Fig. (1) Gp120 decreases CD45RO+/CD45RA- memory phenotype in activated but not resting primary human CD4 T cells. (A and B) CD4+ T cells (98% pure) were stimulated with PHA for 24 hours or left rested, and treated with either p120 (IIIB) (1µg/ml) or BSA control (1µg/ml) and analyzed for CD45RO and CD45RA (gated on CD4 population) by flow cytometry. (C) Resting and activated primary human CD4 T cells were treated with gp120 (IIIB) as above and analyzed for Annexin-V positive cells. Data is representative of three independent experiments.