Expansion and persistence of seven SIV-specific Mamu-B*08-restricted CD8⁺ lymphocyte responses in four EC macaques.

<p>MHC class I alleles detected by PCR-SSP are listed for each animal. A) Unknown CD8⁺ responses from <i>ex vivo</i> ICS assays using SIV peptide pools (containing ten 15-mers overlapping by eleven amino acids) performed one month prior to and four weeks after CD8⁺ cell depletion. Chronic phase (thirty weeks post-infection) <i>ex vivo</i> ICS data is also shown for responses in r99006 to the seven SIV 15-mer peptide pools that contain the novel CD8⁺ T cell epitopes. Grayed responses increased >0.1% after CD8⁺ cell depletion (r00078, r01064, and r98016). B) <i>Ex vivo</i> IFN-γ ELISPOT using one or two overlapping 15-mers containing the minimal optimal Mamu-B*08-restricted SIV-specific epitopes (or the minimal optimal peptide alone, in the case of Vif_172–179RL8) demonstrated that these CD8⁺ responses persist approximately six months post-CD8⁺ cell depletion in ECs r00078, r01064, and r98016. CD8⁺ cell responses persist in r99006 at ∼3.5 years post-SIV infection. Mean values and SD from triplicate wells were calculated for each ELISPOT assay. Background (the mean of wells without peptide) levels were subtracted from each well. Mean responses <50 SFC per 1×10⁶ cells were not considered positive because these counts were not significantly above background.