Figure 6. Mycolactone is present in the mononuclear cells of M. ulcerans-infected animals.

C57BL/6 mice (n = 3) were infected by footpad injection of 10⁴ wtMu or mup045Mu bacilli. The distribution of mycolactone in PBMCs and in the mononuclear cell fraction of draining lymph nodes (DLNs), inguinal lymph nodes (ILNs) and spleens (Spleen) is shown 6 weeks post infection. Mononuclear cells were isolated from pooled samples of whole blood (1 ml), pooled DLNs (n = 3), or from the ILNs and spleens of 3 individual mice. Acetone-soluble lipid were then extracted from cell pellets and mycolactone concentrations determined by quantitative LC/MS-MS analysis. Means and SD are shown for ILNs and spleens. C) IL-2 production after whole blood stimulation with anti-CD3 and -CD28 antibodies for 24 h. Data are mean and SD of IL-2 concentrations, as measured in duplicate for pooled blood samples (n = 4) after 2, 4 and 6 weeks of infection, and are representative of three independent experiments. Differences in IL-2 concentration between groups were analyzed by one-way ANOVA (*: p<0,05; **: p<0,01).