FK506与来氟米特预防异种胰岛移植排斥反应的效果

目的　探讨FK5 0 6、来氟米特 (Lef)应用预防大鼠对小鼠异种胰岛移植排斥反应的效果。方法　将 10 0 0～ 12 0 0个大鼠胰岛移植于化学诱导的糖尿病小鼠肾被膜下 ,实验分为对照组、FK 5 0 6组、Lef组和FK5 0 6+Lef组 ,研究胰岛有功能存活情况 ,并在移植后第 5天行病理组织学观察排斥反应。结果　FK5 0 6( 2和 4mg·kg-1·d-1)、Lef( 5、10、2 0mg·kg-1·d-1)术后用药 10d ,胰岛存活时间分别为 ( 8.9± 2 .1)、( 12 .5± 0 .7)、( 10 .8± 1.9)、( 15 .8± 2 .4)、( 18.8± 2 .2 )d ,较对照组( 5 .9± 1.2 )d明显延长 (P <0 .0 1)。FK5 0 6+Lef组移植物存活时间 ( 2 1.8± 1.2 )d ,较单纯用药组效果更好 (P <0 .0 1)。病理组织学显示Lef组与FK5 0 6+Lef组细胞浸润明显减少 ,有更多的完整胰岛存留。结论　FK5 0 6与Lef对异种胰岛移植有抗排斥作用 ,且两药联合应用有协同作用。     

他克莫司与新型免疫抑制剂FK778或FK779联合应用预防大鼠心脏移植排斥反应

目的 评价他克莫司（FK506）与FK778或FK779联合应用预防大鼠心脏移植排斥反应的效果。方法 大鼠异位心脏移植后单独应用FK506、FK778和FK779进行免疫抑制治疗，并设联合用药组。结果 单独用药组与不用药对照组相比，移植心脏存活时间明显延长，FK779组尤其显著；联合用药组移植心脏存活时间不但比对照组明显延长，而且明显长于各药同剂量单用组，FK506与FK779合用组尤其显著。结论 FK506、FK778和FK779均有很强的免疫抑制效应，FK506与FK778或FK779联合应用具有较强的协同效应。     

T细胞疫苗联合FK506抑制异种神经移植排斥的实验研究

目的 研究T细胞疫苗接种联合应用FK506对大鼠异种神经移植排斥反应的抑制作用. 方法 利用BABL/c小鼠的脾细胞免疫SD大鼠,取后者脾细胞活化所制备的T细胞疫苗对异种神经移植受体的SD大鼠进行免疫,移植后联合应用FK506.以异种神经移植后混合淋巴细胞培养、微量细胞毒测定、移植神经的组织学观察和胫前肌湿重测定等,对该方法抗大鼠异种神经移植排斥反应的作用加以分析. 结果 和对照组相比较,T细胞疫苗接种联合FK506使神经移植大鼠胫前肌湿重明显增加(P＜0.05),淋巴细胞转化率等排斥反应指标差异也具有统计学意义(P＜0.05). 结论 T细胞疫苗接种联合应用FK506能显著抑制大鼠异种神经移植的免疫排斥反应.     

他克莫司与新型免疫抑制剂FK778联合应用预防肾移植急性排斥反应的实验

目的：评价FK778与他克莫司(FK506)联合应用预防猴同种异体肾移植急性排斥反应的效果。方法：Vervet猴同种异体肾移植后联合应用FKS06和FK778预防急性排斥反应，给药60d，同时进行T、B淋巴细胞增殖抑制实验。结果：术后同一时间开始使用FK506和FK778者，其移植肾存活时间与单独用药组比较，差异无显著性；若FK778较FK506延迟1周给予，则移植肾的存活时间明显延长；FK778与FK506联合应用，在体外对B淋巴细胞增殖的抑制作用具有协同效应，而在抑制T淋巴细胞增殖时存在拮抗倾向。结论：FKS06、FK778均有很强的免疫抑制效应，联合应用时以FK778延迟1周应用效果较佳。     

