FIG. 4.

TNF production by BMDM infected with WT M. ulcerans 1615 or with the mycolactone-defective mutant 1615A: kinetics and effects of MOI and supplementation with mycolactone. BMDM were infected with a 1:1 MOI (A and D) or at different MOIs ranging from 10:1 to 1:15 (B and C) with M. ulcerans 1615A or 1615 WT, in the presence (D) or absence (A to C) of mycolactone. For cytokine measurement by ELISA, supernatants of three independent wells were collected from each experimental group. (A) Higher amounts of TNF are produced with infection by M. ulcerans 1615A in comparison to M. ulcerans 1615. (B and C) BMDM infected with M. ulcerans 1615A produce large amounts of TNF at high MOIs, and that production declines as the MOI is decreased. M. ulcerans 1615 induces the production of smaller amounts of TNF peaking at low MOI. (D) Addition of mycolactone to M. ulcerans 1615A-infected macrophages diminishes or abrogates the production of TNF. TNF was not detected in the presence of 50 ng mycolactone. Results are from one representative experiment out of two independent experiments.