(A) PBMCs were stimulated with anti-CD3 and anti-CD28 in the absence (white column, CTRL) or presence (black column, GBM-EXO) of different dilutions of exosomes isolated from plasma of high grade glioma patients (GBM). Healthy donor plasma-derived exosomes were used as control (striped column, EXO-HEALTHY). (B) PBMCs or CD14 negatively-sorted PBMCs (CD14-) were stimulated with anti-CD3 and anti-CD28 in the absence (white column, CTRL) or presence (black column, GBM-EXO) of exosomes isolated from plasma of GBM, 1:10 dilution. Proliferation of CD3+ was measured by CFSE assay on day 4. Columns, mean (n = 6); bars, SD;*, significantly different from the control; P<0.05.