骨化三醇在抑制大鼠同种肢体移植排斥反应中的作用

目的 探讨应用骨化三醇(1,25-二羟维生素D;简称:VD5)在抑制肢体移植排斥反应中的作用.方法 以Wistar大鼠为供者,SD大鼠为受者,建立同种肢体移植模型.随机将受者分为4组,每组12只.(1)对照组:术后不用免疫抑制剂,仅以15 ml·kg-1·d-1.生理盐水灌服.(2)他克莫司(FK506)组:将FK506用生理盐水稀释为0.5 mg/ml,术后前2周的用量为1.0 mg·kg-1·d-1,术后第3周起,每周灌服2次.(3)VD3组:将骨化三醇用生理盐水稀释为0.125 μg/ml,术后用量为2.5μg·kg-1·d-1,连续灌服4周.(4)VD3+FK506组:术后联合应用骨化三醇及FK506,用药方法和用量与FK506组和VD3组相同.术后观察各组受者移植肢体排斥反应发生的时间和存活时间;流式细胞仪检测T淋巴细胞亚群CD4+、CD8+细胞的百分率.结果 对照组、FK506组、VD3组以及VD3+FK506组肢体移植后排斥反应发生的时间分别为:(3.50±0.50)d、(13.13±1.50)d、(10.63±0.38)d和(29.25±0.63)d;移植肢体的存活时间分别为:(8.50±0.50)d、(26.25±1.50)d、(17.25±0.38)d和(62.00±0.63)d;与对照组比较,VD3组排斥反应发生的时间和移植肢体的存活时间均明显延长,差异有统计学意义(P＜0.01);VD3+FK506组抗排斥反应效果更佳,与FK506组和VD3组比较,差异有统计学意义(P＜0.01).VD3组T淋巴细胞亚群CD4+/CD8+细胞的比值明显低于对照组,VD3+FK506组又明显低于VD3组和FK506组(P＜0.01).结论 骨化三醇能明显减轻同种肢体移植排斥反应,延长移植肢体的存活时间;骨化三醇与FK506联合应用效果更佳,二者具有协同作用.     

大鼠同种异体肢体移植中T淋巴细胞亚群的变化及其意义

目的 建立大鼠同种异体肢体移植模型，研究肢体移植中T细胞亚群的变化及其与急性排斥反应的关系。方法 将31只SD雄性大鼠随机分成两组，其中对照组14只为Wista→SD肢体移植术后不用药组，实验组17只为FK506(4mg／kg体重) RS-61443(30mg／kg体重)联合免疫抑制治疗组，观察各组移植术后排斥反应；用免疫荧光染色流式细胞仪检测各组手术前后T细胞亚群。结果 术后第3天，CD4／CDs比值显著增高，移植肢体开始出现肿胀、皮肤红斑等表现；CD4／CD8比值增高与排斥反应程度呈正相关，而用药组术后，CD4／CD8较术前无明显变化，未出现排斥反应。结论 T细胞亚群中CD4／CD8比值的变化与肢体移植急性排斥反应的发生、强烈程度有密切关系，可作为监测异体肢体移植急性排斥反应的免疫学指标。     

他克莫司联合青藤碱抑制大鼠心脏移植急性排斥反应

目的 探讨青藤碱（SIN）对大鼠心脏移植急性排斥反应抑制作用的机制，并评价青藤碱与他克莫司（FK506）联合作用的效果。方法 以PVG大鼠为供者，DA大鼠为受者，建立同种异体心脏移植模型。将受者随机分为4组，每组20只。对照组：采用生理盐水3ml·kg^-1·d^-1灌胃；SIN组：腹腔注射SIN 30mg·kg^-1·d^-1；FK506组：采用FK506 0．25mg·kg^-1·d^-1灌胃；联合组：腹腔注射SIN 30mg·kg^-1·d^-1并联合应用FK506 0．25mg·kg^-1·d^-1灌胃。各组均在术后24h内用药，用药时间共7d。观察各组移植心存活时间，术后第7d取部分受者的移植心做病理检查，检测外周血中肿瘤坏死因子-α（TNF-α）、干扰素-γ（IFN-γ）、T细胞亚群、一氧化氮合酶（iNOS）等的浓度。结果 对照组移植心平均存活时间为（6．0±1．054）d，FK506组为（10．2±2．2）d，SIN组为（9．5±1．84）d，联合组为（16．2±2．1）d，联合组与其他3组比较，差异有统计学意义（P〈0．05）。SIN组、FK506组及联合组与对照组比较，外周血中TNF-α、IFN-γ、iNOS的表达明显减少（P〈0．05），CD4^＋T细胞亚群增殖率也明显下降（P〈0．05）。其中联合组的效果更优于SIN组和FK506组（P〈0．05）。结论 SIN能明显地抑制大鼠心脏移植急性排斥反应的发生，与FK506联合应用有协同作用。     

