OBJECTIVE:To investigate the index of the rejection of lJle retinal pigment epithelium(RPE)cells transplantation. METHOD:Allogenic RPE transplantation on rahbits by transcleral technique, the changes of interleukin-2 (IL-2) activity in peripheral blood and the effect of immunoinhibitor (methylprednisonlone)were detected. RESLILTS:In the group of simple transplantation,the IL-2 activity in peripheral blood begin to rise in the first day after operation. The peak value occured in the third day,and is still much higher than that of the control group in the 14th day,whereas in the group treated with immunoinhibitor ,there was no obvious difference in the first day after operatlon,in the third day,the IL-2 activity rises slightly,and returned to normal level in the 7th day. CONCLUSION: After RPE transplantation, the level of IL-2 activity in peripheral blood might serve as an important index to determining and detecting the rejective response. （Chin J Ocul Fundus Dis,1996,12: 239-241）
Objective To review the methods of overcoming immunological rejection in xenotransplantation.Methods The strategies of overcoming immunological rejection in xenotransplantation were analyzed and summaried on the basis of an extensive review of the latest l iterature concerned. Results The research development of immunological rejection mechanism and molecular biological technique provided new approaches for overcoming immunological rejection in xenotransplantation. Conclusion It is only a matter of time for xenotransplantation to be appl ied cl inically.
PURPOSE:To carry out preliminary study on immunogenicity or'the retina and provide theoretical bassis of transplant rejection of the retina. METHODS:The allogeneic whole retinal or photoreceptor layer from C57BL/6 mice wer transplanted subcutaneously into BALB/C mice for antigen exposure and delayed hypersensitivity (DH) and modified 51Cr-release assay for specific cytotoxic T lymphoeytes (CTL)were emploied. RESULTS:The allogeneic whole retinal transplantation gave rise to DH(Plt;0.05 )and increased function of CTL of which the killing rate was 33.4% in concentration of 1:90 comparing with negative group (4.8% in 1:90,Plt;0.05)and the risen function could be blocked by anti-CD8. CONCLUSION:We deduce that allogeneic whole retina has immunogenicity and should pay attention to transplant rejection postoperatively.but the photoreceptor layer seems to have no immunogenicity and may be no transplant rejection after its transplantation. （Chin J Ocul Fundus Dis,1997,13: 234-236）
Objective To investigate the appropriate concentration of tripterygium wilfordii and immunological rejection of rats’ sciatic nerve allograft with the tripterygium wilfordii’s pretreatment so as to explore tripterygium wilfordii’ s suppression. Methods Sixty SD rats (male, weighing 270-290 g), as sciatic nerve allograft acceptor were randomized into5 groups (groups A, B, C, D and E, n=12). To repair the sciatic nerve defect of SD rats, the Wistar rats’ sciatic nerve allografts about 15 mm long were used with 24 hours’ soak of different concentrations of tripterygium wilfordii (group A: 200 mg/L, group B: 400 mg/L, group C: 800 mg/L). The control groups (group D: the fresh sciatic nerve allograft from donors; group E: the fresh sciatic nerve allograft from themselves) were establ ished. At different time points after operation, the morphological examinations (the observation of histology, l ight microscope, electron microscope), the detection of myelin basic protein’s (MBP) content and the analyses of CD4+ and CD8+ T cells on the allografts in the acute phase were performed Results There was no significant difference in morphology among groups A, B and C, the adhesions between allografts and connective tissue were milder than that of group D, and the allografts’ morphous and the inflammatory cell infiltration were better than that of group D. The degeneration of myel in sheath was observed at different levels and there was no significant difference between group B and group E (P gt; 0.05). There was a significant difference in immunological rejection between groups A, B, C and group D (P lt; 0.05). Conclusion Tripterygium wilfordii can effectively suppress the acute immunological rejection in the early stage after operation, and protect the myel in sheath to a certain extent.
