Figure 1.

Lysozyme promotes the release of soluble TLR2 stimulants from Gram-positive bacteria. Gram-positive organisms (Ef, E. fecalis; Lp, L. plantarum; Sa, S. aureus; Sp, S. pyogenes) were heat-killed, resuspended in PBS at 10⁹ bacteria/ml and treated with or without 1 mg/ml lysozyme for 2 h. Conditioned medium was then filter-sterilized, diluted 1:100 in tissue culture medium and applied to RAW macrophages for the measurement of secreted TNFα (A) or HEK-293 cells transfected with TLR2 and NFκB reporter for the measurement of TLR2-dependent NFκB signalling (B). *p < 0.05 vs. cells cultured in medium alone (Ctrl), ANOVA with Dunnet's test.