CD8⁺T-cell degranulation in response to SIV peptides in naturally SIV-infected SMs. In all experiments, degranulation was measured as the percentage of CD3⁺CD8⁺ T cells coexpressing CD69 and CD107a. (A) Representative plot of a positive response to SIV-Pol pool no. 2 (right) along with the unstimulated negative control (left) and 2 positive controls (SEB and PMA + ionomycin: middle). (B) Percentage of CD8⁺ T cells that degranulate in response to SIV peptide stimulation in 18 naturally SIV-infected SMs. Each bar represents an individual animal. The contribution of each of the tested antigens to the total SIV-specific T-cell response is shown.