FIG 4.

KSHV gH/gL and ephrins bind EphA2 with nanomolar and subnanomolar affinity, resulting in different sensitivities to inhibition. (A) Binding of ephrin A4-Fc, ephrin A5-Fc, and gH-Fc/gL at various concentrations to immobilized EphA2 ectodomain in the presence of compound 1 at 1 mM (squares) or DMSO only (circles) was measured by ELISA. (B) Binding of gH-Fc/gL at increasing concentrations to immobilized EphA2 ectodomain measured in the absence (circles) or presence of compound 1 at 500 μM (squares) in the same fashion as for panel A. (C) Binding of the monoclonal antibody 6F8 to the EphA2 ectodomain at two different dilutions within the dynamic range of the binding reaction was measured as for panel B in the absence (gray bars) and presence of compound 1 at 500 μM (black bars). (D) Binding of soluble gH/gL to immobilized EphA2 or of soluble EphA2 to immobilized gH/gL was measured by ELISA in the presence of compound 1 at 1 mM or 2 mM or DMSO only. The error bars represent the standard errors of the mean.