Exosomes isolated from C57BL/6 mice treated with Exo-MSCs-M.tb induced pro-inflammatory response in vitro. (A) Morphology of exosomes isolated from C57BL/6 mice treated with Exo-MSCs-M.tb, as imaged by TEM. Scale bars: 100 μm. (B) Concentration and diameter distribution of exosomes isolated from C57BL/6 mice treated with Exo-MSCs-M.tb, as detected by NTA. (C) Detection of exosomal markers CD63, CD81, Hsp70, Hsp90, and TSG101, as detected by flow cytometer. (D) TNF-α levels in the lung of C57BL/6 mice injected with BALF-derived exosomes (20μg) isolated from mice treated with Exo-MSCs-M.tb (Exo-M.tb) or mice treated with negative control PBS (Exo-NC). (E) IL-12p40 levels in the lung of C57BL/6 mice injected with BALF-derived exosomes (20μg) isolated from mice treated with Exo-MSCs-M.tb (Exo-M.tb) or mice treated with negative control PBS (Exo-NC). (F) Neutrophil infiltration of C57BL/6 mice injected with BALF-derived exosomes (20μg) isolated from mice treated with Exo-MSCs-M.tb (Exo-M.tb) or mice treated with negative control PBS (Exo-NC). (G) The protein levels of 19-kDa lipoprotein, LAM, Hsp70 in BALF-derived exosomes (20μg) isolated from mice treated with Exo-MSCs-M.tb (Exo-M.tb) or mice treated with negative control PBS (Exo-NC). (H) Graphic summary. *p < 0.05.