[The properties of exosomes secreted by human umbilical cord blood dendritic cells and its enhancement of CTL cytotoxicity].
OBJECTIVE
To investigate the properties of exosomes secreted by dendritic cells(DCs) derived from human umbilical cord blood mononuclear cells(HUBMCs) and its enhancement of CTL cytotoxicity.


METHODS
The HUBMCs were separated from human umbilical cord blood(HUCB). The generation of DCs were induced for 12 days in medium containing SCF, IL-4 and GM-CSF. Tumor antigen extracted by repeated freeze-thawing were added to culture medium and cultured successively for 2 days. The DCs were collected and exosomes were separated from culture supernatant through centrifugation at 100,000 g. The exosomes-associated properties were analyzed by FCM, SDS-PAGE, transmission electron microscope(TEM) and MTT colorimetry.


RESULTS
After being induced for 12 days with SCF, IL-4 and GM-CSF the number of DCs had a 10-fold increase and displayed typically morphological characteristics of DCs. FCM analysis showed that the DCs loaded with tumor antigen expressed highly MHC-I, MHC-II, CD40, CD80, CD86, CD11c and CD54. Exosomes could be separated from culture supernatant of DCs by ultracentrifugation. Mixed lymphocyte reation(MLR) and cytotoxicity assay showed that exosomes secreted by DCs could effectively stimulate T cell proliferation and enhance their cytotoxicity.


CONCLUSIONS
A large number of DCs are obtained from UBMCs and the exosomes are secreted from them in vitro. The exosomes can present tumor antigen to T cells and enhance the cytotoxicity of CTLs.
Du
Ying
Y
Department of Microbiology and Immunology, College of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450052, China. duying@zzu.edu.cn
Chen
Shao-qian
SQ
Huang
Yu-min
YM
Dong
Zi-ming
ZM
D018122:B7-1 Antigen / Q000378:metabolism; D051940:B7-2 Antigen / Q000378:metabolism; D039521:CD11c Antigen / Q000378:metabolism; D019013:CD40 Antigens / Q000378:metabolism; D045744:Cell Line, Tumor; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D055354:Exosomes / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D005312:Fetal Blood / Q000166:cytology*; D005434:Flow Cytometry; D018922:HL-60 Cells; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D020014:K562 Cells; D046529:Microscopy, Electron, Transmission; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism; D014461:Ultracentrifugation
D018122:B7-1 Antigen; D051940:B7-2 Antigen; D039521:CD11c Antigen; D019013:CD40 Antigens; D018799:Intercellular Adhesion Molecule-1