CONICET | Buscador de Institutos y Recursos Humanos

The discovery of immunologically protective Trypanosoma cruzi antigens is a matter of particular interest, given the relevance of human Chagas disease as a major public health issue. Despite efforts in the field are profuse and diverse, they have thus far been of very limited success. Our line of research proposes a T-cell driven approach, by which amplified T. cruzi-specific memory T-cells from infected patients are used to scan combinatorial peptide libraries, allowing the discovery of T epitopes which would be, by definition, immunogenic. The first step on this strategy is the generation of T-cell lines from donors? peripheral blood mononuclear cells (PBMC). This is achieved by an in vitro stimulation and culture protocol, consisting of an initial stimulation with T. cruzi lysate, an antigen-specific T-cells expansion stage and a challenge protocol for specificity evaluation. Among several combinations of experimental conditions tested, our preliminary results allowed us to adjust the following protocol variables: T. cruzi lysate concentration and incubation time (2.5 μg/ml and 1 day, respectively), initial culture density (200,000 PBMC/well), interleukin-2 addition in culture medium (since day 6, every 3-4 days), culture time span before specificity evaluation (27 days), antigen-specific T-cells to antigen presenting cells ratio (1:2), and readouts (Interferon-γ secretion, cell proliferation). Interestingly, experiments showed remarkable differences in the way T-cells respond to parasite antigens, depending on whether the donor was classified as asymptomatic (mainly proliferative response), or cardiac (predominantly interferon-γ secretion). Hopefully, our contribution will help to a better understanding of the immune response against T. cruzi in the context of Chagas disease, as it allows us to advance towards the discovery of potential prophylactic or therapeutic vaccine candidates.