Antigenic and immunogenic characteristics of bovine herpesvirus type-1 glycoproteins GVP 3/9 and GVP 6/11a/16, purified by immunoadsorbent chromatography

Abstract

Glycoproteins GVP 3/9 and GVP 6/11a/16, two of the major glycosylated proteins specified by bovine herpesvirus type-1 (BHV-1), were purified on immunoadsorbents consisting of the appropriate monoclonal antibodies linked to Affigel-10. Each glycoprotein, whether purified from virus-infected cells or from virus, retained antigenic activity and induced high titers of monospecific antibodies in rabbits. These antibodies could neutralize virus and mediate complement-dependent lysis of virus-infected cells. Denatured glycoproteins GVP 3, GVP 6, GVP 11a, and GVP 16, which were purified by immunoadsorbent chromatography, followed by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis, also retained antigenicity and immunogenicity, though to a lesser extent than the native glycoproteins. Antibodies induced by GVP 9, GVP 6, and GVP 11a could also neutralize and mediate immune lysis. Even though GVP 16 induced high levels of antibody, these antibodies could not neutralize virus or participate in antibody and complement-mediated cytolysis. These results may suggest that the orientation of GVP 6/11a/16 in the membrane is such that GVP 11a is better exposed on the virion envelope and the cell surface than GVP 16. Cross-reactivity between monospecific antibodies against GVP 3 and GVP 9, as well as GVP 6, GVP 11a, and GVP 16 supported the previously proposed hypothesis that GVP 3 (180K) is a dimer of GVP 9 (91K) and that GVP 6 exists in two forms: one being a 130K polypeptide and the other composed of GVP 11a (74K) and GVP 16 (55K) linked by disulfide bonds. These data suggest that, thus far, either GVP 6/11a/16 or GVP 3/9 may be a potential candidate for a subunit vaccine against BHV-1 infection.