小鼠自体肝脏星状细胞联合同种异体胰岛细胞移植延长移植物存活时间的研究

目的 研究小鼠自体肝脏星状细胞联合同种异体胰岛细胞移植的新方法对胰岛移植物存活时间的作用.方法 选择雄性BALB/c小鼠为胰岛移植模型的供者,雄性C57BL/6糖尿病小鼠为受者.随机将受者分为A、B两组.A组:仅采用供者的胰岛细胞移植;B组:采用受者的肝脏星状细胞(HSCs)与供者胰岛细胞混合后共同移植.术后定期测定受者尾静脉血的血糖含量.结果 B组受者胰岛移植物的存活时间明显延长,血糖含量维持正常的中位时间为66 d(30～180 d),而A组血糖含量维持正常的中位时间为11 d(9～15 d),两组比较,差异有统计学意义(P＜0.001).结论 受者肝脏星状细胞能延长共同移植的同种异体胰岛移植物存活时间.     

转染细胞毒性T淋巴细胞相关抗原4免疫球蛋白基因的同供体大鼠树突状细胞对胰岛移植物存活的影响

目的　探讨转染细胞毒性T淋巴细胞相关抗原4(转染CTLA4Ig基因)的同供体大鼠DC细胞对同种大鼠胰岛移植的影响。方法　链尿菌素(STZ) 60mg/kg体重腹腔内注射制作SD大鼠糖尿病模型,胶原酶法分离、Ficoll 40 0密度梯度离心法纯化胰岛,GM CSF +IL 4诱生培育的方法,获得高纯度的DC ,含目的基因CTLA4Ig重组腺病毒AdvCTLA4Ig ,转染同供体DC细胞,与胰岛细胞同时移植于糖尿病受体大鼠肾包膜下,免疫组织化学、Dot ELISA、逆转录 聚合酶链反应(RT PCR)检测CTLA4Ig基因在实验组和对照组DC细胞中的表达,并检测受体大鼠的血糖浓度变化,同时观察受体存活情况。结果　实验组DC细胞有CTLA4Ig表达,而对照组DC细胞没有CTLA4Ig表达,实验组正常血糖维持时间(17.3±2 .4)d较对照组(10 .1±1.5 )d、空白对照组(8.3±1.2 )d显著延长,实验组、对照组和空白对照组受体大鼠存活天数分别为(3 4.5±3 .4)d、(14 .7±2 .3 )d和(11.2±1.4)d ,实验组高于对照组(P <0 .0 1)。结论　表达CTLA4Ig基因的DC细胞可能诱异胰岛移植免疫耐受,延长胰岛移植物的存活时间     

经hCTLA4-Ig基因转染的猪胰岛细胞在小鼠体内的存活与功能状况研究

目的研究将人细胞毒T淋巴细胞相关抗原4免疫球蛋白（hCTLA4-Ig）基因转染至猪胰岛细胞后，再将其移植至小鼠体内的存活及功能状况。方法采用腺相关病毒载体（AAV）介导hCTLA4-Ig基因体外转染新生猪胰岛细胞（NIPs），再将转基因的NIPs移植至构建了人免疫系统的SCID糖尿病小鼠左肾被膜下。逆转录聚合酶链（RT-PCR）反应和免疫荧光染色法检测转染后hCTLA4-Ig基因的表达状况；观察小鼠移植转基因NIPs后的生存时间；移植物免疫组织化学分析及酶联免疫（ELISA）法测定受者血清中细胞因子的水平。结果NIPs经转染后，可检测到hCTLA4-Ig基因及其蛋白表达，且葡萄糖刺激胰岛素释放试验与未转染的对照组比较，差异无统计学意义（P〉0．05）；糖尿病小鼠经转基因的NIPs移植后，生存时间及血糖维持正常的平均时间分别为（72．5±30．6）d和（59．1±24．0）d，较未转染的对照组（26．9±6．9）d和（12．7±3．3）d显著延长（P〈0．01）；免疫组织化学染色检测移植后不同时间（15、30、90d）的移植物组织，可见转基因细胞移植部位有完整的胰岛细胞，而对照组胰岛细胞破坏、消失，周围可见较多的炎性细胞浸润；且转基因细胞移植的小鼠血清白细胞介素2（IL-2）、γ干扰素（IFN-γ）、肿瘤坏死因子α（TNF-α）的水平明显低于对照组（P〈0．05）。结论AAv介导hCTLA4-Ig基因体外转染猪胰岛细胞后再移植至受者体内，可提高受者的免疫耐受水平，延长胰岛细胞在异种受者体内的存活时间，而胰岛细胞的内分泌功能不受明显影响。     

