同种异体神经干细胞脑内移植免疫排斥反应的实验研究

目的观察帕金森病(PD)模型大鼠同种异体神经干细胞(NSC)脑内移植是否存在免疫排斥反应。方法取E14.5d SD胚鼠腹侧中脑组织进行分离、培养、扩增,经Brdu、Nestin免疫组化染色鉴定确认为NSC后,借助脑立体定位仪移植到SD大鼠PD模型的纹状体内,分别于10、21、35、60d时检测其旋转行为后分批处死,再行HE、CD4、CD8、酪氨酸羟化酶(TH)和MHC-Ⅱ抗原免疫组化染色。结果移植组10d时,CD4、CD8、、MHC-Ⅱ少量表达,以21d时较为明显,35d时明显减少,60d消失;10d、21d时移植区未见明显TH阳性神经元,35d后数量显著增加。阳性对照组在10d、21d时见少量CD4、CD8、和MHC-Ⅱ阳性细胞,35d时消失,各时间点都未见TH阳性神经元。阴性对照组在各时间点都未见TH阳性神经元和CD4、CD8、MHC-Ⅱ阳性细胞。PD模型移植组旋转行为35d时出现改善。结论神经干细胞脑内移植未见明显免疫排斥反应。     

移植心Th细胞免疫偏离与MHC Ⅱ类抗原表达的关系

目的:探讨Th细胞免疫偏离与移植心MHC Ⅱ类抗原表达的关系。方法:建立大鼠心脏移植模型,以同系移植和无移植动物作为对照,采用逆转录PCR技术测定移植心Ⅰ、Ⅱ类细胞因子IL-2、IL-4 mRNA水平变化,用免疫组化技术和单克隆抗体测定移植心MHC Ⅱ类抗原表达。结果:IL-2 mRNA水平和MHC Ⅱ类抗原表达随着移植心急性免疫排斥病变发展而显著增加(P＜0.01), IL-4 mRNA水平则显著降低(P＜0.01),急性免疫排斥发展到一定阶段Ⅰ、Ⅱ类细胞因子水平出现偏离时MHC Ⅱ类抗原由低表达变为高表达。结论:移植心脏急性免疫排斥过程中,Th细胞免疫偏离与MHC Ⅱ类抗原表达变化有相关性,并参与促进移植心脏MHC Ⅱ类抗原的高表达。     

Rat nigral xenografts survive in the brain of MHC class II-, but not class I-deficient mice

We have examined the role of the indirect pathway of antigen recognition and T cells in neural xenografts rejection by using major histocompatibility complex (MHC) class II-deficient mice as xenograft recipients. Dissociated embryonic ventral mesencephalic tissue from Sprague-Dawley rats was stereotaxically injected as a cell suspension into the striatum of MHC class II-deficient adult mice as well as MHC class I-deficient and wild-type mice as controls. All of the MHC class II-deficient mice had surviving grafts in the striatum 4 weeks post-grafting. In contrast, only a few of the MHC class I-deficient mice exhibited very small grafts and none of the wild-type mice had any surviving grafts. The mean number of surviving transplanted dopamine neurons in the MHC class II-deficient group was significantly larger than that observed in the other two groups. Moderate levels of MHC class I antigen expression were seen in the transplantation sites of some animals in the MHC class II-deficient group. No helper or cytotoxic T cells were observed infiltrating into the graft sites of this group. However, there were markedly increased levels of expression of MHC class I and class II antigens, and a number of T cells infiltrating in the graft sites in both the MHC class I-deficient and wild-type groups. These results show that rat embryonic nigral tissue can survive transplantation in the brain of the MHC class II-deficient mice for at least 4 weeks without any overt signs of rejection, suggesting that the indirect pathway of foreign antigen recognition mediated by host MHC class II molecules and helper T cells plays an important role in the rejection responses to intracerebral xenografts.     

