CONSTRUCTION AND INVESTIGATION OF RECOMBI NANT STRAINS OF VENEZUELAN EQUINE ENCEPHALOMYELITIS VIRUS EXPRESSING PRES(2)-S GENE OF HEPATITIS-B VIRUS

Venezuelan equine encephalomyelitis (VEE) virus-based vectors for expr ession of heterologous genes have been constructed using full-length c DNA copy of the interstrain recombinant virus (Trinidad Donkey and 230 strain). Gene cassettes carrying the subgenomic mRNA promoter of VE v irus and the pre(2)-S gene of hepatitis B virus (HBV) were inserted be fore or after the genes of structural viral proteins. Live virus stock s were obtained by transfection of chick embryo fibroblasts with in vi tro transcribed full-length RNA. Insertions of gene cassettes before t he structural region resulted in expression of HBsAg (VEHB-25 and VEHB -361 viruses), whereas insertions ill the 3' region did not. recombina nt virus VEHB-25 expressed HBsAg during 5 passages in Vero cells. VEHB -25 stimulated immune response to HBsAg and was less virulent than the parental virus.