肝细胞和脾细胞单独或联合输注对异种胰岛细胞移植排斥反应的影响

目的 探讨供者的肝细胞和脾细胞输注对同一供者胰岛细胞移植排斥反应的影响。方法 经尿静脉给BALB/c小鼠糖尿病模型注射供者（猪）的肝细胞和脾细胞，腹腔内注射途径进行猪胰岛细胞移植。移植后测定受者的血糖变化，观察小鼠移植物有功能存活时间。同时测定小鼠巨噬细胞吞噬功能，脾脏淋巴细胞转化功能和自然杀伤细胞活性的变化。结果 胰岛细胞移植前输注肝细胞，脾细胞以及肝细胞和脾细胞混合悬液者，移植物有功能存活时间延长，其淋巴细胞转化率。自然杀伤细胞活性及巨噬细胞的吞噬功能均较低，以肝细胞和脾细胞联合输注者为著。结论 移植前少量多次的供者肝细胞和脾细胞输注可以降低异种胰岛细胞移植排斥反应的强度。     

激活型Akt1转染大鼠胰岛联合免疫抑制剂在异种胰岛移植中的应用

目的 探讨腺病毒载体介导激活性Akt1基因(Adv-CA-Akt1)转染大鼠胰岛对异种移植胰岛功能和存活的影响.方法 以BALB/C糖尿病小鼠为受体,分离纯化雄性Wistar大鼠胰岛,体外培养,Adv-CA-Akt1转染后异种胰岛移植.受体小鼠分3组,实验组:Adv-CA-Akt1转染的大鼠胰岛体外培养24 h,小鼠肾被膜下移植,并口服环孢素A(CsA)30 mg·kg-1·d-1;CsA组:未转染胰岛移植,同剂量环孢素口服;对照组:单纯胰岛移植.每只接受300胰岛当量(IEQs)移植.检测术后血糖,移植物存活时间及组织病理学.结果 实验组和CsA组术后2 d血糖即降至正常,胰岛功能存活时间分别为(21.0±3.65)d和(9.0±2.54)d,而对照组血糖短暂下降后再次升高,胰岛功能存活时间(4.2±2.6)d.实验组小鼠生存时间为(31.0±5.67)d比CsA组(17.0±3.35)d和对照组(10.0±1.52)d明显延长,三组比较差异有统计学意义(P<0.05);胰岛素免疫组化染色实验组.肾被膜下见较多有功能胰岛细胞团,而CsA组和对照组胰岛素染色阳性细胞数减少.结论 Adv-CA-Akt1转染大鼠胰岛联合应用免疫抑制剂,可提高胰岛功能,延长异种胰岛移植物存活时间.     

