Fig. (3) gp120 inhibits SDF-1α -induced F-actin polymerization in CD4 T cells. (A) Purified primary human CD4 T cells were pretreated with either gp120 IIIIB (1µg/ml) for 2 min or BSA, and then either left untreated or stimulated with SDF-1α (40nM) for 1 min, and cells were analyzed for F-actin content. (B) Pooled results of three independent experiments described above (A). P values were determined by Student’s paired t test. (C) Primary human unstimulated CD4 T cells were separated into two populations following chemotaxis in transwell chambers. Cells from upper chamber (no chemotaxis) and lower chamber (chemotaxis) were analyzed for F-actin content as described above. The data is representative of three independent experiments.