普乐可复在异种小肠移植中的作用

目的探讨免疫抑制剂普乐可复(FK506)对于异种小肠移植后迟发异种移植物排斥反应和细胞介导的异种移植物排斥反应的作用。方法采用仓鼠-大鼠动物实验模型,分为对照组和治疗组。治疗1组为单纯用FK506组;治疗2组为FK506加脾切除组。观察移植肠管吸收功能、体重、生存时间、FK506血药浓度及移植肠管苏木精-伊红染色。结果治疗1、2组的生存时间分别为(29.5±2.4)d和(106.6±26.3)d,与对照组(4.3±0.5)d相比显著延长(P<0.01);且治疗1、2组之间相比,差异亦有非常显著性意义(P=0.006)。术后第4d对照组苏木精-伊红染色可见绒毛萎缩,有大量炎性细胞浸润。治疗组小肠黏膜显示高分泌状态。术后126d治疗2组小肠肌层明显增厚、绒毛萎缩、肠壁小动脉壁纤维化。结论FK506可抑制异种小肠移植后迟发异种移植物排斥反应和细胞介导的异种移植物排斥反应;加脾切除可明显延长异种小肠移植的存活时间;但不能逆转异种小肠移植后所发生的慢性排斥反应。     

他克莫司和来氟米特合用抑制大鼠心脏移植排斥反应及T淋巴细胞增殖

目的　评价他克莫司 (FK5 0 6 )和来氟米特联合应用对大鼠心脏移植排斥反应的抑制作用。方法　将实验动物随机分为对照组、FK5 0 6组、来氟米特组以及FK5 0 6与来氟米特合用组 ,观察移植心存活时间 ,于术后 7d切取部分移植心做病理检查 ,并测定各组受者外周血T淋巴细胞亚群及肝、肾功能。结果　不用免疫抑制剂的对照组移植心存活时间为 ( 7.14± 1.0 7)d ,单用FK5 0 6的组为( 11.14± 1.73)d ,单用来氟米特的组为 ( 11.2 9± 1.80 )d ,两药合用组为 ( 14 .0 0± 2 .4 9)d ,合用组的病理切片提示排斥反应明显轻于两药单用组。术后 7d ,合用组外周血T淋巴细胞亚群中 ,CD4 +细胞明显低于两药单用组 (P <0 .0 5 ) ,而CD8+细胞各组间的差异无显著性 ;各组间肝、肾功能的差异也无显著性。结论　FK5 0 6和来氟米特联合应用对大鼠心脏移植的免疫抑制作用优于相同剂量的单一用药     

大鼠小肠移植早期应用趋化因子受体拮抗剂抑制移植物急性排斥反应

目的探讨趋化因子受体拮抗剂(MetRANTES)在小肠移植早期应用对排斥反应的免疫抑制作用及其与他克莫司的协同效应。方法SD大鼠为供者,Wistar大鼠为受者,建立异基因节段性异位小肠移植模型。移植后将大鼠分为4组,每组24只。第1组为对照组,移植前后不作任何处理;第2组为MetRANTES组,小肠移植后(0～7d)腹腔注射MetRANTES200μg/d;第3组为小剂量他克莫司(FK506)组,小肠移植后(0～7d)腹腔注射FK5060.5mg·kg-1·d-1;第4组为MetRANTES联合FK506组,2种药物的应用方法与第2、3组相同。观察移植大鼠的一般状况和存活时间以及免疫细胞浸润情况,并于移植术后3、5、7d分别取各组大鼠移植肠标本(n=6)进行组织病理学检查,采用免疫荧光染色和激光扫描共聚焦显微镜技术对移植肠RANTES和CD4 、CD8 、CD25 T淋巴细胞的表达进行连续定量测定。结果第1～4组大鼠平均存活时间分别为(7.37±1.19)d、(22.32±8.60)d、(23.64±6.58)d和(30.55±4.18)d,第2、3、4组大鼠与第1组相比,存活时间明显延长(P<0.01);第4组大鼠存活时间更长,与第2、3组比较,差异均有统计学意义(P<0.01)。第1组全部死于急性排斥反应及感染,组织病理学检查显示移植后第3、5、7d分别符合轻、中、重度排斥反应。第2、3、4组病理学检查无明显排斥反应征象。第1组大鼠的移植肠RANTES表达在术后各时段均显著高于其他3组(P<0.01),其动态变化与急性排斥反应的进程呈正相关;第2组和第4组大鼠移植肠RANTES、CD4 、CD8 和CD25 T细胞的表达均明显低于第1组(P<0.01)。结论MetRANTES能明显抑制小肠移植急性排斥反应,有效保护移植肠功能,显著延长移植物的存活时间,并可增强小剂量他克莫司的免疫抑制作用。     

