect, said methods for treatment further comprise the administration of said immunogenic composition to pigs not older than .15 weeks of age, more preferably not older than 6 weeks of age, even more preferably not older than 3 weeks, and most preferably not older than 2 weeks. Alternatively, it is preferred that the administration of the immunogenic compositions of the present invention occur within at least 2 and preferably within at least 3 weeks of exposure to virulent PCV.

It was further discovered that the therapeutic use of an immunogenic composition comprising PCV2 antigen, preferabiv a recominant PCV2 antigen, and most prefereably PCV2 ORF2 protein, as provided herewith, can reduce or lessen lymphadenopathy in combination with one or a multiple of the following symptoms in affected swine: (!) interstitial pneumonia with interlobular edema, (2) cutaneous pallor or icterus. (3) mottled atrophic livers, (4) gastric ulcers. (5) nephritis and (6) reproductive disorders, e.g. abortion, stillbirths, mummies, etc.

Thus one aspect of the present invention relates to the use of an immunogenic composition comprising PCV2 antigen, preferably a recombinant PCV2 antigen and more preferably, PCV2 OR.F2 protein as provided herewith, for the preparation of a medicament for the prevention, lessening and/or reduction of lynmhadenopathy in combination with one or a multiple of the following symptoms in pigs: (1) interstitial pneumonia with interlobular edema, (2) cutaneous pallor or icterus, (3) mottled atrophic livers, (4) gastric ulcers, (5) nephritis and (6) reproductive disorders, e.g. abortion, stillbirths, mummies, etc., in pigs. Preferably, said medicament is effective for the prevention, lessening and/or reduction of lyniphadenopatby in combination with one or a multiple of the following symptoms associated with PCV2 infection in pigs: (1 ) interstitial pneumonia with interlobular edema, (2) cutaneous pallor or icterus, (3) mottled atrophic livers, (4) gastric ulcers , (5) nephritis and (6) reproductive disorders, e.g. abortion, stillbirths, mummies, etc. According to a further aspect, said medicament is effective for the prevention, lessening and/or reduction of lymphadenopathy in combination with one or a multiple of the followin symptoms in pigs: (1) interstitial pneumonia with interlobular edema, (2) cutaneous pallor or icterus, (3) mottled atrophic livers, (4) gastric ulcers , (5) nephritis and (6) reproductive disorders, e.g. abortion, stillbirths, mummies, etc., in pigs, when administered to pigs not older than 15 weeks of age. more preferably not older than 6 weeks of age, even more preferably not older than 3 weeks, and most preferably not older than 2 weeks. Alternatively , it is preferred that the administration of the immunogenic compositions of the present invention occur within: at least 2 and preferably within at least 3 weeks of exposure to virulent PCV..

Moreover, the present invention also relates to a methotl for the treatment of iytnphadcnopathy in combination with one or a multiple of the following symptoms in pigs: (I) interstitial pneumonia with interlobular edema, (2) cutaneous pallor or icterus. (3) mottled atrophic livers, (4) gastric ulcers , (5) nephritis and (6) reproductive disorders, e.g. abortion, stillbirths, mummies, etc., said method comprising the administration of an immunogenic composition comprising PCV2 antigen, preferably a recombinant PCV2. antigen, and more preferably PCV2 OR.F2 protein as provided herewith. Preferably, the present invention also relates to a meihod for the treatment of iytnphadenopathy in combination with one or a multiple of the following symptoms associated with PCV2 infection in pigs: (1) interstitial pneumonia with interlobular edema, (2) cutaneous pallor or icterus, (3) mottled atrophic livers. (4) gastric ulcers. (5) nephritis and (6) reproductive disorders, e.g. abortion, stillbirths, mummies, etc., said method comprising the administration of an immunogenic composition comprising PCV2 antigen. prefereaMy recombinant PCV2 antigen and more preferably PCV2 OR.F2 protein, as provided herewith, to a pig. Preferably, said treatment results in the lessening or reduction of the lymphadenopathy, and one or multi le of the following symptoms associated with PCV2 infection in pigs: (1.) interstitial pneumonia with interlobular edema, (2) cutaneous pallor or icterus, (3) mottled atrophic livers. (4) gastric ulcers . (5) nephritis and (6) reproductive disorders, e.g. abortion, stillbirths, mummies, etc. According to a further aspect, said methods for treatment further comprise administration of the immunogenic composition comprising PCV2 antigen, preferably recombinant PCV2 antigen and snore preferably PCV2 O .F2 protein, as provided herein, to pigs not older than 15 weeks of age, more preferably not older than 6 weeks of age. e ven more preferably not older than 3 weeks, and most preferably not older than 2 weeks. Alternatively, it is preferred that tlie administration of the immunogenic compositions o the present invention occur within at least 2 and preferably within at least 3 weeks of exposure to virulent FCV.

It was also unexpectedly found that the therapeutic use of an immunogenic composition comprising PCV antigen, preferably recombinant PCV2 antigen and more preferably PCV2 ORP2 protein as provided herewith, cart also reduce or lessen Pia like lesions, normally known to be associated with Lawsoaia intraeelhdaris injections (Ileitis).

Thus one aspect of the present invention relates to the use of an immunogenic composition comprising PCV2 antigen, preferably recombinant PCV2 antigen and more preferably PCV2 ORF2 protein as provided herewith, for the preparation of a medicament for the prevention, lessening the severity of and/or redaction of Pia like lesions, normally known to be associated with Lawsonia iiitraeelhilaris infections in swine. According (o a further aspect, said medicament is effective for the prevention, lessening of She severity of and/or reduction of Pia like lesions, normally known to be associated with Lawsonia intraceilularis infections, when administered to pigs not older than 1 w eeks of age, more preferably not older than 6 weeks of age. even more preferably not older than 3 weeks, and most preferably not older than 2 weeks. Alternatively, it is preferred that the administration of the immunogenic compositions of the present invention occur within at least 2 and preferably within ai least 3 weeks of exposure to virulent PC V.

Moreover, the present invention also relates to a method for the treatment of Pia like lesions, normally known to be associated with Lawsonia intraceilularis infections, said method comprising the administration of an immunogenic composition comprising PCV2 antigen, preferably recombinant PCV2 antigen and more preferably PCV2 O.RF2 protein as provided herein, to a pig. Preferably, said treatment results in the lessening or reduction of the Pia like lesions, normally known to be associated with Lawsonia intraceilularis infections. According to further aspect, the methods for treatment described above further comprise the administration of the imrminogenic composition comprising PCV2 antigen, preferably recorabiant PCV2 antigen, and more preferably PCV2 GRP2 protein as provided herein, to pigs not older than 1 weeks of age, more preferably not older than 6 weeks of age, even more preferably not older titan 3 weeks, and most preferably not older than 2 weeks. Alternatively,, it is preferred that the administration of the immunogenic compositions of the present mention occur within at least 2 nd preferably within at least 3 weeks of exposure to virulent PCV.

The immunogenic composition

The immunogenic composition as used herein is effective for inducing an immune response against PCV2 and preventing, reducing and/or lessening the seventy of the clinical symptoms associated with PCV2 infection. The composition generally comprises at least one PCV2 antigen.

Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs. The term "immunogenic composition" as used herein refers to any pharmaceutical composition containing a PCV2 antigen, which composition can he used to prevent or treat a PCV2 infection-associated disease or condition in a subject. A preferred immunogenic composition can induce, stimulate or enhance the immune response against PCV2. The term thus encompasses both subunit immunogenic compositions, as described below, as well as compositions containing whole killed, or attenuated and/or inactivated PCV2.

The term "subunit immunogenic composition" as used .herein refers to a composition containing at least one immunogenic polypeptide or antigen., but not all antigens, derived from or homologous to an antigen from PC V2, Such a composition is substantially free of intact PCV2. Thus, a "subunit immunogenic composition" is prepared from at least partially purified or fractionated (preferably substantially purified) immunogenic polypeptides from PC V2. or recombinant analogs thereof A subunit immunogenic composition can comprise the subunit antigen or antigens of interest substantially free of other antigens or polypeptides from FCV2. or in fractionated from. A preferred immunogenic subunit composition comprises the PCV2 O F2 protein s described below.

An "immunological or immune response" to a composition or vaccine is the development in (he host of a cellular and'' or antibody-mediated immune response to the composition or vaccine of interest. Usually, an "immune response" includes but is not limited to one or more of the following effects: the production or activation of antibodies, B ceils, helper T cells, sitppressor T cells, and/or cytotoxic T cells and/or yd T cells, directed specifically to an antigen or antigens included in the composition or vaccine of interest. Preferably, the host will display either a therapeutic or protective immunological response such that: resistance to new infection will be enhanced and/or the clinical se verity of the disease reduced. Such protection will be demonstrated by either a reduction in number or severity of, or lack of one or more of the symptoms associated with PCV2 infections as described above.

The terms "immunogenic" protein or polypeptide or "antigen" as used herein refer to an amino acid sequence which elicits an immunological response as described above. An "immunogenic" protein or polypeptide, as used herein, includes the fuii-iength sequence of any PCV2 proteins, analogs thereof, or immunogenic fragments thereof. The term "immunogenic fragment" refers to a fragment of a protein which includes one or more epitopes and thus elicits the immunological response described above. Such fragments can be identified using any number of epitope mapping techniques, well known in the art. See, e.g.. Epitope Mapping Protocols in Methods in Molecular Biology, Vol. 66 (Glenn E. Morris, Ed., 1996) Humana Press, Totowa, Mew jersey. For example, linear epitopes may be determined by e.g.. concurrently synthesizing large numbers of peptides on solid supports, the peptides corresponding to portions of the protein molecule, and reacting the peptides with antibodies while the peptides are still attached to the supports. Such techniques are known in the art and described in, e.g., U.S. Patent No. 4,708,871; Gey sea et al. (1984) Proc. Na . Acad. Sci. USA 81:3998-4002; Geysen et al (1986) Molec, Immunol. 23:709-715. Similarly, conformational epitopes are readily identified by determining spatial conformation of amino acids such as by, e.g., x-ray cr stallography and 2-diittensional nuclear magnetic, resonance. See, e.g.. Epitope Mapping Protocols, supra.

Synthetic antigens are also iuchided within the definition, for example, polyepiiopes, flanking epitopes, and other recombinant or synthetically derived antigens. See. e.g., Bergsnana et al. (1993) Eur. J. Immunol. 23:2777-2781 ; Bergtnann et al. (1996). J. Immunol 157:3242-3249; Suhrbier, A. (1997). immunol. and Cell Bioi. 75:402-408; Gardner et al.. (1998) 12th World AIDS Conference, Geneva. Switzerland. June 28-July 3, 1998,

In a preferred embodiment of the present invention, an immunogenic composition that induces an immune response and. more preferably, confers protective immunity against the clinical signs of PCV2 infection, is provided. The composition most preferably comprises the polypeptide, or a fragment thereof, expressed by ORF2 of PCV2. as the antigenic component of the composition. PC VI ORF2 ^' DMA and protein, used herein for the preparation of the compositions and within the processes provided herein is a highly conserved domain within PCV 2 isolates and thereby, any PCV2 ORF2 would be effective as die source of the PCV ORF2 DMA and/or polypeptide as used herein. A preferred PCV2 ORF2 protein is that of SEQ ID NO. 11. A preferred PCV ORF2 polypeptide is provided herein as SEQ ID NO. 5, but it is understood by those of skill in the art that this sequence could vary by as much as 6-10% in sequence homology and still retain the antigenic characteristics that render it useful in iratmmogente compositions. The antigenic characteristics of an immunological composition can be, for example, estimated by the challenge experiment as provided by Example 4. Moreover, the antigenic characieiistic of a modified antigen is still retained,, when the modified antigen confers at least 70%, preferably 80%, more preferably 90% of the protective immunity as compared to tiie PCV2 ORF 2 protein, encoded by the polynucleotide sequence of SEQ ID O:3 or SEQ ID O:4. An "immunogenic composition" as used herein, me ns a PCV2 ORF2 protein which elic its an ^' Immunological response" in the host of a cellular and/or antibody-mediated immune response to PCV ^' 2 ORF2 protein. Preferably, this immunogenic composition is capable of eliciting or enhancing an immune response against PCV2 thereby confering protective immunity against PCV2 infection and a reductio in the incidence of, severity of, or pre vention of one or more, and preferably all of the clinical signs associated there with .

In some forms, immunogenic portions of PCV2 ORF2 protein are used as the antigenic component in the composition. The term "immunogenic portion" as used herein refers to truncated and/or substituted forms, or fragments of PCV2 OR.F2 protein and/or polynucleotide, respectively. Preferably, such truncated and/or substituted forms, or fragments will comprise at least 6 contiguous amino acids from the foiS-tength O.RF2 IXiiypeptide. More preferably, the truncated or substituted forms, or fragments iii .have at least HI more preferably at ieast 15, and still more preferably at least .1 contiguous amino acids from the full-length O.RF2 polypeptide. Two preferred sequences in this respect are provided herein as SEC? ID Os. 9 and .10. it is further understood that such sequences may IK a part of larger fragments or truncated forms,

A farther preferred PCV2 ORF2 polypeptide provided herein is encoded by the nucleotide sequences of SEQ ID NO: 3 or SEQ ID NO: 4. However, it is understood by those of skill in the art that this sequence could vary by as much as 6-20% in sequence homology and still retain the antigenic characteristics that render it useful in immunogenic compositions. In. some forms, a truncated or substituted form, or fragment of this PVC2 ORF2 poly eptide is used as the antigenic component in the composition. Preferably, such truncated or substituted forms, or fragments will comprise ai least 18 contiguous nucleotides from the full-length ORF2 nucleotide sequence, e.g. of SEQ ID NO: 3 or SEQ ID NO: 4. More preferably, the truncated or substituted forms, or fragments, will have at Ieasi: 30, more preferably at least 45, and still more preferably at least 57 contiguous nucleotides of the fall- length ORF2 nucleotide sequence, e.g. SEQ D NO: 3 or SEQ ID NO: 4.

