Figure 2: Modulation of CD40 responsiveness in Leishmania-infected macrophages: crosslinking of anti-CD40 antibody activates p38 MAPK-induced leishmanicidal function via iNOS2 induction. Leishmania infection downregulates CD40-induced p38 MAPK phosphorylation and uses the capability of this receptor to signal along an ERK1/2-dependent pathway to produce the proparasitic Th2 cytokine IL-10 from macrophages. iNOS2: inducible nitric oxide synthase 2; NO: nitric oxide; PTP: Protein tyrosine phosphatases.