A. HIV Gag protein expression in Vero cells infected with d106-gag and RJ1-gag recombinant viruses at various times post infection (hours), as detected by Western blots. M=mock-infected; B. Effect of varying the dose of immunizing virus on HIV Gag specific CD8+ responses. Groups of mice (n=6) were immunized with 5×102, 5×104, or 5×106 PFU d106-gag, at days 0, 21, and 42. Splenocytes were collected from each recombinant-infected mice (three mice per group per time point) at 7 days after each boost and were stimulated with an MHC-I Gag peptide. Results are shown as the mean number of interferon-γ spot-forming cells (SFC)/106 splenocytes±standard deviation.