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

BISCARI LUCÍA; CAMBRONERA PAULA; FARRÉ CECILIA; CEBRIAN I; CRIBB PAMELA; VILLAR SILVINA; PÉREZ ANA ROSA ; ALLOATTI ANDRÉS

Congreso; REUNIÓN ANUAL DE SOCIEDADES DE BIOCIENCIAS SAIC - SAI - SAFIS; 2020

SOCIEDAD ARGENTINA DE INMUNOLOGÍA

TRYPANOSOMA CRUZI PROMOTES MATURATION OF DENDRITIC CELLS AND THE RECRUITMENT OF PROTEINS INVOLVED IN ANTIGEN CROSS-PRESENTATION TO THE PARASITOPHOROUS VACUOLE Biscari L1 , Cambronera P1 , Farré C1 , Cebrian I2 , Cribb P3 , Villar S1 , Pérez AR1 , Alloatti A1 1. Instituto de Inmunología Clínica y Experimental de Rosario (IDICER/CONICET ? Universidad Nacional de Rosario) Rosario, Argentina 2. Instituto de Histología y Embriología de Mendoza (IHEM/ CONICET ? Universidad Nacional de Cuyo) Mendoza, Argentina 3. Instituto de Biología Molecular y Celular de Rosario (IBR/ CONICET ? Universidad Nacional de Rosario) Rosario, Argentina 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 BMDCs was 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.