Figure 1.

Characterization of CD6 and PD-1 expression on CD8⁺T-cells in different tissue compartments of chronically SIV-infected macaques. (A) Flow cytometry gating strategy for CD6 expression on CD8⁺ and CD4⁺ T-cells in the spleen during chronic infection (top panels) and frequencies of CD8⁺ and CD4⁺ T-cells expressing CD6 (bottom panel). Data are from 27 macaques. (B) The frequency of CD8⁺CD6⁺ T-cells in the blood (top row), LN (middle row), and bone marrow (bottom row) at different time points following SIV infection. Data for the blood are from 4 to 6 macaques, data for the LN are from 7 to 11 macaques, data for the bone marrow are from 5 to 10 macaques. (C) Representative staining for CD6 and PD-1 co-expression on splenic CD8⁺ T-cells during chronic SIV infection (top panels) and frequencies of CD8⁺CD6⁺ and CD8⁺CD6⁻ cells co-expressing PD-1 (bottom panel). Red arrow indicates CD8⁺CD6⁺PD-1⁺ cells, whereas blue arrow indicates CD8⁺CD6⁻PD-1⁺ cells. Data are from 25 macaques. Data are shown as means ± SEM. For statistical analysis, nonparametric Mann-Whitney tests were performed *p < 0.05, **p < 0.01, ****p < 0.0001.