Objective To investigate the roles of a variety of cytokines including transforming growth factor beta (TGF-β),interleukin-6 (IL-6) and interleukin-2 (IL-2) in the differentiation of CD+4 Tlymphocyte cells.Methods T lymphocyte cells either in human peripheral blood or routine spleen were cultured in vitro under different stimulation conditions.Flow cytometry was used to analyze the percentages of CD+4IL-17+ T-helper 17(Th17) cells,CD+8 IL-17+ T cells,CD+4 CD+25 FOXP+3 T regulatory (Treg) cells among activated T cells.Results Differentiation of Treg cells,Th17 cells and CD+8 IL-17+ T lymphocyte cells was enhanced when murine splenic T cells were cultured with TGF-β.The levels of expression were (7.8±2.2)%,(12.6±3.1)%,(10.1±2.6)% ,respectively.Experimental control group was severally same type of T cells without cytokine treatment.The levels of expression were (4.8±0.6) %,(1.7±0.5) %,(1.0±0.4) %,respectively.There were statistically significant differences among them (q=4.09,8.80,9.61.P<0.05 or P<0.01).Under combination treatment with IL-6 and TGF-β,(17.8±5.3) % Th17 cells and (15.0±4.2)% CDCD+8 IL-17CD+ T cells were induced,whereas the levels of Treg cells whose differentiation were restrained were (4.1±1.2) %.The differences were statistically significant compared with the level of same type of T cells in TGF-β group (q=5.03,5.17,5.04,P<0.01).Moreover,combination treatment with IL-2 and TGF-β decreased percentages of Th17 and CDCD+8 IL-17CD+ T cells and increased percentages of Treg cells in T cell population.There was an opposite effect when anti-IL-2 was apphed.The percentages of Th17 and CD+8 IL-17+ T cells were increased and the percentages of Treg cells were reduced The regulation trend of T lymphocyte cells in human peripheral blood was similar with those in routine spleen.Conclusion Various cytokines are of great importance in the regulation of the balance between Th17 and Treg cell.