Here, we show that B cells and T cells produce IL-10 during murine Litomosoides sigmodontis infection. IL-10-deficient mice produced increased amounts of L. sigmodontis-specific IFN-γ and IL-13 suggesting a suppressive role for IL-10 in the initiation of the T-cell

response to infection. Using cell type-specific IL-10-deficient mice, we dissected different functions of T-cell- and B-cell-derived IL-10. Litomosoides sigmodontis-specific IFN-γ, IL-5, and IL-13 production increased in the absence of T-cell-derived IL-10 at early and late time points of infection. In contrast, B-cell-specific IL-10 deficiency did not lead to significant changes in L. sigmodontis-specific cytokine production compared PR-171 order to WT mice. Our results suggest that the initiation of

Ag-specific cellular responses during L. sigmodontis infection is suppressed by T-cell-derived IL-10 and not by B-cell-derived IL-10. Infection of mice with the nematode Litomosoides sigmodontis is used to model most features of the immune response and immune modulation observed in human filarial infections [1, 2]. Litomosoides sigmodontis third-stage larvae (L3) are transmitted to their natural host, the cotton rat (Sigmodon hispidus), or to laboratory mice during the blood meal of infected mites (Ornithonyssus bacoti). Over the next 3 days, L3 migrate via the lymphatics to the pleural cavity. There the L3 molt to fourth-stage larvae (L4) within 10 days, and to young adults within 26–28 days. In the fully permissive BALB/c mouse strain, L. sigmodontis adults mate and release microfilariae AZD9668 mw (MF) by day 60 post infection (p.i.). Parasites are eventually eliminated by granulocyte recruitment

and encapsulation after more than 3 month of infection. Parasite control was shown to depend on the presence of CD4+ T cells [3] and B1 cells [4]. While IL-4 was central for controlling MF in BALB/c mice, IL-5 obviously contributed to eliminating both MF and adults [5-8]. Despite the importance of an IL-4- and IL-5-driven Th2 response for host defense, IFN-γ production also represented a central element of the protective immune response since IFN-γ-deficient BALB/c mice displayed higher numbers ADP ribosylation factor of parasitic adults and MF [9]. Indeed, IFN-γ and IL-5 were found to act synergistically [10]. L. sigmodontis young adults never reach sexual maturity in the resistant C57BL/6 mouse strain and are removed by granuloma formation by day 60 p.i. [11, 12]. Infected C57BL/6 mice also displayed a mixed Th1/Th2 response. C57BL/6 mice lacking IL-4 displayed a permissive phenotype, which led to patent infections, that is, the production of MF by fertile adults in the context of a Th1 response [5]. This permissive phenotype of IL-4-deficient C57BL/6 mice reverted to resistance by the additional absence of IL-10 [13].