TRYPANOSOMA CRUZI PROMOTES MATURATION OF DENDRITIC CELLS AND THE RECRUITMENT OF PROTEINS INVOLVED IN ANTIGEN CROSS-PRESENTATION TO THE PARASITOPHOROUS VACUOLE

BISCARI, LUCÍA; CEBRIÁN, IGNACIO; PÉREZ, ANA ROSA; CAMBRONERA, PAULA; CRIBB, PAMELA; ALLOATTI, ANDRÉS; FARRÉ, CECILIA; VILLAR, SILVINA

Buenos Aires

Congreso; ANNUAL MEETING OF BIOSCIENCE SOCIETIES 2020; 2020

SAIC-SAI-SAFIS

CD8+ T cells are crucial in the defense against Trypanosoma cruzi infection. Efficient priming of CD8+ T cell responses requires not only the processing and presentation of antigens, but the expression of costimulatory molecules by activated dendritic cells (DCs).To analyze whether the interaction of T. cruzi with DCs promotes cell maturation, primary cultures of DCs were generated from mouse bone marrow (BMDCs) and incubated with trypomastigotes (Tp)of the Tulahuén strain of T. cruzi. DCs activation was analyzed at different time points by measuring the expression of the costimulatory molecule CD86 by flow cytometry. The activation of BMDCswas only evident after 18 hours of co-culture (CD86 expression increased by 40%; statistical significance analyzed by Bonferroni Two-way ANOVA).Then, we analyzed whether DC activation upon interaction with T. cruzi increased the cell capacity to cross-present exogenous antigens. To do so, matured BMDCs (previously stimulated with Tp from T. cruzi for 18 hours) were incubated with soluble ovalbumin (OVA) and co-cultured with the B3Z hybridoma cell line. OVA cross-presentation promote B3Z activation and the generation of a colorimetric reaction measured by OD. Our preliminary results show that BMDCs incubated with Tp increases OVA cross-presentation.We are also interested to understand whether the parasitophorous vacuole (PV) formed upon T. cruzi infection of DCs can serve as an organelle involved in the presentation of parasitic antigens. Hence, by using confocal microscopy, we evidenced the recruitment of Tapasin and Calreticulin (components of the cross-presentation machinery) to the PV after 2 hours of infection of BMDCs suggesting that this organelle can act as a cross-presenting organelle.Summarizing, we consider that antigen cross-presentation after T. cruzi internalization by DCs is a likely efficient mechanism that could actively participates in the orchestration of CD8+ T cell responses against the infection.