Binding of α-defensins to HIV-1 gp120. (A) Competition of synthetic α-defensin-1 (○) and α-defensin-2 (•) with the anti-gp120 mAb F105 (used at 5 μg/mL) for binding to plastic-immobilized recombinant gp120_BaL in ELISA. (B) Effect of synthetic α-defensin-2 on binding of different anti-gp120 mAbs with various epitope specificities (indicated on the x-axis) in ELISA. All the mAbs were used at 5 μg/mL; α-defensin-2 was used at 7.3 μM. Error bars indicate SD of mean values obtained from 3 repeated assays.