Characterization of Fasciola heptica extracellular vesicles recovered by gravity flow

Parasite-derived extracellular vesicles (EVs) are now at the forefront of helminth research, with evidence indicating that they exhibit immune modulatory activity, presenting a strong case to look at their potential as vaccine candidates. In the present study, Fasciola hepatica derived EVs (FhEVs) were isolated from adult worms using a gravity flow method. These gravity flow derived FhEVs were characterised by proteomics and lectin array. Comparative analysis using the same methods was carried out using FhEVs recovered by differential centrifugation. The immunomodulatory properties of the gravity flow derived FhEVs was determined using bone marrow derived murine dendritic cells (BMDCs), which highlighted that the FhEVs induce a novel phenotype that secreted low levels of TNF, enhanced expression of cell surface markers (CD80, CD86, CD40, OX40L and SIGNR1) and intracellular markers (SOCS1 and SOCS3). In conclusion, this study demonstrates that FhEVs modulate immune cells, inducing a unique DC phenotype that supresses IL-2 secretion from T-cells.