RESUMEN
Objective To investigate the stimulation of exosome derived from osteosarcoma cells suppressing cytotoxic T cells and the inhibitory effect of active T cells for surpressing osteosarcoma cells. Methods Exosome derived from tumor cells was isolated and purified by ultracentrifugation. Its morphology was observed with transmission electron microscope, and the major histocompatibility complex-I ( MHC-I) molecules were analyzed by western blot. Mice bone marrow-derived dendritic cells were pulsed with exosome. Surface membrane MHC-I molecules were analyzed with flow cytometry. The effect of active T cells on the growth of osteosarcoma cells were detected by MTT assay after the T cells being stimulated by exosome-pulsed dendritic cells. Results The exosome was round or near round corpuscle, and the diameter was about 50-100 nm by transmission electron microscope. The size was relatively homogeneous. Western blot showed that the exosome expressed MHC-Ⅰmolecules. Surface membrane CD80,MHC-I and II molecules were expressed on 77. 16%, 83. 21%, and 91. 26% of LPS-treated dendritic cells, respectively, which were up-regulated compared to untreated cells. Dendritic cells pulsed with exosome derived from osteosarcoma cells caused significantly higher T cells stimulation and osteosarcoma cells inhibition as compared to un-pulsed dendritic cells. (P<0.05). Conclusion T cells can inhibit the growth of osteosarcoma cells after being stimulated by exosome-pulsed dendritic cells in vitro.