Fig. 4

sEVs from BC cells promoted the PD-L1 expression in M2 cells. (A) Identification of the structure of sEVs isolated from MDA-MB-231 cells observed by TEM; scale bar = 200 nm. (B) Identification of sEVs marker proteins by WB. (C) Size analysis of sEVs by NTA. (D) Schematic diagram of the in vivo experiments. (E) Pictures of dissected tumors of mice. (F) Related sizes of dissected tumors of mice. (G) H&E staining of lung and liver of mice. (H) Weight growth curves of mice during the injection of sEVs. (I) IF detection of phagocytosis of BC cell derived sEVs by macrophages. (J) Inhibition of sEVs secretion by GW4869 observed by WB. (K) Proportion of CD163 + CD68 + macrophages co-cultured with BC derived sEVs detected by flow cytometry. (L-M) Protein and mRNA level of PD-L1 in macrophages after co-culture with BC derived sEVs.