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

PACINI MARIA FLORENCIA; BALBI, CAMILA BULFONI; BRENDA DINATALE; FLORENCIA B GONZÁLEZ; FARRÉ, CECILIA.; CHAPO GUSTAVO; CACIK PAULA; ESTEFANÍA PROCHETO; IVÁN MARCIPAR; PEREZ ANA R.

San Luis

Congreso; LXX REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA (SAI) & 3ER CONGRESO FRANCO-ARGENTINO DE INMUNOLOGÍA (FAIC); 2023

Currently there are no prophylactic vaccines to combat Chagas disease.We previously showed that a nasal vaccine formulated with a N-terminalfragment of Trans-sialidase (TS) combined with c-di-AMP(A), generatedspecific humoral and cellular immunogenicity and protects against theparasite during acute phase. Given that an effective anti-T. cruzi vaccinemight avoid or attenuate myocardial damage, here, we aim to evaluate atmyocardial level the prophylactic efficacy during the acute (17 days postinfection–dpi-) and the chronic (110 dpi) phases. For this, BALB/c femalemice, were intranasal immunized with the TS+A vaccine (3 doses, one every2 weeks). As controls, groups of mice were also immunized with salinesolution (SS) or TS and A alone. After immunization, animals were orallychallenged with 3000 Tulahuen strain/mice. A group of mice not immunizedand not infected (NI) was also included. Hearts were removed at the differentdpi and longitudinally dissected, afterwards part of tissue was fixed inbuffered formalin and later paraffin-embedded and 5-mm tissue sectionswere stained with both hematoxylin/eosin (for the evaluation of intensity andmagnitude of inflammatory infiltrates), and picrosirius red (for fibrosisevaluation). The rest of tissue was cryopreserved for cytokine expressionevaluation by RT-qPCR (IL10, TGF-β, IFN-, TNF-α, IL17a). Additionally,chronic functional impairment was determined by electrocardiogram (ECG),and different parameters (corrected QT interval –QTc-, QRS) were analysed.Acute and chronic myocarditis showed mild infiltrates in TS+A group, whileSS, TS and A groups showed moderated or severe damage(overall,p