阻断趋化因子受体途径对胰岛移植后急性排斥反应的影响

目的探讨趋化因子拮抗剂Met-RANTES对大鼠同种异体胰岛移植后急性排斥反应的影响及其作用机制。方法实验分2个组进行,对照组仅行胰岛移植,实验组在胰岛移植后第1~7d腹腔内注射Met-RANTES200μg/kg。术后监测大鼠的血糖变化及受者的存活情况,并观察移植胰岛的组织病理学变化;采用微量全血3H-胸腺嘧啶掺入法检测单个核细胞在刀豆蛋白A刺激下的增殖程度,流式细胞仪检测外周血CD4+细胞/CD8+细胞比值的变化及CCR5的表达。结果术后对照组和实验组血糖维持正常的时间分别为(3.8±4.5)d和(23.0±10.5)d,受者的存活时间分别为(11.4±4.2)d和(32.0±8.0)d,差异均有统计学意义(P<0.05);术后7d,对照组单个核细胞在刀豆蛋白A刺激下的增殖程度明显强于实验组(闪烁计数值分别为254.4次/min±116.3次/min和175.0次/min±98.2次/min),差异有统计学意义(P<0.05);两个组外周血CD4+细胞/CD8+细胞比值的差异无统计学意义,但对照组CCR5的表达明显强于实验组,差异有统计学意义(P<0.05);术后第7d,对照组移植胰岛周围可见较多淋巴细胞浸润,胰岛细胞减少,而实验组移植胰岛周围淋巴细胞浸润少见,移植胰岛完整。结论Met-RANTES通过阻断趋化因子受体途径抑制单个核细胞的活性;移植术后应用Met-RANTES可明显抑制大鼠胰岛移植后排斥反应的发生,显著延长移植物及受者的存活时间。     

输注胰岛抗原特异性Treg细胞延长同系NOD小鼠移植胰岛的存活时间

目的 探讨输注胰岛抗原特异性调节性T淋巴细胞(Treg细胞)对非肥胖糖尿病(NOD)小鼠同系胰岛移植物存活时间的影响.方法·以未成熟树突状细胞(imDC)联合谷氨酸脱羧酶-65在体外诱导童贞T淋巴细胞分化成胰岛抗原特异性Treg细胞.以已发生糖尿病的NOD小鼠为受者,将分离得到的尚未进展为糖尿病的NOD小鼠的胰岛(500胰岛当量)移植至受者的肾包膜下,对照组不行移植,只观察血糖变化;单纯胰岛移植组只进行胰岛移植,不输注胰岛抗原特异性Treg细胞;实验组于术前1d静脉输注1×106个胰岛抗原特异性Treg细胞,然后进行胰岛移植.术后检测受者的血糖,以判断移植胰岛的存活时间,观察胰岛移植物的病理学变化.结果 对照组血糖持续高于11.1 mmol/L;单纯胰岛移植组小鼠的血糖于术后1～2 d降至正常,到7～17d时开始陆续升高,并维持在术前水平,移植物存活时间为(12.2±2.6)d;实验组小鼠的血糖于术后1～2 d降至正常,至第27天开始有小鼠血糖升高超过11.1 mmol/L,第43天时,所有小鼠的血糖均超过11.1mmol/L,移植物的存活时间为(35.2±4.3)d,明显长于单纯胰岛移植组(P＜0.01).单纯胰岛移植组的移植胰岛有明显的淋巴细胞浸润,并伴有胰岛细胞严重破坏,胰岛素染色未见完整的胰岛存在,仅有极少量残存的分泌胰岛素的胰岛细胞;实验组第15天时移植胰岛形态完整,仅有少量淋巴细胞浸润,分泌胰岛素的胰岛大量存在.结论 体外诱导产生的胰岛抗原特异性Treg细胞可以延缓自身免疫系统对移植胰岛的破坏,明显延长NOD小鼠移植胰岛的存活时间.     