"Sequence Identity' ^" as it is known in the art refers to a relationship between two or more polypeptide sequences o two or more polynucleotide sequences, namely a reference sequence and a given sequence to be compared with the reference sequence. Sequence identity is determined by comparing the given sequence to the reference sequence alter the sequences have been optimally aligned to produce the highest degree of sequence similarity, as determined by the match between sitings of such sequences. Upon such alignment, sequence identity is ascertained on a position-b -position basis, e.g., the sequences are "identical" at a particular position if at that position, the nucleotides or amino acid residues are identical. The total number of such position identities is then divided by the total number of nucleotides or residues in the reference sequence to give % sequence identity. Sequence identity can be readily calculated by known methods, including but not limited to, those described in Computational Molecular Biology, Lesk, A. N., ed., Oxford University Press. New York (1988), Bioeomputmg: Informatics and Genome Projects, Smith, D.W.. ed.. Academic Press, New York (1993): Computer Analysis of Sequence Data, Fart I, Griffin. A.M., and Griffm. H. G.. eds., Humana Press. New Jersey (1994); Sequence Analysis in Molecular Biology, von Heinge, G., Academic Press (1987): Sequence Analysis Primer, Gribskov, M. and Devereux, J., eds., M. Stockton Press, New York (1991); and Carilio, H., and Lipnian, D., SIAM X Applied Math.. 48: 1073 (1988), the teachings of which are incorporated herein by reference. Preferred methods to determine the sequence identity are designed to give the largest match between the sequences tested. Methods to determine sequence identity are codified in publicly available computer programs which determine sequence identity between given sequences. Examples of such programs include, bui re not limited to, die GCG program package (Devereux, i.. et ai., Nucleic Acids Research, 12(1):387 (1984)), BLASTP. BLASTN and FASTA (Altschnl S. F. et aL J. Molec. Biol., 21.5:403-410 ( 1990). The BLA.STX program is publicly available from CBl and other sources {BLAST Manual, Altsc!iul S. et a!., NCVi NLM NIB Bethesda. MD 20894, Altschnl, S. F. et aL, J. Molec. Biol., 215:403-410 (1990), the teachings of which are incorporated herein by reference). These programs optimally align sequences using default gap weights in order to produce the highest level of sequence identity between the given and reference sequences. As an illustration, by a polynucleotide having a nucleotide sequence having at least, for example. 85%, preferably 90%. even more preferably 95% "sequence identity" to a reference nucleotide sequence, it is intended that the nucleotide sequence of the given polynucleotide is identical to the reference sequence except that the given polynucleotide sequence may include up to 13, preferably up io 10. even more preferably up to 5 point mutations per each 100 nucleotides of ihe reference nucleotide sequence. In other words, in a polynucleotide havin a nucleotide sequence having at least 85%, preferably 90%, even more preferably 95% identity relative to the reference nucleotide sequence, up to 15%, preferably .10%, even more preferably 5% of the nucleotides in the reference sequence may be deleted or substituted with another nucleotide, or a number of nucleotides up to .1 %. preferably 10%. even more preferably 5% of the total nucleotides in the reference sequence may be inserted into the reference sequence. These mutations of the reference sequence may occur at the 5' or 3' terminal positions of the reference nucleotide sequence or anywhere between those terminal positions, interspersed either individually among nucleotides in the reference sequence or in one or more contiguous groups within the reference sequence. Analogously, by a polypeptide having a given amino acid sequence having at least, for example, 85%, preferably 90%, even more preferably 95% sequence identity to a reference amino acid sequence, it is intended that the given amino acid sequence of the poly peptide is identical to the reference sequence except that the given polypeptide sequence may include up to 1 . preferably up lo 10, even more preferably up lo 3 amino acid alterations per each 100 amino acids of the reference amino acid sequence. In other words, to obtain a given polypeptide sequence having at least 85%. preferably 90%, even more preferably 95% sequence identity with a re e ence amino acid sequence, up to 15%, preferably up to 10%, even more preferably up to 5% of She amino acid residues in the reference sequence may be deleted or substituted with another amino acid, or a number of amino acids up to i 5%, preferably up to 10%, even more preferably up to 5% of the total number of amino acid residues in the reference sequence may be inserted into the reference sequence. These alterations of the reference sequence may occur at the amino or the carboxy terminal positions of the reference amino acid sequence or anywhere between those terminal positions, interspersed either individually among residues in the reference sequence or in die one or more contiguous groups within the reference sequence. Preferably, residue positions which are not identical differ by conservative amino acid substitutions. However, conservative substitutions are not included as a match when determining sequence identity.

"Sequence homology", as used herein, refers to a method of determining the relatedness of two sequences. To determine sequence homology, two or more sequences are optimally aligned, and gaps are introduced if necessary. However, in contrast to ' ^" sequence identity ^" , conservative amino acid substitutions are counted as a match when determining sequence homology. In other words, to obtain a polypeptide or polynucleotide having 95% sequence omology with a reference sequence, 85%, preferably 90%, even more preferably 95% of the amino acid residues o nucleotides in the reference sequence must match or comprise a conservative substitution with another amino acid or nucleotide, or a number of amino acids or nucleotides up to 15%, preferably up to 10%, even more preferably up to 5% of the total amino acid residues or nucleotides, not including conservative substitutions, in the reference sequence may be inserted into the reference sequence. Preferably the horaolog sequence comprises at least a streich of 50, even more preferably at least .1 0, even, snore preferably at least 250. and even more preferably si: least 500 nucleotides.

A "conservative substitution" refers to the substitution of an amino acid residue or nucleotide with another amino acid residue or nucleotide having similar characteristics or properties including size, hydrophofaicity, etc., such thai the overall functionality does not change significantl .

"Isolated" means altered "fay the hand of man" from its natural state, i.e., if it occurs in nature, it has been changed or removed from its original environment, or both. For example, a polynucleotide or polypeptide naturally present in a living organism is not ^" isolated, ^" but the same polynucleotide or polypeptide separated from the coexisting materials of its natural state is 'isolated", as the term is employed herein.

Thus, the immunogenic composition as used herein also refers to a composition that comprises PCV2 ORF2 protein, wherein said PCV2 ORF2 protein is anyone of those, described above. Preferably, said PCV2 OR.F2 protein is

i) a polypeptide comprising the sequence of SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 9, SEQ ID NO: 10 or SEQ ID NO: 1 1 ;

ii) any polypeptide that is at least 80% homologous to the polypeptide of i), iii) any imrmmogenic portion of the polypeptides of i) and/or ii)

) the immunogenic portion of iii), comprising at least 10 contiguous amino acids included in the sequences of SEQ ID NO: 5, SEQ ID NO: 6. SEQ ID NO: 9. SEQ ID NO: 10 or SEQ ID NO: 1 1 , v) a polypeptide that is encoded by a DMA comprising the sequence of SEQ

ID NO; 3 or SEQ ID NO: 4.

vi) any polypeptide that is encoded by a polynucleotide that is at least 80% homologous to the polynucleotide of v).

vii) any immunogenic portion, of the polypeptides encoded by the polynucleotide of v) aod/or vi}

viii) the immunogenic portion of vii). wherein polynucleotide coding for said immunogenic portion comprises at least 30 contiguous nucleotides included in the sequences of SEQ ID ^" NO: 3, or SEQ ID NO: 4.

Preferably any of those immunogenic portions have the immunogenic characteristics of PCV2 OR.F2 protein that is encoded by the sequence of SEQ ID NO: 3 or SEQ ID NO: 4.

According to a further aspect, PCV2 ORF2 protein is provided in the immunological composition at an antigen inclusion level effective for inducing the desired immune response, namely reducing the incidence of, lessening the severity of or preventing one or more clinical signs resulting from PCV2 infection. Preferably, the FCV2 ORF2 protein inclusion level is at least 0.2 pg antigen / mi of the final immunogenic composition (pg ml), snore preferably from about 0.2 to about 400 pg rol, still more preferably from about 0.3 to about 200 pg ml, even more preferably .front about 0.35 to about 100 pg ml, still snore preferably from about 0.4 to about 50 ug ml. still snore preferably from about 0.45 to about 30 ug/rot still more preferably front about 0.6 to about 15 pg /ml. even more preferably from about 0.75 to about 8 pg/mi, even more preferably from about 1.0 to aboiit 6 pg ml, still more preferably from about 1.3 to about 3.0 pg/mi, even more preferably from about 1.4 to about 2.5 pg ntl, even more preferably from about 1.5 to about 2,0 pg ml, and most preferably about J .6 ug- ml. .According to a farther aspect, the ORP2 antigen inclusion level is at least 0.2 pg/ PCV2 O F2 protein as described above per dose of the final antigenic composition (pg/dose). more preferably from about 0.2 to about 400 pg dose, still more preferably from about 0.3 to about 200 pg/dose. even more preferably from about 0.35 to about 100 pg/dose, still more preferably from about 0.4 to about 50 pg/dose. still more preferably from about 0.45 to about 30 pg/dose, still more preferably from about 0.6 to about 15 pg/dose, even more preferably from about 0.75 to abotit 8 pg/dose. even more preferably from about 1.0 to about 6 pg/dose, still more preferably from about 1.3 to abotit 3.0 pg/dose, even more preferably from abotit 1.4 to about 2.5 pg/dose, even more preferably from about 1.5 to about 2.0 pg/dose, and most preferably about 1.6 pg dose.

The PCV2 O.RF2 polypeptide used in the immunogenic composition in accordance with the present invention can be derived in any fashion including isolation and purification of PCV2 O.RF2. standard protein synthesis, and recombinant methodology. Preferred methods for obtaining PCV2 OR.F2 polypeptide are provided in U.S. Patent Application Serial No. 1 1/034,797, the teachings and content of which are hereby incorporated by reference. Briefly, susceptible cells are infected with a recombinant viral vector containing PCV2 O. F2 DNA coding sequences, PCV2 OR.F2 polypeptide is expressed by the recombinant vims, and the expressed PCV2 ORF2 polypeptide is recovered from the supernate by filtration and inactivated by any conventional method, preferably using binary ethyienimine, which is then neutralized to stop the mactivation process.

The immunogenic composition as used herein also refers to composition that comprises i) any of the PCV2 ORF2 protein described above, preferably in concentrations described above, and ii) at least a portion of the viral vector expressing said FCV2 GRF2 protein, preferably of a recombinant bacuiovirus. Moreover, the immunogenic composition can comprise i) any of the PCV2 OR.F2 proteins described above, preferably in concentrations described above, if) at least a portion of the viral vector expressing ^' said PCV2 ORF2 protein, preferably of a recombinant bacuioviros, and iii) a portion of the cell culture supernate.

The immunogenic composition as used herein also refers to a composition that comprises i) any of the PCV2 ORF2 proteins described above, preferably in concentrations described above, ii) at least a portion of the viral vector expressing said PCV2 OR.F2 protein, preferably of a recombinant baculo virus, and Hi) a portion of the cell culture; wherein about 90% of the components have a sue smaller than 1 ^η *.

The immunogenic composition as used herein also refers to a composition that comprises i) any of the PCV2 0RF2 proteins described above, preferably in concentrations described above, ii) at least a portion of the viral vector expressing said PCV2 O F2 protein, iii) a portion of the cell culture, iv) and inactivating agent to inactivate the recombinant viral vector preferably BEL wherein about 90% of the components i) to iii) have a size smaller than: 1 pin. Preferably, BE! is present in concentrations effective to inactivate the baculovims. Effective concentrations are described above.

The immunogenic composition as used herein: also refers to a composition that comprises i) any of the PCV2 ORF2 proteins described above, preferably i concentrations described above, ii) at least a portion of the viral vector expressing said PCV2 G.RF2 protein, iii) a portion of the cell culture, iv) an inactivating agent to inactivate the recombinant viral veeior preferably Β.ΕΪ, and v) an neutralization agent to stop the inactivatioii mediated by the inactivating agent, wherein about 90% of the components i) to iii) have a size smaller than 1. μηι, Preferably, if the inactivating agent is BEL said composition comprises sodium Ihiosulfate in equivalent amounts to BEL The polypeptide is incorporated into a corapositioa thai can fee administered to art animal susceptible to FCV2 infection. In preferred forms, the composition ma also include additional components known to those of skill in the art (see also Remington's Pharmaceutical Sciences. ( 1990). 18th ed. Mack PubL Easton). Additionally, the composition may include one or more veterinary -acceptable carriers. As used herein, "a veterinary-acceptable carrier" includes any and all solvents, dispersion medi , coatings, adjuvants, stabilizing agents, diluents, preservatives, antibacterial and antifungal agents, isotonic agents, adsorption delaying agents, and the like. In a preferred embodiment, the immunogenic composition comprises FCV2 OR.F2 protein as provided herewith, preferably in concentrations described above, which is mixed with an adjuvant, preferably Carbopol, and physiological saline.

Those of skill in the art will understand thai the composition used herein may incorporate known injectable, physiologically acceptable sterile solutions. For preparing a ready-to-use solution for parenteral injection or infusion, aqueous isotonic solutions, such as e.g. saline or corresponding plasma protein solutions, are readily available. In addition, the immunogenic and vaccine compositions of the present invention can include diluents, isotonic agents, stabilizers, or adjuvants. Diluents can include water, saline, dextrose, ethanol. glycerol, and the like, isotonic agents can include sodium chloride, dextrose, manmtoi. sorbitol, and lactose, among others. Stabilizers include albumin and alkali salts of ethylendiamintetriicetic acid, among others.

"Adjuvants ^" as used herein, can include aluminum hydroxide and aluminum phosphate, saponins e.g., Qui! A, QS-21 (Cambridge Biotech Inc., Cambridge MA), GP1- 0100 (Gaienica Pharmaceuticals. Inc.. Birmingham, AL). water-in-oil emulsion, oil-in-water emulsion. vater-iii-oi.l-in-waier emulsion. The emulsion can be based in particular on light liquid paraffin oil (European Pharmacopea type); isoprenoid oil such as squalane or sqnalene oil resulting from iheoligoraerixation of aikeaes. in particular of isobuiene or dceene: esters of acids or of alcohols containing a linear alkyi group, more particularly plant oils, ethyl oleate. propylene glycol d caprylate/capraie), glyceryl tri-(capr late/caprate) or propylene glycol dioleste: esters of branched laity acids or alcohols, in particular isostearic acid esters. The oil is used in combination wish enntlsifiers to form the emulsion. The enntlsifiers are preferably nonioiuc surfactants, in particular esters of sorbitan, of niaurride {e.g. anlrydroniannitol oleate), of glycol, of poly glycerol, of propylene glycol and of oleic, isostearic, ricinoSeic or hydroxystearic acid, vhich are optionally ethoxylated. andxilyoxypropylene-polyoxycthyicne copolymer blocks, in particular the Plutonic products, especially iJ.21. See Hunter et al. The Theory and Practical Application of Adjuvants (Ed.Ste art-Tull, D.E.S.). JobnWiley and Sons, NY. pp51-94 (1 95) and Todd et al, Vaccine 1 :564-570 (1 97).

For example, if is possible to use the SPT emulsion described on page 147 of "Vaccine Design, The Subanit and Adjuvant Approach" edited by M. Powell and M. ^" Newman, Plenum Press, .1995, and the emulsion MF59 described on page 183 of fers same book.

A further instance of an adjuvant is a compound chosen from the polymers of acrylic or methacrylic acid and the copolymers of maleic anhydride and alkenvl derivative. Advantageous adjuvant compounds are tiie polymers of acrylic or methacrylic acid which are cross-linked, especially with polyalken l ethers of sugars or polyaleohols. These compounds are known by the term carbomer (Phameuropa Vol. 8, No. 2, June 1996). Persons skilled in the art can also refer to U. S, Patent No. 2,909,462 which describes such acrylic polymers cross-linked with a polyhydroxylated compound having at least 3 hydroxy! groups, preferably not more than 8. the hydrogen atoms of at least three hydroxy Is being replaced by unsaturated aliphatic radicals having at least 2 carbon atoms. The preferred radicals are those containing from 2 to 4 carbon atoms, e.g. vinyls, ally Is and other ethylenicaliy unsaturated groups. The unsaturated radicals may themselves contain oilier substituents snch as methyl. The prodwcts sold under the name Carbopol; (BF Goodrich, Ohio. USA) are particularly appropriate. They are cross-linked with an ally! sucrose or with ally! peniaery tkritol. Among theni. there may be mentioned Carbopol 974P, 934P and 971.P. Most preferred is the ose of Carbopol in particular the ose of Carbopol 97 IP, preferably in amounts of about 500 $ to about 5 ru per dose, even more preferred in an amount of about 750 ¾ to about 2.3 ing per dose and most preferred in an amount of about 1 mg per dose.

Further suitable adjuvants include, but are not limited to, the RIB1 adjuvant system (Ribi inc.). Block co-polymer (CylRx, Atlanta GA), SAF-M (Chiron, Emeryville CA.), monophospbory! lipid A. Avridme lipid-amine adjuvant, beat-labile enterotoxm from E. coli (recombinant or otherwise), cholera toxin, IMS 1314, or muramyl dipepiide among many others.

