Figure 1: The S. aureus master regulator of virulence Agr governs the capacity of S. aureus to stimulate TLR2.
From: Toll-like receptor 2 activation depends on lipopeptide shedding by bacterial surfactants
Culture filtrates of S. aureus strains with strong Agr activity but not with weakly active or no Agr have potent capacities to induce either IL-8 in HEK-TLR2 cells (a,b) and in PMN (c), or TNF-α, IL-6 and IL-1β in PBMCs (d–f). The synthetic lipopeptide Pam2CSK4 and TSB medium were used as positive and negative controls, respectively. Expression of TLR2 in HEK cells leads to dose-dependent IL-8 induction by USA300 culture filtrates (g). Culture filtrates are not cytotoxic to HEK cells at indicated dilutions used for stimulation (h). Agr activity of S. aureus strains was measured by qRT–PCR of RNAIII expression (i). Data represent means +/− s.e.m. of at least three independent experiments. *P<0.05, **P<0.01, ***P<0.001; ****P<0.0001 significantly different versus USA300 wild-type (b–f) as calculated by Student’s t test.
