FIG 7.

Small-molecule inhibitors of the gH/gL-EphA2 interaction inhibit entry of KSHV. (A) Inhibition of KSHV entry by two dimethylpyrrolyl benzoic acid derivatives (compounds 1 and 2). 293T cells were preincubated with compound 1 (diamonds) or compound 2 (×) at the indicated concentrations for 30 min before infection with rKSHV.219 (GFP reporter gene) in the continued presence of the inhibitor. The error bars represent the standard deviations; n = 3. (B) Inhibition of viral entry by compound 1 is specific for KSHV. 293T cells were infected as for panel A with GFP encoding rKSHV.219 (diamonds) or a VSV G-pseudotyped SIV239-GFP (circles) in the presence of compound 1 at the indicated concentrations. The error bars represent the standard deviations; n = 3. (C) 293T cells were infected with rKSHV.219 or a VSV G-pseudotyped SIVmac239-GFP as for panel A in the presence of the indicated concentrations of compound 1. The top row of each pair shows GFP fluorescence, the bottom row phase-contrast. The images were taken at ×100 magnification after 2 days. (D) Inhibition of rKSHV.219 infection by compound 1 on LEC, HUVEC, and rhesus fibroblasts. Infection and preincubation with different concentrations of compound 1 was carried out as for panel B. After 24 h, the medium was changed to medium without inhibitor, and the cells were cultured for an additional 24 h. The percentage of GFP-expressing cells was determined after 2 days (diamonds). Infection with VSV G-pseudotyped SIV239-GFP was performed in parallel to control for specificity (circles). EC₅₀ values as calculated by linear approximation of the respective curve segments are given. The error bars represent the standard deviations; n = 3.