Preferably, the adjuvant is added in an amount of about 100 tig to about .10 mg per dose. Even more preferably, the adjuvant is added in an amount of about 1 0 ug to about 10 m per dose. Even .more preferably, the adjuvant is added in an amount of about 500 ^ig to about 5 mg per dose. Even more preferably, the adjuvant is added in an amount of about 750 μ-g to about 2.5 mg per dose. ost preferably, the adjuvant is added in an amount of about .1 mg per dose.

.Additionally, the composition can include one or more pharmaceutical-acceptable carriers. As used herein, "a pharmaceutical-acceptable carrier" includes any and all solvents, dispersion media, coatings, stabilizing agents, diluents, preservatives, antibacterial and antifungal agents, isotonic agents, adsorption delaying agents, and the like. Most preferably, the composition provided herewith, contains PCV2 OS.F2 protein recovered from the sif pernaie of in vitro cultured ceils, wherein said cells were infected with a recombinant viral vector containing PC V2 O.RF2 D A and expressing PC V2 O.RF2 protein, and wherein said cell culture was treated with about 2 to about 8 m ^' M BEL preferably with about 5 niM BEI to inactivate the viral vector, and. an equivalent concentration of a neutralisation agent, preferably sodium thiosulfate solutio to a final concentration of about 2 to about 8 mM, preferably of about 5 mM.

The present invention, also relates to an immunogenic composition that comprises i) tiny of the PCV2 ORF2 proteins described above, preferably in concentrations described above, ii) at least a portion of the viral vector expressing said PCV2 ORF2 protein, tit) a portion of the ceil culture, iv) an inactivating agent to inactivate the recombinant viral vector preferably BEI, and v) an neutralization agent to stop the mactivation mediated by the inactivating agent, preferably sodium thiosulfate in equivalent amounts to ΒΕ.Ϊ; and vi) a suitable adjuvant, preferably Carbopol 97 i in amounts described above-, wherein about 90% of the components i) to iii) have a size smaller than 1 μιη. According to a further aspect, this immunogenic composition further comprises a pharmaceutical acceptable sail; preferably a phosphate salt in physiologically acceptable concentrations. Preferably, the pH of said immunogenic composition is adjusted to a physiological pli .meaning between about 6.5 and 7.5.

The immunogenic composition as used herein also refers to a composition that comprises per one mi 5) at least 1. ¾ of PCV2 O.RF2 protein described above, it) at least a portion of baeuiovirus expressing said PCV2 OR.F2 protein iii) a portion of the cell culture, iv) about 2 to 8 mM BET, v) sodium thiosulfate in eqaivalenl amounts to BEI: and vi) about j trig Carbopol 971 , and vit) phosphate salt i a physiologically acceptable concentration; wherein about 90% of the compo.ne.nis i) to iii) have a size smaller than .1 ujtn and the pH o said immunogenic composition is adjusted to about 6.5 to 7.5. The immunogenic compositions can farther include one or more other immunomodulatory agents such as, e.g., interienkiiis, interferons, or other cytokines. The immunogenic compositions can also include Gentamicin and Merthiola.te. While the amounts and concentrations of adjuvants and additives useful in the context of the present invention can readily be determined by the skilled artisan, the present invention contemplates compositions comprising from about 50 pg to about 2000 $ of adjuvant and preferably about 250 pg nil dose of the vaccine composition. Thus, the immunogenic composition as used herein also refers to a composition that comprises from about l ug/mi to about 60 pg rnl of antibiotics, and more preferably less than about 30 pg ml of antibiotics.

The immunogenic composition as used herein also refers to a composition that comprises i) any of the PCV2 O.RF2 proteins described above, preferably in concentrations described above, ft) a t least a portion of the viral vector expressin said PCV2 ORF2 protein, iii) a portion of the cell culture, iv) an inactivating agent to inactivate the recombinant viral vector preferabiy BEi. and v) an neutralization agent to stop the inaetivation mediated by the inactivating agent, preferably sodium tfaosulfate in equivalent amounts to Β.ΕΪ; vi) a suitable adjuvant, preferably Carbopoi 971 in amounts described above; vii) a pharmaceutical acceptable concentration of a saline buffer, preferably of a phosphate salt, and viii) an anti- microbiological active agent: wherein, about 90% of the components t) to iii) have a size smaller than 1 μηι.

It has been surprisingly found, that the immunogenic composition comprising the PCV2 ORF2 protein was highly stable over a period of 24 months. It has also been found the immunogenic compositions are very effective in reducing the clinical symptoms associated with PCV2 infections. It was also discovered, that the immunogenic compositions comprising the recombinant baculovirus expressed PCV2 ORF2 protein as described above, are surprisingly .more effective than an immunogenic composition comprising the whole PCV2 ims in an inactivated form, or isolated viral PCV2 O.RF2 antigen. in particular, it has been surprisingly found, that die recombinant baculovirus expressed FCV2 ORF2 protein is effective in very km concentrations, which means in couceritratioris up to 0.25 pg/dose. This unexpected high inmiunogeiiic potential of the PCV2. ORF2 protein is increased by Carbopo!. Examples ! to 3 disclose in detail the production of PCV2 OR.F2 comprising immunogenic compositions.

The immunogenic composition as used herein also refers to Ingelvacifc CircoFLEX^ ^'1 , (Boehringer Ingei eini Vetrnediea, Inc., St Joseph, MO, USA.), CircoVac® (Medal SAS, Lyon, France), CircoVent (Intervet inc.. Milisboro. DE. USA), or Suvaxyn PCV-2 One Dose® (Fori Dodge Animal Health, Kansas City. KA, USA).

Administration of the immunogenic composition

The composition according to die invention may be applied intradermal ly, intravrachea.lSy, or iutravagnsaiiy. The composition preferably may be applied iniratnu.se tilarly or iiitranasaliy, most preferably iniramnscularlly. In an animal body, it can prove advantageous to apply the pharmaceutical compositions as described above via an intravenous or by direct injection into target tissues. For systemic application, the intravenous, intravascular, intramuscular, intranasal, intraarterial, intraperitoneal, oral, or intrathecal routes are preferred. A more local application can be effected snbeittaneoasly, intradennally , intracutaneousl , intracardtally, intralobaSly. inlramedtdlat'ly. rlrapulnionarily or directly in or near the tissue to lie treated (connective-, bone-, muscle-, nerve-, epithelial tissue). Depending on the desired duration and effectiveness of the treatment, the compositions according to the invention may be administered, once or several times, also intemuttemiy, for instance on a daily basis for several days, weeks or months and in different dosages.

Preferably, at least one dose of the immunogenic compositions as described above is intramuscularly administered to the subject in need thereof. According to a farther aspect, the PCV-2 antigen or the immunogenic composition comprising any such PCV-2 antigen as described above is formulated and administered in one (1) nit per dose. Thus, according to a further aspect, the present invention also relates to a 1 ml immunogenic composition, comprising PCV-2 antigen as described heren. for reducing or lessening lyniphadenopathy, lymphoid depletion and/or multmucieated/giant histiocytes in pigs infected with PC V2.

According to a further aspect, according to a further aspect, the present invention also relates to a 1 ml immunogenic composition, comprising PCV-2 antigen as described herein, for reducing or lessening lymphadenopathy in combination with one or a multiple of the following symptoms in pigs: (1) interstitial pneumonia with interlobular edema, (2) cutaneous pallor or icterus, (3) mottled atrophic livers. (4) gastric ulcers. (5) nephritis and (6) reproductive disorders, e.g. abortion, stillbirths, mummies.

According to a further aspect, at least one further administration of at least one dose of the immunogemc composition as described above is given to a subject in need thereof, wherein the second or any further administration JS given at least 1 days beyond the initial or any former administrations, .Preferably, the immunogenic composition is administered with an immune stimulant. Preferably, said immune stimulant is given at least twice. Preferably, at least 3 days, more preferably at least 5 days, even more preferably at least 7 days are in between the first and the second or any further administration of the immune stimulant. Preferably, the immune stimulant is given at least 10 da s, preferably 15 days, even more preferably 20. even more preferably at least 22 days beyond the initial administration of the immunogenic composition provided herein. A preferred immune stimulant is, for example, keyhole iimpet hemocyanin ( LH). preferably emulsified with incomplete Fteund's adjuvant (KLHiCFA). However, it is herewith understood, that any other immune stimulant known to a person skilled in the art can also be used. The term "immune stimulant" as used herein, means any agent: or composition at can trigger the immune response, preferably without initiating or increasing a specific immune response, for example the immune response against a specific pathogen. It is further instructed to administer the immune stimulant in a suitable dose.

Moreover, it has also been surprisingly found that the immunogenic potential of the immunogenic compositions used herein, preferably those that comprise recombinant baeu-lovirus expressed PCV2 ORF2 protein, even more preferably in combination with Carbopol, can be further confirmed by the administration of the IngelVac .P.RRS MLV vaccine (see Example 5). PCV2 clinical signs and disease manifestations are greatly magnified when PRRS infection is present. However, the immunogenic compositions and vaccination strategies as provided herewith lessened this effect greatly, and more than expected. In other words, an unexpected s nergistic effect was observed when animals, preferably piglets were treated with any of the PCV2 ORF2 immunogenic compositions, as provided herewith, and the In elvac PRRS MLV vaccine (Boehringer ingelheini).

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic Sow diagram of a preferred construction of PCV2 ORF2 recombinant bacisloviros; and

Figs. 2a and 2b are each schematic flow diagrams of how to produce one of the compositions used in accordance with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following examples set forth preferred materials and procedures in accordance with the present invention. Although say methods and materials similar or equivalent to those described herein can be used in the practice or testing of (he present invention, the preferred methods, devices, and materials are now described. It is to be understood, however, that these examples are provided by way of illustration only, and nothing therein should be deemed a limitation upon (he overall scope of the invention.

EXAMPLE S.

This example compares the relative ields of ORF2 using methods of the present invention with methods that are known in the prior art. Four lOOOm.L spinner flasks were each seeded with approximately 1.0x10° Sf÷ cells/ml in 300mL of insect serum free media. Excel! 420 (JRH Biosciences, Inc., Lenexa, S). The master cell culture is identified as SF+ (Spodopie j giperdd) Master Cell Stock, passage 1 , Lot#NS. l 2-095 W. The cells used to generate the SF+ Master Cell Stock were obtained from Protein Sciences Corporation, Inc.. Meriden, CT. The SF+ cell line for this example was confined between passages 19 and 59. Other passages will work for purposes of the present invention, but in order to scale the process up for large scale production, at least 1 passages will probably be necessary and passages beyond 59 may have an effect ^" on expression, although this was not investigated. In more detail, the initial SF+ cell cultures from liquid nitrogen storage were grown in Excel! 420 media in suspension in sterile spinner flasks with constant agitation. The cultures were grown in 100 niL to 250mL spinner flasks with 25 to 150 mi, of Excell 420 serum-free media. When the cells had multiplied to cell density of 1.0 - 8.0 x Hf cells/raL. they were split to new vessels with a planting densit of 0.5 - 1.5 x lit ee!ls/mL. Subsequent expansion cultures were grown ra spinner .flasks up LO 36 liters ra size or n staraless sieel bsoreaciors of wp to 300 liters for a period of 2-7 days at 25 - 29°C.

After seeding, the flasks were incubated at 27°C for four hours. Subsequently, each flask was seeded with a recombinant: bacuiovirus containin the PCV2 ORF2 gene {SEQ ID NO: 4). The recombinant bacuiovirus containing the PCV2 OR.F2 gene was generated as follows: the PCV2 OR.F2 gene from a North American strain of PCV2 was ^' PCR amplified to contain a 5 ^* Kozak's sequence (SEQ ID NO; 1 _. ) and a 3' EcoRl site (SEQ ID NO: 2), and cloned into the pGEM-T-Easy vector (Promega, Madison, Wf). Then, it was subsequently excised and snbcloned into die transfer vector pVIJ392 (BD Biosciences Phanningen, San Diego, CA). The subcloned portion is represented herein as SEQ ID ΉΟ 7. The pVL1392 plasm.id containing the PCV2 O.RF2 gene was designated N47-064Y and then co-iranslecied with BacnloGoldC- (BD Biosciences Pharmingen) bacuiovirus DMA into Sf÷ insect: ceils (Protein Sciences, Meriden. CT) to generate the recombinant bacuiovirus containing the PCV2 O.RF2 gene. The new construct is provided herein as SEQ I ^' D NO: 8. The recombinant bacuiovirus containing the PCV2 OR.F2 gene was plaque-purified and Master Seed Vims (MSV) was propagated on the SF÷ cell line, aliquotted, and stored at -70°C. The MSV was positively identified as PCV2 O.RF2 ^' bacuiovirus by PCR-RFLP using bacuiovirus specific primers. Insect cells infected with PCV2 O.RF2 bacuiovirus to generate MSV or Working Seed Virus express PCV2 ORF2 antigen as detected by polyclonal serum or monoclonal antibodies in an indirect fluorescent antibody assay. Additionally, the identity of the PCV2 ORF2 bacuiovirus was confirmed by N-temiimtl amino acid sequencing. The PCV2 ORF2 bacuiovirus MSV was also tested lor purity in accordance with 9 C.F.R. i 13.27 (e), 113,28. and 113.55. Each recombinant bacuiovirus seeded into the spinner flasks had varying multiplicities of infection (MQ.Ss). Flask 1 was seeded with 7. :tnL of .088 MQj seed; flask 2 was seeded with !OlmL of 0.36MOI seed: flask 3 was seeded with 1.5mL of 0.18 ΟΪ seed; and flask 4 was seeded with 0.75raL of 0.09MOI seed, A schematic flow diagram illustrating ^' iiie basic steps used to construct a PC V2 ORF2 recombinant baenioviras is provided herein as Figure j .

After being seeded with (he baculovifus, the flasks were then incubated at 27 ± 2 ^ft C for 7 days and were also agitated at lQQrpm during that time. The flasks used ventilated caps to allow for air flow. Samples from each flask were taken every 24 hours for the next 7 days. After extraction, each sample was centrifuged, and both the pellet and the supernatant were separated and then niierofdtered through a 0.45-1.0 μιη pore size membrane.

The resulting samples then had the amount of QR.F2 present within them quantified via an EL ^' SA assay. The EL1SA assay was conducted with capture antibody Swine anti- PC V2 Pab IgG .Prot. 0 purified (diluted 1 :250 in PBS) diluted to 1 :6000 in 0.05M Carbonate buffer (pH 9.6). 100 pL of the antibody was then placed in the wells of the mictroiiier plate, sealed, and incubated overnight at 37 ^¾ C. The plate was then washed three times with a wash solution which comprised 0.5ml.. of Tween 20 (Sigma, St. Louis. MO), J.OOm.L of .I0X D- PBS (Gibco Imdirogen, Carlsbad, ) and 89 .5mL of distilled water. Subsequently. 250 uL- of a blocking solution (5g Carnation Non-fat dry milk (Nestle. Glendale, CA) in l niL of D-.P.BS QS to lOOmL with distilled water) was added to each of the wells. The next step was to wash the test plate and then add pre-diluted antigen. The pre-diluted antigen was produced by adding 200 p.L of diluent solution (O.SniL Tween 20 in 999.5mL D-PBS) to each of the wells on a dilution plate. The sample was then diluted at a 1:240 ratio and a 1 :480 ratio, and 1 0 pL of each of these diluted samples was then added to one of the top wells on the dilution plate (i.e. one top well received 1 0 pL of the 1:240 dilution and tire other received 100 p.L of the 1:480 dilution). Serial dilutions were then done tor the remainder of the plate by removing 100 μΧ form each successive well and transferring it to the nest well on the plate. Each well was mixed prior to doing the next transfer. The test plate washing included washing ^' the plate three times with the wash buffer. The plate was then sealed and incubated for an hour at 37°C before being washed three more times with the wash buffer. The detection antibody used was monoclonal antibody to PCV ORF2. It was diluted to 1 :300 in diluent solution, and 1 0 μL· of the diluted detection antibody was then added to the wells. The plate was then sealed and incubated for an hour at 37°C before being washed three times w ith the wash buffer. Conjugate diluent was then prepared by adding normal rabbit serum (Jackson Immunoresearch. West Grove, PA) to the diluent solution to 1 % concentration. Conjugate antibody Croat anti-mouse (.H + 1)-HRP (Jackson imnnmoresearch) was diluted in the conjugate diluent to 1 : 10,000. 1.00 ΐ, of the diluted conjugate antibody was then added to each of the wells. The plate was then sealed and incubated for 45 minutes at 3?°C before being washed three tunes with die wash buffer. .100 p.L of substrate (TMB Peroxidase Substrate, Kirkgaard and Perry Laboratories ( PL), Gaithersberg. MD), mixed with an equal volume of Peroxidase Substrate B (KPL) was added to each of the wells. The plate was incubated at room temperature for 15 minutes. 100 til. of IN ^' HCL solution was then added to all of the wells to stop the reaction. The plate w as then run through an ELISA reader. The results of this assay are provided in Table 1 below:

Table I

These results indicate that when the incubation time is extended, expression of OR.F2 into the supernatant of the centrifuged cells and media is greater than expression in the peiiet of the centrifuged ceils and raedia. Accordingly, allowing the O.RF2 expression to proceed for ai least .1 d ys and recovering it in the supemate rather than allowing expression to proceed for less than 5 days and recovering QRF2 from the ceils, provides a great increase in ORF2 yields, and a significant improvement over prior methods.

