Effect of culture time on immunomembrane proteins of human monocyte-derived dendritic cells and their exosomes

[Abstract] Objective: To explore the effect of culture time on human monocyte-derived dendritic cells and their exosomal immune membrane proteins, and to provide experimental bases for dendritic cell and exosome-related studies. Methods: Human monocytes were induced to differentiate into dendritic cells by recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 4 (IL-4), and then into mature dendritic cells by adding tumor necrosis factor-alpha (TNF-alpha); exosomes were separated by ultracentrifugation, and dendritic cell exosomes were identified by scanning electron microscopy and Amnis image flow cytometey , and Amnis image flow cytometey detected the expression of immune membrane proteins in dendritic cells and exosomes. Results: On the 10th day of in vitro culture, CD11c, CD80, CD86, MHC-Ⅰ, MHC-Ⅱ immunomolecules could be highly expressed on DC membranes. The peaks were reached on day 18, which were CD11c ( 78.66 ± 20.33) %, CD80 (76.41 ± 10.02) %, CD86 (96.43 ± 0.43) %, MHC-Ⅰ (84.71 ± 2.96) %, MHC-Ⅱ (80.01 ± 7.03) %, and then decreased after day 24, except for CD80 and MHC-Ⅱ molecules, and the differences were statistically significant (P<0.05). Up to day 30 of culture, 80% of DCs still expressed CD80, CD86, and MHC-II proteins. The expression of CD11c, CD80, CD86, MHC-Ⅰ, MHC-Ⅱ on the exosome membrane was the highest on the 18th day, and then with the prolongation of the culture time, there was an overall decreasing trend, and the difference was statistically significant except for the CD80 molecule (P < 0.05). Conclusion: In vitro cultured human monocyte-derived dendritic cells express high levels of immune membrane proteins, which can be stably maintained for a long time under suitable culture conditions. The surface of their secreted exosomes also expressed abundant immune membrane proteins, and the change trend of immune membrane proteins on the surface of the two was basically the same.