52 WPI SIVmac239-specific T cell response reproducibility in MHC-matched MCM. On the x-axis are regions targeted by IFN-γ-secreting T cells in at least one animal of that haplotype, as measured by 52 WPI pooled peptide matrix ELISPOT. On the y-axis is the proportion of animals within that MHC-matched group that mounted a response to each region. In each group, six animals were compared, with the exception of the M1/M1 group. Due to high background IFN-γ-secretion, cy0322 was excluded from comparison with other M1/M1 animals.