The Effect Of B7-H1 Expressing On Keratinocyte In Immunosuppression During Intermingled Skin Transplantation

Objective : To investigate inhibitory effect and mechanism of keratino- cytes in the autologous skin island.Methods:1. Separate lymphocytes and epidermis from peripheral blood and establish MELR model. Simulate autologous skin island effect in vitro by addition of epidermis (whereas addition of allergenic epidermis as a control).2. Analyze the kinetic curve of IFN-γ, IL-2, IL-4 and IL-10 in MELR model with addition of autologous keratinocytes or not and observe the changes of them.3. Investigate the immunosuppressive role of IL-10 in T cells and keratinocytes by inleting the IL-10 knockout mice.4. Analyze of the role of classical co-stimulatory molecules in keratinocyte-induced immunosuppression by transfecting B7-1 on Keratinocyte and the blocking of CTLA-4.5. Observe the B7-H1 expression of keratinocytes in MELR model and approach the role of new B7 molecule in autologous skin island immunosuppression by blocking B7-H1 with monoclonal antibody.Result:1. IL-2 was detected after 8 hours, and IFN-γafter 16 hours in La + Eb + Kcb the group. While low concentrations of IL-2 and IFN-γwere detected in first; then decline and disappearance after 32 hours, whereas detection and gradual incretion of IL-10 and IL-4, especially IL-10 at 48 hours in La + Eb + Kca the group.2. IL-10 secreted by lymphocytes played a major role role in inhibition of proliferation in the allograft but not the IL-10 secreted by keratinocytes. 3. The inhibition to alloantigen-induced proliferate dis- appeared after the transfection B7-1 gene to the autologous keratinocytel and recovered by addition anti-B7-1 monoclonal antibody to blocking, while CTLA-4 had no work in autologous keratinocytes induced inhibition.4. Weak expression of B7-H1 was detectedin in the MELR model at 4 hours and strong expression after 8 hours.And the inhibition of the autologous keratinocytes disappeared by addition of B7-H1 monoclonal antibody or PD-1.conclusion :1. Autologous keratinocytes induced local immune suppression by activating T cells that secreted IL-10 to activate Th2 subsets and inhibit Th1 subsets.2. Autologous keratinocytes provide co-stimulatory signal without B7-1 or B7-2, and its negative regulation had no done with the CTLA-4.3. Autologous keratinocytes induced local immunosuppression through B7-H1 co-stimulation signal activating the secretion of IL-10 in Th2 cells to suppress the Th1 function eventually.