雷公藤内酯醇在器官移植中的研究进展

国内外研究表明,雷公藤内酯醇在抗同种移植排异反应中具有疗效好、适应范围广、不良反应少等优点,被认为是器官移植领域中一种很有应用前景的药物。     

雷公藤内酯醇在器官移植中的研究进展

国内外研究表明，雷公藤内酯醇在抗同种移植排异反应中具有疗效好、适应范围广、不良反应少等优点，被认为是器官移植领域中一种很有应用前景的药物。     

非糖皮质激素的免疫抑制方案对同种异体移植胰岛的保护作用

目的　评价非糖皮质激素的免疫抑制方案对防止大鼠同种异体胰岛移植排斥反应的效果。方法　大鼠同种异体胰岛移植后 ,分别应用他克莫司 (FK5 0 6 ) 霉酚酸酯 (MMF)和FK5 0 6 MMF 泼尼松 (Pred)行免疫抑制治疗两周 ,并设对照组 ,动态观察受者血糖、胰岛素及C肽变化 ,并作移植部位的形态学检测。结果　FK5 0 6 MMF组和FK5 0 6 MMF Pred组与对照组相比 ,移植胰岛存活时间明显延长 ,移植后 2个月在受者肝汇管区可见较多形态完整的胰岛细胞。FK5 0 6 MMF组维持术后正常血糖、胰岛素及C肽的时间超过 6 0d ,而FK5 0 6 MMF Pred组与前者比较 ,分泌C肽较少 (P <0 .0 5 ) ,血糖维持在较高水平 (P <0 .0 1) ,胰岛素水平两组差异无显著性。FK5 0 6 MMF Pred组停药两周以后的血糖水平较用药期间、停药两周内有明显降低 (P <0 .0 5 ) ,胰岛素和C肽分泌有所增多 ,但差异无显著性。结论　应用FK5 0 6 MMF和FK5 0 6 MMF Pred均有很强的免疫抑制效应 ,但糖皮质激素对胰岛细胞有毒性作用。小剂量FK5 0 6与MMF联用对移植胰岛细胞有较强的保护作用。     

胰岛移植基础研究

胰岛移植因为安全、有效而一直成为糖尿病治疗中的研究热点。近年来，随着基因工程技术、干细胞定向诱导分化技术的不断成熟，胰岛移植可能在今后数年内得以广泛开展，现对此作一简述。     

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。     

小鼠异体Sertoli细胞诱导胰岛移植免疫耐受的作用

目的 观察小鼠Sertoli细胞是否能在异体内起到诱导局部免疫耐受、保护共移植异体胰岛的作用.方法 以糖尿病C57小鼠作移植受体,随机分4组,每组6只;以正常BALB/C小鼠为胰岛供体,正常C57小鼠和正常BALB/C小鼠各作为Serloli细胞供体.A组:单纯移植异体胰岛;B组:移植来源于C57小鼠的Sertoli细胞+BALB/C小鼠来源的胰岛;C组:移植均来源于BALB/C小鼠的Sertoli细胞及胰岛;D组:假手术组.监测各组移植受体的血糖尿糖变化,观察移植物的存活时间.结果 A组移植物平均存活时间为(6.50±2.35)d;B组为(55.67±4.84)d;C组为(51.33±5.05)d;D组未观察到血糖正常.B组及C组的移植方式均可逆转糖尿病小鼠的高血糖状态,移植物存活期均较A组有明显延长,其差异有统计学意义(P<0.05);而B组与C组的移植物存活时间差异无统计学意义(P>0.05).结论 同种异体来源的睾丸Sertoli细胞在异体内可起到诱导局部免疫耐受的效果,对共移植同种异体胰岛起到保护作用,其效果与自体睾丸Sertoli细胞相当.     

