Galectin-1-induced Tolerogenic Dendritic Cells Combined With Apoptotic Lymphocytes Prolong Rat Liver Allograft Survival

Part Ⅰ Galectin-1 tolerant dendritic cells combined with apoptotic lymphocytes induces tolerant immune microenvironment in rat[Objectives]:Dendritic cells are important immunoregulatory cells.Tolerant dendritic cells are used in the treatment of a variety of autoimmune diseases due to their immunosuppressive capacity.At the same time,pre-infusion of tolerant dendritic cells before transplantation was also used to alleviate rejection after transplantation and prolong survival of transplant recipients.The basic immunological mechanisms of rejection after transplantation include direct and indirect pathways for antigen presentation.Both tolerant dendritic cells and apoptotic lymphocytes are effective tolerant cells after transplantation,and exert immune tolerance induction by inhibiting direct and indirect pathways of antigen presentation.Galectin-1 is an important immunoregulatory molecule and can induce tolerant dendritic cells.In this study,galectin-1 induced tolerant dendritic cells combined with apoptotic lymphocytes induced tolerant immune microenvironment in vivo,in order to obtain better tolerance induction than single infusion of tolerant cells.[Methods]:Dark Agouti(DA)rat bone marrow-derived dendritic cells were induced to become tolerant dendritic cells(DCgal-1)by recombinant galectin-1 protein.The spleen-derived lymphocytes of DA rats were induced to become apoptotic lymphocytes(AL)by ultraviolet irradiation(UV).The immunological characteristics and function of tolerant dendritic cells induced by galectin-1 and apoptotic lymphocytes was examined in vitro.The DA rat derived tolerant cells were tranfused to the Lewis rats,and the tolerant microenvironment to DA derived antigen was examined by a mixed lymphocyte reaction assay.[Results]:DCgal-1 has low expression of inflammatory molecules MHC II,CD80,CD86 and high expression of IL-10.DCgal-1 and UV-induced apoptotic lymphocytes significantly inhibited mixed lymphocyte response in vitro.The combined transfusion of DCgal-1 and apoptotic lymphocytes significantly decreased the proliferation of CD8+T lymphocytes in Lewis rats.[Conclusions]:Combined reinfusion of DCgal-1 and UV-induced ALs are effective immune tolerance microenvironment induction programs.Part Ⅱ DCgal-1 combined with apoptotic lymphocytes prolong survival after rat liver transplantation[Objectives]:Liver transplantation is the most effective way to treat end-stage liver disease.The use of immunosuppressive agents after liver transplantation has prolonged the survival of liver transplant recipients,and is also associated with complications such as recurrence and infection after liver transplantation.Induction of transplant immune tolerance will achieve long-term survival of transplant recipients without taking immunosuppressive agents,which has great clinical significance.However,the current tolerance therapy of tolerant dendritic cells can prolong the survival of the recipients,but there is still much room for improvement.We found in the first part that galectin-1 induced tolerant dendritic cells(DCgal-1)combined with ultraviolet irradiation(UV)-induced apoptotic lymphocytes(AL)can induce immune tolerance against donor antigens in vivo.The effect is better than that of the single tolerant cells alone.In this part,we apply it to the prevention of liver transplant rejection and explore its effects in a rat model.[Methods]:A rat Dark Agouti(DA)-Lewis liver transplantation rejection model was constructed.Donor-derived DCgal-1 combined with AL were subjected to receptor transfusion seven days before transplantation.The role of DCgal-1 in combination with AL in preventing liver transplant rejection was demonstrated by survival curves,liver function,pathology,changes in T cell balance,and changes in inflammatory factor expression.In addition,we also studied the characteristics of long-term survival receptors after DCgal-1 and AL combined transfusion at 100 days post transplantation.[Results]:DCgal-1 or AL infusion alone significantly prolonged survival of recipient rats after transplantation,whereas combined DCgal-1 and AL transfusion showed better liver rejection inhibition ability than DCgal-1 or AL transfusion alone.This process is related to the reduction of allogeneic reactive effector T cells(IFN-y+T cells)and the increased ratio of liver and spleen Treg cells in the rat.In the study,DCgal-1-AL treatment resulted in long-term survival in more than 30%of recipient rats,without the use of any immunosuppressive drugs after surgery.In addition,DCgal-1-AL infusion significantly inhibited the expression of pro-inflammatory factors on the seventh day after transplantation.The long-term survival livers after DCgal-1-AL treatment was significantly increased in the transforming growth factor-β1/2,which may be related to the maintenance of graft survival.[Conclusions]:The combined transfusion of DCgal-1 and AL is an effective liver transplantation rejection prevention program.