EXAMPLE 2

This example provides data as to the efficacy of the invention claimed herein. A. lOOO iL spinner flask was seeded with approximately 1.0x10' ^' Sf+ eells ml in 300mL of Excel! 420 media. The flask was then incubated at 2TC and agitated at IGOrpm. Subsequently, the flask was seeded with 10 m.L of PCV2 ORF2 Bac p+6 (the recombinant baeu!ovirus containing the PCV2 OR.F2 gene passaged 6 additional times it) the Sf insect celSs) virus seed with a 0.1 MOl after 24 hours of incubation.

The flask was then incubated at 27 for a total of 6 days. Alter incubation, the flask was then eenfrifiiged and three samples of die resulting supernatant were harvested and inactivated. The supernatant was inactivated by bringing its temperature to 37 * 2°C, To die first sample, a 0.4M solution of 2-bromoethyleiieamme hydrobromide winch had been cyclized to 0.2M binary ethlylennnine (BEl) in 0.3N aOH was added to the supernatant to give a final concentration of BEl of 5mM. To the second sample, lOmM BEl was added to the supernatant. To the third sample, no BE! was added to the supernatant. The samples were then stirred continuously for 48 hrs. A 1.0 M sodium thiosuifate solution to give a final minimum concentration of 5 mM was added to neutralize any residual BEL The quantity of ORF2 in each sample was then quantified using the same EL1SA assay procedure as described in Example 1. The results of this may be seen in Table 2 below:

Table 2

Sample O.RF2 in supernatant (pg) I 78.7

2 68.75

83.33

This example demonstrates that neutralisation with BEI does not remove or degrade significant amounts of the recombinant PCV2 O F2 protein produc This is evidenced by the fact that there is no large loss of ORF2 in the supernatant from the BEI or elevated temperatures. Those of skill in the art will recognize that the recovered ORF2 is a stable protein product

EXAMPLE 3

This example demonstrates that the present invention is scalable from small scale production of recombinant PCV2 ORF2 to large scale production of recombinant PCV2 ORF2. 5.0 x i< cells/ml of SF+ eells ml in 7000ml. of ExCeii 420 media was planted in a 20000mL AppSikon Bioreaetor. The media and cells were then incubated at 27°C and agitated at I00RP. for the next 68 hours. At the 68 ^th hour, 4i.3ra.L of PCV2 ORP2 Baeuiovinis SV+3 was added to 7000mL of ExCeli 420 medium. The resultant mixture was then added to the bioreaetor. For the next seven days, the mixture was incubated at 7°C and aghated at 100RPM. Samples from the bioreaetor were extracted every 24 hours beginning at day 4, post-infection, and each sample was centrifuged. The supernatant of the samples were preserved and the amount of ORF2 was then quantified using SDS-PAGE densitometry. The results of this can be seen in Table 3 below:

Table 3 Case J0- 078-FF

{ formatted; Swedsh (Sweden)

EXAMPLE 4

This example tests the efficacy of seven PC V2 candidate vacciBes and further defines

efficacy parameters following exposure to a virulent strain of PCV2. One hundred and eight

(108) cesarean derived colostrum deprived (CDCD) piglets, 9-14 days of age, were .randomly

divided into 9 groups of equal size. Table 4 sets forth the General Study Design for this

Example.

Table 4. General Study Design

2 !2 PCV2 Vaccine No. 0 +

2 - (vORF2 8 μ

12 PCV2 Vaccine No. 0 + 4

3 - (vO F2 4 μ ₈ )

4 12 PCV2 Vaccine Mo. 0 + F

4 - (rOR 2 16 )

5 12 PCV2 Vaccine No. 0 +

5 - {rOR.F2 8 μ )

6 12 PCV2 Vaccine No. 0 +

6 - (rO F2 4 μ&)

7 12 PCV2 Vaccine No. 0 ·( ^■

7 - (Killed whole

cell vims)

8 12 None - Challenge N/A 4- Controls

9 12 None - Strict WA -f- 4

Negative ControS

Group vORF2 = isolated vjral O F2: rORF2 ^™ recombinant baeulovirus expressed ORF2: killed whole cell virus - PCV2 virus grown in suitable cell culture

Seven of the groups (Groups 1 - 7) received doses of PCV 2 ORF2 poly peptide,, one of the groups acted as a challenge control and received no PCV2 ORF2. and another group acted as die strict negative control group and also received no PCV2 ORF2. On Day 0, Groups 1 through 7 were treated with assigned vaccines. Piglets in Group 7 were given a booster treatment on Day 14. Piglets were observed for adverse events and injection site reactions following vaccination and on Day 19, piglets were moved to the second study site. At the second study site. Groups J -8 were group housed in one building while Group 9 was housed in a separate building. All pigs received keyhole limpet heniocyamn. (KLil i/inconiplete Freund ^' s adjuvant (ICFA) on Days 21 and 27 and on Day 24, Groups 1-8 were challenged with a virulent PCV2.

Pre- and post-challenge, blood samples were collected for PCV2 serology. Posi- challenge. body weight data for determination of average daily weight gain (ADWG). and clinical symptoms, as welt as nasal swab samples to determine nasal shedding of PCV2, were collected. On Day 49, all surviving pigs were neeropsied, lungs were scored for lesions, and selected tissues were preserv ed in formalin for ini uno sroche tstry ilHC) testing at a later date.

Materials and Methods

This was a partially blinded vaccination-challenge feasibility study conducted in CDCD pigs, 9 to .14 days of age on Day 0. To be included in the study. PCV2 1FA titers of sows were < 1 : 1000. Additionally, the serologic status of sows were from a known PRRS- negative herd. Twenty-eight (28) sows were tested for PCV2 serological status. Fourteen (14) sows had a PCV2 titer of < 1000 and were transferred to the first study site. One hundred ten (1 10) piglets were delivered by cesarean section surgeries and were available for this study on Day -4. On Day -3, 108 CDCD pigs at the first study site were weighed, identified with ear tags, blocked by weight and randomly assigned to 1. of 9 groups, as set forth above in table 4. If any test animal meeting the inclusion criteria was enrolled in die study and was later excluded for any reason, the Investigator and Monitor consulted in order to determine the use of data collected from the animal in the final analysis. The date of which enrolled piglets were excluded and the reason for exclusion was documented. Initially, no sows were excluded. A total of 108 of an available 1 10 pigs were randomly assigned to one of 9 groups on Day -3. The two smallest pigs (Nos. 17 and 1 ) were not assigned to a group and were available as extras, if needed. During the course of the study, several animals were removed. Pig 82 (Group 9) on Day -1. Pig . 56 (Group 6) on Day 3, Pig No. 53 (Group 9} on Day 4. Pig No. 2 {Group 8} on Day 8. Pig No. 69 (Group 8) on Day 7. and Pig No. 93 (Group 4) on Day 9, were each found dead prior to challenge. These six pigs were not included in the final study results. Pig no 17 (one of the extra pigs) was assigned to Group 9. The remaining extra pig; No. 19, was excluded from the study .

The formulations given to each of the groups were as follows: Group I was designed to administer lml of viral ORF2 (vORF2) containing 16 OR.F2 mi This was done by mixing 1 .24 nil of viral ORF2 (256 ug/25 pg rnl ^« 10.24 ml vORF2) with 3.2 ml of 0.5% Carbopol and 2.56 ml of phosphate buffered saline at a pH of 7.4. This produced 1 ml of formulation for group 1. Group 2 was designed to administer 1ml of vORF2 containing 8 pg vORF2/ml. This was done by mixing 5.12 ml of vORF2 (128 g 25 pg/ml - 5.12 mi V0RF2) with 3.2 ml of 0.5% Carbopol and 7.68 ml of phosphate buffered saline at a pH of 7.4. This produced 16 ml of formulation for group 2. Group 3 was designed to administer lml of vORF2 containing ^' 4 pg vORF2 nil This was done by mixing 2.56 ml of vORF2 (64 pg 25 ½1 ~ 2,56 ml vORF2) with 3.2 ml of 0.5% Carbopol and 10.24 ml of phosphate buffered saline at a pH of 7.4. This produced 16 in! of formulation for group 3. Group 4 was designed to administer lml of recombinant ORF2 (rORF2) containing 16 ¾ rORF2/rnL This was done by mixing 2.23 nil of rORF2 ( 12 _$ tg 230 pg/tnl - 2,23 ml rORF2) with 6.4 ml of 0.5% Carbopol and 23,37 ml of phosphate buffered saline at a pH of 7.4. This produced 32 ml of formulation for group 4, Group 5 w s designed to administer Iml of rO.RF2 containing g rORF2/ml. This was d ne by mixing i.i l ml of rO F2 (256 μ '230 pg/tni ^~ 1.11 ml rQ.RFl) with 6.4 ml of 0.5% Carbopol and 24.49 ml of phosphate-bitffered saline at a pH of 7.4. This produced 32 ml of formulation for group 5. Group 6 was designed to administer lml of rO F2 containing 8 t rQ.RF2/mI. This was done by mixing 0.56 sni of rORF2 (128 μ§/230 pg/fni ~ 0.56 ml rORF2) with 6.4 ml of 0.5% Carbopol and 25.04 ml of phosphate buffered saline at a pH of 7.4. This produced 32 ml of formulation for group 6. Group 7 was designed to administer 2ml of PCV2 whole killed cell vaccine (PCV2 KV) containing the MAX PCV2 KV. This was done by mixing 56 mi of PCV2 KV with 14 ml of 0.5% Carbopol. This produced 7 mi of fomnilation for group 7. Finally group 8 was designed to administer Kl.H at 0.5 ug/ml or .1.0 pg/rnl per 2 ml dose. This was done by mixing 40,75. ml KLH (7.0 fi protein/ml at 0.5 ug/ml - 570 ml (7.0 μ /ηι1)(χ) - (0.5X570 ml)), 244.29 ml phosphate buffered saline at a pH of 7.4, and 285 mi Fretmds adjuvant. Table 5 describes the time frames for the key activities of this Example.

-7 Observed pigs for injection site reactions

14 Boostered Gtoup 7 with PCV2 Vaccine No. 7: Blood samples from all pigs -2.1 Observed Group 7 for injection site reactions - 19 Treated all pigs with antibiotics (data missing)

1 Pigs transported from the first test site to a second test site 1 Treated Groups 1-9 with KLH/ICFA

24 Collected blood and nasal swab sampies from all pigs:

Weighed all pigs: Challenged Groups .1 -8 with .PC VI challenge material , 27, Collected nasal swab samples from ail pigs

1 ]

, 35, , 43,

, 47

27 Treated Groups .1 -9 with KLH/ICFA 1 Collected blood samples from all pigs 49 Collected blood and nasal swab samples from all pigs;

Weighed all pigs: Necropsy oil pigs: Gross lesions noted with

emphasis placed on icterus and gastric ulcers; Langs evaluated

for lessons; Fresh and formalin fixed tissue samples saved; In- life phase of the study completed

Following completion of the in-life phase of the study, formalin fsxed tissues were examined by Immunohistochernisirv (1HC) for detection of PCV2 antigen by a pathologist, blood samples were evaluated for PCV2 serology, nasal swab samples were evaluated for PCV2 shedding, and average daily weight gain (ADWG) was determined from Day 24 to Day 49.

Animals were housed al the first study site in individual cages in five rooms from birth to approximately I I days of age (approximately Day 0 of the study ). Each room was identical in layout and consisted of stacked individual stainless steel cages with heated and filtered air supplied separately to each isolation unit. Each room had separate heat and ventilation, thereby preventing cross-contamination of air between rooms. Animals were housed in two different buildings at lire second study site. Group 9 (The Strict negative control group) w as housed separately in a converted finisher building and Groups 1 -8 were housed in converted nursery building. Each group w as housed in a separate pen (1 1-1.2 pigs per pen) and each pen provided approximately 3.0 square feet per pig. Each pen was on an elevated deck with plastic slatted floors. A pit below the pens served as a holding tank for excrement and waste. Each building had its own separate heating and ventilation systems, with little likelihood of cross-contamination of air between buildings.

At die first study site, piglets were fed a specially formulated milk ration from birth to approximately 3 weeks of age. All piglets were consuming solid, special mixed ration by Day 19 (approximately 4 ¼ weeks of age). At tiie second study site, all piglets were fed a custom non-medicated commercial mix ration appropriate for their age and weight, ad libitt t, Wtiier at both study sites was also available ad libitum.

All test pigs were treated with Vitamin E on Day -2, with iron injections o Day -1. and with AXCEL* (J .0 mL, IM. in alternating hams) on Days 16, 17, I S and J 9. In addition. Pig No. 52. (Group 9) was treated with an iron injection on Da 3, Pig 45 (Group (>) was treated with an iron injection on Day H, Pig No. 69 (Group 8) was treated with AXCEL ; on Day , Pig No. 74 (Group 3) was treated with dexamethassone and penicillin on Day 14, and Pig No. 51 (Group I) was treated with dexamcthasone arid penicillin on Day 13 and with N ^' AXCEL® on Day 1.4 for various health reasons.

While at both study sites, pigs were under veterinary care. Animal health examinations were conducted on Day 0 and were recorded on the .Health Examination Record Form. Ail animals were in good health and nutritional status before vaccination as determined b observation an Day 0. All test animals were observed to be in good health and nutritional status prior to challenge. Carcasses and tissues were disposed of by rendering. Final disposition of study animals was records on the Animal Disposition Record,

On Day 0, pigs assigned to Groups 1 -6 received .1.0 mL of PCV2 Vaccines 1-6, respectively. I ^' M in the left neck region using a sterile 3.0 mL Luer-loek syringe and a sterile 20g x ½" needle. Pigs assigned to Group 7 received 2.0 mL of PCV2 Vaccine No. 7 IM in the left neck region using a sterile 3.0 mL Liter-lock syringe and a sterile 20g x ½" needle. On Day 14, pigs assigned to Group 7 received 2.0 mL of PCV2 Vaccine No. 7 IM in the right neck region using a sterile 3.0 mL Luer-loek syringe and a sterile 20g x ½" needle.

