KINETIC AND SUPPRESSOR FUNCTION OF CD11b+ GR-1+ SPLENOCYTES IN THE PRECLINICAL ASSESSMENT OF THE TSf-ISPA VACCINE AGAINST TRYPANOSOMA CRUZI

ESTEFANÍA PROCHETTO; ELIANA BORGNA; JUAN CRUZ GAMBA; MARÍA FLORENCIA PACINI; MÓNICA VERMEULEN; DIEGO ARIAS; ANA ROSA PÉREZ; IVÁN MARCIPAR; GABRIEL CABRERA

Mar del Plata

Congreso; LXX REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA (SAI) & 3ER CONGRESO FRANCO-ARGENTINO DE INMUNOLOGÍA (FAIC); 2022

Sociedad Argentina de Inmunologia

ntroduction: We have previously reported that a vaccine based ona trans-sialidase fragment (TSf) formulated with a cage-like particleadjuvant (ISPA) protects BALB/c mice against Trypanosoma cruzi(T. cruzi) infection. Alterations of CD11b+Gr-1+ (Ly6G+/Ly6C+)cells, with a phenotype compatible with myeloid-derived suppressor cells (MDSCs), were observed during both the immunizationand the acute phase of infection. Aim: To study the kinetic and suppressor function of CD11b+ Gr-1+ splenocytes in the preclinicalassessment of the TSf-ISPA vaccine against T. cruzi. Methods: 3doses of TSf-ISPA were given to BALB/c mice. For the challenge,immunized mice were intraperitoneally infected with 1000 T. cruzi(Tulahuen strain). Flow cytometry was used to measure CD11b+GR-1+ splenocytes at days 2, 7 and 15 post-immunization (p.imm.),and at days 15 and 21 post-infection (p.i.). Magnetic cell sorting wasused to purify Gr-1+ cells. Suppressive capacity of purified cellswas assessed in vitro by measuring the inhibition of proliferation ofresponder cells labelled with 5,6-carboxifluorescein diacetate succinimidyl ester (CFSE). Results: CD11b+GR-1+ splenocytes in-