血管内皮生长因子促进大鼠的移植胰岛再血管化并提高其存活率

目的探讨血管内皮生长因子（VEGF）对大鼠的移植胰岛再血管化及对其存活率和功能的影响。方法构建质粒pIRES2-EGFP／VEGF165，以脂质体法在体外转染大鼠（供者）的血管内皮细胞。流式细胞术检测转染效率；免疫组织化学染色检测VEGF的表达。将糖尿病大鼠（受者）随机分为3组，每组10只。对照组：于肾被膜下单纯移植供者的300当量胰岛；实验组和空白转染组除移植供者的300当量胰岛外，分别加入供者的1×10^6个转染了质粒pIRES2-EGFP／vEGF165的血管内皮细胞和未经转染的正常血管内皮细胞。移植后监测受者的血糖及血清胰岛素水平。术后第14天，取受者肾脏，行HE染色及Insulin-6、VEGF和CD34免疫组织化学染色。结果血管内皮细胞中VEGFm的转染效率为13．06％。实验组供者的血管内皮细胞胞核和胞浆中均有VEGF表达。实验组受者于移植术后第3天血糖及胰岛素水平恢复正常；对照组和空白转染组虽有所改善，但未恢复到正常水平，与实验组相比，差异有统计学意义。实验组受者肾被膜下可见成团胰岛，Insulin-6免疫组织化学染色呈阳性，周围及内部有大量内皮细胞；VEGFm及CD34免疫组织化学染色呈阳性。对照组和空白转染组肾被膜下的细胞团中心细胞较少，部分被纤维组织代替，内部仅有少量CD34染色阳性的内皮细胞；Insulin-6免疫组织化学染色仅有少量细胞染成棕黄色；VEGF165免疫组织化学染色呈阴性。结论供者的胰岛与转染了VEGF165的血管内皮细胞共同移植给受者可以促进移植胰岛的再血管化，提高其存活率，并使其功能恢复正常。     

胰岛FasL基因转染对大鼠胰岛移植的影响

目的 探究胰岛细胞FasL基因转染对同种大鼠胰岛移植的影响。方法 通过磷酸钙沉淀法构建含目的基因FasL的重组腺病毒AdV-FasL,感染胰岛细胞后移植于糖尿病受者大鼠,通过RT-PCR和免疫组织化学检测移植物FasL表达,观察移植物存活情况及基因转染胰岛细胞凋亡情况。结果 单纯移植胰岛组平均存活期为（6.3±0.56）d,FasL基因转染组并未出现排斥延迟,反而排斥加速,存活期缩短至（3.4±0.24）d。FasL转染的胰岛细胞在移植后24h见FasL表达,在 48 h表达增强,AdV-5感染组及未转染组未见FasL表达。TUNEL标记见移植后FasL转染胰岛细胞凋亡。结论 尽管表达FasL的睾丸细胞与胰岛共移植可诱导活化的淋巴细胞凋亡,使胰岛移植物获得免疫豁免、存活期延长,但通过FasL基因转染使胰岛细胞直接表达FasL,引起胰岛细胞凋亡和粒细胞浸润,导致排斥加速。     

诱导供者胰岛细胞高表达血红素加氧酶-1延长大鼠胰岛移植物的存活时间

目的 探讨钴原卟啉(CoPP)诱导大鼠胰岛细胞高表达血红素加氧酚1(HO-1)后,对延长胰岛移植物存活时间的作用.方法 (1)将分离和纯化的供者(BN大鼠)胰岛细胞分为CoPP诱导组和未诱导组.CoPP诱导组供者在分离胰岛细胞前3天和前1天腹腔注射2.5 mg/kg的CoPP,未诱导组不注射CoPP.诱导后,采用免疫荧光法及Western免疫印迹法检测两组胰岛细胞中HO-1的表达情况,采用酶联免疫吸附试验(ELISA)和葡萄糖刺激试验检测胰岛细胞的胰岛素释放水平.(2)Lewis大鼠经四氧嘧啶静脉注射后建立糖尿病模型,取10只成功建立糖尿病模型的大鼠作为胰岛细胞移植的受者,随机平均将受者分为实验组和对照组,分别移植经CoPP诱导和未经诱导的供者胰岛细胞.移植后,观察和比较两组受者胰岛移植物的存活时间和发生排斥反应后胰岛移植物的组织病理学变化.结果 CoPP诱导组胰岛细胞高表达HO-1,而未诱导组不表达HO-1;CoPP诱导组和未诱导组供者胰岛细胞胰岛素分泌量,在低糖刺激下分别为(15.65±0.89)mU/L和(12.28±0.89)mU/L(P>0.05),在高糖刺激下分别为(46.60±1.13)mU/L和(19.01±1.49)mU/L(P<0.05),刺激指数分别为2.98±0.10和1.55±0.01(P<0.05).实验组和对照组胰岛移植物平均存活时间分别为(12.20±5.67)d和(5.60±1.14)d(P<0.05);当受者发牛排斥反应时,对照组胰岛移植物周边可见明显的淋巴细胞、成纤维细胞以及单个核细胞浸润,而实验组细胞浸润的程度明显较轻.结论 CoPP可诱导大鼠胰岛细胞高表达HO-1,其对胰岛细胞有明显保护作用.移植高表达HO-1的胰岛细胞能显著延长胰岛移植物的存活时间.     

