RESUMEN
The objective of this study was to investigate the effect of human bone marrow mesenchymal stem cells (MSCs) on T lymphocyte killing K562 cells. MSCs were isolated from bone marrow and cultured, T cells were harvested by using nylon column method from peripheral blood. The T cells were co-cultured with MSCs, the phenotype expressions of T cell subsets were detected by flow cytometry. Killing effects of T cells (culture alone and co-culture with MSCs) on K562 cells were detected by LDH, expressions of IFN-gamma and IL-4 were detected by ELISA. The results showed that after T cells were co-cultured with MSCs for three days, the proportion of CD4+ and CD4+CD25+ T cells raised significantly (p<0.05) as compared with group of culture alone, but the proportion of CD8+ T cell were not significantly changed (p>0.05). In group of T cells co-cultured with MSCs, killing effects of T cells on K562 cells weakened, at the same time, expression of IFN-gamma decreased while expression of IL-4 increased. It is concluded that the MSCs weaken killing effects of T cells on K562 cells, which associates with increase of CD4+CD25+ T cell subsets and changes of IFN-gamma and IL-4 levels.