Subtype AE HIV-1 DNA and recombinant Fowlpoxvirus vaccines encoding five shared HIV-1 genes: Safety and T cell immunogenicity in macaques

To induce broad T cell immunity to HIV-1, we evaluated the safety, immunogenicity and dose-response relationship of DNA and recombinant Fowlpoxvirus (rFPV) vaccines encoding five shared HIV subtype AE genes (Gag, Pol, Env, Tat, Rev) in pigtail macaques. The DNA (three doses of either 1 mg or 4.5 mg) and rFPV (a single boost of either 5 × 10⁷ or 2 × 10⁸ plaque forming units) vaccines were administered intramuscularly without adjuvants. Broadly reactive HIV-specific T cell immunity was stimulated by all doses of the vaccines administered, without significant differences between the high and low doses studied. The vaccines induced both CD4 and CD8 T cell responses to Gag, Pol, Env and Tat/Rev proteins, with CD4 T cell responses being greater in magnitude than CD8 T cell responses. The vaccine-induced T cell responses had significant cross-recognition of heterologous HIV-1 proteins from non-AE HIV-1 subtypes. In conclusion, these subtype AE HIV-1 DNA and rFPV vaccines were safe, induced broad T-cell immunity in macaques, and are suitable for progression into clinical trials.