Effects of IL-7 and IL-2 on CD4+CD25-T cells proliferation in vitro / 中国免疫学杂志

ABSTRACT

Objective:To explore the promoting effects of IL-7 and IL-2 on CD4+CD25-T cells proliferation in vitro and construct a stable culture system in vitro for CD 4+CD25+regulatory T cells from human umbilical cord blood.To compare the inhibiting effects between induced proliferated CD 4+CD25+Tregs and naturally isolated CD 4+CD25+Tregs on PBMCs functional activity.Methods:CD4+CD25-T cells and CD4+CD25+T cells were isolated from human umbilical cord blood mononuclear cells by magnetic activated cell sorting ( MACS) system and then expanded in vitro.Four different concentration levels of IL-7 combined with proper concentration of IL-2 were added as inducer and the efficiency and optimal concentration of IL-7 on inducing,CD4+CD25-T cells were analyzed via 4 different methods.Flow cytometry method was used to detect the changes of CD 4+CD25-T cells.The inhibitory effect of expanded CD 4+CD25+T cells on peripheral blood mononuclear cells (PBMCs) was tested by MTS.The expressions of Foxp3,IL-10 and TGF-βgenes in CD4+CD25+T cells were test by RT-PCR.Results:The CD4+CD25+T cells from each groups were expanded significantly after three weeks of culture.The results indicated that use of IL-7 combined with IL-2 resulted in the highest cell expansion comparing to the other groups.It was shown by the inhibitory test that the expanded CD 4+CD25+regulatory T cells could inhibit the proliferation of PBMCs ,but IL-7 induced CD4+CD25+regulatory T cells exerted weaker suppressor activity than natural regulatory T cells .Only IL-7 (4 ng/ml) and IL-2 (2 000 U/ml) induced CD4+CD25+regulatory T cells showed the strongest killing activity.Conclusion:We successfully expand CD4+CD25+regulatory T cells in vitro.The protocol is established in which the use of mAbCD 3/CD28 combined with IL-7 and IL-2 resulted in the highest cell expansion ,and intensely expressed cell phenotype of CD 4 and CD25.