Preliminary Studies On The Immuno-regulatory Phenotype Of Murine γδT Cells

Regulatory T cells are a subset of T cells with function to suppress the activity and proliferation of responder T cells. It plays a critical role in the homeostasis maintenance of immune system. Diverse types of Treg cells were classified with distinct origins, regarding to disparate and multiple functions, such as classical CD4~+CD25~+ Treg, NK Treg, andγδTreg etc.The best studied Treg is CD4~+CD25~+ phenotype with high expression of Foxp3, Foxp3 is as the most characteristic marker, and was considered the major controlled gene of Treg.To investigate that the exist subgroup ofγδT with regulatory function, we chose the murine system for researching ofγδTreg. It was found that partialγδT cells freshly isolated from murine splenocytes, intestinal-IEL and thymocytes, highly express Foxp3. Furthermore, anti-γδTCR antibody and TGF-βcostimulate could enhance Foxp3 expression, likewise induced by TGF-β,immunoregulation related surface molecule and cytokines such as IL-10,GITR,CTLA-4,TLR-8,CCR2 and TGF-βwere increased, whereas the INF-γdecreased. The expression of Foxp3 inγδT cells that were induced in vitro by IL-10 can not increase; TGF-βand IL-6 costimulated were unable to induce IL-17 expression inγδT cells. The result show that Foxp3~+γδT cells is similar to CD4~+CD25~+ Treg can be induced by TGF-βin vitro, butγδT cells can not be induced to TH17 or IL-17 expression.Otherwise in model of mouse melanoma, the functions ofγδT cells in tumor were preliminarily studied. The result showed that the percentage of Foxp3~+γδT in TIL and intestinal-IEL increase. It suggests that the relationship of Foxp3~+γδT and tumor could be negative correlation.In conclusion, the phenotype and functions of Foxp3~+γδT cells were studied. The research results suggest the existence of murineγδT regulatory cells and provided clues and basis for the further research in vivo experiment.