Objective      To investigate the underlying mechanism of exosomes derived from renal cancer cell lines 786-0 to mediate tumor immune escape in vitro.       Methods      CCK-8 assay was used to determine the effects of exosomes on proliferation in Jurkat T cells. Morphological changes were  by wright-giemsa staining;flow cytometry with Annexin V-FITC/PI double staining was used to detect the apoptosis;secretion functions of Jurkat T cell were detected by ELISA assay; effects of exosomes on apoptosis of Jurkat T cell were detected by soluble Fas block experiment; effects on the protein expression of FasL

caspase

Bax and Bcl-2 were assessed by Western blot analysis.       Results      Exosomes could inhibit Jurkat T cell proliferation

10 μg/mL exosomes act on Jurkat T cell for 24 and 72 h

growth inhibition rate was (19.64±0.92)% and (36.24±1.12)%; while 400 μg/mL exosomes act on it for 24 h and 72 h

growth inhibition rate was (55.96±1.35)% and (76.51±1.37)% respectively. Exosomes could induce Jurkat T cell apoptosis

10 μg/mL exosomes act on Jurkat T cell for 8 h

apoptosis rate was (7.31±1.32)%

extending this monitoring to 24 h

apoptosis rate was (20.19±1.47)%; while 400 μg/mL exosomes act on it for 8 and 24 h

apoptosis rate was (27.28±1.29)% and (41.72±0.88)% respectively. Exosomes also suppressed IL-2

IFN-γ

IL-6 and IL-10 secretion obviously. FasL was highly expressed in exosomes

soluble Fas block could reverse Jurkat T cell apoptosis. In this course

caspase-3

caspase-8

caspase-9 were activated

and the ratio of Bax/Bcl-2 increased.       Conclusion      Exosomes could inhibit the growth of Jurkat T cell and induce apoptosis.It could mediate tumor immune escape.