Antigenic differences among porcine circovirus type 2 strains, as demonstrated by the use of monoclonal antibodies

• Published in: Journal of general virology 2008, Vol.89 (1), p.177-187
• Main Authors: Lefebvre, D.J, Costers, S, Doorsselaere, J. van, Misinzo, G, Delputte, P.L, Nauwynck, H.J
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antibodies, Monoclonal; Antibodies, Viral - immunology; antigen-antibody reactions; Antigenic Variation - genetics; Biological and medical sciences; Cell Line; Circovirus - classification; Circovirus - genetics; coat proteins; Conserved Sequence; cross reaction; DNA Primers; Fundamental and applied biological sciences. Psychology; genes; Genotype; immunoassays; immunoperoxidase monolayer assay; Mice; Mice, Inbred BALB C; Microbiology; Miscellaneous; Molecular Sequence Data; monoclonal antibodies; Neutralization Tests; neutralizing antibodies; nucleotide sequences; Open Reading Frames; Phylogeny; Porcine circovirus; Sensitivity and Specificity; Sequence Alignment; strains; Swine; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies; viral antigens; Virology; virus neutralization
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/vir.0.83280-0

1 Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium 2 Department of Health Care and Biotechnology, KATHO Catholic University College of South-West Flanders, Wilgenstraat 32, 8800 Roeselare, Belgium Correspondence H. J. Nauwynck hans.nauwynck{at}ugent.be This study examined whether antigenic differences among porcine circovirus type 2 (PCV-2) strains could be detected using monoclonal antibodies (mAbs). A subtractive immunization protocol was used for the genotype 2 post-weaning multisystemic wasting syndrome (PMWS)-associated PCV-2 strain Stoon-1010. Sixteen stable hybridomas that produced mAbs with an immunoperoxidase monolayer assay (IPMA) titre of 1000 or more to Stoon-1010 were obtained. Staining of recombinant PCV-2 virus-like particles demonstrated that all mAbs were directed against the PCV-2 capsid protein. Cross-reactivity of mAbs was tested by IPMA and neutralization assay for genotype 1 strains 48285, 1206, VC2002 and 1147, and genotype 2 strains 1121 and 1103. Eleven mAbs (9C3, 16G12, 21C12, 38C1, 43E10, 55B1, 63H3, 70A7, 94H8, 103H7 and 114C8) recognized all strains in the IPMA and demonstrated neutralization of Stoon-1010, 48285, 1206 and 1103, but not VC2002, 1147 and 1121. mAbs 31D5, 48B5, 59C6 and 108E8 did not react with genotype 1 strains or had a reduced affinity compared with genotype 2 strains in the IPMA and neutralization assay. mAb 13H4 reacted in the IPMA with PMWS-associated strains Stoon-1010, 48285, 1206 and VC2002, and the porcine dermatitis and nephropathy syndrome-associated strain 1147, but not with reproductive failure-associated strains 1121 and 1103. mAb 13H4 did not neutralize any of the tested strains. It was concluded that, despite the high amino acid identity of the capsid protein ( 91 %), antigenic differences at the capsid protein level are present among PCV-2 strains with a different genetic and clinical background. The GenBank/EMBL/DDBJ accession numbers of the ORF2 sequences from strains 1206, VC2002-k2 and VC2002-k39 determined in this study are EF990644, EF990645 and EF990646, respectively.