CD4 and infection: Although the levels of these parameters did not display significant differences between the age groups prior to infection, there was a more dramatic increase in the frequency of CD38+HLA-DR+CD4+, Ki67+CD4+, Ki67+CD4+ naïve and Ki67+CD8+ naïve T cells in the old ChRM than in the young macaques after infection (Supplementary Tables S2 and S3).