Fig. 6.

Extracellular vesicle (EV)-treated peripheral blood mononuclear cells (PBMCs) retain ability for activation and re-stimulation by mixed lymphocyte reaction (MLR) but only in the absence of EVs. (A) Outline of PBMC treatment: one group of PBMCs was only co-incubated with unrelated HD PBMCs (MLR), and IFNγ release was measured by ELISA; a second PBMC group was PHA-treated and then utilized in MLR, with IFNγ release measured; a third group was PHA-stimulated and treated to low and high EV concentrations followed by MLR (with EVs remaining during the MLR), and IFNγ release measured; a fourth group was treated as above, but EVs were washed out prior to MLR/IFNγ release. (B) IFNγ concentration of media from PBMCs treated as described in (A). Background release of IFNγ without MLR stimulation was 0.158 ng/mL (Fig. 1B). *P < .05, **P < .01, ***P < .001 compared to No Tx control.