EXPRESSION AND CELLULAR-DISTRIBUTION OF BACULOVIRUS-EXPRESSED BOVINE HERPESVIRUS-1 (BHV-1) GLYCOPROTEIN-D (GD) SEQUENCES

Glycoprotein D (gD) of bovine herpesvirus 1 (BHV-1), a homolog of herp es simplex virus go, represents a major component of the viral envelop e and is a dominant immunogen. To study the antigenic properties of th e different regions of go, we have expressed the full-length go encodi ng gene and overlapping fragments spanning various regions of the go o pen reading frame in a baculovirus (Autographa californica nuclear pol yhedrosis virus) - insect cell (Spodoptera frugiperda, SF-9) system. M aximum levels of expression for all proteins were obtained 48 to 72 h post infection of SF-9 cells by recombinant viruses. Full-length and t runcated recombinant go proteins reacted specifically with anti-gD mon ospecific serum as determined by immunoprecipitation and immunoblottin g, indicating that the proteins retained their antigenicity. However, based on the reactivity with a panel of go-specific monoclonal antibod ies (Mabs), the full-length recombinant go lacked proper expression fo r two highly neutralizing linear epitopes identified by Mabs R54 and 9 D6. The rest of the epitopes appeared to be preserved and antigenicall y unaltered. Immunofluorescence studies of recombinant baculovirus inf ected SF-9 cells using go monospecific serum, revealed no direct corre lation between cellular localization of the expressed proteins and the ir amino acid sequences.