Fig. (3) Gp120 increases subset of double positive CD45RA+/CD45RO+ CD4 T cells that undergo apoptosis. (A) Activated primary human CD4 T cells were treated with gp120 IIIIB and CD45RA+/CD45RO-, CD45RA-/CD45RO+ and double positive CD45RA+/CD45RO+ cells were quantified by flow cytometry. (B) Same as Fig. (3A) except that CD27 expression and Annexin-V positivity were measured by four color flow cytometry. The data is representative of three independent experiments.