Gene expression to contaminated or not contaminated Triatoma dimidiata faeces with Trypanosoma cruzi in vivo and in vitro assay.

Triatoma dimidiata is considered one of the most important vectors in the spread of Chagas disease in Mesoamerica. Hematophagous insects may deposit faeces contaminated or not with Trypanosoma cruzi on the surface of the skin during the feeding process. In endemic areas humans can be in contact several times to this fluid before get infection. Due to limited work on the of immune response to insect's fluids in mammals. In this work, we explored the early response of chemokine and cytokines of skin tissue at the inoculation site against faeces from T. dimidiata contaminated or not with T. cruzi in murine model, also we explored the in vitro response of epitheloid cells line "HeLa cells" to this fluid. Mice were exposed intradermically to faeces free of metacyclic trypomastigotes, oneor multiple times along the experiment before challenged with faeces contaminated with metacyclic trypomastigotes, mimicking natural conditions. In in vitro assay with HeLa cells only one exposure was carried out. It was observed that mice multiexposed to faeces, induced the strong response of TNF-α and CXCL3 expression at the inoculation site; but faeces contaminated with metacyclic trypomastigotes lower the response of TNF-α, and CXCL3. In in vitro assay with HeLa cell line, the faeces induced a strong response of CXCL8 and IL-6, but the presence of faeces contaminated with metacyclic trypomastigotes lower the response of CXCL8. In contrast, to in vivo model null response of TNF α and IL-1-α was observed in HeLa cells. In conclusion, Triatoma dimidiata faeces induces at the inoculation site chemokines that mediate preferentially chemotaxis of neutrophils and macrophages but the presence of metacyclic trypomastigotes moderate their induction. Epithelial cells act as efficient sentinels producing chemokines that may recruit neutrophils and monocytes.