异体脐带间充质干细胞对大鼠心脏移植的免疫调节**☆

背景：有资料表明骨髓间充质干细胞可延长小鼠和狒狒异体皮肤移植存活时间,降低造血干细胞移植后急性和慢性移植物抗宿主病的发生,但目前尚未见关于大鼠脐带间充质干细胞用于心脏移植减少排斥反应的报道。 目的：观察异体脐带间充质干细胞对大鼠心脏移植的免疫调节作用。 方法：DA大鼠20只作为供体,Lewis大鼠20只作为受体,均随机分为2组,即药物干预组、对照组,每组供受体大鼠各10只。采用双套管法将供体大鼠的左肺动脉和无名动脉分别与受体大鼠心脏的颈外静脉和颈总动脉在显微镜下行端端吻合,建立异位心脏移植模型。Wistar孕鼠1只,采用胶原酶消化法分离培养脐带间充质干细胞。造模后,细胞移植组经尾静脉注射脐带间充质干细胞,对照组同法注射氯化钠注射液。检测移植心脏的存活时间,采用心脏移植急性排斥反应诊断标准对移植心脏进行组织病理学评分,苏木精-伊红染色观察移植心脏淋巴细胞浸润程度。 结果与结论：与对照组比较,细胞移植组移植心脏存活时间显著延长(P=0.001),急性排斥反应病理学评分显著降低(P=0.000 4)。对照组心肌组织内有大量淋巴细胞和单核细胞浸润,细胞移植组心肌组织内有少量淋巴细胞浸润,心肌间质轻度水肿。结果证实大鼠脐带间充质干细胞可诱导心脏移植免疫耐受,减轻免疫排斥反应,延长心脏存活时间。     

胸腺内注射异基因抗原诱导鼠异体骨移植的免疫耐受

背景：同种异体骨同其他异体组织一样具有抗原性,移植后可引起以细胞免疫为主的排斥反应,应用免疫抑制剂可抑制免疫排斥反应的发生,但对机体有一定的不良影响。 目的：探讨胸腺内注射异基因抗原在建立特异性骨移植免疫耐受中的作用。 方法：取60只Wistar大鼠随机分为3组,均制作骨缺损模型,供体异基因胸腺内注射组于同种异体骨移植前胸腺内注射受体大鼠脾细胞MHC抗原,同时另设自体骨移植组、同种异体骨移植加用免疫抑制剂组为对照,移植后观察切口情况。移植后1,2,4,6周进行X射线检查,苏木精-伊红染色,可溶性白细胞介素2受体、混合淋巴细胞培养免疫学检测。 结果与结论：大体表现、X射线及组织学检查见供体异基因胸腺内注射组、自体骨移植组表现相近,均有炎性细胞浸润及新骨形成。同种异体骨移植加用免疫抑制剂组再生血管较少,骨愈合延迟,炎性细胞浸润明显,移植骨逐渐吸收,无新骨形成。证实了异基因MHC抗原注入小鼠胸腺内,能成功诱导受体对供体鼠骨移植物的耐受。免疫学检查各项数据表明供体异基因胸腺内注射的成骨效果接近于自体骨移植组,优于同种异体骨移植加用免疫抑制剂,证实了胸腺内注射异体MHC抗原可诱导对供体骨移植物的免疫耐受。     

