Antibody responses of horses to five major glycoproteins of equine herpesvirus 1 and specificity of responses to antigenic domains of glycoproteins B and C

Five major equine herpesvirus-1 (EHV-1) glycoproteins, gp2, gp10, gC, gB, and gp21/22a were purified by immunoaffinity chromatography and used in an immunoblot assay to measure EHV-1 glycoprotein specific antibody responses of horses. Following primary EHV-1 infection, horses developed serum antibody to all five glycoproteins. The postinfection response was dominated by antibody targeting gB. Glycoprotein C elicited the second highest glycoprotein specific antibody responses in most EHV-1 infected horses. EHV-1 glycoprotein specific antibody responses of horses experiencing primary equine herpesvirus-4 (EHV-4) infection were almost exclusively directed against gB. Secondary EHV-1 or EHV-4 infection of horses, or heterologous EHV infections, resulted in heightened antibody responses to all five EHV-1 glycoproteins tested compared to those seen after primary infection. EHV-1 infections consistently stimulated stronger responses to the purified glycoproteins than EHV-4 infections. The pattern of serum antibody development in horses immunized with an inactivated EHV-1 vaccine or an attenuated EHV-1 vaccine differed markedly from that of horses convalescing from infection. EHV-1 gC elicited the strongest response in both vaccinated groups.;A competitive enzyme linked immunosorbent assay was developed and standardized for quantitating equine serum antibody directed against individual antigenic domains on EHV-1 gC and gB. Murine monoclonal antibodies targeting five domains on gC and five domains of gB competed with equine serum antibody for binding to EHV-1 viral antigens. The strongest domain specific antibody responses in all groups of EHV-1 or EHV-4 infected horses were directed against EHV-1 gC domain IV and gB domains I, III, and IV, all of which possess virus type common epitopes. Vaccinated horses responded most strongly to gC domain IV, but developed antibody to serval type specific gC domains as well. Glycoprotein B domains I, III, and IV also elicited immune responses in vaccinated horses. Antibody titers to these domains, however, were consistently lower than the gC domain IV specific response of vaccinates.