Fig 1: M1 exosomes augment IFN-γ expression in T cells in a direct manner. (A) BMDCs, generated from bone marrow precursor cells with GM-CSF + IL-4, were co-cultured with M1 exosomes (50 μg/mL) for 24 h to evaluate the effects of exosomes on BMDC maturation, and expression of MHC II (left) and CD80 (right, gated on MHC II+ cells) were detected by flow cytometry (n = 3 in each group). (B) Representative flow cytometry plots depicting purity of splenic T cells isolated by magnetic separation. (C) Images displaying direct uptake of PKH26-labeled M1 and M2 exosomes by T cells. (D–G) Isolated splenic T cells were co-cultured with M1 exosomes at indicated concentrations for 48 h following pre-activation by plate-bound α-CD3 (1 μg/mL) and α-CD28 (1 μg/mL) for 24 h, and were then detected for IFN-γ expression in T cells by flow cytometry (n = 6 in each group). Representative flow cytometry plots (D, gated on CD4+ cells) and summary data illustrating the proportion of IFN-γ+ cells in CD4+ T cells (E), MFI of IFN-γ expression in CD4+ T cells (F), and the proportion of IFN-γ+ cells in CD4- T cells (G). Data are expressed as mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001, calculated by one-way ANOVA, with normally distributed data, followed by LSD test with equal variances (A,E,F) or Dunnett's T3 test without equal variances (G).