Objective:To investigate the influence ofexosomes tumor vaccine on immunity and grouth ofmouse hepatocellular carcinoma xenograft in mice.Methods:Hepatoma carcinoma H22 cell-derived exosomes were isolated and purified from the culture supernatants by serial ultracentrifugation and sugar density ultracentrifugation.BALB/c mice inoculated with H22 cell were used as tumor models.The mice inoculated with H22 cell were divided into two groups at random:exosomes group and PBS control group.15 days later

the mice were killed;then the tumor inhibitory rate was calculated.The spleens and thymuses were weighed

and the effect of exosomes on spleens and thymus index was determined.The proliferation and cytotoxicity of splenocytes were detected by MTT assay.The level of IL-2 and INF-γ in splenocyte culture supernants was detected by enzyme-linked immunoabsorbent assay(ELISA).Results:Exosomes cancer vaccine depressed the growth of tumor remarkably

and its tumor inhibitory rate was 42.38%.Compared with these in PBS control group

the spleen indexes and thymus indexes of mice bearing tumor in experiment group were increased(P<0.05).Exosomes could induce lymphocyte pro- liferation

and generate strong specific cytotoxic spleen lymphocyte response.The level of IL-2 and INF-γwas increased after vaccina- tion.Conclusion:Vaccination of H22 cell-derived exosomes may enhance immune function and depresse the growth of hepatoma carcinoma H22 xenografts in mice.