Temporal pattern of host responses against intrastriatal grafts of syngeneic,allogeneic or xenogeneic embryonic neuronal tissue in rats

The host response to immunologically incompatible intrastriatal neural grafts was studied using immunohistochemical techniques. Dissociated ventral mesencephalic tissue from embryonic donors of either syngeneic, allogeneic or xenogeneic (mouse) origin was stereotaxically implanted into adult rats. The brains were analysed 4 days, 2 weeks or 6 weeks after grafting with antibodies against the following antigenic structures: major histocompatibility complex (MHC) class I antigens; MHC class II antigens; complement receptor (CR) 3 (marker for microglia and macrophages); helper T-lymphocyte antigen-cluster of differentiation (CD) 4; cytotoxic T-lymphocyte antigen-CD8; tyrosine hydroxylase (TH) (marker for transplanted dopaminergic neurons). The number of surviving TH-positive cells was not different at the various time points in either the syngeneic or allogeneic groups, whereas the xenogeneic cells were all rejected by 6 weeks.The host reactions were similar in character in the syngeneic and allogeneic groups. At 4 days after implantation, there were increased levels of expression of MHC class I and II antigens. In and around the grafts, there were cellular infiltrates consisting of activated microglia, macrophages, CD4- and CD8-positive lymphocytes. At 6 weeks, MHC expression was reduced and the cellular infiltrates had subsided with only low numbers of activated microglia cells and CD8-positive lymphocytes remaining. In the xenogeneic group, at 4 days, some grafts contained cavities, possibly reflecting acute rejection. At later stages, the xenografts were heavily infiltrated by macrophages, activated microglial cells and T-lymphocytes, and at 6 weeks all the xenografts were rejected.Taken together, the results suggest that there is an inflammation caused by the implantation process which leads to an accumulation of host defence cells. This, in turn, leads to increased MHC expression in and around the grafts. In syngeneic grafts, these reactions are short lasting and weak; for allografts slightly more pronounced and longer lasting than syngeneic grafts, but not sufficient to cause rejection. For xenografts, the reactions are more intense and lead to transplant rejection. Thus, a strong sustained inflammatory response may be an important determinator for the failure of histoincompatible neural grafts. It can be speculated that a short-term anti-inflammatory treatment of graft recipients may be a sufficient immunosuppressive regimen to allow long-term graft survival.     

胚胎干细胞源性神经前体细胞移植脑缺血大鼠局部细胞的免疫反应

背景：神经前体细胞的免疫原性各家研究结果不一,尤其是体内移植后的机体免疫反应模式需要进一步研究。 目的：体外观察神经前体细胞组成型及诱导型主要组织相容性抗原表达情况;体内观察神经前体细胞移植入大鼠脑缺血组织后局部免疫细胞活化情况,探讨神经前体细胞的移植排斥可能性及模式。 方法：自pCX-hrGFP ES-D3胚胎干细胞诱导分化神经前体细胞,流式细胞术体外检测主要组织相容性抗原Ⅰ,Ⅱ类分子表达及γ-干扰素诱导前后表达变化。实验分3组,磷酸盐缓冲液组、神经前体细胞组分别于大脑中动脉缺血大鼠模型造模后经侧脑室给予磷酸盐缓冲液注射及神经前体细胞移植,假手术组不造模。免疫组化法观察纹状区ED1+、CD4+、CD8+细胞浸润情况;淋巴细胞再刺激增殖实验观测神经前体细胞诱导移植大鼠颈部淋巴细胞的增殖指数。 结果与结论：神经前体细胞组成型高表达主要组织相容性抗原Ⅰ类分子,几乎不表达主要组织相容性抗原Ⅱ类分子;经γ-干扰素诱导后,主要组织相容性抗原Ⅰ类分子进一步上调,主要组织相容性抗原Ⅱ类分子亦有轻度上调,提示神经前体细胞有可能引起机体免疫反应。移植实验表明,与假手术组相比,磷酸盐缓冲液组及神经前体细胞组均表现强烈的ED1+、CD4+、CD8+细胞浸润(P < 0.05),说明脑缺血损伤本身能导致局部免疫细胞活化;神经前体细胞组比磷酸盐缓冲液组有更强的ED1+、CD4+细胞浸润(P < 0.05),提示神经前体细胞移植可能导致局部免疫更进一步活化,且以CD4+T细胞反应为主。磷酸盐缓冲液组及神经前体细胞组神经前体细胞诱导下的增殖指数值均较假手术组升高(P < 0.01),但前两组增殖指数值比较差异无显著性意义(P > 0.05),提示脑组织局部炎症导致颈部淋巴细胞增殖性增加,而离体神经前体细胞不足以单独刺激致敏淋巴细胞增殖。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

Expression of MHC class II antigens on bile duct epithelium in experimental graft versus host disease

Recently we observed the expression of MHC class II antigens on bile duct epithelium in human liver transplantation rejection. In this report we present evidence for the expression of MHC class II antigens on bile duct epithelium in experimental GVHD. These findings support the idea, that the target tissue elements in liver transplantation rejection and GVHD are the bile ducts, on the other hand this is a new experimental model for the analysis of MHC class II antigen expression on epithelial tissue.     

