The Regulatory Function And Mechanism Of CD4～+CD25～+T Cell On Gastric Cancer Immunology

Objective: CD4~+CD25~+T regulatory cell (Treg) is a kind of multi-cytokine secreting (interleukin 4, interleukin 10 and TGF-beta), affecting T cell suppressing cell. Its function in autoimmune disease occurring, developing was firstly studied. And gradually its effects in tumor surveillance were also explored. Reports show that deletion of Treg from mice will promote its anti-tumor ability. But the exact effect and mechanism are still unclear. The objective of this research is to enforce and block the suppressing ability of Treg, to illustrate the function changes of CD8+ CTL and NK, and the changes of anti-tumor related cytokine levels. The transwell cell culture system was used to investigate the possible mechanism of the Treg suppression on CD8 CTL and NK. And the antigen specific suppression of Treg was also investigated. The results of our research may provide experimental support for future CD4~+CD25~+Treg based anti-tumor immunotherapy.Methods.1 T cell enrichment colon was used to purify T cell from mouse spleen cell, and MACS was used to separate CD4~+CD25~+Treg. GITR and FOXp3 were chosen as surface molecule marker of Treg to determine the purity of Treg with FACS method. 2 MFC tumor cells was injected into abdominal cavity of 615 mice to establish tumor model. CD4~+CD25~+Treg and its antigen anti-GITR were also injected into tumor model. The apoptosis of tumor cells were detected. Thymectomy was performed on mouse to show the function of thoracic gland on the changes of amounts and function of CD4~+CD25~+Treg. 3. In Transwell system, separated and mixed culture methods were used to show CTL and NK's antitumor ability and mechanism under the influence of CD4~+CD25~+Treg and its antigen.Results: 1 T cell enrichment colon get enough target cells with low damage and high enrichment rat. These target cells could be conveniently separated into CD8+ and CD4~+CD25~+T cells with MACS method. 2 Tumor-bearing mouse shows lifted CD4~+CD25~+Treg level but without statistic significance. The tumor cells from abdominal cavity arise with CD4~+CD25~+Treg injecting into the mouse by a dose-depending mode. And with the applying of Treg antigen, anti-GITR antibody treatment, the tumor cells from...