同种异体肢体移植特异性免疫耐受诱导方案

背景：通过诱导受体产生免疫耐受能够解决移植领域存在的许多问题,如长期应用免疫抑制剂带来的毒副作用,慢性排斥反应等。 目的：观察联合应用亚致死量放射线照射、氟达拉滨及骨髓腔内骨髓移植对诱导大鼠同种异体肢体移植产生特异性免疫耐受的影响。 设计、时间及地点：随机同期对照动物实验,于2004-01/2008-12在哈尔滨医科大学完成。 材料：40只雄性Wistar大鼠随机分成4组：单纯移植组、氟达拉滨组、骨髓移植组、氟达拉滨＋骨髓移植组,每组各10只。40只SD大鼠为骨髓移植供体。供体DA大鼠用于皮肤移植实验。 方法：制作同种异体右后肢移植模型,单纯移植组仅进行肢体移植;氟达拉滨组在肢体移植前1 d,受体给予亚致死量60Co照射及腹腔内注射氟达拉滨50 mg/kg;骨髓移植组肢体移植当天受体接受供体骨髓腔内骨髓移植1×1012 L-1,10 μL;氟达拉滨+骨髓移植组受体联合应用亚致死量照射、注射氟达拉滨及骨髓腔内骨髓移植。 主要观察指标：观察移植物排斥反应征象及存活情况,并对氟达拉滨+骨髓移植组产生免疫耐受大鼠进行SD大鼠及DA大鼠皮肤移植及脾细胞中细胞因子mRNA检测。 结果：与其他实验组比较,氟达拉滨＋骨髓移植组移植物发生排斥反应的时间及存活时间均显著延长(P < 0.01)。氟达拉滨+骨髓移植组大鼠仅对第3方DA大鼠的皮肤呈现强烈的免疫反应,移植皮肤初为水疱、渗出,逐渐溃疡、糜烂、焦痂、变黑坏死。 与单纯移植组比较,氟达拉滨+骨髓移植组大鼠Th1型细胞因子的表达明显降低,而Th2型细胞因子的表达明显增高。 结论：氟达拉滨与骨髓移植联合方案可以诱导大鼠同种异体肢体移植产生特异性免疫耐受。     

大鼠双侧供肾左侧原位肾移植模型的建立及肾功能监测

背景：大鼠肾移植模型是移植免疫耐受、免疫抑制及器官库开发的重要实验手段。 目的：建立实验动物使用效率高,重复性好的耐受、急性排斥、慢性排斥肾移植模型,及移植肾功能动态无创检测方法。 方法：封闭群Wistar大鼠用于解剖及预实验。采用改良左侧原位肾移植术,分次顺序使用供体左肾与右肾,动静脉及输尿管端端吻合,7 d后行右侧肾切除。DA、Lewis大鼠分别为供受体作为急性排斥组。F344、Lewis大鼠分别为供受体作为慢性排斥组。Lewis大鼠自体肾移植组作为移植耐受组。观测大鼠双侧肾脏应用解剖,供肾热缺血时间、冷缺血时间,肾移植手术成功率。检测分析肾移植模型生存曲线、蛋白尿水平动态变化。 结果与结论：解剖观测大鼠43例,灌注肾29例,行单侧原位肾移植21例。移植肾热缺血时间小于10 s,冷缺血时间(47.2± 3.7) min,成功率85.7%(18/21)。其中自体肾移植3例,急性排斥肾移植3例,慢性排斥肾移植12例。改良的单侧原位肾移植术简捷经济,分次顺序使用供体左肾与右肾,不干扰受体腹主动脉及下腔静脉血流,重复性好。结果提示,建立的近交系大鼠移植耐受、急性排斥、慢性排斥肾移植模型生存曲线、蛋白尿动态检测具有显著性差异。     

胸腺内注射脾细胞诱导神经移植的免疫耐受反应

背景：心脏等移植时常采用胸腺内注射脾细胞抑制或减弱移植排斥反应，而在神经移植中很少有报道。 目的：应用大鼠胸腺内注射脾细胞的方法，诱导大鼠同种异体坐骨神经产生特异性免疫耐受。 设计、时间及地点：随机对照动物实验，于2007-06/2008-06在哈尔滨医科大学动物实验中心完成。 材料：选用清洁级雄性SD大鼠30只为受体，随机分为自体神经移植组，异体神经移植组，异基因抗原注射组，每组10只。雄性Wistar大鼠20只为供体。 方法：异体神经移植组大鼠在显微镜下，从犁状肌下孔0.5 cm处整齐剪下长约1 cm的坐骨神经，将供体神经桥接于神经缺损处。自体神经移植组神经缺损处进行自体神经移植。异基因抗原注射组在异体神经移植后注入供体异基因抗原。 主要观察指标：移植后2周进行运动神经传导速度、病理学、混合淋巴细胞培养和血清白细胞介素检查。 结果：运动神经传导速度异基因抗原注射组与自体神经移植组无显著差别(P > 0.05)，但明显优于异体神经移植组（P < 0.05）。病理学及透射电镜观察，与运动神经传导速度检测结果一致。混合淋巴细胞培养和白细胞介素水平异基因抗原注射组明显优于异体神经移植组（P < 0.05）。 结论：胸腺内注射异基因抗原可以诱导大鼠对异体坐骨神经移植的免疫耐受。     