小鼠异体Sertoli细胞诱导胰岛移植免疫耐受的作用

Objective To study whether the sertoli cell allograft can achieve the immunotolerance and protect the co-transplant islet allograft on the heterotopic situation. Methods The diabetic C57 mice were used as recipients, and healthy BALB/C mice as islet donors,respectively. Healthy BALB/C and C57 mice were used as testis sertoli cell donors. The recipients were randomly divided into 4 groups,6 mice in each group : group A: only transplant with islet allograft;group B: co-transplant with islet allograft and serto-li isograft;group C:co-transplant with islet allograft and sertoli allograft;group D:sham-operated group. The blood and urine glucose levels in the models, and the survival time of the graft were observed. Results The mean survive time of graft in groups A, B, and C was (6.50±2.35 ), (55.67±4.84), and (51.33± 5.05 ) days respectively. In group D, blood glucose level was abnormal. The hyperglycemia of the diabetic C57 mice could be reversed by the transplant methods of groups B and C. The mean survival time in groups B and C was longer than in group A P < 0.05, but there was no significant differences between groups B and C,P > 0.05. Conclusion The sertoli cells can induce local immunotolerance and protect the co-transplant islet allograft. Sertoli cell isograft can obtain the same local immunotolerance as the sertoli cell allograft.     

小鼠异体Sertoli细胞诱导胰岛移植免疫耐受的作用

Objective To study whether the sertoli cell allograft can achieve the immunotolerance and protect the co-transplant islet allograft on the heterotopic situation. Methods The diabetic C57 mice were used as recipients, and healthy BALB/C mice as islet donors,respectively. Healthy BALB/C and C57 mice were used as testis sertoli cell donors. The recipients were randomly divided into 4 groups,6 mice in each group : group A: only transplant with islet allograft;group B: co-transplant with islet allograft and serto-li isograft;group C:co-transplant with islet allograft and sertoli allograft;group D:sham-operated group. The blood and urine glucose levels in the models, and the survival time of the graft were observed. Results The mean survive time of graft in groups A, B, and C was (6.50±2.35 ), (55.67±4.84), and (51.33± 5.05 ) days respectively. In group D, blood glucose level was abnormal. The hyperglycemia of the diabetic C57 mice could be reversed by the transplant methods of groups B and C. The mean survival time in groups B and C was longer than in group A P < 0.05, but there was no significant differences between groups B and C,P > 0.05. Conclusion The sertoli cells can induce local immunotolerance and protect the co-transplant islet allograft. Sertoli cell isograft can obtain the same local immunotolerance as the sertoli cell allograft.     

小鼠异体Sertoli细胞诱导胰岛移植免疫耐受的作用

Objective To study whether the sertoli cell allograft can achieve the immunotolerance and protect the co-transplant islet allograft on the heterotopic situation. Methods The diabetic C57 mice were used as recipients, and healthy BALB/C mice as islet donors,respectively. Healthy BALB/C and C57 mice were used as testis sertoli cell donors. The recipients were randomly divided into 4 groups,6 mice in each group : group A: only transplant with islet allograft;group B: co-transplant with islet allograft and serto-li isograft;group C:co-transplant with islet allograft and sertoli allograft;group D:sham-operated group. The blood and urine glucose levels in the models, and the survival time of the graft were observed. Results The mean survive time of graft in groups A, B, and C was (6.50±2.35 ), (55.67±4.84), and (51.33± 5.05 ) days respectively. In group D, blood glucose level was abnormal. The hyperglycemia of the diabetic C57 mice could be reversed by the transplant methods of groups B and C. The mean survival time in groups B and C was longer than in group A P < 0.05, but there was no significant differences between groups B and C,P > 0.05. Conclusion The sertoli cells can induce local immunotolerance and protect the co-transplant islet allograft. Sertoli cell isograft can obtain the same local immunotolerance as the sertoli cell allograft.     

小鼠异体Sertoli细胞诱导胰岛移植免疫耐受的作用

Objective To study whether the sertoli cell allograft can achieve the immunotolerance and protect the co-transplant islet allograft on the heterotopic situation. Methods The diabetic C57 mice were used as recipients, and healthy BALB/C mice as islet donors,respectively. Healthy BALB/C and C57 mice were used as testis sertoli cell donors. The recipients were randomly divided into 4 groups,6 mice in each group : group A: only transplant with islet allograft;group B: co-transplant with islet allograft and serto-li isograft;group C:co-transplant with islet allograft and sertoli allograft;group D:sham-operated group. The blood and urine glucose levels in the models, and the survival time of the graft were observed. Results The mean survive time of graft in groups A, B, and C was (6.50±2.35 ), (55.67±4.84), and (51.33± 5.05 ) days respectively. In group D, blood glucose level was abnormal. The hyperglycemia of the diabetic C57 mice could be reversed by the transplant methods of groups B and C. The mean survival time in groups B and C was longer than in group A P < 0.05, but there was no significant differences between groups B and C,P > 0.05. Conclusion The sertoli cells can induce local immunotolerance and protect the co-transplant islet allograft. Sertoli cell isograft can obtain the same local immunotolerance as the sertoli cell allograft.     

