HIV-1 IIIB gp120 induces a chemotactic response in T cells in a CD4-independent manner. Migration of the human Th2 cell clone CB-828 in response to stimulation with increasing amounts (from 10⁻¹ nmol/L to 10³ nmol/L) of SDF1 (○), gp120 wt (□), or gp120 ▵HX1 (▵) was analyzed in an invitro migration assay as described in Materials and Methods. The data depicted are representative of one of three independent experiments. Each point represents the mean ratio of migrated cells/total cells ± standard deviation (SD) from a representative experiment performed in triplicate. The number of spontaneously migrating cells was subtracted from the total number of cells present in the lower compartment.