Histological signs of immune reactions against allogeneic solid fetal neural grafts in the mouse cerebellum depend on the MHC locus

Summary Using an immunocytochemical method, we examined the immunological responses of adult mice to intracerebellar syngeneic and allogeneic fetal mouse brainstem transplants (embryonic days 12–14). Syngeneic grafts and major histocompatibility complex (MHC)-compatible and non-MHC-incompatible allogeneic grafts survived well, showing no histological signs of rejection even 6 months after transplantation, and with no expression of MHC antigens being observed in any of the grafts. However, most cases of both MHC- and non-MHC-incompatible allografts showed rejection responses, such as marked neovascularization, cellular infiltration and necrosis, two weeks to one month after transplantation. In animals showing rejection, Class I MHC antigens were found on grafted neuronal tissue. An increased number of reactive astrocytes was also observed in the grafts. High levels of Class I antigen expression and prominent gliosis correlated with vigorous cellular infiltration. A quantitative analysis of T cell subsets in the animals showing rejection revealed that the L3T4/Lyt-2 ratio was 1.02±0.21 (mean ± S.D.), indicating that helper/inducer and cytotoxic/suppressor T cells appeared equally in the rejection of MHC- and non-MHC-incompatible allografts. We consider that in these experiments, the brain was not completely an immunologically privileged site, and that MHC- and non-MHC-incompatible intraparenchymal neural transplants were not shielded from host immune surveillance.     

Coronary arteriosclerosis after T-cell-mediated injury in transplanted mouse hearts: role of interferon-gamma.

This study evaluated the contribution of acute parenchymal rejection and interferon (IFN)-gamma to the development of graft arterial disease (GAD) in totally allogeneic murine cardiac transplants. BALB/c (H-2d) hearts were transplanted into wild-type C57BL/6 (B6, H-2b) or B6 IFN-gamma-deficient (GKO) recipient mice. Assessing the role of acute parenchymal rejection in the GAD process involved two different immunosuppression protocols using anti-CD4 and -CD8 monoclonal antibodies (MAbs): virtually complete long-term immunosuppression (denoted as complete immunosuppression) was achieved by administering both MAbs 6, 3, and 1 day before transplantation and weekly thereafter; in contradistinction, a single, early, transient episode of rejection (transient rejection) was attained by administering MAbs beginning 4 days after transplant and then at weekly intervals. The extent and duration of T cell depletion under these two regimens were evaluated using flow cytometric analysis of peripheral blood lymphocytes. After a single injection of MAbs, peripheral blood CD4+ and CD8+ T cell depletion was approximately 98% at 1 week and approximately 88% at 2 weeks. After three injections (analogous to days 6, 3, and 1 before transplant), peripheral blood CD4+ and CD8+ T cell depletion was >98% at 2 weeks and approximately 87% at 4 weeks. Functioning cardiac allografts were removed at 8 and 12 weeks after transplant and analyzed by hematoxylin and eosin, elastic tissue, and immunohistochemical stains, and the severity of parenchymal rejection versus GAD was scored. With complete immunosuppression (antibody before and after transplant), BALB/c allografts showed little parenchymal rejection or GAD, suggesting that persistent depletion of T cells blocked subsequent development of GAD. However, even a single transient acute rejection episode allowed the subsequent development of GAD accompanied by augmented major histocompatibility complex (MHC) class II, VCAM-1, and ICAM-1 expression at 12 weeks; these allografts showed no residual CD4+ or CD8+ T cells. In comparison, allografts undergoing transient rejection in GKO recipients did not develop GAD, despite persistent macrophage and natural killer cell (NK) infiltrates comparable to those seen in wild-type recipients. Moreover, the arterioles of hearts transplanted into GKO recipients showed no or minimal increases in MHC class II, ICAM-1, and VCAM-1 relative to baseline expression. In conclusion, a single episode of allogeneic injury mediated by T cells suffices to evoke subsequent graft arteriosclerosis, even in the absence of additional T-cell-mediated injury, and the process appears to depend on IFN-gamma.     

