Characterization of Trypanosoma cruzi infectivity, proliferation, and cytokine patterns in gut and pancreatic epithelial cells maintained in vitro.

Trypanosoma cruzi infects all nucleated cells in both humans and experimental animals. As a prelude to our studies of T. cruzi pathogenesis in the gastrointestinal system, we have initiated in vitro cultures of gut (Caco-2 and HT-29) and pancreatic (Panc-1) epithelial cells. We show that along with primary human fibroblasts, all three cell lines are susceptible to infection and support proliferation of T. cruzi. Infection with T. cruzi modified dramatically the cytokines elaborated by these cells. Substantially greater quantities of IL-5 and TGF-β1 were produced by fibroblasts and Caco-2 and Panc-1 cells, whereas secretion of IFN-γ and TNF-α was greatly reduced in all three cell types. Since these cells are not known to be the primary sources of IFN-γ, we examined IFN-γ mRNA expression in these cells. Both Caco-2 and Panc-1 cells were found to express IFN-γ mRNA, validating its secretion. These findings may provide insight into signaling pathways that mediate innate immunity to T. cruzi and pathogenesis of gastrointestinal and pancreatic alterations in Chagas disease.