Fig 3. GSC-derived exosomes stimulate CD25 expression and proliferation of isolated CD4+ T cells but do not affect differentiation and suppressive activity of Treg cells.

CD4+ T cells, isolated from PBMCs by negative selection, were stimulated with anti-CD3, anti-CD28 and IL-2 in the absence (white column, CTRL) or presence (black column, GSC-EXO) of GSC-derived exosomes. Expression of CD25 (A), percentage of proliferative CFSE-labelled cells in the presence of indicated stimuli (B) and frequency of CD4+/CD25+/FoxP3+ (C) was determined by flow cytometry on day 4. Columns, mean (n = 6); bars, SD; *, significantly different from the control; p<0.05. (D) CFSE-labelled purified CD4+ T cells, stimulated with anti-CD3, were co-cultured for 4 days with mitomycin-treated PBMCs and CD4+/CD25+/CD127^dim T-reg cells pre-incubated without (white column, CTRL) or with (black column, GSC-EXO) GSC-derived exosomes. Percentage of proliferative CFSE-labelled CD4+ T cells was measured by flow cytometry. Columns, mean (n = 4); bars, SD.