激活型Akt1转染大鼠胰岛联合应用细胞毒T淋巴细胞相关抗原4免疫球蛋白延长异种胰岛移植存活

目的 观察激活型Akt1基因转染大鼠胰岛对异种胰岛移植功能和存活的影响.方法 提取大鼠胰岛培养转染,AO/EB和Tunel染色检测存活和凋亡;BALB/C糖尿病小鼠肾被膜下胰岛移植.分4组,实验组:Akt1转染胰岛联合应用细胞毒T淋巴细胞相关抗原4免疫球蛋白(CTLA-4Ig);Akt1组:移植Akt1转染的胰岛;未转染组:单纯胰岛移植,CTLA-4Ig组:单纯胰岛联合应用CTLA-4Ig;观察胰岛移植后功能存活时间和平均生存时间.结果 Akt1转染胰岛体外细胞抗凋亡生存率提高了25%;实验组移植物功能存活(32.5±6.6)d,平均生存时间(39.6±5.9)d比Akt1组(15.4±3.5)、(22.5±1.7)d和CTLA-4Ig组(18.7±4.5)、(21.7±3.5)d未转染组(4.5±2.8)、(6.8±3.1)d明显延长(P<0.05).结论 激活型Akt1转染大鼠胰岛联合应用CTLA-4Ig,可减少移植胰岛凋亡,延长异种胰岛移植物存活时间.     

Inhibitory effects of immunosuppressive drugs on insulin secretion from HIT-T15 cells and Wistar rat islets

Until recently, islet allotransplantation for type 1 diabetic patients has been largely unsuccessful. Previous pharmacologic studies of single drugs have suggested that one factor contributing to this poor success is toxicity of immunosuppressive drugs on transplanted islets. However, no comprehensive study of agents currently used for islet transplantation has been previously reported. Consequently, we exposed HIT-T15 cells and Wistar rat islets to various concentrations of five immunosuppressive agents for 48 and 24 hr, respectively, and measured glucose-stimulated insulin secretion during subsequent static incubations. Results are expressed as percent reduction of insulin secretion at the lower and upper limits, respectively, of plasma drug concentrations used in clinical transplantation compared with control (no drug exposure). Insulin secretion from HIT-T15 cells was significantly inhibited by 74% and 90% after exposure to methylprednisolone (P<0.05), 11% and 24% after exposure to cyclosporine (P<0.01), 60% and 83% after exposure to mycophenolate (P<0.05), 56% and 63% after exposure to sirolimus (P<0.001), and 10% and 20% after exposure to tacrolimus (P<0.001). Insulin secretion from Wistar rat islets was reduced by 0% and 48% after exposure to mycophenolate (P<0.001) and 20% and 31% after exposure to tacrolimus (P<0.05). No reduction in insulin secretion was observed from either HIT-T15 cells or rat islets after exposure to daclizumab. The results support the hypothesis that toxicity of certain immunosuppressive drugs on beta-cell function plays a role in the poor success of islet allotransplantation. This is especially true of intrahepatically transplanted islets, which are exposed to higher portal concentrations of immunosuppressive agents. These findings support the use of low-dose immunosuppressive drug protocols in clinical islet transplantation.     

