Influence of Bcl-2 expression on TNFR-induced apoptotic response of CD4 and CD8 T cells.

(A) Ex vivo expression of Bcl-2 on CD8 T lymphocytes from a representative control and an HIV-infected patient. Populations expressing low, normal and high levels of Bcl-2 were determined as we previously reported.10 (B) PBMCs were stimulated overnight by coated anti-TNFR1 or anti-TNFR2 mAbs or incubated in medium, and further triple stained with anti-CD8 and anti–Bcl-2 mAbs and 7-AAD. Each dot plot shows the relationship between the level of Bcl-2 expression and the rate of apoptosis in gated CD8 T cells. Numbers in quadrants indicate the percentage of apoptotic cells within the corresponding Bcl-2 subset. (C) This experiment has been performed on PBMCs from 16 HIV⁺ patients. Data represent the susceptibility to apoptosis induced by medium, TNFR1, or TNFR2 of CD4 or CD8 T cells expressing low, normal, or high levels of Bcl-2. The ΔTNFR1 and ΔTNFR2 represent the difference between the percent apoptosis in TNFR-stimulated cultures and the percent apoptosis in medium. Statistical significance was assessed by the Wilcoxon signed rank test for paired data.