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。     

Ex vivo and systemic transfer of adenovirus-mediated CTLA4Ig gene combined with a short course of FK506 therapy prolongs islet graft survival

Adenovirus-mediated CTLA4Ig gene transfer has been reported to enhance graft survival in several rodent transplantation models. In this study, we investigated the efficacy of ex vivo and systemic transfer of the CTLA4Ig gene by adenoviral vectors in pancreatic islet allo-transplantation. Islet grafts from BN rats were transplanted to chemically induced diabetic LEW rats. First, ex vivo CTLA4Ig gene transfer into isolated islets was performed prior to transplantation. Survival of transduced grafts under the kidney capsule was slightly prolonged (8.6+/-1.3 days) compared with survival of untransduced grafts (6.7+/-1.2 days); when combined with a short course of FK506, graft survival was further extended (32.6+/-10.7 days vs. 13.7+/-1.0 days with FK506 alone). Secondly, systemic gene transfer was accomplished by intravenous administration immediately after the transplantation procedure. In these animals, islet grafts under the kidney capsule survived longer (15.2+/-3.3 days) than in controls (6.7+/-1.2 days), and when FK506 was administered perioperatively, all the islet grafts survived for more than 100 days. In systemically transduced recipients, the survival of islet grafts transplanted into the liver was not significantly different from that of the grafts placed under the kidney capsule. In order to examine organ-specific immunogenicity, heterotopic BN cardiac grafts were transplanted to LEW rats intra-abdominally, with the virus transferred systemically as in the islet model. In contrast to the islet grafts, all the cardiac grafts were accepted for longer than 100 days, even without FK506 therapy. Finally, the LEW recipients with long-surviving islet or cardiac grafts were re-transplanted with islet grafts from the same donor strain (BN) on day 100. The second islet grafts survived longer than 100 days in half of the cardiac recipients, but consistently failed in the islet recipients. We conclude that in this transplant model, CTLA4Ig gene transfer and FK506 treatment synergistically improved islet graft survival, systemic transfer of the gene was more effective than ex vivo transfer to the islets, and donor-specific tolerance could not be achieved for islet transplantation but was achieved for cardiac transplantation.     

Acceptance of islet allografts in the liver of mice by blockade of an inducible costimulator

BACKGROUND: An inducible costimulator (ICOS) has been found to be a novel costimulator for T-cell activation, although its precise role in transplant immunobiology remains unclear. This study determined whether ICOS plays an essential role in rejection of intrahepatic islet allografts in streptozotocin-induced diabetic mice. METHODS: Mononuclear cells in the liver of mice were isolated and examined by flow cytometry with respect to expression of ICOS in association with rejection, and the effects of in vivo treatment with an anti-ICOS antibody on survival of intrahepatic islet allografts were determined.RESULTSFlow cytometric analysis of mononuclear cells in the liver of normal untreated mice revealed that ICOS is expressed on CD4+CD3int natural killer T cells. The expression of ICOS was up-regulated on CD4+CD3bright T cells and expanded CD8 T cells in the liver in association with rejection. Posttransplant short-term administration of anti-ICOS antibody alone produced a significant prolongation of islet allograft survival. Administration of the antibody in conjunction with a subtherapeutic regimen of FK506 prevented rejection, leading to the acceptance of islet allografts. CONCLUSION: ICOS has an essential role in rejection of intrahepatic islet allografts and the blockade of ICOS interaction might be a novel approach for preventing islet allograft rejection.     

Role of CD4+ and CD8+ T cells in early and late acute rejection of small bowel allograft