重组人白细胞介素10抗家兔同种异体皮肤移植排斥模型的建立

背景：研究表明,白细胞介素10在移植排斥反应的预防和治疗中具有一定的应用前景,有望成为一种新的临床用免疫抑制剂。动物移植模型是研究免疫抑制剂常用的实验平台,最常用的皮肤移植模型动物是小鼠,但小鼠属于小动物模型,移植技术要求较高。 目的：建立家兔同种异体皮肤移植模型,观察重组人白细胞介素10抗家兔皮肤移植排斥反应的效果。 方法：取家兔背部皮肤修剪成含真皮层的全厚皮片、中厚皮片和不含真皮层的薄层皮片进行家兔自体皮肤移植,随机分为固定组和非固定组,固定组用自制脖套对家兔头颈部活动进行一定限制;药物抗家兔同种异体移植排斥设重组人白细胞介素10组、环孢素A阳性对照组和生理盐水阴性对照组。采用混合淋巴细胞反应法观察家兔混合淋巴细胞反应增殖指数。在30 d内连续观察移植皮肤出现排斥的时间和移植皮片平均存活时间。 结果与结论：供、受体混合淋巴细胞培养呈增殖反应,表明家兔同种异体主要组织相容性复合体不同,相互皮肤移植可发生排斥反应。移植皮片厚度以含真皮的中厚皮片为最佳;自制脖套固定可有效限制家兔脖头颈部活动,有利于移植创面的保护。实验成功建立了重组人白细胞介素10抗家兔同种异体皮肤移植排斥模型,重组人白细胞介素10具有抗移植排斥的作用。 关键词：皮肤移植;人白细胞介素10;免疫抑制剂;固定;移植排斥     

低温保存同种异体带瓣主动脉移植的免疫反应

背景：前期研究证实,液氮低温保存同种异体主动脉能保持其细胞的生物活性和组织结构的完整性,但有关同种异体带瓣主动脉移植的排斥反应研究较少。 目的：观察同种异体带瓣主动脉移植后移植物的免疫指标变化特点。 方法：将低温保存的SD大鼠带瓣主动脉异位植入Wistar大鼠腹主动脉,分组干预：同种异体移植组不进行干预;免疫干预组移植后给予环孢素A;对照组为假移植,将腹主动脉切断后直接吻合。移植后1,2,3,4,5周收集移植动物血清标本,免疫组织化学染色测量MHCⅡ阳性表达,淋巴细胞涂片免疫组织化学测定CD4+、CD8+百分率;应用酶联法测定血清中白细胞介素2,肿瘤坏死因子α水平。 结果与结论：同种异体主动脉移植后1~4周可见MHC显著阳性,CD4+、CD4+/CD8+比值明显增高,血清中白细胞介素2和肿瘤坏死因子α水平明显增高,并在移植后5周内维持较高水平,与对照组比较差异有显著性意义(P < 0.05)。环孢素A对同种异体主动脉移植物内膜增厚、淋巴细胞浸润、MHCⅡ表达、T淋巴细胞激活、白细胞介素2和肿瘤坏死因子α水平的增高具有明显抑制作用(P < 0.05)。说明低温保存同种异体主动脉移植后有明确的免疫排斥反应发生,环孢素A对同种异体移植后的免疫排斥反应有明显抑制作用。     

抗白细胞介素2受体单克隆抗体联合免疫吸附预处理致敏肾移植受者24例

近年来随着器官移植的快速发展尤其是肾移植围手术期管理的成熟，群体反应性抗体阳性的致敏肾移植受者较前增加很多，肾移植后易发生急性排斥反应造成移植肾功能延迟恢复，甚至移植失败。文章对24例致敏肾移植受者进行抗白细胞介素2受体α单克隆抗体联合免疫吸附预处理后，观察其发生急性排斥反应情况，并与正常肾移植受者进行比较。结果显示两组肾移植受者发生急性排斥反应相似，无统计学差异。结果表明应用抗白细胞介素2受体α单克隆抗体及免疫吸附对致敏肾移植受者预处理后群体反应性抗体水平降至正常后，可以安全地实施同种异体肾移植。     

