FIG. 5.

SEVI and semen enhance infectivity of HIV-derived particles pseudotyped with XMRV Env. Undiluted and serial 10-fold dilutions of HIV particles encoding luciferase that were pseudotyped with XMRV Env were treated with the indicated concentrations of SEVI or semen and used to infect CaSki (A and C) or HEK 293T (B and D) cells. Nonpseudotyped particles served as the control (No XMRV Env). Infection rates were determined at 3 days postinfection by luciferase assay. Shown are average values and standard deviations derived from triplicate infections. *, slightly cytotoxic. RLU/s, relative light units per second. Numbers above bars indicate fold enhancement rates relative to untreated virus.