Systematic analysis of attenuated Coxsackievirus expressing a foreign gene as a viral vaccine vector.

Recombinant viruses expressing foreign antigens may provide a convenient vaccine vector capable of inducing preventative immunity. In this study, we explored the capacity of highly attenuated Coxsackievirus B3 (CVB3) to act as a recombinant vector to deliver foreign genes into experimental animals for the purpose of vaccination. The infectious cDNA of highly attenuated CVB3, YYFF, which has been reported previously (Vaccine 27:1974), was used to construct a recombinant YYFF cDNA (YYFF-HCV) by inserting a truncated form of hepatitis C virus (HCV) envelope protein E2 as an antigenic marker immediately upstream from the gene encoding the VP4 capsid protein. In YYFF-HCV-infected HeLa cells, HCV E2 expression was confirmed by immunoblotting and fluorescence microscopy. YYFF-HCV induced the production of antibodies and the cytotoxic T-lymphocyte (CTL) response to HCV E2 in the inoculated mice. Moreover, YYFF-HCV induced no inflammation in the virus-immunized mice. These results demonstrate that recombinant CVB3 expressing a foreign gene can act as a live vaccine vector capable of inducing humoral and cell-mediated immune responses directed against a foreign protein.