供体凋亡淋巴细胞预输注对猪肝移植受体CD4+T、CD8+T、CD4+CD25+调节性T细胞的影响

背景：凋亡细胞能够主动调节机体的免疫功能,并能通过调节机体细胞免疫和体液免疫的途径诱导免疫耐受,但这些结果只在大鼠肝脏移植模型中证实。 目的：探讨通过60Co γ射线体外处理后的供体淋巴细胞预输注诱导猪肝移植特异性免疫耐受的作用中,对淋巴细胞亚群的影响。 方法：建立非转流小型猪原位肝移植模型。将受体猪随机摸球法均分为2组：空白对照组,受体猪无特殊处理,行肝移植;淋巴细胞组：受体猪在肝移植前7 d经耳静脉注射60Co γ射线处理过的5×108个供体淋巴细胞。观察两组受体猪移植后的存活时间,移植后T淋巴细胞亚型CD4+T、CD8+T、CD4+CD25+Tr变化及病理。 结果与结论：移植后3 d,两组病理活检均呈急性中、重度排斥反应;移植后6 d,两组均呈急性重度排斥反应。移植后1,3,6 d CD4+T、CD8+T、CD4+CD25+Tr升降趋势,两组间差异无显著意义(P > 0.05)。提示,60Co γ射线体外处理过的淋巴细胞预输注未能够诱导猪同种异体肝移植特异性免疫耐受,未能引起T淋巴细胞亚群变化有关。     

转化生长因子β1质粒对静脉移植的影响

背景：大量实验表明，转化生长因子β1质粒在神经移植过程中可抑制或减弱移植排斥反应，而对静脉移植的影响却很少有报道。 目的：探讨大鼠局部注射转化生长因子β1质粒诱导同种异体异基因股静脉移植免疫耐受的作用途径。 设计、时间及地点：随机分组，动物实验观察，于2007-03/2008-04在哈尔滨医科大学动物实验中心完成。 材料：供体Wistar大鼠18只，受体SD大鼠48只随机分为自体移植组，异体移植组，免疫抑制剂组，转化生长因子β1质粒组，每组12只。 方法：免疫抑制剂组在移植前3 d开始腹腔内注射环孢霉素A(10 mg/kg)，1次/d，直到处死。转化生长因子β1质粒组大鼠于局部股静脉两断端内注射40 μg/只的转化生长因子β1质粒。自体移植和异体移植组仅进行静脉移植。 主要观察指标：于2周后进行影像学、组织学、免疫学检测。 结果：自体移植组：内皮细胞扁平，核膜增厚。异体移植组：脱落内皮细胞及碎片，可见内膜下层。免疫抑制剂组：血管内皮细胞核膜增厚，广泛粗面内质网扩张。转化生长因子β1质粒组：血管内皮细胞可见粗面内质网扩张，线粒体空泡变。相邻细胞间可见紧密连接。转化生长因子β1质粒组优于免疫抑制剂组和异体移植组。4组混合淋巴细胞培养A值分别为1.07±0.14、4.15±0.67、1.77±0.23和1.38±0.23。转化生长因子β1质粒组与异体血管移植组和免疫抑制剂组比较，有显著差异(P < 0.05)。异体血管移植组对供体大鼠淋巴细胞的刺激呈正常反应，转化生长因子β1质粒组对供体鼠淋巴细胞的刺激反应性减弱，与免疫抑制剂组比较，差异有显著性意义(P < 0.05)。 结论：局部注射转化生长因子β1质粒可以协同减轻移植后产生的免疫排斥反应。     

Immunological reactions following intracerebroventricular transplantation of adrenal medulla

Immunological reactions after intracerebroventricular syn-, allo- and xenogenic transplantation of adrenal medulla were investigated histologically. In xenografts only, T cell infiltration and graft rejection were observed. Syngrafts and allografts were not rejected and were not infiltrated by T cells, although expression of MHC class II antigen was observed at all survival times. Major histocompatibility complex (MHC) class I immunoreactivity was strongly expressed in adrenal cortex syngrafts, which could play a role in the rejection of grafts containing mixed cell populations. The survival of chromaffin cells in allografts was decreased as compared to syngrafts, and there were fewer allograft animals with large numbers of surviving chromaffin cells. There was some increased cellularity (microglia and macrophages) in allografts even though no T cell infiltration was found. Therefore, it appears that this limited survival of intracerebral adrenal medulla allografts is not due to T cell-mediated graft rejection.     

