Figure 4.

Old ChRM display a decreased number of naïve CD4⁺ T cells and B cells, as compared with young macaques. (a) The absolute number of naïve CD4⁺ T and B cells in the peripheral blood of young (n = 6, red circle) and old macaques (n = 8, blue square) is shown in scatter plots. (b) Comparison of the TREC (T cell receptor rearrangement excision circle) content in T cells or the KREC (kappa-deletion recombination excision circle) content in B cells from PBMCs in young and old macaques. The data are shown as the mean ± SEM. p (dpi) < 0.05 with color, statistically significant differences over the entire infection time, as determined by one-way ANOVA in the young (red) or old (blue) group. P (age) < 0.05, statistically significant differences between the young and old groups, as determined by two-way ANOVA. (c) Principal component analysis (PCA) of an immunophenotype data set in the acute and postacute phase was calculated by a varimax rotation method in package psych and graphed by package ggbiplot2 with R. Each dot represents a sample from a time point that is plotted against its expression levels for 9 variables that differed over time and between age groups, as determined by two-way ANOVA. The variables are shown in capital letters and are arranged alphabetically according to their communalities from high to low. CD4TCells, CD4⁺ T cell number; CD4TN, naïve CD4⁺ T cell number; CD8TN, naïve CD8⁺ T cell number; Ratio, CD4/CD8; BN, naïve B cell number; Ki67⁺CD4TN, % of Ki67⁺CD4⁺ naïve T cells; Ki67⁺CD8TN, % of Ki67⁺CD8⁺ naïve T cells; Ki67⁺CD4T, % of Ki67⁺CD4⁺ T cells; CD38⁺HLA-DR⁺CD4T, % of CD38⁺HLA-DR⁺CD4⁺ T cells.