Culture supernatants containing TCTs were centrifuged at 1000 × g, 15 min, washed three times in phosphate-buffered saline, pH 7.4 (PBS), and incubated for 2 h in DMEM containing 2% glucose at 37°C, 5% CO2 for release of EVs. The parasites (109 trypomastigotes per mL) were removed by centrifugation (1000 × g, 10 min, room temperature), and the supernatant (1 mL) was filtered, diluted 1:2 in 200 mM ammonium acetate, pH 6.5, and EVs purified by size-exclusion chromatography (SEC) using a Sepharose CL-4B column (1 × 40 cm, GE Healthcare, Piscataway, NJ), pre-equilibrated with 100 mM ammonium acetate, pH 6.5. After loading the filtered parasite supernatant (1 mL), the column was eluted with the same buffer at a flow rate of 0.2 mL/min. Fractions of 1 mL were collected and then screened by nanoparticle tracking analysis (NTA) and enzyme-linked immunosorbent assay (ELISA) to locate the fractions containing the EVs, as previously described [21 ].
Soluble VF fraction was obtained by ultracentrifugation for 16 h at 100,000 × g, 4°C, as described [13 ]. The ensuing supernatant contained soluble, secreted proteins released by the parasite, and the pellet total EVs. For proteomic analysis, pooled preparations of purified total EVs or VF fractions were subjected to (LC-MS/MS), as previously described [10 ,13 ], with some modifications (see below). The experimental workflow including the purification and characterization of EVs and VF fraction is depicted in Figure 1 .10.1080/20013078.2018.1463779-F0001 ![]()
Soluble VF fraction was obtained by ultracentrifugation for 16 h at 100,000 × g, 4°C, as described [
Workflow employed for the production, fractionation, and characterization of Trypanosoma cruzi EVs and vesicle-free fraction from Y and YuYu strains. The details of each step are explained in the Materials and Methods section. DMEM, Dulbecco’s Modified Eagle’s Medium; NTA, nanoparticle tracking analysis; SEM, scanning electron microscopy; SEC, size-exclusion chromatography.
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