Mechanisms of neutralization by monoclonal antibodies to different antigenic sites on the bovine herpesvirus type 1 glycoproteins

Monoclonal antibodies directed to different antigenic sites on bovine herpesvirus type 1(BHV-1) glycoproteins were used to study the mechanisms of neutralization of the virus. Three nonoverlapping neutralizing antigenic sites, designated Ia, Ib, and Ic, were defined on gp87. Antibodies to site la which mediated viral neutralization without complement were effective on inhibition of virus adsorption. Antibodies to a single neutralization site on gp71, designated IIa, were able to neutralize the virus without complement even when they were incubated with the virus which had already adsorbed onto the cells. Antibodies directed against gp117 and antibodies against sites Ib and Ic on gp87 required complement for virus neutralization.