Autologous regulatory T cells in clinical intraportal allogenic pancreatic islet transplantation

Allogeneic islet transplantation in type 1 diabetes requires lifelong immunosuppression to prevent graft rejection. This medication can cause adverse effects and increases the susceptibility for infections and malignancies. Adoptive therapies with regulatory T cells (Tregs) have shown promise in reducing the need for immunosuppression in human transplantation settings but have previously not been evaluated in islet transplantation. In this study, five patients with type 1 diabetes undergoing intraportal allogeneic islet transplantation were co-infused with polyclonal autologous Tregs under a standard immunosuppressive regimen. Patients underwent leaukapheresis from which Tregs were purified by magnetic-activated cell sorting (MACS) and cryopreserved until transplantation. Dose ranges of 0.14–1.27 × 10⁶ T cells per kilo bodyweight were transplanted. No negative effects were seen related to the Treg infusion, regardless of cell dose. Only minor complications related to the immunosuppressive drugs were reported. This first-in-man study of autologous Treg infusion in allogenic pancreatic islet transplantation shows that the treatment is safe and feasible. Based on these results, future efficacy studies will be developed under the label of advanced therapeutic medical products (ATMP), using modified or expanded Tregs with the aim of minimizing the need for chronic immunosuppressive medication in islet transplantation.     

Gene transfer of manganese superoxide dismutase extends islet graft function in a mouse model of autoimmune diabetes

Islet transplantation is a promising cure for diabetes. However, inflammation, allorejection, and recurrent autoimmune damage all may contribute to early graft loss. Pancreatic islets express lower levels of antioxidant genes than most other tissues of the body, and beta-cells in particular are sensitive to oxidative damage. Therefore, damage from oxidative stress may pose a major obstacle to islet replacement therapy in that both the islet isolation and transplantation processes generate oxygen radicals. To determine whether antioxidant gene overexpression in isolated pancreatic islets can prevent oxidative damage and prolong islet function after transplantation, we used the NOD mouse model to study oxidative stress encountered during both transplantation and autoimmune attack. We transferred an antioxidant gene, manganese superoxide dismutase (MnSOD), by adenoviral infection into isolated islets that were transplanted into streptozotocin-treated NODscid recipient mice. Functioning islet grafts were subsequently exposed to diabetogenic spleen cells and monitored until graft failure. The results show that islet grafts overexpressing MnSOD functioned approximately 50% longer than control grafts. This significant prolongation of graft function suggests that the antioxidant activity of MnSOD is beneficial to transplanted islet survival and may be used in combination with other strategies aimed at islet graft protection.     

Quantitative in vivo islet potency assay in normoglycemic nude mice correlates with primary graft function after clinical transplantation

Reliable assays are critically needed to monitor graft potency in islet transplantation (IT). We tested a quantitative in vivo islet potency assay (QIVIPA) based on human C-peptide (hCP) measurements in normoglycemic nude mice after IT under the kidney capsule. QIVIPA was initially tested by transplanting incremental doses of human islets. hCP levels in mice were correlated with the number of transplanted islet equivalents (r(2) = 0.6, P<0.01). We subsequently evaluated QIVIPA in eight islet preparations transplanted in type 1 diabetic patients. Conversely to standard criteria including islet mass, viability, purity, adenosine triphosphate content, or glucose stimulated insulin secretion, hCP in mice receiving 1% of the final islet product was correlated to primary graft function (hCP increase) after IT (r(2)=0.85, P<0.01). QIVIPA appears as a reliable test to monitor islet graft potency, applicable to validate new methods to produce primary islets or other human insulin secreting cells.     

Effect of various immunosuppressive monotherapies on survival and histopathology of monkey islet xenografts in rats

BACKGROUND: The isolation and testing of monkey islets after transplantation in small animal models provides basic information about their functional capacity. We describe the effect of cyclosporine A (CsA), tacrolimus (FK506) or prednisolone monotherapy on preventing monkey islet graft rejection after xenoTx in a rat model. Histopathological aspects are reported. METHODS: Indian bonnet monkey (Macaca radiata radiata) islets were isolated by a simple stationary digestion technique using collagenase. The islets were purified with dextran density gradients and were transplanted under the renal capsule of normal or diabetic rats. The rats received a daily dose of CsA, or FK506, or prednisolone, and the grafts were removed at different intervals to determine islet survival. The effect of discontinuation of CsA on islet graft survival was also monitored. Histological examination of islets transplanted into normal or streptozotocin-induced diabetic rats was carried out. In diabetic rats, islet survival was determined by the graft's ability to achieve euglycemia. RESULTS: Reversal of diabetes was achieved in all transplanted diabetic rats, demonstrating the efficacy of the isolated monkey islets. Histological examination indicated that monkey islets survived in the presence of continuous high-dose immunosuppressive monotherapy in rats. Various types of infiltrating cells were observed in the grafted area at varying times after transplantation, depending on the immunosuppressive treatment. After discontinuation of CsA, the grafts were protected for a short period. CONCLUSIONS: This study provided evidence for monkey islet survival after transplantation into rats receiving immunosuppressive monotherapy. Basic information on infiltrating cell types may be important in the study of xenograft rejection.     

