Effect of different antiretroviral treatment regimens on apoptosis and CD69 expression in CD4⁺ and CD8⁺T cell subpopulations in HIV-1–infected patients and healthy controls.

(A) Spontaneous apoptosis, (B) anti-CD95–induced apoptosis, (C) anti-CD3–induced apoptosis, (D) spontaneous CD69 expression, (E) anti-CD95–induced CD69 expression, (F) anti-CD3–induced CD69 expression. ● indicates CD4⁺ T cell subpopulations, and ○, CD8⁺ T cell subpopulations. Horizontal bars indicate the group median. Data from HIV-1–infected patients receiving either no effective antiretroviral therapy (group I, n = 26) or at least 6 months of treatment with 2 inhibitors of HIV-1 reverse transcriptase (RTIs; group II, n = 20) or 2 RTIs plus at least 1 inhibitor of HIV-1 protease (HAART; group III, n = 16) were compared to 28 age-matched healthy controls (CTRLs). The respective patient numbers for measurements of CD69 expression were group I, n = 11; group II, n = 20; group III, n = 16; and CTRL, n = 12. Methods: Freshly isolated peripheral blood mononuclear cells (PBMCs) (2 × 10⁵ cells/well) were cultured in the presence or absence of either anti-CD3 monoclonal antibodies (moAbs; OKT3; 10 μg/mL) or anti-CD95 moAb (anti–APO-1; 10 μg/mL) and protein A (5 ng/mL) as described.3 Cells were collected after 21 ± 1 hours and stained for surface expression of CD4, CD8, and CD69 using fluorochrome-labeled moAbs (Becton Dickinson, Heidelberg, Germany), and cell death was determined in CD4⁺ and CD8⁺ T cells by flow cytometry. The percentage of specific anti-CD3– and anti-CD95–induced apoptosis was calculated by 100 × (% of experimentally induced cell death − % of spontaneous cell death)/(100 − % of spontaneous cell death). Spontaneous and experimentally induced CD69 expression on viable CD4⁺ and CD8⁺ T cells was determined as a marker for T-cell activation as described,3 specific anti-CD3– and anti-CD95–induced CD69 expression on both T-cell subpopulations was calculated using the formula for specific cell death.