The nigrostriatal dopaminergic system in MPTP-treated mice shows more prominent recovery by syngeneic adrenal medullary graft than by allogeneic or xenogeneic graft

Following systemic injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), young (2-month-old) C57BL/6 mice show decreased dopaminergic (DA) nigrostriatal fibers and DA concentration in the striatum. We transplanted syngeneic, allogeneic and xenogeneic adrenal medullary grafts into the striatum of the MPTP-treated young mice and compared the survivability of grafted chromaffin cells and the recovery of intrinsic host DA fibers using computerized image analysis of tyrosine hydroxylase (TH)-immunoreactive (IR) fibers and high performance liquid chromatography with electrochemical detection (LCEC). The grafted syngeneic adrenal chromaffin cells survived better than allogeneic or xenogeneic chromaffin cells, and host DA nigrostriatal fiber recovery was more prominent in mice with a syngeneic graft than in mice with an allogeneic or xenogeneic graft. However, the degree of host fiber recovery in mice with allogeneic or xenogeneic mice was greater than in mice with a sham operation alone, even though the allografts and xenografts had no surviving chromaffin cells. Allografts and xenografts showed prominent rejection responses, with T lymphocyte infiltration in addition to macrophages. We conclude that a syngeneic adrenal graft survives better than an adrenal allograft or xenograft and promotes recovery of the intrinsic host nigrostriatal DA fibers. We also conclude that grafted chromaffin cell survivability influences the degree of host DA fiber recovery following MPTP depletion. Adrenal medullary grafts to Parkinsonian patients are currently under way in a large number of hospitals; we suggest that greater attention be paid to methods which lead to enhanced survival of the grafted chromaffin cells, since survivability might be closely related to the functional recovery of these patients.     

Muscle allograft survival after cyclosporin A immunosuppression

In normal rats, autografts of skeletal muscle survive, whereas allografts of muscle are immunologically rejected. In the present study we sought to determine whether or not the new immunosuppressive drug cyclosporin A (CyA) would prevent the rejection of muscle allografts. Autografts and allografts of rat extensor digitorum longus muscles were made into recipients that went untreated (i.e., no treatment or vehicle injected) or that received daily injections of CyA (5 mg/kg). Autografts of muscle survived throughout the 12-week period of study. On the other hand, untreated rats rejected muscle allografts within 2 weeks, whereas allografts in CyA-treated recipients survived, even at 12 weeks when the experiment was terminated. In another study, CyA therapy was discontinued after 4 weeks in rats that received bilateral muscle allografts, both of which had survived; one was removed at that time. The second muscle allograft from these rats was examined 2 months later, and all were found rejected. CyA was also effective in preventing the rejection of muscle allografts in rats that were previously sensitized to the same transplantation antigens present on the allogeneic muscle cells. These results demonstrated that CyA can prevent the rejection of muscle allografts but only if drug treatment is continued. We conclude that CyA is a potent immunosuppressive agent which could prove useful in clinical muscle allotransplantation or in experimental animal studies that require immunosuppression.     

Rejection and regeneration through peripheral nerve allografts: immunoperoxidase studies with laminin, S100 protein and neurofilament antisera

The pattern and temporal sequence of histopathological events in a rat nerve allograft model were evaluated. Following grafting and varying survival periods (from 1 to 30 weeks), the host and donor nerve were removed and assessed by light and electron microscopy. Nerve allografts underwent Wallerian degeneration and rejection. Wallerian degeneration was the dominant pathologic process at weeks 1 and 2 after engraftment. Histologic rejection started as an epineurial process at weeks I and 2, became progressively endoneurial and was most prominent at 4 and 6 weeks after engraftment. Rejection was accompanied by evidence of graft Schwann cell and endoneurial tube loss. The rejection process delayed, but did not prevent, nerve regeneration by the host. Regeneration of fine neurofilament-positive axonal sprouts into the proximal portions of the graft was observed as early as week 2. Subsequently, regeneration occurred through the periphery and around the exterior of the rejected nerve allograft fascicle. Regenerating axons were accompanied by S100 protein reactive Schwann cells and newly synthesized laminin-positive endoneurial tubes. Regenerating axons reinnervated the distal host segment at week 8 and increased in number and myelination thereafter. The observations of rejection and regeneration through nerve allograft segments are discussed in reference to previous studies.     

