Fig. (4) CD4 and Lck are required for gp120 mediated increase of double positive CD45RA+/CD45RO+ CD4 T cells. (A) Activated primary human CD4 T cells were left untreated or were pre-treated with either Lck inhibitor, PP2 (5µM) or CXCR4 inhibitor, AMD3100 (2µM) or sCD4 (2µg/ml) followed by gp120. Then number of single positive CD45RA+/CD45RO-, CD45RA-/CD45RO+ and double positive CD45RA+/CD45RO+ cells were analyzed by flow cytometry. (B) The data represents three independent experiments as described above. P values were determined by Student’s paired t test. *=P<0.05 compared to gp120 alone.