On Day 21 all test pigs received 2.0 mL of KXH/ICFA IM in the right ham region using a sterile 3.0 mL Luer-loek syringe and a sterile 20g x " needle. On Day 27 ail test pigs received 2.0 raL of KLH/ICPA in the left ham region using a sterile 3.0 mL User-lock syringe and a sterile 2 g x 1 " needle.

On Day 24, pigs assigned to Groups 1-8 received 1.0 nil. of PCV2 ISUVDL challenge material (5.1 1 lo jo TClD« raL) 1M in the left neck region using a sterile 3.0 niL Luer-lock syringe and a sterile 20g x 1" needle. An additional 1.0 nil. of the same material was administered IN to each pig (0.5 mL per nostril) using a sterile 3.0 nil. Luer-lock syringe and nasal eanula.

Test pigs were observed daily for overall health and adverse events on Day -4 and from Day 0 to Day 1 . Observations were recorded on the Clinical Observation Record. All test pigs were observed from Day 0 to Day 7. and Group 7 w as further observed from Day 14 to 21, for injection site reactions. Average daily weight gain was determined by weighing each pig on a calibrated scale on Da s -3, 24 and 49, or on the day that a pig was found dead after challenge. Body weights were recorded on the Body Weight Form. Day -3 body weights were utilized to block pigs prior to randomization. Day 24 and Day 49 weight data was utilized to determine the average daily weight gain (ADWG) for each pig during these time points. For pigs that died after challenge and before Day 49, the ADVV'G as adjusted to represent the ADVV'G from Day 24 to the day of death.

in order to determine PCV2 serology, venous whole blood was collected from each piglet from the orbital venous sinus on Days -3 and .14. For each piglet, blood was collected from the orbital venous smus by inserting ^' a sterile capillary tube into the medial canfhus of one of the eyes and draining approximately 3.0 mL of whole Mood into a 4.0 mL Serum Separator Tube (SST). On Days 24, 31 , and 49, venous whole blood from each pig was collected from the anterior vena cava using a sterile 18g x 1 ½" Vacuiainer needle (Becton Dickinson and Company, Franklin Lakes, New jersey), a Vaeutainer needle holder and a 13 mL SST. Blood collections at each time point were recorded on the Sample Collection Record Blood m each SST was allowed to clot, each SST was then spun down and the serum harvested. Harvested serum was transferred to a s erile snap tube and stored at -7 ± l ⁽ Y' C until tested at a later date. Serum samples were tested for die presence of PCV2 antibodies by BIVl-R&D personnel.

Pigs were observed once daily from Day 20 to Day 49 for clinical symptoms and clinical observations were recorded on the Clinical Observation Record.

To test for PCV2 nasal shedding, on Days 24. 25, and (hen every other odd numbered study day up to and including Day 49, a sterile dacron swab was inserted intra nasally into either the left or right nostril of each pig (one swab per pig) as aseptic-ally as possible, swished around for a few seconds and then removed. Each swab was then placed into a single sterile snap-cap tube containing .1.0 mi, of EMEM media with 2% FBS. 500 uniis/mL of Penicillin. 500 μξ/mL of Streptomycin and 2.5 fig/mL of Fungizone. Tire swab was broken off in the tube, and the snap tube was seated and appropriately labeled with animal number, study number, date of collection, study day and "nasal swab." Sealed snap tubes were stored at -40 * 1 ° C until transported overnight on ice to BiVl-St. Joseph. Nasal swab collections were recorded on the Nasal Swab Sample Collection Form. BIVI-R&D conducted quantitative virus isolation (VI) testing for PCV2 on nasal swab samples. The results were expressed in og _t o values. A value of 1.3 logs or less was considered negative and any value greater than 13 logs was considered positive.

Pigs that died (Nos. 28, 52, 56. 69, 82, and 93) at the first study site were necropsied to tire level necessary to determine a diagnosis. Gross lesions were recorded and no tissues were retained from these pigs. At the second study site, pi s that died prior to Day 49 ( os. 45, 23, 58, 35), pigs .found dead on Day 49 prior to euthanasia (Nos. 2, 43), and pigs euthanwed on Day 49 were necropsied. Any gross lesions were noted and the percentages of lung lobes with lesions were recorded on the Necropsy Report Form. From each of the 103 pigs aecropssed ai the second study site, a tissue sample of tonsil, hiag, heart, liver, mesenteric lymph node, kidney and inguinal lymph node was placed into a single container with buffered 10% formalin; while another tissue sample from the same aforementioned organs was placed into a Whirl-pak (M-Tech Diagnostics Lid., Thefwaii, UK.) and each Whirl-pak was placed on tee. Each container was properly labeled. Sample collections were recorded on the Necropsy Report Form. Afterwards, formalin-fixed ⁽ issue samples and a Diagnostic Request Form, were submitted for IHC testing. IHC testing was conducted in accordance with standard iSti laboratory procedures for receiving samples, sample and slide preparation, and staining techniques. Fresh tissues in Whirl-paks were shipped with ice packs to the Study Monitor for storage (-70° ± 10° C) and passible future use. Fomialio-fixed tissues were examined by a pathologist for detection of PCV2 by IHC and scored using the following scaring system : 0 ~ None; 1 - Scant positive staining, few sites; 2 = Moderate positive staining, multiple sites: and 3 = Abundant positive staining, diffuse throughout the tissue. Due to the fact that the pathologist could not positively differentiate inguinal LN from mesenteric LN, results for these tissues were si.nip.ty labeled as Lymph Node and the score given the highest score for each of the two tissues per animal.

Results

Results for this example are given below. It is noted that one pig from Group 9 died before Day 0, and 5 more pigs died post-vaccination ( I pig from Group 4; I pig from Group 6; 2 pigs from Group 8; and 1 pig from Group 9). Post-mortem examination indicated all six died due to underlying infections that were not associated with vaccination or PMWS. Additionally, no adverse events or injection site reactions were noted with any groups.

Average daily weight gain (ADWG) results are presented below in Table 6. Group 9, the strict negative control group, had the highest ADWG (1.06 . 0.17 lbs/day}, followed by Group 5 (0.94*- 0.22 lbs/day), which received one dose of 8 | of rORF2. Group 3, which received one dose of 4 μ$ ofvORFZ, had the lowest ADWG (0.49 * 0.2i lbs/day), followed by Group 7 (0.50i 0.15 lbs/day), which received 2 doses of killed vaccine.

Table 6. Summary of Group Average Daily Weight Gain (ADWG)

Group Treatment I ISi AD WG - lbs/day (Day 24 to Day 49) or adjusted for pigs dead before Day 29

S. vORF2 - 16 (1 dose) 1 1.2 0.87 ± 0.29 lbs/day vORF2 - S pg (1 dose) I 12 0.70 ± 0.32 lbs/day vORF2 - 4 (ig (1 dose) I 12 0.49 * 0.21 lbs/day

4 rORf ^' 2 - 16 ¾ (.1 dose) 1 11 0.84 * 0.30 lbs/day

5 rORF2 - 8 jig ( l dose) 1 12 0,94 ± 0,22 lbs/day

6 rORF2 - 4 pg (1 dose) I H 0.72 * 0.25 Ibs/day

7 K V (2 doses) I 12 0.50 ± 0. 1 lbs/day

8 Challenge Controls 1 io 0.76 * 0.19 lbs/day

9 Strict Negative Controls 1 1 1 0.17 lbs/day vORF2 isolated viral ORF2; rORF2 - - recombinant baculovirus expressed ORF2; killed whole eel! virus ~ PCV ^' 2 virus grown in suitable cell culture

PCV2 serology results are presented be!ow in Table 7. All nine groups were seronegative for PCV2 on Day -3. On Day 1 . Groups receiving vORF2 vaccines had the highest titers, which ranged from 187.5 to 529.2. Pigs receiving killed viral vaccine had the next highest titers, followed by tbe groups receiving rORF2 vaccines. Groups 8 and 9 reraaiaed seronegative at this lime. On Day 24 and Day 31, pigs receiving ^' vORF2 vaccines continued to demonstrate a strong serologicai response, followed closely by the group that received two doses of a killed viral vaccine. Pigs receiving iO ^' F2 vaccines were slower to respond serologically and Groups 8 and 9 continued to remain seronegative. On Day 49, pigs receiving vORF2 vaccine. 2 doses of the killed viral vaccine and the lowest dose of rO ^' RF2 denKmsirated She strongest serological responses. Pigs receiving 16 }ig and 8 pg of rQ.RFl vaccines had slightly higher IFA titers than challenge controls. Group 9 on Day 49 denKmsirated a strong serological response.

Table 7. Summary of Group PCV2 IFA Titers

AVERAGE IFA TITER

V0RF2 - isolated viral ORF2: rORF2 ~ recombinant bacukwims expressed. ORf 2; killed whole ceil virus ~ PCV.2 virus grown in suitable cell culture

*For calculation purposes, a <100 IFA titer was designated as a titer of "50"; a >6400 IFA titer was designated as a titer of " i 2,800".

**Day of Challenge

*** Day of Necropsy

The results from the post-challenge clinical observations are presented below in Tabie 8. This summary of results includes observations for Abnormal Behavior, Abnormal Respiration. Cough and Diarrhea. Table 9 includes the results from the Summary of Group Overall Incidence of Clinical Symptoms and Tabie 10 includes results from the Summary ¹ of Group Mortality Rates Post-challenge. The most common clinical symptom noted in Shis study was abnormal behavior, which was scored as mild to severe lethargy. Pigs receiving the 2 lower doses of vOR.F2, pigs receiving 16 ¾ of rORF2 and pigs receiving 2 doses of KV vaccine had incidence rates of 27.3%. Pigs receiving 8 g of rORF2 and ihe strict negative control group had no abnormal behavior. None of the pigs in {his stud demonstrated any abnormal respiration. Coughing was noted frequently in all groups (0 to 25%}, as was diarrhea (0-20%). None of the clinical symptoms noted were pathognomic for PMWS.

The overall incidence of clinical symptoms varied between groups. Groups receiving any of the vORF2 vaccines, the group receiving 16 μ of rOR.F2, the group receiving 2 doses of V vaccine, and ihe challenge control group had the highest incidence of overall clinical symptoms ( 36.4%). The strict negative control group, the group receiving 8 fig of rO ^' RF2 and the group receiving 4 gg of rORF2 had overall incidence rates of clinical symptoms of 0%, 8.3% and 9.1%, respectively.

Overall mortality rates between groups varied as well. The group receiving 2 doses of KV vaccine had the highest mortality rate (16.7%); while groups that received 4 ug of vORF2, .16 pg of rORF2, or 8 pg of rORF2 and the strict negative control group all had 0% mortality rates.

Table 8. Summary of Group Observations for Abnormal Behavior, Abnormal

Respiration, Cough, and Diarrhea

virus - PCV2 vims grown in suitable cell culture

'Total number of pigs in each group that demonstrated any abnormal behavior for at least one day

otal number of pigs in each group that demonstrated any abnormal respiration for at least one day

Total number of pigs in each group that demonstrated a cough for at least one day

Total number of pigs in each group that demonstrated diarrhea for at least one day

Table 9. Summary of Group Overall Incidence of Clinical Symptoms

rORF2 - 8 g ^' (l dose) 12 i ¹ I 8.3%

virus - CV2 vims grown in suitable ceil culture

⁵ Total number of pigs in each group that demonstrated any clinical symptom for at least o«e day

Tabic 1 . Summary of Group Mortality Rates Post-challenge

8 Challenge Controls 10 1 Η>··„

9 Strict ^" Negative Controls Π 0 0%

VORF2 - isolated viral ORF2; rORF2 - reeorabin ant bacul vinir i expressed ORF2; killed whole cell virus ~ PCV2 virus grown in suitable cell culture

PCV2 nasai shedding remits are presented below in Table S.1 . Following challenge on Day 24, .1 pig in Group 7 began shedding PCV2 on Day 27. None of the other groups experienced shedding until Day 33. The hulk of nasal shedding was noted from Day 35 to Day 45. Groups receiving any of the three vORF2 vaccines and groups receiving either 4 or 8 pg of rORF2 had Che lowest incidence of nasai shedding of PCV2 (< 9.1%). The challenge control group (Group 8) had the highest sheddin rate (80%). followed by the strict negative control group (Group 9), which had art incidence rate of 63.6%.

Table I I . Summary of Groan Incidence of Nasai Shedding of PCV2

7 KV (2 doses) 12 1 5 41.7%

8 Challenge Controls io 1 8 80%

9 Strict Negative Controls n ! 7 63.6% vORF2 - isolated viral O F2; rORP2 - recombinant bsculovims expressed ORP2: killed whole cell virus ^™ PCV2 virus grown in suitable cell culture

The Summary of Group incidence of Icterus, Group incidence of Gastric Ulcers, Group Mean Lung Lesion Scores, and Group incidence of Lung Lesions are shown below in TableI2. Six pigs died at the first test site during the post-vaccination phase of the study (Group 4, Group 6, ^::: 1 ; Group 8, ^::: 2; Group 9, N ^::: 2). Four out of six pigs bad fibrinous lesions in one or more body cavities, one pig (Group 6) bad lesions consistent with clostridial disease, and one pig (Group 9) had no gross lesions. None of the pigs that died during the post- accination phased of (he study had lesions consistent with PMWS.

Pigs that died post-challenge and pigs euthanized on Day 49 were neeropsied. At necropsy, icterus and gastric ulcers were not present in any group. With regard to mean % .lung .lesions. Group 9 had lowest mean % lung lesions (0%), lo!lowed by Group .1 with 0.40 * 0.50% and Group 5 with 0.68 * 1.15%. Groups 2. 3, 7 and 8 had the highest mean % lung lesions i> 7.27%). Bach of these four groups contained one pig with % lung lesions >71.5%, which skewed the results higher for these four groups. With the exception of Group 9 with 0% lung lesions noted, the remaining 8 groups had < 36% lung lesions. Almost all lung lesions noted were described as red/purple and consolidated.

Table 12. Summary of Group incidence of Icterus, Group incidence of Gastric Ulcers, Group Mean % Lung Lesion Scores, and Group incidence of Lung Lesions Noted Group Treatment Icterus Gastric Mean % l.img Incidence of

Ulcers Lesions Lang Lesions

Noted

S. vORF2 - K» {ig (i 0/S.2 (0%) y/12 0.40 ± 0.50% 10/12 dose) (0%) (83%)

2 vORF2 - 8 iig (1 dose) 0/12 (0%) 0/12 7.41 -fc 20.2% 10/12

(0%) (83%) vORF2 - 4 ( 1 dose) 0/12 (0%) 0/12 9.20 .:. 20,9% 1 /12

(0%) (83%)

4 rORF2 - 16 Ε (1 0/1 1 (0%) 0/11 1.5 4.74% 4/13 dose) (0%) (36%)

5 iORF2 - 8 μ ( 1 dose) 0/5.2 (0%) 0/12 0.68 * 1.15% 9/12

(0%) (75%)

6 J-ORF2 - 4 (1 dose) 0/11 (0%) 0/1 1 2.95 ± 5.12% 7/1 1

(0%) (64%)

7 KV (2 doses) 0/12 (0%) 0/1.2 7.27 & 22.9% 9/12

(0%) (75%)

8 Challenge Controls 0/10 O/iO 9.88 * 29.2% 8/10

(0%) (0%) (80%)

9 Strict Negative 0/1 1 (0%) o/n o/n 0/11

Controls (0%) (0%) (0%) vQRF2 = isolated viral ORF2; rORF2 ^::: recombinant baculoviras expressed ORF2; KV or killed whole ceil virus ~ PCV2 virus grown in suitable cell culture

The Summary of Group LUC Positive Incidence Results is shown in Table 13. Group 1 (vQRF2 - 16 μ and Group 5 (rORF2 - 8 ) had the lowest rate of ! I IC positive results (16.7*4). Group 8 (Challenge Controls) and Group 9 (Strict Negative Controls) had the highest rate of lHC positive results, 90% and 90,9%, respectively .

