HIV R5-tropic Env induces tonsil CD4 T cell death. (A) Tonsil CD4 T cells were purified by negative selection. (B) Purified tonsil CD4 T cells were treated with or without soluble gp120 (BaL, CN54 or CM) at 10 μg/ml (n = 7); or (C) treated with BaL-gp120 at different concentrations (μg/ml); or (D) were cocultured with HeLa cells or HeLa cells expressing HIV ADA-envelope (HeLa-ADA) at a ratio of 1:2 (n = 4); or (F) treated with pseudo virion expressing HIV BaL envelope and GFP at 50 ng/ml of p24 (n = 4) for 3 days. Cell death was evaluated every 24 hours. The statistical significance was analyzed with Student’s t test; *P < 0.05, **P < 0.005, ***P < 0.0001. (E) Purified tonsil CD4 T cells were treated with pseudo-viruses expressing HIV BaL envelope and GFP at 50 ng/ml of p24 for 24 hours. The GFP positive cells were detected by flow cytometry. Data are representative of four independent experiments.