Changes in central memory CD4⁺ T cells in neonatal tissues on SIV infection. Bar charts (A) indicate percentages of central memory (CD95⁺CD28⁺) CD4⁺ T cells in SIV-infected (solid bars) to age-matched control neonatal macaques (open bars) over time. Note that a selective loss of central memory CD4⁺ T cells occurs in the jejunum of SIV-infected neonates by 12 days of infection compared with age-matched controls. Bars represent the percentage of CD95⁺CD28⁺ cells after gating through CD4⁺ T lymphocytes as demonstrated in panel B. (B) Dot plots of CD4⁺ T cells from tissues of a representative SIV-infected neonate (DP53, left column) to an age-matched uninfected neonate (DP44, right column), demonstrating selective loss of CD95⁺CD28⁺ CD4⁺ T cells in all tissues. Plots were generated by gating through lymphocytes and then CD4⁺ T cells.