Trypomastigote small surface antigen ablation causes infection impairment in Trypanozoma Cruzi

CARLOS A BUSCAGLIA; MARIA DE LOS MILAGROS CAMARA; VIRGINIA BALOUZ

Resistencia

Congreso; XXX; 2018

Sociedad Argentina de Parasitologia

Trypanosoma cruzi is the etiological agent of Chagas disease. tssa (Trypomastigote Small SurfaceAntigen) is a mucin-like gene coding for a glycoprotein displayed on the surface of infective trypomastigoteforms that shows amino acids polymorphisms among parasite isolates. These polymorphisms correlatewith dierential antibody responses in T. cruzi-infected humans and dierential adhesion towards nonmacrophagiccell monolayers. The TSSAII variant (present in TcII, TcV and TcVI DTUs) has been characterizedas a parasite adhesin, engaging surface receptor(s) and inducing signaling pathways on the hostcell as a prerequisite for trypomastigote internalization. Most interestingly, trypomastigotes over-expressingTSSAII displayed improved adhesion and infectivity towards non-macrophagic cell lines in vitro. Moreover,TSSAII overexpression leads to an enhanced trypomastigote-to-amastigote conversion, indicating a possiblerole of TSSA also in parasite dierentiation. To get further insights into the functional signicance ofTSSA, we applied CRISPR/Cas9 technique in the RA strain (TcVI) to obtain TSSAII-KO parasites. Afterantibiotic selection, epimastigotes were cloned and genotypied by PCR and sequencing. tssa genes weresuccessfully ablated. Clones of interest were cycled in vitro to obtain infective forms. We conrmed thelack of expression of TSSAII protein in trypomastigotes by Western blot and IFA. Most interestingly, atleast 2 independent TSSAII-KO clones were signicantly less infective in non-macrophagic cell monolayersthan control cell lines in in vitro infection assays (p