Table 13. Summary of Group ifiC Positive Incidence Rate

vORF2 ~ isolated viral ORP2; xORP2 ~ reeonibtnant. bacu!ovirus ex ressed ORF2: KV or killed whole ceil virus ^::: PCV2 virus grown in suitable ceil culture Post-challenge. Group 5, which received one dose of S ¾ of rORF2 antigen, outperformed the other 6 vaccine groups. Group 5 had the highest ADWG (0.94 * 0.22 lbs/day), the lowest incidence of abnormal behavior (0%), the second lowest incidence of cough (8.3%). the lowest incidence of overall clinical symptoms (8,3%), the lowest mortality raie (0%), the lowest rate of nasal shedding of PCV2 (8.3%), the second lowest rate for mean % lung lesions (0.68 ± 1 ,15%) and the lowest incidence rate for positive tissues 06.7%). Groups receiving various ieveis of rORF2 antigen overall outperformed groups receiving various le els of vO.RFl and the group receiving 2 doses of killed whole eel! PCV2 vaccine performed the worst Tables 14 and 15 contain summaries of group post-challenge data.

Table 14. Summary of Group Post-Challenge Data - Part 1

5 12 rORF2 - 8 ug 0.94. 0/12 (0%) 1/12 8.3% (1 dose) 0.22 (8.3%

6 11 iORF2 - 4 g 0.72 ± 1/11 (9.1% 0/1! 9.1%

(1 dose) 0.25 (0%)

12 V 0.50.·. 7/12(58.3) 0/12 58.3% (2 doses) 0/15 (0%)

8 It) Challenge 0.76 ± 1/10(10%) 2/10 40%

Controls 0.19 (20%

9 11 Strict Negative 1.06* 0/11 (0%) 0/11 0%

Controls 0.17 (0%) vORF2 ~ isolated viral OEF2: rORF'2 - recombinant baeu!ovirus expressed ORF2; KV or killed whole cell virus - PCV2 virus grown in suitable cell culture

Table 15. Summary of Group Post-Challenge Daa - Part 2

2 vORP2 - 4 μ 0% 8.3% 9.20 ± 66.7% (1 dose) 20.9%

4 1 1 rORF2 - 16 _, «g 0% 18.2% .! .50 ± 36.3%

i dose) 4.74%

5 12 rO ^' RF2 - 8 ¾ 0% 8.3% 0.68 ± 16.7%

(1 dose) 1.15%

6 1 1 fORF2 - 4 _μ8 9.1% 9.1% 2.9:5 ± 36.4%

(1 dose) 5.12%

7 12 KV 16,7% 41 ,7% 7.27 ± 41.7%

(2 doses) 22.9%

8 10 Challenge 10% 80% 9.88 dt 90.0%

Controls 29.2%

9 .1 Strict Negative 0% 63.6% 0/1 1 90.9%

Controls (0%) vO P2 - isolated viral ORF2; rGRF2 - re aiabinant baculovirus expressed OR.F2; KV or killed whole cell virus ~ PCV2 virus grown in suitable cell culture

Results of this study indicate that ail further vaccine efforts should focus on a rORF2 vaccine. Overall, nasal shedding of PC V2 was delected post-challenge and vaccination with a PCV2 vaccine resulted in a redaction of shedding, imnuinoluslcchemistry of selected iytnphoid tissues also served as a good parameter for vaccine efficacy , whereas large differences in ADWG, clinical symptoms, and gross lesions were not detected between groups. This study was complicated by she fact that extraneous PCV2 was introduced at some point dining the study, as evidenced by nasal shedding of PCV2, PCV2 seroconversion and positive IHC tissues ia Group 9, the strict negative control group. Discussion

Seven PCV2 vaccines were evaluated in this study, which included three different dose levels of vORF2 antigen administered once on Day 0, three different dose levels of I0 F2 antigen administered once on Day 0 sad one dose level of killed whole cell PCV2 vaccine administered on Day 0 and Day 14, Overall, Group 5, which- received 1 dose of vaccine containing 8 § of rORF2 antigen, had the best results. Group 5 had the highest ADWG, the lowest incidence of abnormal behavior, the lowest incidence of abnormal respiration, the second lowest incidence of cough, the lowest incidence of overall clinical symptoms, the lowest mortality rate, the lowest rate of nasal shedding of PCV2, the second lowest rate for mean % lung lesions and the lowest incidence rate for positive IHC tissues.

Interestingly, Group 4, which received a higher dose of rORF2 antigen than Group 5, did not perform as well or better than Group 5. Group 4 had a slightly lower ADWG, a higher incidence of abnormal behavior, a higher incidence of overall clinical symptoms, a higher rate of nasal shedding of PCV2, a higher mean % lung lesions, and a higher rate for positive IHC tissues than Group 5. Statistical analysis, which may have indicated that the differences between these two groups were not statistically significant, was not conducted on these data, bat there was an observed trend that Group 4 did not perform as well as Group 5.

Post-vaccination, 6 pigs died at the first study site. Four of the six pigs were froni Group 8 or Group 9. which received no vaccine. None of the six pigs demonstrated lesions consistent with PMWS, no adverse events were reported mid overall all seven vaccines appeared to be safe when administered to pigs approximately 1 1 days of age. .During the post-vaccination phase of the study, pigs receiving either of three dose levels of V0 F2 vaccine o killed whole cell vaccine had the highest IF AT levels, while Group 5 had the lowest IF. AT levels just prior to challenge, of the vaccine groups.

Although not formally proven, the predominant route of transmission of PCV2 to young swine shortly after weaning is believed to be by oronasai direct contact and an efficacious vaccine that reduces nasal shedding of PCV2 in a production setting would help control the spread of infection. Growps receiving one of three vO ^' F2 antigen levels and the group receiving 8 § of rORJF2 had the Iowest incidence rate of nasal shedding of PCV ^' 2 (8.3%). Expected!y, the challenge control group had the highest incidence rate of nasal shedding (80%).

Gross lesions in pigs with PMWS secondary to PCV2 infection typically consist of generalised lymphadenopathy in combination with one or a multiple of the following: (1) interstitial pneumonia with interlobular edema, (2) cutaneous pallor or icterus, (3) mottled atrophic livers, (4) gastric ulcers, (5) nephritis and (6) reproductive disorders, e.g. abortion, stillbirths, mummies, etc. At necropsy, icterus, .hepatitis, nephritis, and gastric ulcers were »oi noted in any groups and lymphadenopathy was not specifically examined for. The mean % lung lesion scores varied between groups. The group receiving 16 . of vO F2 antigen had the lowest mean % king lesio score (0.40 ± 0.50%), followed by the group that received 8 jig of rORF2 (0.68 * 1.15%). As expected, the challenge control group had the highest mean % lung lesion score (9.88 * 29.2%). In ail four groups, the mean % Sung lesion scores were elevated due to one pig in each of these groups that had very high lung lesion scores. Most of the king lesions were described as .red purple and consolidated. Typically, king lesions associated with PMWS are described as tan and non -collapsible with interlobular edema. The lung lesions noted in this study were either not associated with PCV2 infection or a second pulmonary infectious agent may have been present. Within the context of this study, the % lung lesion scores probably do not reflect a true measure of the amount of king infection due to PCV2. Other researchers have demonstrated a direct correlation between the presence of PCV2 antigen by IHC and histopathology. Histopaihology on select tissues was not conducted with this study. Group ! (1.6 μ of vOR.F ^' 2) and Group 5 {8 of rOR.F2) had the iowest incidence rate of pigs positive- for PC V2 antigen (8.3%), while Group 9 (the strict negative control group - 90.9%) and Group 8 (the challenge conirol group - 90.0%) had the highest incidence rates for pigs positive for PCV2 antigen. Due to She non-subjective nature of this test. IHC results are probably one of the best paraineters to judge vaccine efficacy on.

Thus, in one aspect of the present invention, the Minimum Portective Dosage (MPD) of a I ml/1 dose recombinant product with extracted PCV2 O.RF2 (rORF2) antigen in the CDCD pig model in the face of a PCV2 challenge was determined. Of the three groups that received var ing levels of rOR.F2 antigen. Group 5 (8 pg of rOR.F2 antigen) clearly had the highest level of protection. Group 5 either had the best results or was tied for the most favorable results with regard to all of the parameters examined. ^' When Group 5 was compared with the other six vaccine groups post-challenge, Group 5 had the highest ADWG (0.94 A. 0.22 lbs/day), the lowest incidence of abnormal behavior (0%). the second lowest incidence of cough (8.3%). the lowest incidence of overall clinical symptoms (83%). the lowest mortality rate (0%). the lowest rate of nasal shedding o PCV2 8.3%), the second .lowest rate for mean % lung lesions (0.68 * J ..15%) and the lowest incidence rate for positive IHC tissues (16.7%).

In another aspect of the present invention, the MPD of a I ml/1 dose conventional product that is partially purified PCV2 ORF2 (vORFZ) antigen in the CDCD pi model in the lace of a PCV2 challenge was determined. Of the three groups that received varying le vels of VO.R-F2 antigen. Group I (16 pg of vQRFZ) had the highest level of protection. Group I outperformed Groups 2 and 3 with respect to A.DWG, mean. % lung lesions, and IHC. Groups 1 and 2 ( ,ug of vO F2 antigen) performed equally with respect to overall incidence of clinical symptoms, Group 3 (4 » of vO ^' RF2 antigen) had the lowest mortality rate, and all three groups perfomied equally with respect to nasal shedding. Overall, vORF vaccines did not perform as well as rOR ^' F vaccines.

In yet another aspect of the present invention, (he efficacy of a maximum dose of a IveiVt dose Conventional Killed ^' PCV2 vaccine in the CDCD pig model in the face of a PCV2 challenge was determined. Of the seven vaccines evaluated in this study, she killed whole cell PCV2 vaccine perfomied Ihe worst. Piglets receiving two doses of killed whole cell PCV2 vaccine had the lowest ADWG, the second highest rate of abnormal behavior (58.3%), the second highest overall incidence of clinical sympiams (58.3%), the highest mortality rate (16.7%). the second highest incidence of nasal shedding (41.7%), highest mean % lung lesions (9.88 * 29.2%), a high incidence of lung lesions noted (75%) and a moderate IRC incidence rate in tissues (41.7%). However, it was still effective at. invoking an immune response.

In still another aspect of the present invention, nasal shedding of PCV2 was assessed as an efficacy parameter and the previous PCV.2 efficacy parameters from previous studies were reconfirmed Results from this study indicate that nasal shedding of PCV2 occurs following intra nasal challenge and that PCV2 vaccines reduce nasal shedding of PCV2 post- challenge. Furthermore, results from this study and reports in the literature indicate that THC should continue to lie evaluated in future PC. V'2 vaccine trials as well

Some additional conclusions arising from this study are that lyrnphadenopathy is one of the hallmarks of PMWS, Another one of the hallmarks of PMWS is lymphoid depletion and nuiltinuc lea ted/giant histiocytes. Additionally, no adverse events or injection site reactions were noted for any of the 7 PCV2 vaccines and all 7 PCV2 vaccines appeared to be safe when administered to young pigs. This example tests the efficacy of eight PCV2 candidate va cines and reconfirms PCV2 challenge parameters from earlier challenge studies following exposure to a virulent strain of PCV2, One hundred and fifty ( 50) cesarean derived colostrum deprived (CDCD) piglets, 6-16 day s of age. were blocked by weight and randomly divided into 10 groups of equal size. Table 16 sets forth the General Study Design for this Example.

Table 16. General St«dy Desi a

The vaccine formulations given to each group were as follows. PCV2 Vaccine No. 1, administered at 1 x 2 ml dose to Group 1 , was a high dose (16 ug/2 ml dose) of inactivated recombinant ORF2 anligen adjuvanted with IMS 13 ! 4 (16 ug fORF2 - IMS 1314). PCV2 Vaccine No. 2, administered at 1 x 2 ml dose to Group %, was a high dose (16 itg/2 ml dose) of a partially purified VIDO R- l generated PCV2 ORF2 antigen adjnvanted with Carbopol ( 16 ug vOR.F2 - Carbopol). PCV2 Vaccine No. 3. administered at 1 2 nil dose to Group 3. was a high dose (.16 ug/2 ml dose) of inactivated recombinant O.RF2 anligen adjuvanted with Carbopol (16 ug rORF2 - Carbopol). PCV2 Vaccine No. 4, administered at 1 x 1 ml dose lo Group 4, was a high dose (16 ug .I nil dose) of a partially purified V.1.DO R- 1 generated PCV2 ORF2 antigen adjuvanted with Carbopol (1 ug vORF2 - Carbopol). Vaccine No. 5. administered at .1 x 2 ml dose io Group 5, was a 4 ug 2 ml dose of an inactivated recombinant O.RF2 antigen adjuvanted with Carbopol (4 ug rOR.P2 - Carbopol). PCV2 Vaccine No. 6. administered at 1 x 2 ml dose to Group 6, was a .1 itg/2 mi dose of an inactivated recombinant O.RF2 antigen adjuvanted with Carbopol (.1 ug rORF2 - Carbopol). PCV2 Vaccine No. 7, administered at 1 x 2 nil dose to Group 7 _* was a low dose (0.25 ug/2 ml dose) of inactivated recombinant ORP2 antigen adjirvanted with Carbopol (0.25 ug rO.RF2 - Carbopol), FCV2 Vaccine No. 8. administered at 1 2 mi dose to Group 8, was a high dose (pre-inactivation titer > 8.0 iog/2 nil dose) inactivated Conventional Killed VlDQ R-l generated PCV2 Strove antigen adjnvanted with Carbopol (>8.0 log V - Carbopol). On Day 0, Groups 1-8 were treated with their assigned vaccines. Groups 1-3 and 5-8 received boosters of their respective vaccines again on Day 14. The effectiveness of a single dose of 16 $rg of vORF2 - Carbopol was tested on Group 4 which did not receive a booster on Day 14. Piglets were observed for adverse events and injection site reactio s following both vaccinations- OB Day 21 the piglets were moved to a second study site where Groups 1 -9 were group housed in one budding and Group was housed in a separate budding. Ail pigs received keyhole limpet heinocyanin emulsified with incomplete Freund ^' s adjuvant ( LH TCFA) on Days 22 and 28. On Day 25. Groups 1-9 were challenged with approximately 4 logs of virulent PCV2 virus. By Day 46, very few deaths had occurred in the challenge control group, in an attempt to immunostiinulate the pigs and increase the virulence of the PCV2 challenge material, all Groups were treated with 1NGFLVAC¾ ^: PRRSV MLV (Porcine Reproductive and Respiratory' Vaccine, Modified Live Virus) on Day 46.

