Modified-vaccinia-virus-Ankara (MVA) priming and fowlpox-virus booster elicit a stronger CD8+ T-cell response in mice against an HIV-1 epitope than does a DNA/poxvirus prime-booster approach.

A prime-boost strategy combining FWPV (fowlpox virus) and the MVA (modified vaccinia virus Ankara), both expressing HIV-1 multi-V3 epitope polypeptides, was compared with a DNA-based Semliki Forest virus replicon/poxvirus approach for the induction of a CD8(+) T-cell response. Priming mice with recombinant MVA and boosting with recombinant FWPV, and not in the reverse order, increased the number of specific interferon-gamma-secreting cells in relation to the homologous combinations. Moreover, the improvement of the CD8(+) T-cell response with this combination was remarkably higher than that obtained by priming with a DNA vector containing a Semliki Forest virus replicon expressing the multi-epitope polypeptide and boosting either with recombinant MVA or FWPV. These results open a new and attractive alternative for vaccine preparation against HIV-1 using different immunogens.