Development of a novel bivalent antigen effective to control Trypanosoma cruzi infection.}

VAZQUEZ ME; ZABALA BA; MESIAS AC; PARODI C; PEREZ BRANDAN C; ACUÑA LA

Mendoza

Congreso; XI Congreso de la Sociedad Argentina de Protozoología; 2022

Chagas disease (CD) is a neglected and silent disease caused by a flagellar protozoan, namedTrypanosoma cruzi, that affect over 8 million people around the world. CD is the principal causeof an infectious heart disease in the world. Nowadays, there is not an available vaccine for theCD prevention, but the research around vaccines development is improving. One of these newperspectives is the multi-component vaccine strategy. In this sense, we constructed a fusionprotein based on two T. cruzi antigens with different goals. On one hand, the N-terminus Tc52(N-Tc52) develops a humoral response, and in the other hand, an epitope of TS protein calledTSKB20 possess immunodominance in cellular response against the parasite. N-Tc52 wasamplified by PCR from T. cruzi CL Brener strain and subsequently reamplified to incorporate,with specific primers, two TSKB20 sequences in tandem. Next, this genetic construct was clonedinto a bacterial plasmid, pRSET-A and finally, we expressed and purified the chimeric proteinresulting (N-Tc52/TSKB20). No genomic mutations and its primary structure were confirmed. Toprove the biological activity of this bivalent antigen, an immunization scheme in mice wasdiagrammed. Animals were inoculated with chimera protein plus a saponin-type adjuvant 3times separated between 21 days. Blood was collected before each dose and 21 days after lastdose when the half of animals were sacrificed, and spleens were taken to evaluate the immuneresponse. The other half of mice were challenged with a lethal dose of T. cruzi trypomastigotes.Parasitemias were recorded twice a week for 25 days for assessed vaccine effectiveness. Lastlyanimals were sacrificed, and hearts, colon and muscle were taken to measure parasitic load. Inbrief, mice inoculated with chimeric protein were able to control parasitemias and reduceparasitic burden in target organs exhibiting an immune response against T. cruzi in comparationwith controls.