Objective To study whether the porcine endothelial cells (PECs) lines transfected by HLA-G1 can alter the lysis mediated by human peripheral blood mononuclear cell (PBMC) and natural killer cell 92(NK-92). Methods By use of liposomes pack, the pcDNA3.0 eukaryotic expression vector carrying HLA-G1 was transfected into PECs. Using indirect immunofluorescence and RT-PCR assays, the HLA-G1 expression in PECs was detected. The alteration of the lysis mediated by PBMC and NK-92 was detected by51Cr-release assays. Results HLA-G1 expression could be detected in PECs after transfection of HLA-G1 at the levels of protein andRNA. It also could be found that the survival rate of transfected PECs was muchhigher than that of non-transfected PECs, when both of them faced the lysismediated by human PBMC and NK-92.After transfecting the expression of HLA-G1 could be found in the transfected PECs and the lysis mediated by PBMC and NK-92 to PECs decreased obviously (Plt;0.05). Conclusion The PECs- transfected by HLAG1 can decrease the NK lysis, so that it may provide us a new thought to inhibit the xeno-cell-rejection.
Objective To study the effect of recombinant lentiviral vector mediated human hepatocyte growth factor (hHGF) gene-modified bone marrow mesenchymal stem cells (BMSCs) on the immunological rejection after allograft l iver transplantation in rats, and to reveal the mechanism of immune tolerance. Methods Eight male Sprague Dawley (SD)rats of clean grade (aged 3 to 4 weeks, weighing 75-85 g) were selected for the isolation and culture of BMSCs; 64 adult male SD rats of clean grade (weighing 200-250 g) were used as donors; and 64 adult male Wistar rats of clean grade (weighing 230-280 g) were used as receptors. After establ ishing a stable model of rat allogeneic l iver transplantation, 1 mL sal ine, 2 ×106/mL of BMSCs 1 mL, 2 × 106/mL of BMSCs/green fluorescent protein 1 mL, and 2 × 106/mL of BMSCs/hHGF 1 mL were injected via the portal vein in groups A, B, C, and D respectively. Then the survival time of the rats was observed. The hepatic function was determined and the histological observation of the l iver was performed. The hHGF mRNA expression was detected by RT-PCR, the level of cytokine including hHGF, interleukin 2 (IL-2), IL-4, IL-10, and interferon γ (IFN-γ) by ELISA assay, the level of apoptosis by TUNEL method, and the expression level of prol iferating cell nuclear antigen (PCNA) by immunohistochemical method. Results The survival time of group D was significantly higher than that of groups A, B, and C (P lt; 0.01); the survival time of groups B and C was significantly higher than that of group A (P lt; 0.01), but there was no significant difference between group B and group C (P gt; 0.05). RT-PCR demonstrated the transcription of hHGF mRNA in the grafts of group D; the serum cytokine hHGF reached to (6.2 ± 1.0) ng/mL. Compared with groups B and C, group D exhibited significant inhibitory effect, significantly improved l iver function, and showed mild acute rejection. In addition, the levels of cytokine IL-2 and IFN-γ decreased; the levels of cytokine IL-4 and IL-10 increased; the level of apoptosis reduced; and the expression level of PCNA increased. Except for the expression of IL-4 (P gt; 0.05), there were significant differences in the other indexes between group D and groups B, C (P lt; 0.05). Conclusion BMSCs/hHGF implanting to rat l iver allograft via portal vein can induce immune tolerance. Compared with injection of BMSCs alone, BMSCs/hHGF treatment can alleviate acute rejection and prolong the survival time significantly. The immunosuppressive effect of BMSCs/hHGF is correlated with Th2 shifts up of Th1/Th2 shift, reduced apoptosis, promoted l iver regeneration.
Objective To establ ish the modified model of cervical heterotopic cardiac transplantation in rats for investigation of cardiac chronic rejection. Methods Forty healthy male Wistar rats, aged 10 weeks, weighing 250-300 g, were appl ied as the donor group, and forty healthy male SD rats, aged 10 weeks, weighing 300-350 g, served as the recipient group. The donors’ pulmonary artery was anastomosed to the reci pients’ right external jugular vein by non-suture cuff technique while the donors’ innominate artery was anastomosed to the recipients’ right common carotid artery by suture microvascular anastomosis. All recipients received cyclosporin to prevent acute allograft rejection. Results Forty consecutive successful transplantations were performed. Neither anastomosis leakage nor vessel obstruction occurred. The total operation time was 40-50 minutes. The time of cuff vascular anastomosis was 2-3 minutes and that of microvascular anastomosis was 9-12 minutes. All recipients survived for more than 30 days and all allografts were examined at 30 days after the transplantation. Pathological manifestations of allograft vessels were chronic rejection. Conclusion This modified model of cervical heterotopic cardiac transplantation is simple, practical and highly reproducible and is appl icable for investigation of chronic rejection in various organ transplantation studies.
