YEAST-SECRETED BOVINE HERPESVIRUS TYPE-1 GLYCOPROTEIN-D HAS AUTHENTICCONFORMATIONAL STRUCTURE AND IMMUNOGENICITY

Bovine herpesvirus-l (BHV-1) glycoprotein D (go), an envelope glycopro tein, engenders mucosal and systemic immunity protecting cattle from v iral infection. Production of go with authentic immunogenicity is requ ired for a subunit vaccine. We placed the truncated BHV-1 go gene, lac king its putative transmembrane and cytoplasmic domains, under the con trol of the methanol-inducible AOX1 promoter in the yeast Pichia pasto ris. Truncated BHV-1 go (tgD) was efficiently secreted into the cultur e medium as a 68 kDa protein using either the yeast alpha prepro or na tive BHV-1 go signal sequences. The yeast-secreted tgD had N-linked gl ycosylation and appears to have authentic conformational structure and immunogenicity based on the following observations. A panel of monocl onal antibodies recognizing five neutralizing epitopes reacted with ye ast tgD. Sera from yeast tgD-immunized mice immunoprecipitated native BHV-1 go and neutralized BHV-1 infection in vitro. Yeast tgD competiti vely blocked all reaction between native go and monospecific go polycl onal sera from cattle. Based on these data, yeast-derived BHV-1 tgD is an excellent candidate for a subunit vaccine. (C) 1997 Elsevier Scien ce Ltd.