A study of serologic relationships among non-cytopathogenic strains of bovine viral diarrhea-mucosal disease virus by reverse plaque technique.

Abstract

Neutralizing antibody in serial serums from calves infected with non-cytopathogenic (NCP) strain No.12 of bovine viral diarrhea-mucosal disease (BVD-MD) virus was comparatively titrated by the semi-micro reverse plaque fromation (RPF) and the END methods. There was a tendency that the neutralizing antibody titer was estimated eightfold higher in the semi-micro RPF method than in the END method. Antigenic relationships among three Japanese strains and two American strains were examined by the cross-neutralization and kinetic neutralization tests using the RPF technique. In cross-neutralization test, differences in antibody titers were not more than twofold among three Japanese strains. However, there were eightfold differences in some combinations of the Japanese and American strains. Kinetic neutralization test also demonstrated that three NCP strains of BVD-MD virus isolated in Japan were closely related. The American strains were antigenically distinct from three Japanese strains used in this study although some antigenic similarity was recognized in some combinations of the strains and the antisera. Moreover, these two American strains appeared to differ one another slightly.