BM-based CD4⁺ T-cell renewal is preserved in naturally SIV-infected SMs, but not in SIV-infected RMs. The fraction of CD4⁺ and CD8⁺ T cells expressing Ki-67 was assessed in the BM and PB of SIV-infected SMs and RMs. (A) Percentage of Ki-67 expression in CD4⁺ and CD8⁺ cells isolated from the BM and PB in 10 SIV-infected SMs (left) and RMs (right). (B) Percentage of CD4⁺ (left) and CD8⁺ (right) T cells expressing Ki-67 in the BM and PB of 10 uninfected (○) and 10 SIV-infected (●) RMs. P values are shown when significant differences between groups are present.