Figure 2.

Binding of X5 to gp140 (120)s lacking variable loops and disulfide bond stabilized gp140. Wild-type gp120_JR-FL, gp120 with deleted V3 loop (gp120_JR-FLΔV3), and gp140 with deleted V1 and V2 loops (gp140_JR-FLΔV1V2*) or deleted V1, V2, and V3 loops (gp140_JR-FLΔV1V2*V3) (15), as well as cleaved disulfide bond stabilized gp140_HXB (SOS gp140_HXB2) (16), were captured by the antibody D7324 to 96-well plates and X5 added at the indicated concentrations in the absence (A) or presence (B) of sCD4 (2 μg/ml). The amount of bound X5 was detected by Fab-specific alkaline phosphatase conjugate and represented as optical density at 490 nm.