IMMUNO-ENDOCRINE ASPECTS AFFECTING THE VACCINE RESPONSE TO TRYPANOSOMA CRUZI ANTIGENS

CAMILA BULFONI; FLORENCIA PACINI; BRENDA DINATALE; FLORENCIA GONZALEZ; SILVINA VILLAR; CECILIA FARRE; GUSTAVO CHAPO; IVAN MARCIPAR; GABRIEL CABRERA ; ANA ROSA PEREZ

Congreso; Reunión de BIOCIENCIAS SAIC-SAI-SAFIS; 2020

T. cruzi infection induces the activation of hypothalamus?pituitary?adrenal axis with the consequent release of corticosterone (CT) as a counter-regulatory mechanism. Previously, our group showed that CT is the main responsible of thymus atrophy, characterized by a decrease in the number of immature double positive (DP) thymocytes and the accumulation of regulatory T cells within the CD4 simple positive compartment. Here, we evaluated if the deleterious immune-endocrine response caused by T. cruzi infection upon the thymus is modified by the administration of our promissory experimental vaccine candidate.Therefore, BALB/c female (5-6/group) were immunized intranasally (three doses, one every two weeks) with vaccine formulations based in trans-sialidase (TS) antigen plus c-di-AMP as adjuvant. As controls, mice were treated with saline solution (SS) or with TS or c-di-AMP alone. Fifteen days after the last immunization mice were orally challenged with 3000 parasites of Tulahuen strain. Parasitemia and clinical score were evaluated several times after infection. To assess the impact of immunization over the immune-endocrine response mice were sacrificed after 100 days of infection. The thymus was weighted and thymocyte subpopulations were evaluated by flow cytometry. Also, adrenal response was evaluated indirectly by determination of gland weight and StAR gene expression by qPCR (enzyme involved in CT synthesis). The vaccinated group (TS+c-di-AMP) showed a diminished parasitaemia (p