Antigenic structure and variation of canine parvovirus type-2, feline panleukopenia virus, and mink enteritis virus.

The antigenic structure and variation of canine parvovirus type-2 (CPV), feline panleukopenia virus (FPV), mink enteritis virus (MEV), and a closely related virus of raccoons (RPV) was investigated using a panel of 13 monoclonal antibodies (mAb) formed against CPV and 8 mAb formed against FPV. Each mAb both neutralized and inhibited the hemagglutination of the homologous virus. All mAb tested immunoprecipitated the two capsid proteins. Five mAb were specific for the CPV isolates and one reacted with the FPV, MEV, and RV isolates, but not the CPV. Another mAb reacted only with certain FPV and MEV isolates. The remaining 14 mAb reacted with most parvoviral isolates from the four animal species. Antigenic variation was observed both within and between the parvovirus isolates from each species. The 12 MEV isolates could be grouped into three antigenic types based on their reactivity with the panel of mAb. Antigenic variants of either CPV or FPV were readily selected with several mAb. Analysis of these variant viruses by direct serological tests and competition radioimmune assays between different mAb revealed that the capsid surface contained at least two determinants, each being comprised of many different but overlapping epitopes.