SIV- and RhCMV-specific T cell responses in peripheral blood. (A) PBMCs before and after immunizations were stimulated with either SIV gag or RhCMV pp65 peptide pools and stained for IL-2, TNF-α, and IFN-γ. The percentages of cytokine-producing CD8+ T cells were determined by multi-color flow cytometry. The percent of CD8+ T cells able to make any cytokine is shown. The average of all animals is shown on the indicated days post immunization. Error bars are the standard error of the mean, p-values using the student's t-test comparing the levels before immunization (Day 0) to time points post-immunization are shown as a * indicating a p < 0.05. (B) Measurement of p11c tetramer+, CD8+ T cells throughout the experiment. The results are expressed as percent of tetramer+, CD8+ T cells on indicated days post SIV infection for each animal.