ObjectiveTo investigate the aim antigen coursing the hyperacute rejection of xenotransplantation. MethodsDocuments about hyperacute rejection in xenotransplantation were reviewed and summarized in detail. ResultsPig is thought to be one of the ideal donors of xenotransplantation, but the major obstacle is hyperacute rejection mediated by complement that is activated though human serum. αGal is recognized as the major antigen and its expression is controlled by α1,3 galactosyltransferase. Immunoabsorption of preexsisted antibody, enzymatic digestion of αGal, knockout αGT gene and transgenic technology have been used to solve this problem. Even so, there remain other antigens which can combine with natural antibodies in human serum, such as, 40×103 molecule in erythrocyte, 210×103, 105×103 and 50×103 antigen in pig embryo brain cell, etc. Conclusion αGal is the major antigen which course the hyperacute rejection. Besides αGal, many nonalphagal need further investigation.
Insufficient supply of organ for allotransplantation made the study on finding new organ resources from animal progress. Pig is regarded as one of the optimal donor animals for human. The major obstacle in this field is hyperacute reaction (HAR), which is triggered after the xenogenic natural antibodies preexisting in recipient blood combine to the antigens on the surface of the endothelium and activate the complement system. alpha-Galactose residues (alpha-Gal) on the endothelial cell have been identified as the major xenoantigens. NJZ Pig has been closely breed since 1938, whose family history is clear. Tissue samples from heart, liver, kidney, pancreas, lung, small intestine, skin, spleen, thymus and lymph node were obtained and embedded in paraffin. The sections were performed the immunohistochemical staining with the sera from health volunteers (including all the blood types) as the primary antibodies as well as the biotin labeled bandeirae simplicifolia I isolectin B4 (BS I-B4), which has specific affinity to alpha-galactose. All the staining sections were compared with the tissues digested with alpha-galactosidase. There was no difference between the antigens recognized by sera of different blood types. alpha-Gal was still the major xenoantigen on the endothelial cells. There might exist non-alpha-Gal antigens on the distal convoluted tubules and collecting tubules of the kidney. There was no alpha-Gal distributing on the secreting part of pancreas, either the islet cells or the matrix cells, but surely on pancreatic duct and vessels. All the antigenity was destroyed after the enzyme digestion except that the small intestine gland still positive with the BS I-B4. alpha-Gal is the major xenogenic antigen in NJZ Pigs. There exist some unknown antigens on the distal convoluted tubules and collecting ducts of the kidney. The blood type of recipient is not the first affair to be considered in pig-to-human xenotransplantation. The specificity of BS I-B4 for the alpha-galactose needs more detail research.
Limitation of donor source for allograft makes the research on xenograft progress. Pig is regarded as one of the ideal donor animals. The major obstacle in xenograft is hyperacute rejection, which is caused by complements after they are activated by xenogeneic antigens combined with natural antibodies. It has been confirmed that alpha-Gal is the major target antigen, whose expression is incharged by alpha-1,3 galactosyltransferase (alpha-GT). The approaches to overcome hyperacute rejection against alpha-Gal included: immunoadsorption of xenogeneic natural antibodies, lysis of antigen by enzyme and genetic manupilation to obtain animal lack of alpha-GT. Besides alpha-Gal, there were other antigens binding to human serum antibody, such as gp65 and gp100, which was expressed on PAEC after induced by TNF, the A-like antigen. But their function was still unknown. It was debatable on the role of MHC in xenograft. Both direct and indirect pathway were involved in cellular response in xenograft.