Fig. 3

MSCs-exo suppressed the activation and infiltration of lymphocytes into the lung of cGVHD mice. a Draining lymph nodes were isolated and analyzed by flow cytometry. MSCs-exo suppressed the expression of CD44, an activation marker of CD4+ T cells, which indicates the immunosuppressive effect of MSCs-exo in cGVHD. The plots in b were gated on CD4+ T cells, and the numbers in quadrants indicate the percent of CD4+ T cells expressing CCR6. c Lung tissues obtained from mice treated with PBS, Fib-exo, or MSCs-exo were isolated on day 39 after BMT; digested with collagenase; and analyzed for effector CD4+ T cells by flow cytometry. A significant reduction of CD4+ T cells was observed in MSCs-exo-treated mice. Data are representative of three independent experiments for a–c. Data are expressed as the mean ± SEM. *P < .05, **P < .01, and ***P < .001; ns not significant