Responses to a set of 3 peptide pools, selected for their high probability to trigger a response in most of all HIV-1 positive participants, were compared between CD8 T cells negatively isolated from PBMC and from polyclonally expanded CD8 T cells. The peptide pools used included: HCMV pp65 (135 peptides), HIV-1 group M gag (320 peptides), and HIV-1 nef (127 peptides), all from the NIH AIDS reagent programme. Responses between direct PBMC isolated CD8 T cell and polyclonally expanded and isolated CD8 T cells from the same sample were correlated using spearman correlation rank test (left panel) and response magnitudes compared using wilcoxon matched pairs signed rank test (right panel). The dashed line indicates the positive response threshold of 1.58 Log10 SFC/106 CD8 T cells.