FIG 3.
TLR2 enhances S. aureus invasion independently of Lpl's. (A) A total of 106 HEK293 cells either untransfected (HEK-0) or transfected with the human TLR2 gene (HEK-TLR2) or the FLAG tag gene (HEK-FLAG) were infected with USA300 or its Δlpl mutant at an MOI of 30. (B) Additionally, 105 cells were blocked with 10 μg/ml anti-TLR2 antibody (αTLR2 AB). The host cells were infected for 1.5 h, followed by lysostaphin treatment for another 1.5 h to kill adherent S. aureus cells. (C) Detection of IL-8 levels in HEK-TLR2 cells after incubation with anti-TLR2 antibodies. Before the addition of 100 ng P3C, 105 HEK-TLR2 cells were incubated for 1 h at 37°C with function-blocking antibodies (2.5 μg, 5.0 μg, and 10.0 μg) directed against TLR2. IL-8 levels were detected after 18 h of stimulation. All experiments were performed at least in triplicate in three independent replications. Error bars indicate standard deviations. Statistical significance was calculated by using Student's t test (ns, no statistical difference; *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001).