Figure 4.

AP-1 repressor blocked S. pneumoniae-induced IL-8 release. HEK293 cells were transfected with plasmids encoding TLR2, as well as empty vector (CMV500), AP-1 repressor (CMV500-A-Fos), Fra1 antisense (AS Fra1), or Fra2 antisense (AS Fra2), respectively. Then, cells were infected with S. pneumoniae strain R6x (10⁵ cfu/ml) or stimulated with TNFα (50 ng/ml) for 15 h, and IL-8 concentration was measured in the supernatant. *, p < 0.01 vs. control; #, p < 0.01 vs. infected cells with empty vector at least in three independent experiments.