【Abstract】Objective This study was conducted to build experimental model of orthotopic liver transplantation in rat (ROLT) with the character of acute rejection; and to study the effect of cytotoxic T lymphocyte antigen 4 immunoglobulin G (CTLA4Ig) on prevention of rejection and the induction of immune tolerance of ROLT. Methods Build model of Wistar→SD ROLT(performed by the two cuff method) with character of acute rejection.Recipients were injected with CTLA4Ig 75 μg per ROLT into abdominal cavity after 2 days of operation. Contrast was made with no treatment group, the clinical characters, the liver function, the transplantated liver pathologic character and the concentrations of TNFα in serum were observed and measured on postoperative day 7. In treatment group, all above observation were done on postoperative month 4. Above all, determination of the effect of CTLA4Ig on preventing acute rejection and inducing tolerance in ROLT was observed.Results ①Recipients (no treatment group) died one by one within 6th～14th days; pathologic character of rejection in transplantation liver could be found; ② In treatment group, on postoperative day 7 and month 4, no clinical rejection character and no pathologic character of rejection in transplantation liver were found and serum concentration of cytokins related to TNFα found lower than that of contrast group(P＜0.05), and serum concentration of ALT、AST、TBIL、DBIL found lower too(P＜0.05); But serum concentration of TP and Alb was found higher than that of contrast group(P＜0.05). Conclusion ① CTLA4Ig treatment alone inhibits the rejection responce in ROLT. ② CTLA4Ig treatment can Prevent rejection and induce immune tolerance in ROLT model with characters of acute rejection; the serum concentration of cytokins related to TNFα can probably be used as evaluation standard of rejection in ROLT rejection.
ObjectiveTo evaluate the effect of pre-infusion of allogeneic lymphoyctes treated with 5-FU on the rat liver graft. MethodsRat liver transplant models from Wistar to SD were established. Four groups were designed as following: control group: only liver transplantation without any other intervention; lymphocytes group: 1 ml of untreated lymphocytes (5×106/ml) from Wistar rats were preinfused into SD rats on day 7 and 4 separately before transplantation; lymphocytes with low concentration of 5-FU group: low concentration 5-FU (7.5 μg) treated lymphocytes were preinfused as above; lymphocytes with high concentration of 5-FU group: high concentration 5-FU (15 μg) treated lymphocytes were preinfused as above. Fas-L and CD8 expression were detected by immunohistochemistry method on day 7 after transplantation. ResultsThe integral opticaldensity (IOD) of Fas-L positive lymphocytes in the lobules of liver and portal areas were higher in lymphocytes with low concentration of 5-FU group than in the other groups （Plt;0.05）. There was no difference between lymphocyte group and lymphocytes with high concentration of 5-FU group （Pgt;0.05）. The IOD of CD8+ expression in lobules of liver was not different among all the three lymphocytes treated groups （Pgt;0.05）. But in portal areas, CD8+ expression was lower in the lymphocytes with low concentration of 5-FU group than in the other groups （Plt;0.05）. ConclusionPreinfusion of lymphocytes treated with low concentration 5-FU can induce graft immune tolerance, the probable mecanism of which is the increasing Fas-L expression in graft.
Objective To summarize the advancement of immune tolerance in pancreas transplantation.Methods Relevant literatures about immune tolerance in pancreas transplantation, which were published recently domestic and abroad were collected and reviewed. Results The main methods to induce immune tolerance are peripheral tolerance and central tolerance. The induction of chimerism by infusion of donor-specific bone marrow cells is the research hot spot recently. Conclusion The infusion of donor-specific bone marrow cells in combination with one or more peripheral tolerance maybe can induce immune tolerance successfully. However, it should be researched further.
ObjectiveTo investigate the relationship between peripheral T cell apoptosis and specific immune tolerance induced by T cell vaccination（TCV）. MethodsT cell vaccinations were made from the spleen cells of SD rats, which were induced by ConA and were challenged with the spleen cells of Wistar rats. Normal SD rats were vaccinated intraperitoneally with TCV (experimental group) or RPMI 1640 culture buffer (control group) respectively .Oneway mixed lymphocyte reaction (MLR) were performed,the apoptosis of peripheral T cell were assayed using flow cytometric analysis before and after vaccination.ResultsIn experimental group, the result of MLR showed that the response captivity of SD rat spleen cells were suppressed significantly after vaccination in comparison with prevaccination (Plt;0.01) and the percentage of peripheral T cell apoptosis was increased significantly after vaccination compared with prevaccination (Plt;0.01); In control group, there was no significant difference between prevaccination and postvaccination about MLR and peripheral T cell apoptosis. ConclusionT cell vaccination is capable of inducing Agspecific immune tolerance, the T cell apoptosis of peripheral blood induced by T cell vaccination may result in the depletion of Agspecific reactive T cells, which is vital in inducing specific immune tolerance.