肝移植术后合并脓毒症患者外周血调节性T细胞比例及功能变化的分析

目的探讨肝移植患者在脓毒症不同阶段外周血调节性T细胞（Treg）比例和功能的变化。方法选取自2009年1月至2010年12月期间在中山大学附属第三医院行外科手术,术后合并脓毒症的47例患者作为研究对象,根据手术方式和美国胸科和危重症医师协会制订的脓毒症诊断和分期标准指南分为4组：肝移植脓毒症组（sepsis after liver transplantation group,TS组;11例）、肝移植严重脓毒症组（severe sepsis after liver transplantation group,TSS组;10例）、非肝移植脓毒症组（sepsis without liver transplantation group,NTS组;15例）、非肝移植严重脓毒症组（severe sepsis without liver transplantation group,NTSS组;11例）,另外选取20名健康正常人作为健康对照组。4组脓毒症患者通过急性生理和慢性健康评估（acute physiology and chronic health evaluation,APACHE）Ⅱ和感染相关的序贯器官衰竭评估（sequential organ failure assessment,SOFA）来评价与比较脓毒症严重程度。分别采集各组研究对象的外周血,采用流式细胞术检测CD4＋CD25＋Foxp3＋调节性T细胞比例（Treg％）,采用荧光定量逆转录聚合酶链反应检测Foxp3信使核糖核酸（messengerRNA,mRNA）。结果TSS和NTSS组的APACHEⅡ评分、SOFA评分均高于TS组和NTS组（均为P〈0．01）,且TS组的APACHEⅡ评分高于NTS组,TSS组的APACHEⅡ评分和SOFA评分均高于NTSS组（均为P〈0．01）。与健康对照组比较,NTS组Treg％明显降低（P〈0．001）,NTSS组明显升高（P=0．003）;而TS组与健康对照组相比差异无统计学意义（P=0．398）,TSS组也高于健康对照组（P=0．006）,但变化幅度不如NTSS组显著。4组脓毒症组的组间比较发现,NTSS组患者Treg％显著高于NTS组（P〈0．01）,而TSS组与Ts组两组比较差异无统计学意义（P=0．099）,NTS组患者Treg％低于Ts组（P=0．05）,而NTSS组则显著高于TSS组（P=0．002）。与健康对照组比较,NTSS组的Foxp3mRNA表达显著升高,差异有统计学意义（P〈0．05）。4组脓毒症组的组间比较发现,TSS组和NTSS组Foxp3mRNA表达值均高于TS组和TSS组,但移植组内（TS组与TSS组）的差异没有非移植组（NTS组与NTSS组）显著（分别为P=0．038、P〈0．001）;另外NTSS组的Foxp3mRNA表达显著高于TSS组（P=0．012）。结论免疫抑制剂的应用使移植患者在发生脓毒症时Treg的比例和功能的变化有别于普通人群,评估机体免疫状态时需要综合多个免疫指标。     

Transient Depletion of Dividing T Lymphocytes in Mice Induces the Emergence of Regulatory T Cells and Dominant Tolerance to Islet Allografts

We previously showed that transient depletion of dividing T cells at the time of an allogeneic transplantation induces long-term tolerance to the allograft. Here we investigated the role of homeostatic perturbation and regulatory T cells (Treg) in such tolerance. Transient depletion of dividing T cells was induced at the time of an allogeneic pancreatic islets graft, by administration of ganciclovir for 14 days, into diabetic transgenic mice expressing a thymidine kinase (TK) conditional suicide gene in T cells. Allograft tolerance was obtained in 63% of treated mice. It was not due to global immunosuppression, permanent deletion or anergy of donor-alloantigens specific T cells but to a dominant tolerance process since lymphocytes from tolerant mice could transfer tolerance to naïve allografted recipients. The transient depletion of dividing T cells induces a 2- to 3-fold increase in the proportion of CD4⁺CD25⁺Foxp3⁺ Treg, within 3 weeks that persisted only in allograft-bearing mice but not in nongrafted mice. Tolerance with similar increased proportion of Treg cells was also obtained after a cytostatic hydroxyurea treatment in normal mice. Thus, the transient depletion of dividing T cells represents a novel means of immuno-intervention based on disturbance of T-cell homeostasis and subsequent increase in Treg proportion.     

