AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human...AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human hepatocytes was established by injection of primary human hepatocytes or Huh7 human hepatoma cells into the peritoneal cavities of fetal rats. Corresponding cells were subsequently transplanted into newborn rats via intrasplenic injection within 24h after birth. RESULTS: Mixed lymphocyte assays showed that spleen cells from non-tolerized rats were stimulated to proliferate when exposed to human hepatocytes, while cells from tolerized rats were not. Injections made between 15 d and 17 d of gestation produced optimal tolerization. Transplanted human hepatocytes in rat livers were visualized by immunohistochemical staining of human albumin. By dot blotting of genomic DNA in livers of tolerized rats 16 weeks after hepatocyte transplantation, it was found that approximately 2.5 X 10(5) human hepatocytes survived per rat liver. Human albumin mRNA was detected in rat livers by RT-PCR for 15 wk, and human albumin protein was also detectable in rat serum. CONCLUSION: Tolerization of an immuno-competent rat can permit transplantation, and survival of functional human hepatocytes.展开更多
Background With potent suppressive effect on responder T cells, CD 4 +CD 25 + regulatory T (Treg) cells have become the focus of attention only recently and they may play an important role in transplantation ...Background With potent suppressive effect on responder T cells, CD 4 +CD 25 + regulatory T (Treg) cells have become the focus of attention only recently and they may play an important role in transplantation tolerance However, the mechanism of action is not clear This study was designed to assess the possibility of using CD 4 +CD 25 + Treg cells to induce transplantation tolerance and to investigate their mechanism of action KH*2/5DMethods CD 4 +CD 25 + Treg cells were isolated using magnetic cell separation techniques Mixed lymphocyte reactions were used to assess the ability of Treg cells to suppress effector T cells Before skin transplantation, various numbers of CD 4 +CD 25 +Treg cells, which have been induced using complex skin antigens from the donor, were injected into the host mice either intraperitoneally (0 5×10 5, 1×10 5, 2×10 5, 3×10 5, 4×10 5, or 5×10 5) or by injection through the tail vein (5×10 3, 1×10 4, 2×10 4, 5×10 4, 1×10 5, 2×10 5) Skin grafts from two different donor types were used to assess whether the induced Treg cells were antigen-specific The survival time of the allografts were observed Single photon emission computed tomography was also used to determine the distribution of Treg cells before and after transplantation Results Treg cells have suppressive effect on mixed lymphocyte reactions Grafts survived longer in mice receiving CD 4 +CD 25 + Treg cell injections than in control mice There was a significant difference between groups receiving intraperitoneal injection of either 2×10 5 or 3×10 5 CD 4 +CD 25 +Treg cells and the control group ( P <0 05, respectively) Better results were achieved when Treg cells were injected via the tail vein than when injected intraperitoneally The transplantation tolerance induced by CD 4 +CD 25 + Treg cells was donor-specific Analysis of the localization of Treg cells revealed that Treg cells mainly migrated from the liver to the allografts and the spleen KH*2/5DConclusions CD 4 +CD 25 +Treg cells can induce donor-specific transplantation tolerance Cell-to-cell contact may be the primary mechanism by which Treg cells act on effector T cells展开更多
文摘AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human hepatocytes was established by injection of primary human hepatocytes or Huh7 human hepatoma cells into the peritoneal cavities of fetal rats. Corresponding cells were subsequently transplanted into newborn rats via intrasplenic injection within 24h after birth. RESULTS: Mixed lymphocyte assays showed that spleen cells from non-tolerized rats were stimulated to proliferate when exposed to human hepatocytes, while cells from tolerized rats were not. Injections made between 15 d and 17 d of gestation produced optimal tolerization. Transplanted human hepatocytes in rat livers were visualized by immunohistochemical staining of human albumin. By dot blotting of genomic DNA in livers of tolerized rats 16 weeks after hepatocyte transplantation, it was found that approximately 2.5 X 10(5) human hepatocytes survived per rat liver. Human albumin mRNA was detected in rat livers by RT-PCR for 15 wk, and human albumin protein was also detectable in rat serum. CONCLUSION: Tolerization of an immuno-competent rat can permit transplantation, and survival of functional human hepatocytes.
基金ThisworkwassupportedbygrantsfromtheNationalNaturalScienceFoundationofChina (No 3 0 2 0 0 264)andtheKeyProjectoftheNationalNaturalScienceFoundationofChina (No 3 9993 43 0 2 )
文摘Background With potent suppressive effect on responder T cells, CD 4 +CD 25 + regulatory T (Treg) cells have become the focus of attention only recently and they may play an important role in transplantation tolerance However, the mechanism of action is not clear This study was designed to assess the possibility of using CD 4 +CD 25 + Treg cells to induce transplantation tolerance and to investigate their mechanism of action KH*2/5DMethods CD 4 +CD 25 + Treg cells were isolated using magnetic cell separation techniques Mixed lymphocyte reactions were used to assess the ability of Treg cells to suppress effector T cells Before skin transplantation, various numbers of CD 4 +CD 25 +Treg cells, which have been induced using complex skin antigens from the donor, were injected into the host mice either intraperitoneally (0 5×10 5, 1×10 5, 2×10 5, 3×10 5, 4×10 5, or 5×10 5) or by injection through the tail vein (5×10 3, 1×10 4, 2×10 4, 5×10 4, 1×10 5, 2×10 5) Skin grafts from two different donor types were used to assess whether the induced Treg cells were antigen-specific The survival time of the allografts were observed Single photon emission computed tomography was also used to determine the distribution of Treg cells before and after transplantation Results Treg cells have suppressive effect on mixed lymphocyte reactions Grafts survived longer in mice receiving CD 4 +CD 25 + Treg cell injections than in control mice There was a significant difference between groups receiving intraperitoneal injection of either 2×10 5 or 3×10 5 CD 4 +CD 25 +Treg cells and the control group ( P <0 05, respectively) Better results were achieved when Treg cells were injected via the tail vein than when injected intraperitoneally The transplantation tolerance induced by CD 4 +CD 25 + Treg cells was donor-specific Analysis of the localization of Treg cells revealed that Treg cells mainly migrated from the liver to the allografts and the spleen KH*2/5DConclusions CD 4 +CD 25 +Treg cells can induce donor-specific transplantation tolerance Cell-to-cell contact may be the primary mechanism by which Treg cells act on effector T cells