Enhanced CD8+ T cell response to HIV-1 env by combined immunization with influenza and vaccinia virus recombinants

With the aim to determine if immunization with two different live recombinant viral vectors could lead to an enhancement of the cellular immune response to HIV-1 antigens, we have characterized the CD8(+) T cell response elicited against the V3 loop epitope from HIV-1 env protein in Balb/c mice immunized with either: a recombinant influenza virus (Flu-Env) expressing the V3 loop epitope from HIV-1 strain IIIB, a vaccinia virus recombinant (VV-Env) expressing the complete HIV-1-IIIB enu protein, or a combination of both. The CD8(+) T cell response, measured by the ELISPOT assay, in animals primed with Flu-Env and boosted with VV-Env was 5 to 6 times higher than in animals inoculated with either Flu-Env or VV-Env alone. Similar results were obtained with recombinant viruses expressing the V3 loop epitope or the complete env protein, respectively, from the MN strain of HIV-1. Our results indicate that the use of two different live vectors for priming and boosting has a synergistic effect on the immune response against HIV-1, and could represent a novel vaccination strategy against AIDS. (C) 1999 Elsevier Science Ltd. All rights reserved.