ANTI-TRYPANOSOMA CRUZI PROPHYLACTIC VACCINE DECREASES HEART TISSUE DAMAGE AND IMPROVES CARDIAC FUNCTION IN MICE

MARIA FLORENCIA PACINI; CAMILA BULFONI BALBI; BRENDA DINATALE; FLORENCIA BELÉN GONZÁLEZ; CECILIA FARRÉ; GUSTAVO CHAPO; OSCAR BOTTASSO; PAULA CACIK; ESTEFANÍA PROCHETTO; IVÁN MARCIPAR; ANA ROSA PÉREZ

Congreso; LXXI Reunión Anual de la Sociedad Argentina de Inmunología; 2023

Currently there are no prophylactic vaccines to combat Chagas disease. We previously showed that a nasal vaccine formulated with a N-terminal fragment of Trans-sialidase (TS) combined with c-di-AMP(A), generated specific humoral and cellular immunogenicity and protects against the parasite during acute phase. Given that an effective anti-T. cruzi vaccine might avoid or attenuate myocardialdamage, here, we aim to evaluate at myocardial level the prophylactic efficacy during the acute (17 days postinfection–dpi-) and the chronic (110 dpi) phases. For this, BALB/c female mice, were intranasal immunized with the TS+A vaccine(3 doses, one every 2 weeks). As controls, groups of mice were also immunizedwith saline solution (SS) or TS and A alone. After immunization, animals were orally challenged with 3000 Tulahuen strain/mice. A group of mice not immunized and not infected (NI) was also included. Hearts were removed at the different dpi and longitudinally dissected, afterwards part of tissue was fixed in buffered formalin and later paraffin-embedded and 5-mm tissue sections were stained withboth hematoxylin/eosin (for the evaluation of intensity and magnitude of inflammatory infiltrates), and picrosirius red (for fibrosis evaluation). The rest of tissue was cryopreserved for cytokine expression evaluation by RT-qPCR (IL10,TGF-β, IFN-, TNF-α, IL17a). Additionally, chronic functional impairment was determined by electrocardiogram (ECG), and different parameters (corrected QTinterval –QTc-, QRS) were analysed. Acute and chronic myocarditis showed mildinfiltrates in TS+A group, while SS, TS and A groups showed moderated or severe damage (overall,p