MIF Synergizes with Trypanosoma cruzi Antigens to Promote Efficient Dendritic Cell Maturation and IL-12 Production via p38 MAPK
2011
Cesar A. Terrazas, EriK Huitron, Alicia Vazquez, Imelda Juarez, Griselda M. Camacho, Elsa A. Calleja, Miriam Rodriguez-Sosa
Macrophage migration inhibitory factor (MIF) has been found to be involved in host resistance to several parasitic infections. To determine the mechanisms of the MIF-dependent responses to Trypanosoma cruzi, we investigated host resistance in MIF-/- mice (on the BALB/c background) during an intraperitoneal infection. We focused on the potential involvement of MIF in dendritic cell (DC) maturation and cytokine production. Following a challenge with 5 x 10<sup>3</sup> T. cruzi parasites, wild type (WT) mice developed a strong IL-12 response and adequate maturation of the draining mesenteric lymph node DCs and were resistant to infection. In contrast, similarly infected MIF<sup>-/-</sup> mice mounted a weak IL-12 response, displayed immature DCs in the early phases of infection and rapidly succumbed to T. cruzi infection. The lack of maturation and IL-12 production by the DCs in response to total T. cruzi antigen (TcAg) was confirmed by in vitro studies. These effects were reversed following treatment with recombinant MIF. Interestingly, TcAg-stimulated bone marrow-derived DCs from both WT and MIF<sup>-/-</sup> mice had increased ERK1/2 MAPK phosphorylation. In contrast, p38 phosphorylation was only upregulated in WT DCs. Reconstitution of MIF to MIF<sup>-/-</sup> DCs upregulated p38 phosphorylation. The MIF-p38 pathway affected MHC-II and CD86 expression as well as IL-12 production. These findings demonstrate that the MIF-induced early DC maturation and IL-12 production mediates resistance to T. cruzi infection, probably by activating the p38 pathway.
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