Fig. 2. Inhibition of the NF-κB pathway facilitates TLR2-mediated apoptosis. (A) 293 cells were transiently transfected with 0.25, 0.1, 0.04, 0.01 and, in addition for co-transfections with NIK-DN, 0.002, 0.0004 and 0.00008 µg of an expression plasmid encoding gD-TLR2 indicated in a gray gradient from black (0.25 µg) to white (0.00008 µg). Where indicated, the cells were also transfected with 0.25 µg of an expression plasmid encoding NIK-DN. Control cells transfected with vector DNA only are indicated with hatched bars. At 24 h post-transfection, the cells were incubated with or without 1 µg/ml sBLP as indicated and apoptosis was determined by TUNEL staining. (B) Anti-gD western blot of lysates prepared from cells transfected as in (A). Cells transfected with 0.002 µg or less had undetectable levels of gD-TLR2.