Time-dependent expression of donor- and host-specific major histocompatibility complex class I and II antigens in allogeneic dopamine-rich macro- and micrografts: comparison of two different grafting protocols

Neural transplantation, as a therapeutic approach to Parkinson’s disease, still requires allogeneic graft material and raises questions of immunosuppression and graft rejection. The present study investigated the time course of major histocompatibility complex (MHC) expression and astrocytic response in allogeneic dopaminergic grafts, comparing two different grafting protocols. Adult 6-hydroxydopamine-lesioned Lewis 1.W rats received intrastriatal cell suspension grafts from the ventral mesencephalon of DA rat fetuses, either as single 1-μl macrograft via metal cannula or as four micrografts of 250 nl/deposit via a glass capillary. No immunosuppression was administered. Immunohistochemistry was performed at 1, 3, 6, and 12 weeks after grafting, using antibodies against donor- and host-specific MHC class I and II antigen, glial fibrillary acidic protein (GFAP) and tyrosine hydroxylase (TH). Most animals showed good allograft survival up to 12 weeks after transplantation with no signs of rejection. Reinnervation of the lesioned striatum by TH-positive neurites was observed from 3–6 weeks on. Expression of donor-specific MHC class I was comparably low in both allogeneic grafting groups, while host MHC class I and II reaction as well as astrocytic response tended to be higher in the macrografted animals. Donor MHC class II was not observed at any time point. It is concluded that intraparenchymal allografts of fetal mesencephalic cell suspensions can survive well in the rat Parkinson model without immunosuppression for at least 12 weeks, and that the expression of moderate amounts of donor-specific MHC class I antigen does not suffice to initiate a rejection process. In addition, the microtransplantation approach may reduce the level of trauma and subsequent MHC and GFAP expression and may, thereby, minimize the risk of graft rejection. Received: 14 May 1997 / Revised, accepted: 17 July 1997     

The fate of neurons and neurilemmal cells in allografts of ganglia in the spinal cord of normal and immunologically tolerant rats

Neurons and neurilemmal cells (i.e., satellite cells and Schwann cells) in allografts (i.e., grafts between genetically different members of the same species) of ganglia are rejected after transplantation into the anterior chamber of the eye or into muscle of normal rats, but not when transplanted into immunologically tolerant animals. These results demonstrate that nervous tissue allografts are immunogenic and that they are not afforded any protection against rejection even when transplanted into a putative immunologically privileged graft site (i.e., a graft site where an allograft may survive indefinitely without recourse to immunosuppression) such as the eye. Because the central nervous system is regarded as a privileged transplantation site, the fate of isografts (i.e., grafts between genetically identical members of the same species) and allografts transplanted to this location has been determined. The allografts were incompatible with respect to both major and minor, or only to minor, transplantation antigens. The grafts were transplanted into the cervical spinal cord of normal and immunologically tolerant rats and their survival after 65 days was appraised histologically. It was found that, whereas neurons and neurilemmal cells survived in all ganglia isografts and in all allografts to tolerant hosts, allograft survival in normal recipients depended on the magnitude of the histoincompatibility. When both major and minor incompatibilities prevailed, all neurons were rejected in allografts except for two which had a few neurons remaining. Neurilemmal cells in all these ganglia were markedly reduced. No obvious rejection of neurological cells occurred in allografts when only minor antigenic differences existed. It is concluded that the immunological rejection of neurological cells in allografts can occur in the spinal cord of normal rats when major antigenic differences exist but that this rejection is either delayed or absent in situations where the graft is incompatible only with regard to minor antigens. Moreover, all rejections can be prevented by rendering the hosts immunologically tolerant.     

