Gag-specific IFN-gamma-secreting T cells from immunized macaques. (A) PBMC from individual monkeys were tested at the indicated time points for Gag-specific IFN-gamma secreting T cells by in-vitro stimulation with overlapping HIV-Gag peptide pools. Vaccinations were given at q.d. x3 at weeks 0, 6, and 19. (B) Mean IFN- γ SFU over successive prime and boosting with Lmdd-HIV-gag. No significant differences in ELISPOT generation were observed between groups of naïve rhesus macaques and those having prior oral Lm-vector exposure, P = 0.4 (Wilcoxon rank sum test). (C) HIV-Gag specific proliferative responses in Lmdd-HIV-gag-immunized macaques. (D) Listeria LLO-specific proliferative responses at the indicated time points during vaccination protocol. Stimulation indices (SI) were calculated as described. No significant differences were observed for Gag- or LLO-specific stimulation, P = 0.8 and 0.4 respectively (Wilcoxon rank sum test).