Hemagglutination inhibition and virus neutralizing response of rabbits inoculated with bovine herpesvirus 1 subunit vaccine

The immunogenicity of bovine herpesvirus type 1 (BHV-1) hemagglutinin has been investigated. Both live and nonionic detergent solubilized vaccines were prepared and 5000 hemagglutinating units (HAU) were injected subcutaneously into rabbits. Both types of vaccine induced a good antibody response but live virus was four times more efficient in inducing hemagglutination inhibiting and neutralizing antibodies than either Triton X-100- or octylglucoside-solubilized subunit vaccine. Blotting analysis revealed that five proteins, of 105,000, 90,000, 74,000, 64,000 and 54,000 mol. wt, were recognized by the serum of vaccinated animals. Triton X-100-solubilized vaccine did not induce antibodies against the 105,000 and 64,000 mol. wt proteins, indicating the important role of VP 90,000 and VP 74,000 in hemagglutination and neutralization. The order in which antibodies to the different viral proteins were induced was VP 90,000, (VP 105,000, VP 64,000, VP 54,000) and VP 74,000. Our data indicate that VP 90,000 is the hemagglutinin. Using convalescent serum from intranasally infected animals, we could identify nine structural proteins for BHV-1; VP 105,000, VP 90,000, VP 74,000, VP 64,000, VP 54,000, VP 50,000, VP 47,000, VP 40,000 and VP 31,000.