Study On CD4～+ CD25～+ Regulatory T Cells In Type Ⅰ Allergic Disease

Objective: To investigate the changes of CD4+CD25+ regulatory T cells in type I Allergic diseases, and to explore the mechanism of allergy. Give new approach of treat. Methods: CD4+ T cells were isolated by Dynabeads M-450 from PBMC, CD25+ Microbeads isolated CD4+CD25+ regulatory T cells from CD4+T cells. Phenotype of the T cell lines was detemined by Flow cytometry. In the presence of allergen or anti-CD3 mAb and anti-CD28 mAb, we studied the function of CD4+ CD25+ regulatory T cells isolated from non-allergy donors and allergy donors. ELISA and 3H-TdR were used to investigate the function of CD4+CD25+ regulatory T cells. Results: DThese results show that CD4+ CD25+ regulatory T cells from non-allergy donors can inhibit CD4+CD25" T cells activation and the production of cytokines. Din presence of allergen, Th2 cytokines were secreted by CD4+ CD25" T in allergy, such as IL-5, IL-10 and IL-13, not Thl cytokines, such as IFN- . The number of CD4+CD25+ regulatory T cells has no significantly difference between non-allergy donors and allergy donors. In function, CD4+ CD25+ regulatory T cells from non-allergy donors and allergy donors don't proliferate in the presence of allgern or anti-CD3 mAb and anti-CD28 mAb. It is only in the presence of allergen that CD4+ CD25+ regulatory T cells secrete IL-10. So, these regulatory T cells still are in anergic. But inhibition of proliferation by CD4+CD25+ regulatory T cells from allergy donors was significantly reduced under the stimulation of allgen, not anti-CD3 mAb and anti-CD28 mAb. D Suppression of allergen-driven T cell proliferation by CD4+CD25+ regulatory T cells was reversed by antibody to glucocorticoid-induced TNF receptor (GITR), but this did not reverse suppression of cytokine production. Conclusion: DCD4+CD25+regulatory T involved in the immune response to allergen in human. It play a crucial role in the development of allergy. CD4+CD25+ regulatory T in type allergic diseases donors may have defect in the function of CD4+CD25+ regulatory T cells. GITR can involved in the process ofinhibition of CD4+CD25+ regulatory T cells.