IL-17 neutralization reverses the pathology induced after blockade of IL-10R signaling.

<p>C57BL/6, or <i>Il-10^−/−</i> mice were infected intradermally with <i>L. major</i> metacyclic promastigotes. Either isotype, anti-IL-10R or anti-IL-17 or both mAbs were administrated at day-1 and twice weekly during 4 weeks. Lesion development was assessed by measuring ear thickness (A, F). Values represent mean induration in mm (mean ± SEM) of 5 mice per group. Numbers of parasites in ear lesions were quantified using limiting dilution assays at 6 and 5 wk after infection (B, F). Mean ± SEM parasite numbers are shown as individual parasite counts per ear. Bar graph showing number of Ly6G⁺ cells per ear (C). Level of cytokines was measured in supernatants from <i>in vitro</i> stimulated draining lymph node cells with <i>L. major</i> FTAg (D, E) (ND: not detectable). (G) H&E staining of histological sections of paraffin-embedded ears at 6 wks of infection showing epithelial hyperplasia (head arrow), leukocyte infiltration in epidermis (black arrows) and localized neutrophils infiltration in deep dermis marked as * in the anti-IL-10R treated sections (Bars, 100 µm; EP: epidermis, D: dermis). The data shown are from one experiment and are representative of at least three experiments (*, <i>p</i><0.05).