慢病毒介导核受体相关因子1基因修饰骨髓间充质干细胞移植治疗帕金森病模型大鼠

目的探讨慢病毒介导核受体相关因子1(Nurrl)基因修饰骨髓间充质干细胞(BMSCs)移植至帕金森病(PD)模型大鼠纹状体后对PD大鼠的治疗作用。方法采用神经毒素6-羟多巴胺(6-OHDA)纹状体注射成功制备PD大鼠模型18只,将携带绿色荧光的慢病毒GV287-Nurr1感染大鼠BMSCs,然后随机移植入6只PD模型大鼠的纹状体内(实验组),设生理盐水组(假移植组)6只及感染空慢病毒GV287的BMSCs组(对照组)6只;术后第1、2、4周观察大鼠的行为改善情况;免疫组织化学染色法检测纹状体及黑质中Nurrl和酪氨酸羟化酶(TH)蛋白的表达变化;RT-PCR法检测黑质Nurrl mRNA和TH mRNA的表达变化。结果慢病毒感染后的BMSCs及上清中均检测到Nurr1蛋白;对照组与实验组大鼠在移植后第1、2、4周的旋转行为较假移植组均有所改善,且实验组比对照组改善更明显;实验组纹状体Nurr1阳性细胞有效存活并沿胼胝体向皮质及对侧脑组织迁移;实验组纹状体及黑质损毁侧Nurrl和TH蛋白及mRNA的表达较假移植组和对照组明显增高,差异均有统计学意义(P0.05)。结论慢病毒介导Nurr1基因修饰大鼠BMSCs移植治疗PD大鼠,能有效地改善PD模型大鼠的行为学症状,增加大鼠脑内纹状体和黑质区Nurr1和TH的表达。     

Intraparenchymal allografts in the mouse brain in relation to immunocytochemical identification of T lymphocyte subsets

In a study of intracerebellar allografts of mice brainstem anlagen (embryonic day 12-14), we examined immunocytochemically the expression of two different types of T lymphocytes in and around the grafts. Helper/inducer and cytotoxic/suppressor T cells were identified with anti-L3T4 and anti-Lyt-2 monoclonal antibodies, respectively. Allografts into major histocompatibility complex (MHC)-compatible recipients showed no histological signs of rejection such as marked neovascularization and cellular infiltrates even 6 months after transplantation, but those into MHC-incompatible recipients generally had rejection reactions within one month after transplantation. In the latter cases, the L3T4/Lyt-2 ratio for the T lymphocytes in the infiltrates of the grafts was 1.03 +/- 0.14 (mean +/- S.D.), suggesting that both helper/inducer and cytotoxic/suppressor T cells may play important roles in the mediation of intraparenchymal brain allograft rejection.     

Blockade of the B7-CD28 pathway by CTLA4-Ig counteracts rejection and prolongs survival in small bowel transplantation

Allograft rejection involves T-cell activation, requiring T-cell receptor interactions with major histocompatibility complex (MHC) molecules and costimulatory signals delivered through the B7-CD28 pathway. We evaluated the effect of blocking this pathway on graft rejection and survival, in a rat experimental model of small bowel transplantation. Heterotopic small bowel transplantation was performed between PVG donor rats and DA recipient rats. The recipient animals were treated with CTLA4-Ig or irrelevant immunoglobulin (Ig)G as control and followed for 18, 30 or 90 days. The survival rate and degree of inflammation and accumulation of CD4+ T cells and macrophages were determined in the transplanted bowels. We found that administration of CTLA4-Ig significantly improved the survival rate compared to control rats: after 30 days 73% of the treated rats had survived and at 90 days 5/8 rats were still living, whereas in the control group only 2/8 rats had survived. The grafts showed preserved mucosal structure with only a mild degree of subacute inflammation and the accumulation of CD4+ T cells and macrophages was noticeably reduced in treated animals as compared to control rats. Necrosis was extensive in control rats, whereas CTLA4-Ig treated animals had grafts with at least some preserved villus morphology and no necrotic tissue. Although small bowel transplantation has proven exceptionally difficult, in this study we have shown that CTLA4-Ig treatment may provide a promising strategy to prevent rejection and induce long term tolerance and graft survival.     

