BACULOVIRUS-EXPRESSED NONSTRUCTURAL PROTEIN NS2 OF BLUETONGUE VIRUS INDUCES A CYTOTOXIC T-CELL RESPONSE IN MICE WHICH AFFORDS PARTIAL PROTECTION

Virus-specific cytotoxic T lymphocytes were generated in two strains o f mice (BALB/c and CBA/Ca) against baculovirus recombinant proteins (m inor and nonstructural) derived from bluetongue virus serotype 10. Imm unization of mice with recombinant baculovirus insect cell extracts ex pressing the nonstructural protein NS2 (Bac-NS2) conferred partial pro tection against infection with vaccinia virus expressing the NS2 prote in. This protective immunity was mediated by CD8(+) cells. In contrast , no protection was observed when mice were immunized with similarly e xpressed Bac-NS1 or -NS3 or the virion minor structural proteins (Bac- VP1, -VP4, or -VP6), Furthermore, the in vitro cytotoxicity activity o f T cells derived from immunized animals did not correlate to the prot ective efficacy of baculovirus recombinant proteins. The implications of this work with regard to the design of noninfectious subunit vaccin es are discussed.