FIG. 4.

HIV-1 gp120 binds specifically to immobilized PF4. (A) Graded amounts of PF4 were immobilized overnight before incubating with varying concentrations of purified HIV-1 JRFL gp120. JRFL gp120 bound to PF4 in a concentration-dependent manner. (B) To assess selectivity of gp120 binding, we tested the ability of other chemokines of similar size and charge to PF4 to bind gp120. RANTES was used as a positive control and bound JRFL gp120. However, gp120 did not bind IL-8 or SDF-1. All experiments were done in at least triplicate in each of at least three independent experiments. Error bars represent standard deviations. IL-8, interleukin-8; SDF-1, stromal cell-derived factor 1.