大鼠心脏移植后淋巴细胞5种免疫分子表达的变化

目的：观察大鼠异体异位心脏移植术后不同时间点，淋巴细胞相关免疫分子的表达水平、供心存活率及心肌组织的病理学改变，探讨免疫排斥反应的相关时间进程。方法：分别经供体SD大鼠的心脏主动脉、肺动脉与受体Wistar大鼠的腹主动脉及下腔静脉吻合，进行异位心脏移植术。于术前及术后不同时间点，取血分离淋巴细胞。用流式细胞仪分别检测淋巴细胞上CD4、CD8、IL-2R、ICAM-Ⅰ和MHC-Ⅱ类分子的表达水平。对供心心肌组织进行常规病理学检查。结果：于移植后24h，只有MHC-Ⅱ类分子的表达水平增加，CD4、IL-2R和ICAM—Ⅰ的表达水平降低，CD8无改变。术后72h，CD4、CD8及IL．2R的表达增加，其中CD8和IL-2R达峰值。术后7～10d，除CD4的表达继续增加外，其他4种免疫分子的表达水平逐渐降低。术后不同时间点移植心脏的存活率分别为：100％(24h)、85．7％(72h)、16．7％(7d)、0(10d和12d)。病理学检查显示，移植后24h，心肌组织无明显的病理学变化，术后3d，7只大鼠中4只出现ⅠA级及以上病理改变。术后7d，6只大鼠全部发生Ⅱ级以上的病理学变化。结论：大鼠心脏移植后的24h内，外周血淋巴细胞为以MHC-Ⅱ分子表达为主的抗原识别、呈递期，并伴有一过性免疫功能降低；术后24—72h为T细胞活化期，术后3-7d为免疫排斥反应效应期。CD4、CD8和IL-2R等免疫分子表达的峰值与开始出现轻度排斥反应时病理学变化的时间相一致。     

间α胰蛋白酶抑制剂水平反映肾移植慢性排斥反应

背景：目前,肾移植病理学检查仍为移植肾慢性排斥反应的“金标准”,但肾移植程序性活检在中国尚难以普及,且存在一定的风险;由于诸多原因,使患者慢性排斥反应早期因未及时发现而错失治疗时机。 目的：观察肾移植慢性排斥反应大鼠血浆中间α胰蛋白酶抑制剂的水平。 方法：实验以正常雄性Wistar大鼠为供体,正常雄性SD大鼠为受体进行肾移植。移植后分为慢性排斥反应组和正常肾移植组。慢性排斥反应组受体于移植前3 d起,每日给予腹腔注射环孢素A微乳化剂2 mg/kg,正常肾移植组则每日给予环孢素A微乳化剂腹腔注射5 mg/kg。 结果与结论：移植后4,6,8,10,12周,Western blot检测结果显示,与移植前1周相比,正常肾移植组和慢性排斥反应组间α胰蛋白酶抑制剂蛋白表达量明显降低(P < 0.01)。移植后第4,6周,慢性排斥反应组间α胰蛋白酶抑制剂蛋白表达高于正常肾移植组(P < 0.01),而在8,10,12周低于正常肾移植组(P < 0.01)。慢性排斥反应组血浆间α胰蛋白酶抑制剂呈时间依赖性下降(P < 0.01)。结果证实,大鼠肾移植后出现慢性排斥反应时,血浆α胰蛋白酶抑制剂水平显著下调。间α胰蛋白酶抑制剂水平变化与肾移植慢性排斥反应关系密切,可为肾移植后慢性排异反应的预测提供参考依据。     

脐血干细胞移植对帕金森病大鼠旋转行为的影响

背景：目前帕金森病的临床治疗还是以药物为主,细胞移植实验也多见于骨髓间充质干细胞,脐血来源干细胞移植能否改善帕金森病的旋转行为报道较少。 目的：观察脐血间充质干细胞移植对帕金森病大鼠旋转行为的影响。 方法：帕金森病模型大鼠随机分成实验组和对照组。实验组大鼠纹状体内植入用Hoechst33258标记的第4代脐血间充质干细胞,对照组注射PBS。此后每周腹腔注射阿扑吗啡以观察大鼠的旋转行为;并在移植后3,6,9周用免疫荧光双标法检测间充质干细胞的存活、迁移情况以及胶质纤维酸性蛋白、神经元特异性烯醇化酶、酪氨酸羟化酶和突触素的表达。 结果与结论：移植脐血间充质干细胞后大鼠的旋转行为与对照组相比有明显改善(P < 0.05);间充质干细胞可在大鼠脑内存活,随时间延长迁移范围扩大,分布于纹状体、胼胝体和皮质;胶质纤维酸性蛋白、神经元特异性烯醇化酶、酪氨酸羟化酶都有表达,突触素无表达。结果可见移植脐血间充质干细胞后能明显改善帕金森病大鼠旋转行为,有望成为治疗帕金森病的种子细胞。      

