Figure 3.

S. pneumoniae induced AP-1 activation in human lung epithelial cells. BEAS-2B cells were infected with S. pneumoniae R6x (10⁶ or 10⁷ cfu/ml as indicated) (A/B/C) for the indicated times or TNFα (50 ng/ml, 0.5 h). DNA binding of AP-1 (A) was detected by EMSA and of phosphorylated c-Jun by transcription factor activation assay (B). *, p < 0.01 vs. control. Recruitment of Ser^63/73-phosphorylated c-Jun and RNA polymerase II to the endogenous il8 promoter was detected by chromatin immunoprecipitation (C). Representatives of at least three independent experiments are shown.