Indexed on: 20 Aug '14Published on: 20 Aug '14Published in: Research in Veterinary Science
Glycosylated protein 3 (GP3) of PRRSV is variable between different PRRSV strains, so it is helpful for subtype classifying by using distinct epitopes. In this study, two dominant linear GP3 epitopes that were recognized by highly dilute serum in an enzyme-linked immunosorbent assay (ELISA) were identified. Sequence alignments of 36 North American (NA) PRRSV isolates revealed that the epitope H(87)DELGFMV(94) is well conserved, whereas the epitope T(59)RQAAAEILE(68) differs in other low-virulence NA-type strains, which have at least one amino acid mutation in this region. A mutational analysis revealed that none of these mutations could be recognized by the purified antibodies directed against the corresponding epitope, indicating that the genetic variations altered the antigenicity of the antigenic region. Using ELISA, we also found that antibodies directed against the two epitopes were present in more than 45 of 50 HP-PRRS-positive pig sera, suggesting that their antigenicity is excellent in vivo.