Prime-boost immunization with DNA, recombinant fowlpox virus and VLPSHIV elicit both neutralizing antibodies and IFNγ-producing T cells against the HIV-envelope protein in mice that control env-bearing tumour cells

Different primings with DNA and fowlpox virus (FP) recombinants or FP alone were used in a preclinical trial to evaluate and compare immunogenicity and efficacy against HIV/SHIV. Three immunization regimens were tested in three groups of mice in which the SIV gag/pol and HIV-1 env transgenes were separately expressed by DNA and FP vectors, followed by VLPSHIV boosting. All of the protocols were effective in eliciting homologous neutralizing antibodies, although the mice immunized with DNA followed by FP recombinants or DNA+FP recombinants showed both high titres of neutralizing antibodies and high frequencies of env-specific IFNγ-producing T lymphocytes. Vaccine efficacy, as demonstrated by growth control of env-expressing tumours, was obtained in both of these two groups of mice. These results establish a preliminary profile for the combined use of these recombinant vectors in protocols to be tested in the SHIV-macaque model of HIV-1 infection.