BN rats do not reject F344 brain allografts even after systemic sensitization

Embryonic brain tissue allografts under many circumstances survive transplantation into the brain. It is generally believed that such grafts will not survive if the host animal is systemically sensitized, by skin grafting or other means, to major histocompatibility complex (MHC) antigens of the donor animal. We have found that F344 brain grafts survive in BN hosts even when the host is systemically sensitized to F344 tissue. Embryonic cerebral neocortex from F344 donors was transplanted into BN host rats (n = 95). Subsequently, the host rats were systemically sensitized with donor skin (n = 25), brain tissue (n = 41), or spleen cells (n = 6) and compared with a control group of rats consisting of allografts with no sensitization or sham procedures (n = 23). Rejection of the transplants in BN rat hosts was not provoked by any of the sensitization methods tested. Minor immunological responses that did not result in rejection were, however, present in many host animals. We did not observe infiltration of W3/13+ T cells and OX8+ cytotoxic lymphocytes in any of the groups. Nevertheless, substantial infiltrations of OX6+ antigen-presenting cells and W3/25+ helper T cells were present. There was also an extensive enhancement of MHC class I immunoreactivity in parts of the grafted tissue developing within the third ventricle, but not for the same type of graft in the lateral ventricle. This increase of MHC class I expression was not accompanied by infiltration of cytotoxic T cells. Our findings thus suggest that neural graft rejection depends on general genetic susceptibility to immune reactions, particularly experimental allergic encephalomyelitis and not only on disparity between donor and host antigens encoded by the MHC. Moreover, enhancement of MHC class I and class II expression within transplanted tissue does not predict graft rejection.     

移植肾切除标本中C4d的表达及其体视学测定

背景：2003年Banff移植病理会议正式将C4d在肾小管周围毛细血管中的特异性沉积列入体液性排斥反应的Banff诊断标准,体视学测定是一种重要的分析手段。 目的：检测C4d在难治性排斥反应移植肾组织中的表达情况,对C4d阳性细胞进行体视学定量测定,分析其体视学指标与移植肾存活时间的关系。 设计、时间及地点：回顾性病例分析,2006-12/2007-06在解放军总医院第二附属医院器官移植完成。 对象：选择难治性排斥反应导致移植肾切除患者40例,所有移植肾标本石蜡切片均由解放军总医院第二附属医院病理科提供,移植肾存活时间大于5年者17例,小于5年者23例。 方法：应用C4d多克隆抗体对移植肾组织石蜡切片行免疫组织化学染色,检测C4d在切除移植肾中的表达情况,运用图像分析系统在显微镜下测量C4d阳性细胞的体视学参数。 主要观察指标：患者性别、年龄、冷缺血时间、热缺血时间、免疫抑制方案、移植后高血压以及是否为2次移植,C4d细胞群在移植肾标本中的分布情况,体视学分析结果。 结果：40例切除移植肾中C4d阳性17例（42.5％）,移植肾存活时间小于5年者的C4d细胞阳性率明显大于存活时间大于5年者（70.6％,29.4％）。移植肾组织中C4d阳性沉积与移植供受者的年龄、性别、免疫抑制方案、冷、热缺血时间以及是否为2次移植无关。存活时间大于5年的移植肾组织中C4d阳性细胞体视学参数核体密度、核表面积密度均小于存活时间小于5年者（F=12.741 5,9.733 7,P < 0.01）。 结论：C4d阳性沉积预示着移植肾功能预后较差,移植肾组织中C4d阳性细胞的核体密度、核表面积密度是影响其存活时间的重要指标。     

Integrity of the blood-brain barrier in retinal xenografts is correlated with the immunological status of the host

The purpose of this study was to determine the immunological correlates of blood-brain barrier breakdown in retinal xenografts in rats by utilizing skin grafting to initiate a timed immune response to the transplanted neural tissue. Embryonic day 13-14 CD-1 mouse retinae were grafted into the brainstem parenchyma of neonatal Sprague-Dawley rats. In one group of animals a 100 mm2 CD-1 skin graft was placed on the flank 21 days after the initial neural transplant in order to provoke an immune response to the neural graft. Control animals received no skin graft. Animals were injected with horseradish peroxidase (HRP) in the femoral vein 2-8 days after skin grafting. Brains were processed for Nissl, HRP-tetramethylbenzidine, and anti-M-6, -lymphocyte, -macrophage, and -astrocyte antibodies. Experimental and control animals injected 2-4 days after skin grafting showed no leakage of reaction product in the grafted tissue. A small percentage (one of eight) of 5-day animals showed isolated, patchy leakage, but no evidence of rejection of the neural graft. At 6 days all of the grafts showed evidence of leakage, and 71% of these grafts showed infiltration of lymphocytes. By 7-8 days extensive leakage of HRP and widespread infiltration of lymphocytes and macrophages were clearly evident. The present study demonstrates that blood-brain barrier breakdown is correlated closely with the sequence of immunological rejection of the graft. While these results confirm that a barrier exists in healthy neural transplants, they suggest that immunological factors should be considered in cases in which grafts are not protected by an intact barrier.