Sertoli cells induce systemic donor-specific tolerance in xenogenic transplantation model

Cell therapy is a potentially powerful tool in the treatment of many grave disorders including leukemia, immune deficiencies, autoimmune diseases, and diabetes. However, finding matched donors is challenging and recipients may suffer from the severe complications of systemic immune suppression. Sertoli cells, when cotransplanted with both allo- and xenograft tissues, promote graft acceptance in the absence of systemic immunosuppression. How Sertoli cells do this is not, as yet, clearly defined. We have examined the ability of Sertoli cells to produce systemic immune tolerance. For this purpose, Sertoli cells were injected into an otherwise normal C57/BL6 mouse host via the lateral tail vein. No other immunosuppressive protocols were applied. Six to 8 weeks posttransplantation, blood was collected for analysis of cytokine levels. Tolerance to donor cells was determined by mixed lymphocytic culture, and production of T-cell-dependent antibody was determined by an in vitro anti-sheep red blood cell plaque-forming assay. Results showed a marked modulation of immune cytokines in the transplanted mouse host and donor-specific transplantation tolerance was achieved. Tolerant mouse lymphocytes maintained a competent humoral antibody response. Additionally, C57/BL6 mice transplanted with rat Sertoli cells tolerated rat skin grafts significantly longer than control non-Sertoli cell transplanted mice. We conclude that systemic administration of rat Sertoli cells across xenogenic barrier induces transplantation tolerance without altering systemic immune competence. These data suggest that Sertoli cells may be used as a novel and potentially powerful tool in cell transplantation therapy.     

局部应用缓释免疫抑制剂对胰岛细胞移植的影响

目的 探索局部应用免疫抑制剂对提高移植胰岛细胞的存活率及改善全身不良反应的影响.方法 造模:将链脲霉素按200 mg/kg注射到昆明小鼠腹腔内,48、72 h后测血糖,连续测两次≥20 mol/L作为实验动物糖尿病型.腹腔内移植入胰岛细胞的量为8 000 IE/kg,环孢素用量为1.5 mg/(100 g·d).实验分...     

抗原特异性CD4+CD25+T细胞对同种异体胰岛移植影响及作用机制研究

目的:探讨抗原特异性CD4+CD25+Treg细胞免疫对同种异体胰岛急性移植排斥反应的影响和机制。方法:用MACS分选供体抗原特异性CD4+CD25+Treg细胞免疫糖尿病BALB/cByJ受体小鼠，以ICR小鼠胰岛为供体行同种异体胰岛移植。观察移植后小鼠的存活时间、移植前后外周血CD4+和CD8+T细胞亚群的变化和移植物中Th1/Th2细胞因子mRNA表达水平的变化。结果:抗原特异性Treg细胞联合胰岛移植组(C组)胰岛移植物平均生存期为(34.57±17.15)d，显著长于单纯胰岛移植组(B组)的(10.6±1.82) d (P<0.01)；移植后第3天，C组外周血CD4+/CD8+的值显著低于B组(P<0.01)；C组移植物中IL-10,TGF-β mRNA表达比B组显著增强。B组移植物中IL-1β，IL-2及IFN-γ mRNA表达明显强于C组。结论:抗原特异性CD4+CD25+ Treg细胞可通过调节Th2/Th1之间的反应平衡而延长同种异体胰岛移植物的存活时间。