Objective To study the effect of allogeneic canine cord blood mesenchymal stem cells（cbMSC）transplantation on the distribution of CD4+T and CD8+T in infracted area of hearts. Methods Mononuclear cells of cord blood were isolated by density gradient centrifugation and amplified by adherent culture. 36 adult male dogs were divided into experimental group and control group. Animal models of acute myocardial infarction were established by ligating anterior descending coronary artery. The fourth generations of mesenchymal stem cells (MSC) were transplanted into infarcted area of hearts by left anterior descending coronary artery after 72h induced by 5-aza and transfected by LacZ. The survival of transplanted cells in hearts can be confirmed by βgal expression. CD4+T and CD8+T cells distributed in infarcted area were detected by immunohistochemical staining method. The ImagePlus 5.1 software was used to analyze the images. Results Cells transplanted into infarcted area could survive for a long time. 2, 4, 8 weeks after transplantation, the IOD of CD4+T in experimental group were 44.35±7.03, 19.29±4.11 and 20.27±3.51 respectively, and the CD4+T/CD8+T ratios were 0.63±0.12, 0.51±0.15 and 0.66±0.08. In control group, the IOD of CD4+T at 2, 4, 8 weeks after transplantation were 65.78±10.27, 28.02±2.59, 29.79±6.83, and the CD4+T/CD8+T ratios were 1.28±0.20, 1.34±0.09 and 1.50±0.16. The IOD of CD4+T and CD4+T/CD8+T ratio in experimental group were significantly lower than that in control group. In experimental group the IOD of CD8+T at 2, 4, 8 weeks after transplantation were 69.88±7.84 , 37.80±8.83 and 30.81±7.42, higher than that in control group which were 51.28±10.01, 20.87±4.50 and 19.91±2.87. Conclusion The preliminary results indicated that allogeneic cbMSC transplanted in infarcted area can escape from immune rejection, its mechanism may be associated withdecreasing the amount of CD4+T cells infiltrated in periphery of infarcted area and maintaining CD4+T/CD8+T ratios at a lower level.
Abstract: Objective To investigate the phonetype and tolerogenic function of semimature dendritic cells (DC) transfected by myeloid differentiation marker 88（MyD88） small interfering ribonucleic acid（siRNA）. Methods Bone marrow of BALB/c mice was inoculated and cultured in vitro，and induced into DC by 10ng/ml recombinated granulocyte macrophage colony stimulating factor (rmGM-CSF) ，then DC was divided into three groups at the 8th day: blank control group: added nothing; lipopolysaccharide （LPS）group: added with 1μg/ml LPS; and experimental group: added with 1μg/ml LPS after transfected by MyD88 siRNA for 4 hours. The phonetype of three groups was analysed by fluorescenceactivated cell sorting (FACS). The concentration of interleukin 10（IL-10）and interleukin 12（IL-12） in culture supernatant was detected by enzyme linked immunosorbent assay（ELISA）.The function of stimulating alloreactive T cell roliferation were evaluated by primary and secondary mixed lymphocyte reaction （MLR）. The cardiac allograft survival time was compared after DC of three groups injected into recipient mice. Results The phonetype of blank control group DC was CD11c＋，CD25-，CD40low，CD80low，CD86low，MHC-Ⅱlow， which could be induced to mature DC by LPS. Experimental group DC was phonetypically semimature DC (CD11c＋，CD25－，CD40mid，CD80low，CD86low，MHC-IIid) and the IL-10/IL-12 ratio of semimature DC increases significantly. yporesponsiveness of alloactive T cells can be induced by experimental group DC and the survive time of heart allograft was prolonged. Conclusion Immature DC could become semimature DC after transfected by MyD88 siRNA and stimulation by LPS. These semimature DC are more tolerogenic than immature DC.
Objective To summarize the research progress of programmed cell death protein 1 (PD-1)/programmed cell death protein-ligand 1 (PD-L1) inhibitors before liver transplantation of liver cancer. Method The literatures on the application of PD-1/PD-L1 inhibitors before liver transplantation of liver cancer were collected and reviewed. Results PD-1/PD-L1 inhibitors preoperatively treated liver transplantation recipients had a low incidence of postoperative rejection, and routine usage of hormone and immune tolerance induction therapy in liver transplantation recipients might reduce the incidence of rejection caused by PD-1/PD-L1 inhibitors. Conclusion Preoperative usage of PD-1/PD-L1 inhibitors have more benefits than risks for patients with advanced liver cancer.
Objective To explore the effect of cytotoxic T lymphocyte-associated antigen 4 (CTLA4-Ig) fusion protein on the function of orthotopic liver allograft. Methods Orthotopic liver allograft models of rhesus monkeys were established in this study. The survival time, liver function and morphologic changes of graft were observed, respectively. The levels of IL-2 and IL-10 were detected by ELISA. Apoptosis was monitored by TUNEL.Results The average survival of control group was 6.57 d, while the average survival of CTLA4-Ig group was 14.92 d, which was statistically prolonged (Plt;0.05). Serum ALT level was highly increased, and Alb level decreased obviously in control group. While the levels of ALT and Alb kept in normal in CTLA4-Ig group. After day 3-7, the expressions of IL-2 were highly expressed in control group, while the expressions of IL-10 in CTLA4-Ig group were higher than those of control group. The severity of rejection reaction after day 3 was weaker in CTLA4-Ig group than that of control group by histological assessment. The apoptosis index after day 3 in the liver cells was highly increased in control group as compared with the CTLA4-Ig group. Conclusions CTLA4-Ig fusion protein therapy can induce immunotolerance and prolong the survival of recipients. The increasing of cytokines IL-2 or the decreasing of cytokines IL-10 may be one of the laboratory indexes in monitoring immunotolerance of transplantation.