An Anti-CD103 Immunotoxin Promotes Long-Term Survival of Pancreatic Islet Allografts

Previous studies using knockout mice document a key role for the integrin CD103 in promoting organ allograft rejection and graft-versus-host disease. However, a determination of whether blockade of the CD103 pathway represents a viable therapeutic strategy for intervention in these processes has proven problematic due to the lack of reagents that efficiently deplete CD103⁺ cells from wild type hosts. To circumvent this problem, we conjugated the nondepleting anti-CD103 monoclonal antibody, M290, to the toxin, saporin, to produce an immunotoxin (M290-SAP) that efficiently depletes CD103⁺ cells in vivo . Herein, we show that M290-SAP dramatically reduces the frequency and absolute numbers of CD103-expressing leukocytes in the blood, spleen, mesenteric lymph nodes and intestinal epithelium of treated mice. We further demonstrate that M290-SAP promotes indefinite islet allograft survival in a fully MHC mismatched mouse model. The prolonged islet allograft survival resulting from M290-SAP treatment was associated with multiple effects in the host immune system including not only depletion of CD103-expressing leukocytes, but also an increase in CD4⁺CD25⁺FoxP3⁺ T regulatory cells and a predominance of effector-memory CD8 T cells. Regardless of the underlying mechanisms, these data document that depletion of CD103-expressing cells represents a viable strategy for therapeutic intervention in allograft rejection.     

预防性添加胰蛋白酶抑制剂对成年猪胰岛分离的影响

目的　开发成年猪胰岛分离方法。方法　取成年猪胰体尾部,胰管内注入0.1%冷胶原酶(type Ⅺ)消化液, 在38.5 ℃水箱中消化后,放入4 ℃Hanks液中分离并用600μm的滤过网过滤。残留的组织重新悬浮在冷Hanks液中,并放入Ricordi’s chamber内振荡5 min后再次过滤。胰岛分离分为对照组(n=14)、Pefabloc(胰蛋白酶抑制剂)组(n=8)及FOY(胰蛋白酶抑制剂)组(n=5)。Pefabloc组和FOY组消化液中分别添加1.0 mmol/LPefabloc或FOY。结果　Pefabloc组及FOY组的胰岛收获量分别为(11 848±3 530) 个/g 和(14 496±3 693)个/g,明显高于对照组的(8 505±3 349) 个/g,P<0.05。消化后的消化液胰蛋白酶活性对照组为(114.7±50.0)BAEEU,明显高于胰管内注入前的(4. 0±1. 8) BAEEU 及Pefabloc 组的(5. 5±2. 7) BAEEU(P<0. 01),但Pefabloc组与胰管内注入前却差异无统计学意义。对照组胰岛收获量≥8 000 个/g组的胰蛋白酶活性明显低于收获量<8 000 个/g组的活性〔(78.3±26.7) BAEEU vs (137.5±48.4) BAEEU〕,P<0.05。对照组、Pefabloc组及FOY组纯化后的胰岛对不同浓度葡萄糖显示了良好的胰岛素分泌能力。结论　本实验采用的胰岛分离方法能够获得大量的猪胰岛细胞,而且预防性添加胰蛋白酶抑制剂后进一步稳定地提高了胰岛收获     

Islet Transplantation for Brittle Type 1 Diabetes: The UIC Protocol

This prospective phase 1/2 trial investigated the safety and reproducibility of allogeneic islet transplantation (Tx) in type I diabetic (T1DM) patients and tested a strategy to achieve insulin-independence with lower islet mass. Ten C-peptide negative T1DM subjects with hypoglycemic unawareness received 1–3 intraportal allogeneic islet Tx and were followed for 15 months. Four subjects (Group 1) received the Edmonton immunosuppression regimen (daclizumab, sirolimus, tacrolimus). Six subjects (Group 2) received the University of Illinois protocol (etanercept, exenatide and the Edmonton regimen). All subjects became insulin- independent. Group 1 received a mean total number of islets (EIN) of 1460   080 ± 418   330 in 2 (n = 2) or 3 (n = 2) Tx, whereas Group 2 became insulin- independent after 1 Tx (537   495 ± 190   968 EIN, p = 0.028). All Group 1 subjects remained insulin free through the follow-up. Two Group 2 subjects resumed insulin: one after immunosuppression reduction during an infectious complication, the other with exenatide intolerance. HbA1c reached normal range in both groups (6.5 ± 0.6 at baseline to 5.6 ± 0.5 after 2–3 Tx in Group 1 vs. 7.8 ± 1.1 to 5.8 ± 0.3 after 1 Tx in Group 2). HYPO scores markedly decreased in both groups. Combined treatment of etanercept and exenatide improves islet graft function and facilitates achievement of insulin-independence with less islets .     

