Characterization of monoclonal antibodies against rinderpest and peste des petits ruminants viruses : identification of shared or virus-specific epitopes on the nucleoprotein

Abstract

Twenty-nine monoclonal antibodies (MAbs) prepared against two rinderpest virus (RPV) vaccine strains (RPV-RBOK and RPVL) and the NIG 75/3 isolate of peste des petits ruminants virus (PPRV) were characterized by radioimmunoprecipitation essay (RIPA), immunofluorescent antibody (IFA) staining and enzyme-linked immunosorbent assay (ELISA). Twenty-seven MAbs had specificity for the nucleoprotein (N); two recognized the fusion (F1) and the matrix (M) protein of the homologous virus. The specificity of MAbs that did not react with a structural protein in RIPA was determined by IFA staining and ELISA. Based on IFA reactivity, these MAbs were used to classify RPV, PPRV isolates of various origins and to compare them to two other morbilliviruses, measles virus (MV) and canine distemper virus (CDV). The anti-M MAb did not show any epitopic variations among PPRV isolates and the anti-F1 MAb delineated a single site on all RPV and PPRV isolates, which distinguished them from MV and CDV. The anti-N MAbs were purified, biotinylated and analyzed by reciprocal competition using RPV-RBOK and PPRV-NIG 75/1 strains as ELISA antigens. They defined in the N of each virus 6 and 7 antigenic sites, respectively. Among the delineated sites, some were specific to RPV (2 sites) and others to PPRV (3 sites). MAbs which recognized these specific sites were used to unequivocally differentiate between the two viruses. Four overlapping sites in RPV and PPRV were shared among all morbilliviruses and the remaining sites were common to at least 2 morbilliviruses. Three MAbs characterized in this study are good candidates for differential diagnostic tests (Libeau G. et coll., 1994, Vet. Rec., 134: 300-304 ; Libeau G. et coll., 1995, Res. vet. Sci., 58: 50-55).