Pre- and post-challenge blood samples were collected for PCV2 serology. Post- challenge, tody weight data for determination of average daily weight gain (ADWG) and observations of clinical signs were collected. On Day 50, all surviving pigs were necropsied, gross lesions were recorded, lungs were scored for pathology, and selected tissues were preserved in formalin for examination by lmmxmohisiochemistry (HiC) for detection of PC V2 antigen at a later date. Materials and Methods

This was a partially-blind vaccmation-challenge- fusibility st»dy conducted in CDCD pigs, 6 to 1 days of age on Day 0. To be included in the study, PCV2 1FA titers of sows were < 1 : 1000. Additionally, the serologic status of sows were from a known PRRS-negaiive herd. Sixteen (16) sows were tested for PCV2 serological status and all sixteen. ( 16) had a PCV2 titer of < 1000 and were transferred to the first study site. One hundred fifty {I SO} piglets were delivered by cesarean section surgeries and were available for this study on Day -3. On Day -3, 150 CDCD pigs at the first study site were weighed, identified with ear tags, blocked by weight and randomly assigned to 1 of 10 groups, as set forth above in table 16. Blood samples were collected from all pigs. If any test animal meeting the inclusion criteria was enrolled in the study and was later excluded for any reason, the Investigator and Monitor consulted in order to determine the use of data callecied from the animal in the final analysis. The date of which enrolled piglets were excluded and the reason for exclusion was documented. No sows meeting the inclusion criteria, selected for the study and transported to the .first study site were excluded. No piglets were excluded from the study, and no test animals were removed from the study prior to termination. Table 17 describes the time frames for the key activities of this Example.

Table 17, Study Activities

Following completion of the in-life pha.se of the study, formalin fixed tissues were examined by fcmiunohisioehejnistrv (IRC) for detectio , of PCV2 antigen by a pathologist, blood samples were evaluated for PCV2 serology, arid average daily weight: gain. (ADWG) was determined from Day 25 to Day 50.

Animals were housed at the first study site in individual cages in seven rooms from birth to approximately 11 day s of age (approximately Day 0 of the study). Each room was identical in layout and consisted of stacked individual stainless steel cages with heated and filtered air supplied separately io each isolation unit. Each room had separate heat and ventilation, {hereby preventing cross-contamination of air between rooms. Animals were housed in two different buildings at the second study site. Group 10 (The Strict negative control group) was housed separately in a converted nursery building and Groups 1 -9 were housed in a converted farrowing building. Each group was housed in a separate pen (14-15 pigs per pen) and each pen provided approximately 2.3 square feet per pig. Groups 2. 4 and 8 were penned in three adjacent pens on one side of the alleyway and Groups 1, 3. 5, (>, 7, end 9 were penned in six adjacent pens on the other side of the alleyway. The Group separation was due to concert) by She Study Monitor that vaccines administered to Groups 2, 4, and 8 had not been fully inactivated. Each pen was on an elevated deck with plastic slatted floors. A. pit below the pens served as a holding tank for excrement and waste. Each building had its own separate heatin and ventilation systems, with l.iitle likelihood of cross- coirtamination of air between buildings.

At the first study site, piglets were fed a specially formulated milk ration from birth to approximately 3 weeks of age. All piglets were consuming solid, special mixed ration by Day 21 (approximately 4 ¼ weeks of age). At the second study site, all piglets were fed a custom non-medicated commercial mix ration appropriate for their age and weight, ad libitum. Water at both study sites was also available ad libitum.

All test pigs were treated with 1 ,0 m.L of NAXCEL®, S.M, in alternating hams on Days 19, 20, and 21. in addition. Pig No. I I (Group 1) was treated with 0.5 ml, of ^" N AXCEL& 1M on Day 10. Pig No. 13 (Group 10) was treated with 1 raL of Penicillin and 1 m.L of PRE.DEF* 2X on Day 10. Fig No. 4 (Group 9) was treated with 1.0 mi of NAXCEL& ΓΜ. on Day 1.1 , and Pigs 1 (Group i), 4 and i l were each treated with i.O rn ^' L of NAXC.ELC ' on Day 1.4 for various health reasons.

While at both study sites, pigs were under veterinary' care. Annual health examinations were conducted on Day -3 and were recorded on the Health Examination Record Form. All animals were in good health and nutritional status before vaccination as determined by observation on Day 0. All test animals were observed to be in good health and nutritional status prior to challenge. Carcasses and tissues were disposed of by rendering. Final disposition of study animals was recorded on the Animal Disposition Record.

On Days 0 and 14, pigs assigned to Groups 1-3 and 5-8 received 2,0 mL of assigned PCV2 Vaccines 1-4, respectively,, IM in the right and left neck region, respectively, using a sterile 3.0 mL Luer-iock syringe and a sterile 20g x ½" needle. Pigs assigned to Group 4 received 1,0 mL of PCV2 Vaccine No, 2, IM in the right neck region using a sterile 3.0 mL Lner-lock syringe and a sterile 20g x ½," needle on Day 0 only.

On Day 22 all test pigs received 2.0 mL of KLH/ICFA. IM in the left neck region using a sterile 3.0 mL Luer-loek sy ringe and a sterile 20g xl " needle. On Day 28 all test pigs received 2.0 mL of KLH/ICFA in the right ham region using a sterile 3.0 mL Luer-loek syringe and a sterile 20g x I " needle.

On Day 25. pigs assigned to Groups 1.-9 received .1.0 nil. of PCV2 ISO VOL challenge material (3.98 log;,, TCIDja/mt.) IM in the right neck region using a sterile 3.0 mL Liter-lock syringe and a sterile 20g x 1." needle. An additional 1.0 ml, of the same material was administered IN to each pig (0.5 mL per nostril) using a sterile 3.0 mL Lner-lock syringe and nasal caniita.

On Day 6, all test pigs received 2.0 ml, i GELVACS PRRS MLV, IM, in the right neck region using a sten!c 3.0 ml, L erOlock syringe and a sten!c 20g x 1 " needle. The PRRSV MLV was administered in an attempt to increase virulence of the PCV2 challenge material.

Test pigs were observed daily for overall health and adverse events on Day -3 and from Day 0 to Day 2.1. Each of the pigs were scored for normal or abnormal behavior, respiration, or cough. Observations were recorded on the Clinical Observation Record. All test pigs were observed from Day 0 to Day 7, and Group 7 was further observed from Day 14 to 21 , for injection site reactions. Average daily weight gain wa determined by weighing each pig on a calibrated scale on Da s -3, 25 and 50. or on the day that a pig was found dead after challenge. Body weights were recorded on die Body Weight Form. Day -3 body weights w ere utilized to block pigs prior to randomization. Day 25 and Day 50 weight data was utilized to determine the average daily weight gain (ADWG) for each pig during these time points. For pigs that died alter challenge and before Day 50, the ADWG was adjusted to represent the A.DWG from Day 25 to the day of death.

In order to determine PCV2 serology, venous whole blood was collected from each piglet from the orbital venous sinus on. Days -3 and. 14. For each piglet, blood was collected from the orbital -venous sinus by inserting a sterile capillary tube into the media! eauthus of one of the eyes and draining approximately 3.0 mL of whole blood into a 4.0 mL Serum Separator Tube (SST). On Days 25, 32, and 50. venous whole blood from each pig was collected from the anterior vena cava using a sterile 20g 1 W Vacutainer¾£ needle (Becton Dickinson and Company, Franklin Lakes, Mew Jersey), a VaccutainerD needle holder and a 13 mL SST. Blood collections at: each time point: ere recorded on the Sample Collection Record. Blood in each SST was allowed to clot, each SST was then span down and the serum harvested. Harvested serum was transferred to a sterile snap tube and stored at -70*. 10* C until tested at a later date. Serum samples were tested for die presence of PCV2 antibodies by BiVI-R&D personnel.

Pigs were observed once daily from Day 22 to Day 50 for clinical symptoms and scored for normal or abnormal behavior, respiration or cough. Clinical observations were recorded on the Clinical Observation Record.

Pigs Nos. 46 (Group 1 ) and 98 (Groups 9) died at the first study site. Both of these deaths were categorized as bleeding deaths and necropsies were not conducted on these two pigs. At the second study site, pigs that died after challenge and prior to Day 50, and pigs euthanized on Day 50, were necropsied. Any gross lesions were noted and the percentages of lung lobes with lesions were recorded on the Necropsy Report Form.

From each of the pigs necropsied at the second, study site, a tissue sample of tonsil, lung, heart, and mesenteric lymph node was placed into a single container with buffered 1 % formalin; while another tissue sample from the same aforementioned organs was placed into a WhirJ-pakiRi (M-Tech Diagnostics Ltd., Theiwall, UK.) and each WliM-pak® was placed on ice. Each container was properly labeled. Sample collections were recorded on the Necropsy Report Form. Afterwards, formalin-fixed tissite samples and a Diagnostic Request Fonn were submitted for I ^' HC testing. IHC testing was conducted in accordance with standard laboratory procedures for receiving samples, sample and slide preparation, and staining techniques. Fresh tissues in W rl-paks-f ¹ were shipped with ice packs to the Study Monitor for storage (-70° ±· 10° C) and possible future use.

Formalin-fixed tissues were examined by a pathologist for detection of PC V2 by IHC and scored using: the following scaring system: 0 ~ None; J - Scant positive staining, few sites; 2 = Moderate positive staining, multiple sites; and 3 - Abundant positive staining, diffuse throughout the tissue. For analytical purposes, a score of 0 was considered ^" negative," and a score of greater than 0 was considered ^" positive. ^"

Results

Results for this example are given below. It is noted that Pigs No. 46 and 98 died on days 1 and 25 respectively. These deaths were categorized as bleeding deaths. Pig No. .11 (Group 1) was panting with rapid respiration on Day 15. Otherwise, ail pigs were normal for behavior, respiration and cough during this observation period and no systemic adverse events were noted with any groups. No injection site reactions were noted following vaccination on Day 0. Following vaccination on Day 14, seven (7) out of fourteen ( 14) Group 1 pigs (50.0%) had swelling with a score of "2 ^" on Day 15, Four (4) out of fourteen (14) Group 1 (28.6%) still had a swelling of ~2 ^W on Day 16. Hone of the other groups experienced injection site reactions following either vaccination.

Average daily weight gain (ADWG) results are presented below in Table 18. Pig Nos. 46 and 98 that died from bleeding were excluded from group results. Group 4, which received one dose of 16 ug vORF2 -- ^■ Carbopol had the highest ADWG (1.16 ± 0.26 lbs/day), followed by Groups 1, 2 3, 5, 6, and 10 which had ADWGs that ranged from 1.07 ± 0.23 Ibs/day to 1.1 1 ± 0.26 lbs/day. Group 9 had the lowest ADWG (0.88 ± 0.29 lbs/day.), followed by Groups 8 and 7, which had ADWGs of 0.93 ± 0.33 lbs/day and 0.99 ± 0.44 lbs/day , respectivel .

Table 18, Summary of Group Average Daily Weight Gains (ADWG)

vQKF2 - isolated viral ORF2; tORF2 ~ recombinant baculovtrtis expressed OR.F2

whole c ll virus ~ PCV.2 virus grown in suitable cell culture

PVC2 serology results are presented below in Table 19. All ten (.1 ) groups were seronegative for PCV2 on Day -3. On Day 14. PCV2 titers remained low for ail ten ( 10) groups (range of 50-113), OK Day 25, Group 8, which received the whole cell tailed virus vaccine, had She highest PCV2 titer {4617), followed by Group % which received 16 ug vORF2 - Carbopol, Group 4, which received as single dose of 16 ug vORF2 - Carbopol and Group 3, which received 16 ug rORF2 - Carbopol, which had titers of 2507, 1920 and 1503 respectively. On Day 32 {one week post challenge}, titers for Groups 1-6 and Group 8 ranged from 2360 to 7619; while Groups 7 (0.25 ug rO F2 - Carbopol). 9 (Challenge Control), and 10 (Strict negatiye control) had titers of 382, 129 and 78 respectively . On Day 50 (day of necropsy), ail ten (10) groups demonstrated high PCV2 titers (> 1257).

On Days 25, 32, and 50. Group 3, which received two doses of 16 ug rORF2 - Carbopol. had higher antibody liters than Group L which received two doses of 16 ug rORF2 - IMS 1314. On Day s 25, 32 and 50, Group 2. which received two doses of 16 ug vORF2, had higher titers than Group 4, which received only one does of the same vaccine. Groups 3, 5, 6, 7, which received decreasing levels of rORF2 - Carbopol, of 1.6, 4, 1, and 0,23 ug respectively, demonstrated correspondingly decreasing antibody titers on ays 25 and 32.

Tabic 19. Summary of Group PCV2 1 A Titers

Group Treatment Day -3 Day 14** Day 25*** \ Day 32 Day

1 rORF2 - 1 ug - I 50 64 646 j 3326 431.4 IMS 1314 2 doses

2 vORF2 - 16 50 1 .10 2507 i 5627 4005 Carbopol 2 doses

rORF2 - 16 - 50 80 1 03 1 5120 6720 Carbopol 2 doses

4 - .16 - . I 50 1 13 1920 Ϊ 3720 1257 Carbopol 1 dose

5 rORF2 - 4 - I 50 61 1867 1 3933 4533 Carbopol J dose

*For calculation purposes, a 1 0 1FA titer was designated as a titer of "50"; a >6400 1FA titer was designated as a titer of ^" 12.800".

**Day of Challenge

***Day of ^" Necropsy

The results from the post-challenge clinical observations are presented below. Table 20 includes observations for Abnormal Behavior, Abnormal Respiration. Cough and Diarrhea. Table 21 includes the results from the Summary of Group Overall incidence of Clinical Symptoms and Table 22 includes results from the Summary of Group Mortality Rates Post-challenge. The incidence of abnormal behavior, respiration and cough post- challenge were low in pigs receiving 16 ug rORF2~iM.S 1314 (Group I), 16 ug rORF2~ Carbopol (Group 3), 1. ug rORF2- arbopol (Group 6). 0.25 ug :rORF2~Carbopol (Group ?), and in pigs in the Challenge Control Group (Group 9). The incidence of abnormal behavior, respiration, and cough posi-ehalleuge was zero in pigs receiving .16 ug vORF2-Carbopol (Group 2), a single dose of 1.6ug vORF2~Carbopol (Group 4). 4 ug rORF2~Carbopol (Group 5). >% log V-Carbopol (Group 8), and in pigs in the strict negative control group (Group 10). The overall incidence of clinical symptoms varied between groups. Pigs receiving 16 ifg ^' vORF2-Carbopol (Group 2), a single dose of 16 ug vORF2 -Carbopol (Group 4), and pigs in the Strict: negative control group {Group 1 ) had. incidence rates of 0%: pigs receiving 16 ug rORF2 ---Carbopol (Group 3), and 1 tig rORF2 -Carbopol (Group 6) had incidence rates of 6,7%; pigs receiving 16 ug rORF2~lMS 1314 (Group 1 ) had an overall incidence rate of 7. 1%: pigs recei ving 4 ug rO F2-Car opol (Group 5), 0.25 og rORF2-€arbopol (Group 7), and >8 lo V vaccine had incidence rates of 13,3%; and pigs in the Challenge Control Group (Group 9) had an incidence rate of 14.3%.

Overall mortality rates between groups varied as well. Group 8. which received 2 doses of KV vaccine had the highest mortality rate of 20.0%; followed by Group 9, the challenge control group, and Group 7, which received 0.25 ug ri RF2-Carbopol and had mortality rates of 14.3% and i 3.3% respectively. Group 4. which received one dose of 16 ug had a 6.7% mortality rate. All of the other Groups, 1. 2, 3, 5, 6, and 10, had a 0% mortality ¹ rale.