BACKGROUND/PURPOSE: Results of small bowel transplantation remain unsatisfactory because of severe immune rejection. The current study aims to elucidate the role of activation of CD4+ and CD8+ T cells in early and late acute rejection of small bowel allograft and, hence, provide the immunologic basis for developing new therapeutic strategies. METHODS: We used an MHC fully mismatched (DA to Lewis) heterotopic rat small bowel transplant model and a unique FK506-based immunosuppressive regimen, which suppresses early acute rejection but does not prevent late acute rejection. Flow cytometric analysis was used to quantitate the number of activated CD4+ and CD8+ T cells in graft and host mesenteric lymph nodes. RESULTS: The survival (mean +/- SD) of intestinal allograft was significantly prolonged, from 6.6 +/- 0.84 days for the untreated group to 40.7 +/- 14.1 days for the FK506-treated group. Activation of CD4+ cells was suppressed significantly in the FK506-treated group on postoperative day 7 compared with the untreated group (29.4% +/- 3.55% v 52.83% +/- 11.9%; P <.01). Activation of CD8+ cells was similarly suppressed (31.5 +/- 10.34% v 48.53 +/- 14.34%; P <.05). Interestingly, at late acute rejection, activated CD4+ and CD8+ T cells remained at almost the same low levels as those on postoperative day 7 in the FK506-treated group. The spleen to body weight ratio was significantly increased in the untreated group (0.53 +/- 0.07), and slightly increased in the FK treated group (0.27 +/- 0.07, on postoperative day 7; 0.24 +/- 0.07 at late acute rejection) compared with the syngeneic group (0.18 +/- 0.02). CONCLUSION: The activation of CD4+ and CD8+ T cells was suppressed effectively by early potent immunosuppressive treatment resulting in prolonged survival of intestinal allograft. At late acute rejection, the CD4+ and CD8+ T cells remained at low-level activation status, in contrast to the surge of CD4+ and CD8+ activation during early acute rejection. This suggests that persistent T cell activation even at low level is sufficient to cause the late acute rejection eventually. A therapeutic strategy targeting these cells is needed for long-term engraftment.     

Optimization of immunosuppressive therapy for spinal grafting of human spinal stem cells in a rat model of ALS

Previous rodent studies employing monotherapy or combined immunosuppressive regimens have demonstrated a variable degree of spinal xenograft survival in several spinal neurodegenerative models including spinal ischemia, trauma, or amyotrophic lateral sclerosis (ALS). Accordingly, the characterization of optimal immunosuppressive protocols for the specific neurodegenerative model is critical to ensure reliable assessment of potential long-term therapeutic effects associated with cell replacement. In the present study we characterized the survival of human spinal stem cells when grafted into the lumbar spinal cords of a rodent model of ALS, SOD1 (G93A) male and female rats (60-67 days old). Four different immunosuppressive protocols were studied: i) FK506 (q12h); ii) FK506 (qd) + mycophenolate (PO; q12h, up to 7 days postop); iii) FK506 (qd) + mycophenolate (IP; q12h, up to 7 days postop); and iv) FK506 (qd) + mycophenolate (IP; qd, up to 7 days postop). Three weeks after cell grafting the number of surviving human cells was then systematically assessed. The highest density of grafted cells was seen in animals treated with FK506 (qd) and mycophenolate (IP; qd; an average 915 ± 95 grafted cells per spinal cord section). The majority of hNUMA-positive cells colocalized with doublecortin (DCX) immunoreactivity. DCX-positive neurons showed extensive axodendritic sprouting toward surrounding host neurons. In addition, migrating grafted cells were identified up to 500 μm from the graft. In animals treated with FK506 (q12h), FK506 (qd) + mycophenolate (PO; q12h) or FK506 (qd) + mycophenolate (IP; q12h), 11.8 ± 3.4%, 61.2 ± 7.8%, and 99.4 ± 8.9% [expressed as percent of the FK506 (qd) and mycophenolate (IP; qd)] cell survival was seen, respectively. In contrast to animals treated with a combination of FK506 + mycophenolate, robust CD4/8 immunoreactivity was identified in the vicinity of the injection tract in animals treated with FK506 only. These data suggest that a combined, systemically delivered immunosuppression regimen including FK506 and mycophenolate can significantly improve survival of human spinal stem cells after intraspinal transplantation in SOD1 (G93A) rats.     

Development of donor-specific immunoregulatory T-cells after local CTLA4Ig gene transfer to pancreatic allograft

BACKGROUND: CTLA4Ig gene transfer directly to graft tissue might have the potential to avoid the need for systemic immunosuppression. In our previous studies of bio-breeding (BB) rats, local adenovirus-mediated CTLA4Ig gene transfer protected the pancreas from autoimmune and alloimmune responses. This study investigated the potency of local CD28/B7 costimulatory blockade for induction of donor-specific tolerance and further examined the existing mechanisms. METHODS: Brown Norway (BN; RT1)-pancreaticoduodenal grafts transfected with Ad.CTLA4Ig via intraarterial ex vivo perfusion were transplanted into streptozotocin-induced diabetic Lewis (LEW; RT1) rats. RESULTS: Ad.CTLA4Ig transduced grafts combined with a short course of FK506 resulted in indefinitely prolonged survival (>156 days vs. 19.5 days with FK506 alone). CTLA4Ig was predominantly expressed in grafts on day 4. The expression was gradually diminished and was only slightly detectable at day >100. The proliferative responses against BN antigen were remarkably enhanced among recipients with rejected grafts, but the T-cells from tolerant recipients (>100 days) showed poor cytotoxic responses. On adoptive transfer assay, the splenic T-cells of tolerant recipients were able to suppress the rejection of BN, but not third-party Wistar Furth (WF; RT1) hearts in irradiated (480 cGy) LEW recipients. The percentage of CD4CD25 splenic T-cells was significantly increased in tolerant recipients (13.53 +/- 4.06% vs. 6.06 +/- 0.56% in naive rats). CONCLUSION: CTLA4Ig gene transfer to the pancreaticoduodenal allograft combined with a short course of FK506 induces donor-specific tolerance. The mechanism of maintaining tolerance could be explained by development of splenic T suppressor cells.     

