FIG 1.

Supernatants from EV71-infected cells activate TLR9 signaling. mTLR9/293 cells were transfected with 0.25 μg of pNF-kB-luc and 0.25 μg of the pRL-TK internal control plasmid. After 24 h, the cells were cultured with various reagents for another 24 h, and the cell lysates were harvested to detect luciferase activity. (A) Medium alone; EV71 at an MOI of 5, 10, or 50; and CpG ODN (10 μg/ml) were used to stimulate mTRL9/293 cells. (B) Supernatants from EV71-infected RD cells (sEV71-RD) were collected to stimulate 293 or mTLR9/293 cells. DNase-treated sEV7I-RD was used to digest DNA. (C) mTLR9/293 cells were stimulated with EV71 at an MOI of 50, sEV71-RD, sEV7I-RD treated with UV (sEV71-RD-UV), or heat-inactivated sEV7I-RD (sEV71-RD-Heated). The data are expressed as means and SD of three independent experiments. *, P < 0.05; **, P < 0.01.