Table 20. Summary of Group Observations for Abnormal Behavior, Abnormal

Respiration, and Cough Post-Challenge

"Total number of pigs in each group that demonstrated my abnormal behavior for at .least one day

otal number of pigs in each group that demonstrated any abnormal respiration for at least one day

Total number of pigs in each group that demonstrated a cough for at least one day

Table 21. Summary of Group Overall Incidence of Clinical Symptoms Post-

Challenge

7 1 rO.RF2 - 0.25 Mg - Carbopoi 15 1 2 1 2 doses

8 i KV > 8.0 log - Carbopoi 2 15 1 2 13.3% Ϊ doses

9 i Challenge Controls 14 1 2 14.3%

! 0 j Strict Negative Controls 15 I 0 0.0%

V0RP2 ^» isolated viral ORF2; rORF2 = recombinant baeulovirus expressed O F2; KV or killed whole cell virus ~ PCV2 virus grown itt suitable cell culture

'Total number of pigs in each group that defnoiisirated any clinical symptom for at least one day

Table 22. Summary of Group Mortality Rates Post-Challenge

vORF2 = isolated viral ORP2; rORF2 = recombinant bacn!ovirus expressed ORF2: KV or killed whole cell virus - PCV2 vims grown in suitable cell culture The Summary of Group Mean Percentage Lung Lesions and Tentative Diagnosis is given below in Table 23. Group 9, the challenge control group, had the highest percentage lung lesions with a mean of 10,81 ± 23.27%, followed fay Group 7, which received 0.25 ug rO.RF2-Carbopo! and had a mean of 6.57 ± 24.74%. Group 5. which received 4 ug rORF2- Carbopol and had a mean of 2.88 ± 8.88%, and Group 8, which received She V vaccine and had a mean of 2.01 ± 4.98%, The remaining six (6) groups had lower mean percentage lon lesions that ranged from 0.1 1 ± 0.38% to 0.90 ± 0.1 %.

Tentative diagnosis of pneumonia varied among the groups. Group 3. which received two doses of 16 ug rORF2~Carbopol, had the lowest tentative diagnosis of pneumonia, with 13.3%. Group 9, the challenge control group, had 50% of the group tentatively diagnosed with pneumonia, followed by Group 10. the strict negative control group and Group 2. which received two doses of > ug \ORF2-Carbopol, with 46.7% and 40% respectively, tentatively diagnosed with pneumonia.

Groups 1 , 2. 3, 5, 9, and 10 had 0% of the group tentatively diagnosed as PCV.2 infected; while Group 8, which received two doses if KV vaccine, had the highest group rate of tentative diagnosis of .PCV2 infection, with 20%. Group 7, which received two doses of 0.25 ug iORF2-CarbopoL and Group 4, which received one dose of 16 ug vORF ^' 2-Carbopol had tentative group diagnoses of .PC VI infection in .13.3% and 6.7% of each group, respectively.

Gastric ulcers were only diagnosed in one pig in Group 7 (6.7%); while the other 9 groups remained free of gastric- ulcers. Table 23, Summary of Group Mean % Lung Lesion and Tentative Diagnosis

vORP2 ~ isolated viral ORF2: rORF2 - recombinant b culovirus expressed ORF2; KV or killed whole ceil virus - CV2 vims grown in suitable ceil culture

The Summary of Group IHC Positive incidence Results is shown below in Table 24. Croup 1 116 tig rORF2 -- IMS 1314) had ⁽ he lowest group rate of iHC positive results with 0% of the pig positive for PCV2, followed by Group 2 (16 tig vOR.F2 ~ Carbopol) and Group 4 (single dose 16 ug vORF2 - Carbopol), which had group IHC rates of 6.7% and 13.3% respectively. Group 9, the challenge control group, had the highest iHC positive incidence rate wish 100% of the pigs positive for PCV2. followed by Group 10. the strict negative control group, and Group 8 (KV vaccine), with 93.3% and 80% of the pigs positive for PCV2. respectively.

Tabic 24. Summary of Group IHC Positive Incidence Rate

vORF2 ~ isolated viral OR.F2; rORF2 ^::: recombinant bacu!ovirus expressed ORF2: KV or killed whole ceil vims - PCV2 vints grown in suitable ceil culture

Discussion

Seven PCV2 vaccines were evaluated in this example, which included a high dose (16 μφ of rORF2 antigen adjuvanted with IMS 1314 administered twice, a high dose (16 μ of vORF2 antigen adjuvanted with Carbopol administered once to one group of pigs and twice to a second group of pigs, a high dose (16 u,g) of rORF2 antigen adjuvanted with Carbopol administered twice, a 4 p.g dos of rORF2 antigen adjuvanted with Carbopol adiamistered twice, a i ug dose of rORF2 antigen adjuvanted with Carbopol administered twice, a low dose (0.25 jig) of rORF2 antigen adjuvanted with Carbopol administered twice, and a high dose (> 8 log) of killed whole cell PCV2 vaccine adjuvanted with Carbopol. Overall, Group 1. which received two doses of 16 ug iORF2 - IMS 1314, performed slightly better than Groups 2 through 7, which received vaccines containing various levels of either vORF:2 or rORF2 antigen adjuvanted wiiit Carbopol and much belter than Group 8, which received two doses of killed whole cell PCV2 vaccine. Group 1 had the third highest ADWG (1.80 ± 0.30 lbs/day ), the lowest incidence of abnormal behavior (0%). the lowest incidence of abnormal respiration (0%). a low incidence of cough (7.1%). a low incidence of overall clinical symptoms (7.1%), was tied with three other groups for the lowest mortality rate (0%), the second lowest rate for mean % lung lesions (0.15 & 0.34%), the second lowest: rate for pneumonia (21.4%) and the lowest incidence rate for positive IMC tissues (0%). Group I was. however, the only group in which injection site reactions were noted, which included 50% of the vaccinates 1 day after the second vaccination. The other vaccines administered to Groups 2 through 7 performed better than the killed vaccine and nearly as we!.! as the vaccine administered to Group 1.

Group 8, which received two doses of killed FCV2 vaccine adjuvanted with Carbopol. had the worst set of results for any vaccine group. Group 8 had the lowest ADWG (0,93 0.33 lbs/day), the second highest rate of abnormal behavior (6.7%), the highest rate of abnormal respiration (6.7%), was tied with three other groups for the highest overall incidence rate of clinical symptoms (13.3%), had the highest inortalitv rate of all groups (20%), and had the highest positive IMC rate (80%) of any vaccine grotip. There was concern that the killed whole eel! PCV2 vaccine may not have been fully inactivated prior to administration to Group 8, which may explain this group ^' s poor results. Unfortunately. definitive data was not available to confirm this concern. Overall ia the context of this example, a Conventional Killed FCV2 vaccine did not aid in the reduction of PCV2 associated disease.

As previously mentioned, no adverse events were associaied with the test vaccines with exception of the vaccine adjuvarited with IMS 1314. Injection site reactions were noted in 50.0% of She pigs I day after the secoad vaccination with die vaccine formulated with IMS 13.1 and in 2.8.6% of the pigs 2 days after the secoad vaccination. o reactions were noted in any pigs receiving Car opol adjnvariied vaccines. Any further studies that include pigs vaccinated with IMS 1314 adjuvanted vaccines should continue to closely monitor pigs for injection site reactions.

All pigs were sero-negaiive for PCV2 on Day -3 and only Group 2 .had a titer above 100 on Day 14. On Day 25 (day of challenge). Group 8 had the highest PCV2 antibody titer (4619), followed by Group 2 (230?)., With the exception of Groups 7, 9 aad 1 , all groups demonstrated a strong antibody response by Day 32. By Day 50, ail groups including Groups 7, 9 and 10 demonstrated a strong antibody response.

One of the hallmarks of late stage PCV2 infection and subsequent PMWS development is growth retardation in weaned pigs, and in severe cases, weight loss is noted. Average daily weight gain of groups is a quantitative method of demonstrating growth retardation or weight loss. In this example, there was not a large difference in ADWG between groups. Group 8 had the lowest ADWG of 0.88 0.29 lbs/day. while Group 4 had the highest ADWG of 1.16 ± 0.26 lb/day. Within the context of this study there was not a sufficient difference between groups to base future vaccine efficacy on ADWG,

la addition to weight loss - dyspnea, leghargy, pallor of the skin and sometimes icterus are clinical symptoms associated with PMWS. in this example, abnormal behavior and abnormal respiration and cough were noted infrequently for each group. As evidenced in this study, this challenge model and challenge strain do not result in overwhelming clinical s mptoms and this is not a strong arameter on which to base vaccine efficacy.

Overall, mortality rates were not high in tb.ts example and the lack of a high mortality rate in the challenge control group limits this parameter on which, to base vaccine efficacy. Prior to Da 46. Groups 4 and 7 each had one out of fifteen pigs die. Group 9 had two out of fourteen pigs die and Group 8 had three oat of fifteen pigs die. Due to the fact that Group 9, ⁽ he challenge control group was not demonstrating PCV2 clinical symptoms and only two deaths had occurred in tins group by Day 46, Porcine Respiratory and Reproductive Syndrome Vims (PRRSV) MLV vaccine was administered to all pigs on Day 46. Earlier studies had utilized INGELVAC- PRRS MLV as an urmnmostinruianl to exasperate PCV2- associated PMWS disease and mortality ¹ rates were higher in these earlier studies. Two deaths occurred shortly after administering the PRRS vaccine on Day 46 - Group 4 had one death on Day 46 and Group ? had one death on Day 4? - which were probably not associated with the administration of the PRRS vaccine. By Day 50, Group 8, which received two doses of kilted vaccine, had the highest mortality rate (20%), followed by Group 9 (challenge control) and Group 7 (0.25 ug rORF2 - Carbopol), with mortality rates of 14.3% and 13.3% respectively . Overall, administration of the PRRS vaccine to the challenge model late in the post-challenge observation phase of this example did not significantly increase mortality rates.

Gross lesions in pigs with PMWS secondary to PCV2 infection typically consist of generalized lymphadenopathy in combination with one or more of the following: (i) interstitial pneumonia with interlobular edema, (2) cutaneous pallor or ictenss, (3) mottled atrophic livers. (4) gastric ulcers, (5 ) nephritis and (6) reproductive disorders, e.g. abortion, stillbirths, mummies, etc. At necropsy (Day 50). icterus, hepatitis, and nephritis were not noted in any groups, A gastric ulcer was noted in one Group 7 pig, but lymphadenopathy was not specifically examined for. Based on the presence of iesioas thai were consistent with PC V2 infection, three groups had at least one pig teniatively diagnosed with FCV2 (FMWS). Group 8, which received two doses of killed vaccine, had 20% tentatively diagnosed with PCV2, while Group ? a d Group 4 had 13.3% and 6.7%, respectively, tentatively diagnosed with PCV2. The mean % lung lesion scores varied between groups at necropsy . Groups 1. 2, 3, 4. 6 and 10 had low % lung lesion scores that ranged from 0.11 £ 0.38% to 0.90 ± 0.15%. As expected. Group 9, the challenge control group, had the highest mean % lung lesion score (10.81 23.27%). In four groups, the mean % lung lesion scores were elevated due to one to three pigs in each of these groups having very high lung lesion scores. The lung lesions were red/purple and consolidated. Typically, lung lesions associated with PMWS are described as tan, non-collapsible, and with interlobular edema. The lung .lesions noted in this study were either not associated with PCV2 infection or a second pulmonary infectious agen may have been present. Within the context of this study, the % lung lesion scores probably do no reflect a true measure of the amount of lung infection due to PCV2. Likewise, tentative diagnosis of pneumonia may have been over-utilized as well. Any pigs with lung lesions, some as sraail as 0.1 % were listed with a tentative dia nosi of pneumonia. In this example, there was no sufficient difference between groups with respect to gross lesions and % lung .lesions on which to base vaccine efficac .

IHC results showed tiie largest differences between groups. Group I. (16 § rORl ^' 2 - IMS 1314) had the lowest positive IHC results for PCV2 antigen (0%); while Groups 9 and 10 had the highest positive IHC results with incidence rates of 100% and 93.3% respectively. Groups 3, 5, 6 and 7, which received 16, 4, 1 or 0.25 ug of rO F2 antigen, respectively, adjuvanted with Carbopol. had IHC positive rates of 20%, 20%, 40% and 46.7%, respectively. Group 2, which received two doses of 16 ug vQ.RP2 adjuvanted with Carbopol had an IHC positive rate of 6.7%, while Group 4 which received only one dose of the same vaccine, had an 1HC positive r te of 13.3%, Due to ihe objective nature of this test and the fact that IHC results correlated with expected results, IHC testing is probably one of the best parameters on which to base vaccine efficacy.

Thus in one aspect of the present invention, the Minimum Protective Dosage (MPD) of PC V2 fO.RFl antigen adjnvanted with Carbopol in the CDC.D pig mode] in the face of a PCV ^' 2 challenge is determined. Groups 3. 5. 6 and 7 each received two doses of rO.RF2 antigen adjuvanied with Carbopol, bat the le el of rORF2 antigen varied for each group. Groups 3, 5, 6 and 7 each received 16, 4, 1 or 0.25 u.g of ^' rORF2 antigen respectively. In general, decreasing the level of rORF2 antigen decreased PCV2 antibody titers, and increased the mortality rate, mean % lung lesions, and the incidence of IHC positive tissues. Of the four groups receiving varying levels of i ORF2 ~ Carbopol, Groups 3 and 3, which received two doses of 16 or 4 μ§ of rOR.F2 antigen, respectively, each had an IHC positive rate of only 20%. and each had similar antibody titers. Overall, based on IHC positive results, the minimum protective dosage ofrQR.F2 antigen administered twice is approximately 4 jig.

In another aspect of the present invention, the antigenicity of recombinant (rORF2) and V.1DO R-l (vORF2) PCV2 antigens were assessed. Group 2 received two doses of 16 § vORF2 and Group 3 received two doses of .1 ug rORF2. Both vaccines were adjuvanted with Carbopol. Both vaccines were found to be safe and both had 0% mortality rate. Group 2 had a PCV2 antibody titer of 2507 on Day 25, while Group 3 had a PCV2 antibody titer of 1503. Group 3 had a lower mean % lung lesion score than Group 2 (0..11 * 0.38% vs. 0.90 ± 0.15%), but Group 2 had a lower IMC positive incidence rate that Group 3 (6.7% vs. 20%). Overall, both vaccines had similar antigenicity, but vORF2 was associated with slightly better IHC results.

In yet another aspect of the present invention, the suitability of two different adjuvants (Carbopol and IMS 1314) was determined. Croups 1 and 3 both received two doses of vaccine containing 16 ug of rORP2 antigen, but Group .1 received the antigen adjuvauted with IMS 1314 while Group 3 received die antigen adjuvauted with Carbopoi. Both groups had essentially the same ADWG, essentially die same incidence of clinical signs post-challenge, (he same mortality rate, and essentially the same mean % kin lesions; but Group ^} . had an 1HC positive rate of 0% while Group 3 had an MC positive rate of 20%. However, Group 3, which received She vaccine adjuvauted wish Carbopoi, had higher IFAT PCV2 liters on Days 25, 32, and 50 than Group 1, which received the vaccine adjuvauted with IMS 1314, Overall, although the PCV2 vaccine adjuvauted with IMS 1314 did provide better IMC results, it did not provide overwhelmingly tetter protection from PCV2 infection and did induce injection site reaction. Whereas the PCV2 vaccine adjuvauted with Carbopoi performed nearly as well as the IMS 1314 adjuvauted vaccine, but was not associated with any adverse events.

In stiii another aspect of the present invention, the feasibility of PCV2 O .F2 as a Imi. 1 dose product was determined. Groups 2 and 4 both received 16 μ§ of vORF2 vaccine adjuvauted with Carbopoi on Day 0, but Group 2 received a second dose on Day 1 . Group 4 had a sli htly higher ADWG and a lower mean % lun lesions than Group 2, but Group 2 had higher IFAT PCV2 titers on Day 25, 32 and 50, and a slightly lower incidence rate of lHC positive tissues. AH other results for these two groups were similar. Overall, one dose of vORF2 adjo vanted wi th Carbopoi performed similar to two doses of the same vaccine.