FIG 3 .

A small-molecule inhibitor of S1P selectively inhibits hantavirus entry. (A) U2OS cells pretreated with the indicated concentrations of the S1P inhibitor PF-429242 or the 1% DMSO vehicle for 24 h were exposed to the indicated viruses (0.1 to 0.2 IU per cell) (n = 3; representative of 3 independent experiments). After 2 h of incubation, NH₄Cl (20 mM, final concentration) was added to the medium to prevent subsequent rounds of infection. Infected cells were enumerated as described for Fig. 2. (B) HUVECs were pretreated with the indicated concentrations of the S1P inhibitor or the 1% DMSO vehicle for 24 h and then exposed to authentic hantaviruses (1 PFU per cell). Viral-antigen-positive cells were enumerated by 24 h postinfection.