The Experimental Study On Gene Therapy Of A New Biologic Immunosupression Agent-Soluble Tumor Necrosis Factor-a Receptor(sTNF-RI)in Transplantation

The Experimental Study on Gene Therapy of A New Biologic Immunosupression Agent-Soluble Tumor Necrosis Factor- a Receptor (sTNF-RI) in TransplantationAbstractAllograft rejection is a serious problem to affect the survival time of grafts in organ transplantation. Tumor necrosis factor a (TNF-a) is a potent proinflammatory cytokine produced by stimulated monocytes/macrophages, activated T cells, and dendritic cells and is recognized as a critical mediator of alloreactive responses. Many aspects of tissue damage following acute or chronic allograft rejection in vivo were directly attributed to the concomitant induction of TNF biosynthesis and release, and provide the therapeutic rationale for developing TNF antagonists. DC play key role either in initiating immune response or in inducing central and peripheral immune tolerance. TNF-a emerge important effect on DC activation and maturation. The development of DC from progenitor cells into mature DC which possess potential immune response need several cytokines including TNF-a.The biological activities of TNF-a are mediated by two structurally related but functionally distinct receptors p55 and p75. It has also been demonstrated that the TNF/p55TNF-R pair is essential for many physiological or pathological processes which TNF- a mediated pathogenesis of inflammatory disease. It is reported that both sTNFr-p55 and sTNFr-p75, which are formed by shedding of extra-cellular domain of TNFR respectively, were effectively used to block and neutralized TNF-a.In the present study, soluble tumor necrosis-a receptor (sTNFr-p55) gene was transferred into DC progenitors to investigate the effects of tolerogeneic DC in vitro and in vivo. Whether infusion into the recipients of AdmsTNFr modified DC could prolong the survival of cardiac grafts was investigated. In another study, soluble TNF-a receptor (sTNFr-p55) gene was transferred into donor heart during cold preservation before transplant to the allogeneic recipients. The effects of sTNFr-p55 gene transfer on the survival of grafts were observed. The functions of both grafts infiltrating-cells and host T lymphocytes and APCs were also investigated.Part I: Improved method of heterotopic cervical heart transplantation in mice (by a cuff technique)Objective: The model of heterotopic cervical heart transplantation in mice is one of ideal models to study the immunology of grafts rejection. We develop an improved cuff technique to simplified mouse heterotopic cervical heart transplantation. BALB/C and C57BL/6 mice are unrelated and congenic strains of mice species, and are available to study immunology of the graft rejection. Methods: The donor heart combination with lung was transected and placed in chilled Ringer's lactate solution and after repaired, one cuff was fixed to the left main pulmonary artery. Another cuff was fixed to the recipient carotid artery during operation. The function of the transplanted heart was monitored by direct palpation and electrocardiography. Results: This method greatly shortened the time of operation. Mean time of operation was 40-50 minutes. The operative successful rate was 96%. The judgment of rejection by direct palpation and electrocardiography combination was an objective and reliable method. By observation of survival of the allografts, the rate of acceptance varied depending on the donor-recipient strain cross-over combination (p<0.05). Conclusion: This method simplified operative difficulties and can be widespread use. Part II:Soluble TNF-a receptor gene modified dendritic cells induce antigen-specific tolerance totumor-isograft and allogrqftDendritic cells (DC), the highly effective specialized antigen-presenting cells (APCs), in the proper context provides the required antigenic and costimulatory molecules to initiate T cell-mediated immune responses. The functions are highly correlated with their differentiation status. Mature DC highly express major histocompatibility complex class-II (MHC-II) molecules and costimulatory molecules has the ability to activate T c...