A critical role for human CD4+ T-cells in rejection of porcine islet cell xenografts

T-cell-mediated rejection is likely to present a significant barrier to porcine islet xenotransplantation. Little is known, however, about human anti-porcine islet rejection because no suitable model exists to study this process. To address this problem, we have developed an immunodeficient mouse model to study rejection of fetal porcine islet cell clusters (ICCs) by human lymphocytes. Transplantation of porcine ICCs into hyperglycemic recombinase activating gene-deficient (R-) mice restores normal blood glucose levels within 5 weeks. Adoptive transfer of in vitro-stimulated human peripheral blood mononuclear cells into R- mice before islet cell transplantation leads to acute cellular rejection of porcine ICCs. The first human cells observed to infiltrate rejecting grafts are CD4+ T-cells. Although CD8+ T-cells are observed within the grafts at later time points, CD4+ T-cells predominate until the graft is destroyed. Adoptive transfer of purified human CD4+ T-cells before ICC transplantation is sufficient to cause acute cellular rejection. These data demonstrate that human CD4+ T-cells play a critical role in porcine ICC xenograft rejection.     

Pig islet xenografts are resistant to autoimmune destruction by non-obese diabetic recipients after anti-CD4 treatment

Abstract: In addition to providing a large source of donor tissue, xenogeneic islet transplantation might avoid recurrent autoimmunity in patients with type 1 diabetes. To examine this possibility further, xenogeneic pig islets were transplanted into recipient mice in the presence or absence of autoimmunity. Spontaneously, non-obese diabetic (NOD) recipients rejected isografts rapidly whether or not the recipients were depleted of CD4+ T-cells. Young NOD mice made diabetic with streptozotocin accepted islet isografts without immunosuppression, indicating that destructive autoimmunity did not develop in these recipients. Pig xenografts were rejected equally quickly in the two types of NOD recipients in the absence of immunosuppression and survived for up to 9 weeks in both types of NOD recipients after CD4 depletion. BALB/c mice often accepted pig xenografts indefinitely after anti-CD4 antibody treatment. These results suggest that pig islets are resistant to recurrent autoimmunity when CD4+ T-cells are depleted. The difficulty in obtaining indefinite islet xenograft survival in NOD recipients occurs independently from the development of destructive autoimmunity.     

联合药物预处理对非协调性异种心脏移植物的影响

目的　观察联合应用环孢素A(CsA)和来氟米特 (Lef)预处理对豚鼠 大鼠非协调性异种心脏移植物的影响并探讨其作用机制。方法　移植大鼠分为 4组 :A组 (CVF ,n =10 ) ;B组(CVF CsA ,n =8) ;C组 (CVF Lef,n =5 ) ;D组 (CVF CsA Lef ,n =11) ;记录移植物存活时间 ,检测移植物病理组织学 ,用免疫组织化学检测移植物CD68、CD5 7表达情况 ,TUNEL法检测移植物细胞凋亡。结果　移植物的平均存活时间 :A组为 41h、B组为 68h、C组为 5 5h、D组为 82h。各组移植物病理表现均为急性血管性排斥反应 (AVR)改变。B、C、D组移植物炎症细胞浸润数减少 ,CD68和CD5 7表达下调 ,凋亡指数较低 ,半定量测定与A组比较差异有显著性 (P <0 .0 5 ) ;D组凋亡指数最低而CD68和CD5 7表达最弱 ,与其他各组比较差异有显著性 (P <0 .0 5 )。结论　联合应用CsA和Lef预处理可明显延长非协调性异种移植物存活时间 ,减少炎症细胞浸润 ,抑制心肌细胞凋亡 ,减轻异种AVR损害。