Characterization of Monoclonal Antibodies Against Four Structural Proteins of Rinderpest Virus

Twenty-four monoclonal antibodies (MAbs) against rinderpest virus (RPV) were established and characterized by several serological tests. Of the 24 MAbs. 10 recognized the nucleoprotein (NP), six the phosphoprotein (P), four the haemagglutinin (H), and two the fusion (F) protein as determined by radioimmunoprecipitation assay. The specificities of the remaining two MAbs could not be determined. From a competitive binding assay using MAbs against each structural protein, at least five, four and two separate antigenic sites were identified on the NP, P and H proteins, respectively. MAbs against the H protein neutralized the infectivity of the virus, but those against the F protein were only neutralizing in the presence of guinea-pig complement. The reactivities of each of the MAbs for other strains of morbillivirus were tested using an indirect immunofluorescent antibody assay. The MAbs against four out five antigenic sites on the NP showed cross-reactivity amongst all the strains of morbillivirus tested whereas the fifth antibody reacted only with RPV. Of the antibodies specific for the P protein, the antibody against one site was cross-reactive with all the strains of RPV, measles virus (MV) and canine distemper virus (CDV), the antibody against another site was reactive with RPV and MV but not with CDV, and the antibodies against the other two sites were specific for RPV.