Antiparasitic Mechanisms of the Human Placenta

Trypanosoma cruzi , during vertical transmission, crosses the placental barrier. The trophoblast, a continuous renewing epithelium, is the first tissue of this anatomical barrier to have contact with the parasite. The epithelial turnover, including the trophoblast, is part of the innate immune response due to the fact that pathogens attach to the surface of cells prior invasion. Cellular processes such as proliferation, differentiation, and apoptotic cell death are part of the trophoblast turnover. Interestingly, T. cruzi induces all of them. In addi tion, the placenta expresses TLRs, whose activation leads to the secretion of pro-inflam - matory and immunomodulating cytokines. T. cruzi is recognized by TLR-2, TLR-4, TLR-7, and TLR-9. In the present review, we analyze the current evidence about the trophoblast epithelial turnover, the induction of a specific cytokine profile as a local placental innate immune response, as well as other possible defense mechanisms against the parasite. Phospholipase C gamma and ERK1/2 mitogen activated kinase pathways are differentially modulated by