过继性回输Treg对小鼠同种胰岛移植物免疫排斥反应的影响

目的探讨过继性回输调节性T细胞(Treg)对同种胰岛移植术后胰岛功能恢复及移植物存活时间的影响。方法以C57BL/6小鼠为受体建立糖尿病模型,以Balb/c小鼠为供体进行肾包膜下同种小鼠胰岛移植。根据处理方法不同将受体小鼠分为3组:Treg实验组(Treg组,术前1 d经尾静脉注射1×10~6个Treg细胞)、阳性对照组[西罗莫司(SRL)组,术前1 d开始给予300μg/(kg·d)SRL灌胃]和空白对照组(对照组,术前1 d开始每日给予等体积生理盐水灌胃),每组3只。采用酶联免疫吸附试验(ELISA)检测小鼠术后14 d内血糖、C肽变化情况;通过活体成像技术动态监测小鼠移植物术后14 d内存活情况。结果与移植术前比较,术后3 d各组小鼠血糖水平均显著降低(均为P0.001)。术后1 d各组小鼠C肽水平均出现不同程度的爆发性回升,术后3 d各组小鼠C肽水平较术前明显升高(均为P0.001)。在术后14 d观察期结束时,与对照组比较,SRL组与Treg组C肽水平仍相对较高[(427±50)、(833±57)pmol/L];而两组的血糖水平[(14.5±0.5)、(12.1±0.6)mmol/L]均显著低于对照组(均为P0.001)。与SRL组比较,Treg组C肽爆发性释放量更低,下降趋势明显更加平缓,观察期结束时C肽水平较高(均为P0.001)。术后14 d对照组的移植物几乎完全凋亡,SRL组有50%的移植物存活,Treg组有80%的移植物存活。结论过继性回输Treg能有效保护胰岛移植物,延长移植物存活时间,维持移植小鼠血糖以及C肽的正常水平。     

雷公藤内酯醇对AngⅡ介导的肾小球系膜细胞核因子-κB活化及MCP-1表达的影响

目的：观察不同剂量雷公藤内酯醇对血管紧张素Ⅱ（AngⅡ）介导的肾小球系膜细胞（GMC）核因子-κB（NF-κB）活化及单核细胞趋化因子-1（MCP-1）表达的影响，探讨雷公藤内酯醇抑制肾小球系膜细胞炎症因子表达的可能机制。方法：分离培养大鼠GMC，用10^-6mol／L AngⅡ刺激GMC，将培养的大鼠GMC随机分为5组：正常培养对照组、AngⅡ刺激组、AngⅡ和3种不同浓度的雷公藤内酯醇共孵育组。分别采用酶联免疫激光扫描共聚焦显微镜、ELISA、RT—PCR法、Western Blot法，检测GMC内NF-κB p65核易位阳性率、细胞培养上清液中MCP-1水平、GMC内MCP-1 mRNA表达及ⅠκBα蛋白表达水平。结果：雷公藤内酯醇呈剂量依赖性下调AngⅡ介导的大鼠GMC内NF-κB p65水平，抑制AngⅡ诱导的大鼠GMC MCP-1及MCP-1 mRNA的表达，抑制AngⅡ诱导的大鼠GMC内ⅠκBα蛋白表达下调。结论：雷公藤内酯醇能够抑制AngⅡ诱导的大鼠GMC ⅠκB的磷酸化降解及NF—κB活化；抑制AngⅡ诱导的大鼠GMCMCP-1 mRNA表达MCP-1分泌。     

