IMMUNOGENICITY OF BOVINE HERPESVIRUS-1 GLYCOPROTEIN-D IN MICE - EFFECT OF ANTIGEN FORM ON THE INDUCTION OF CELLULAR AND HUMORAL IMMUNE-RESPONSES

For the development of veterinary subunit vaccines, modifications to t he antigen may be needed to make the production of these vaccines cost effective. To investigate the effect of antigen modifications on immu ne response, we used glycoprotein D, one of the major glycoproteins of bovine herpesvirus-1 (BHV-1), as a model antigen. We developed a mous e model to assess the immune response elicited by immunization with ei ther a recombinant truncated (tgD) or the authentic full-length (gD) f orm of BHV-1 gD in VSA3, a novel water-in-oil adjuvant. Both forms of BHV-1 gD antigen induced good levels of cell-mediated immunity, as eva luated by antigen-specific proliferative response and cytokine (IFN-ga mma and IL-4) production. Following primary immunization, the humoral immune response induced by gD was superior to that elicited by vaccina tion with tgD, However, after a secondary immunization, a strong and s imilar antibody response to BHV-1 gD was induced by both forms of the antigen. The difference in immunogenicity between gD and tgD after pri mary immunization was not due to the loss of immunogenic epitopes in t he truncated antigen or the ability to associate with the adjuvant VSA 3. Our results indicate that both gD and tgD are capable of efficientl y inducing a cell-mediated immune response, and although recombinant t gD is less efficient in inducing a primary humoral immune response whe n compared to the full-length gD, tgD effectively primed for a seconda ry antibody response.