Trypanosomatid Extracellular Vesicles as Potential Immunogens for Chagas Disease

Chagas disease remains a significant public health concern, with limited treatment options and an urgent need for novel preventive strategies. Extracellular vesicles (EVs) from <i>Trypanosoma cruzi</i> have been shown to modulate host immune responses, often favoring parasite persistence. In this study, we characterized EVs derived from the non-pathogenic trypanosomatids <i>Trypanosoma rangeli</i> and <i>Phytomonas serpens</i> and evaluated their potential as immunogens capable of inducing cross-protection against <i>T. cruzi</i> infection. Isolated EVs were characterized by Nanoparticle Tracking Analysis (NTA) and electron microscopy. A comparative proteomic analysis of EVs was performed using Mass Spectrometry-Based Proteomic Analysis (LC-MS/MS). The effects of EVs on immunomodulation and <i>T. cruzi</i> infection were assessed through in vitro and in vivo assays, using peripheral blood mononuclear cells (PBMCs) and BALB/c mice. The proteomic analysis identified shared proteins between the EVs of <i>T. rangeli</i>, <i>P. serpens</i>, and <i>T. cruzi</i>, including immunogenic candidates such as calpain-like cysteine peptidase and elongation factor 2. In vitro, pre-stimulation with the <i>T. rangeli</i> EVs reduced infection rates of the host cells by <i>T. cruzi</i>. In vivo, immunization with the EVs from <i>T. rangeli</i> and <i>P. serpens</i> led to a significant reduction in parasitemia in the BALB/c mice challenged with <i>T. cruzi</i>, though this did not translate into improved survival compared to controls. Interestingly, the EVs from <i>T. cruzi</i> also reduced parasitemia but did not confer protection against mortality. These findings suggest that while non-pathogenic trypanosomatid EVs exhibit potential immunogenic properties and can reduce parasitic load, their efficacy in preventing disease progression remains limited. Further research is needed to explore the mechanisms underlying these effects and to optimize EV-based strategies for protective immunity against Chagas disease.