抑制巨噬细胞对异种胰岛移植物的作用

目的　观察普伐他汀 (pravastatin)对异种胰岛移植物存活的影响。方法　将猪→小鼠胰岛移植模型分成A组 (对照组 )、B组 (CsA组 )、C组 (普伐他汀组 )、D组 (CsA +普伐他汀组 )。观察指标 :移植物存活时间、病理检查、免疫组化染色、血清NO含量及移植物IFN γmRNA的表达。结果　A、B、C和D组移植物平均存活时间分别为 (6 .2±0 .82 )d、(9.2± 1 .92 )d、(7.2± 1 .30 )d及 (1 1 .2± 1 .76)d,D组存活时间明显长于其它 3组 (P<0 .0 5) ;D组移植物浸润细胞较其它 3组少。术后第 4天 ,血清NO水平A组为 (1 0 5 .8± 1 9.3)mmol/L ,明显高于B组的 (88.2± 2 1 .4)mmol/L(P<0 .0 5)、C组的 (70 .7± 1 7.8)mmol/L(P<0 .0 1 )及D组的 (56 .3± 1 6 .4)mmol/L(P<0 .0 1 ) ,出现移植排斥时 ,C、D组的血清NO水平分别为 (83 .7± 1 0 .6)mmol/L及 (71 .3± 1 3 .8)mmol/L ,仍较A组低 (P<0 .0 5) ,B组为 (1 0 4 .7± 1 6 .3)mmol/L ,与A组比较差异无显著性意义 (P>0 .0 5)。术后第 4天血清IFN γmRNA表达 ,D组为 2 3 .5± 4 .6 ,较A组的2 8.8± 4 .8低 (P<0 .0 5) ,而B、C组与A组间差异无显著性意义 (P>0 .0 5)。结论　普伐他汀能抑制巨噬细胞活性 ,延长异种胰岛移植物存活 ,尤其与CsA联用效果更好     

Porcine Endogenous Retroviral Nucleic Acid in Peripheral Tissues Is Associated with Migration of Porcine Cells Post Islet Transplant

Porcine islets represent an alternative source of insulin-producing tissue, however, porcine endogenous retrovirus (PERV) remains a concern. In this study, SCID mice were transplanted with nonencapsulated (non-EC), microencapsulated (EC) or macroencapsulated (in a TheraCyte trade mark device) neonatal porcine islets (NPIs), and peripheral tissues were screened for presence of viral DNA and mRNA. To understand the role of an intact immune system in PERV incidence, mice with established NPI grafts were reconstituted with splenocytes. Peripheral tissues were screened for PERV and porcine DNA using PCR. Tissues with positive DNA were analyzed for PERV mRNA using RT-PCR. No significant difference was observed between non-EC and EC transplants regarding presence of PERV or porcine-specific DNA or mRNA. In reconstituted animals, little PERV or porcine DNA, and no PERV mRNA was detected. No PERV or porcine-specific DNA was observed in animals implanted with a TheraCyte trade mark device. In conclusion, an intact immune system significantly lowered the presence of PERV. Microencapsulation of islets did not alter PERV presence, however, macroencapsulation in the TheraCyte device did. Lower PERV incidence coincided with lower porcine DNA in peripheral tissues, linking the presence of PERV to migration of porcine cells.     

Human Peripheral Blood Lymphocyte-Reconstituted, Severe Combined Immunodeficient Mice as a Model for Porcine Islet Xenograft Rejection in Humans

Abstract: Previously we established human peripheral blood lymphocyte-reconstituted severe combined immunodeficiency (SCID) (hu-PBL-SCID) mice as a model for human islet allograft rejection. The function of xenografted hu-PBL was confirmed to reject human allois-lets in hu-PBL-SCID mice. In this study, we modified this model as a porcine islet xenograft to study porcine islet rejection in humans. Chimeric mice were used as the recipients of porcine islets to reveal the mechanisms of xenograft rejection in humans. SCID mice were reconstituted with 30 times 10⁶ of hu-PBL initially, and 10 times 10⁶ of antihuman CD3-primed PBL was injected intraperitoneally 2 days later as a booster. An additional booster injection provided greater possibility (86.7%, n = 15) of chimera establishment as well as a higher human immunoglobulin concentration in SCID mice than the single injection group. In an in vitro assay, sera from hu-PBL-SCID mice were found to recognize porcine islets by FACS staining. In an in vivo study, immunofluorescent analysis of a frozen section showed that human immunoglobulins adhered to the xenografted porcine islet under the kidney capsule of hu-PBL-SCID mice. Although no mouse immunoglobulins were detected on sections, mouse complement (C3) was shown to adhere to the xenografted porcine islet. Thus, hu-PBL-SCID mice provide a useful model for investigating the real-life situation of porcine islet xenograft rejection in humans.