VEGF转基因神经干细胞移植对大鼠急性放射性脑损伤后脑组织中NSE表达的影响

目的： 探讨血管内皮生长因子（VEGF）转染的神经干细胞(NSC)对放射性脑损伤的影响。方法：将Sprague-Dawley(SD)大鼠随机分为对照组、放射性脑损伤组、NSC和转染VEGF的NSC治疗组, 放射性脑病模型成功制备后1周脑内移植转染VEGF的NSC,移植后1周、2周、3周、4周和6周末取其脑组织,用免疫组织化学法测定神经元特异性烯醇化酶(NSE)阳性细胞数,Western blotting法检测NSE蛋白表达情况。结果：与对照组相比, 放射性脑损伤组大鼠脑组织中NSE阳性细胞数显著下降(P<0.05);与放射性脑损伤组相比,NSC治疗组和转染VEGF的NSC治疗组在移植3周后NSE阳性细胞数明显增加(P<0.05), 与NSC治疗组比较,在移植6周末转染VEGF的NSC治疗组NSE的阳性细胞数增加更明显(P<0.05)。与放射性脑损伤组比,NSC治疗组和转染VEGF的NSC治疗组在移植3周末NSE蛋白表达量明显增加(P<0.05), 与NSC治疗组比较,在移植6周末转染VEGF的NSC组NSE蛋白表达量增加更明显(P<0.05)。结论：转染VEGF的NSC移植可提高放射性脑损伤组织中NSE的含量。     

微囊化牛视网膜色素上皮细胞移植治疗帕金森大鼠的研究

目的： 观察微囊化牛视网膜色素上皮细胞（RPE）移植治疗帕金森病（PD）大鼠的疗效。方法： 酶消化法原代培养牛RPE细胞，纯化、传代后用高压静电微胶囊成型装置制作海藻酸钠-多聚赖氨酸微囊化细胞，将其立体定向移植入6-OHDA大鼠PD模型的右侧纹状体，移植分为NS组、RPE组、空微囊组（APA组）和微囊化RPE组（RPE-APA组）。观察移植后：阿朴吗啡诱导的旋转行为变化、移植侧纹状体中多巴胺和高香草酸含量的变化、移植区HE染色及TH免疫组化染色。结果： RPE-APA组阿朴吗啡诱发的旋转次数在移植后第2周开始减少，减少幅度为39.29％（与APA组相比，P<0.05），至第4周减少更加明显，减少幅度为：56.89％（与第2周相比，P<0.05），改善现象一直持续到第14周。行为学出现改善的大鼠纹状体多巴胺和高香草酸含量的增加同其阿朴吗啡诱发的旋转次数的减少相符合。行为学有改善的大鼠囊内细胞TH染色呈弱阳性，微囊周边的纹状体可见TH阳性纤维密度较APA组高。结论： 微囊化牛RPE细胞对6-OHDA大鼠PD模型有治疗作用，是一种前景良好的新型供体。     

恒河猴肝移植模型急性排斥反应中白细胞介素6的表达

背景：白细胞介素6是免疫炎症反应中一种重要的细胞因子,它与移植排斥反应具有密切的关系,在移植排斥反应诊断和抗排斥疗效评价中发挥着重要作用。 目的：检测白细胞介素6在恒河猴肝移植后急性排斥反应中的表达水平,以评价其作为肝移植后急性排斥反应早期诊断指标的价值。 方法：以16只恒河猴为研究对象,将其随机分为实验组(围手术期不给予免疫抑制治疗)和对照组(围手术期给予免疫抑制治疗),然后建立恒河猴同种异体原位肝移植模型;分别在移植后6,12,24,72 h时间点收集血清及肝脏组织,通过检测肝功指标和移植肝组织苏木精-伊红染色Banff评分反映其移植排斥反应情况,并应用酶联免疫吸附法、免疫组织化学技术分别检测白细胞介素6的表达水平。 结果与结论：肝移植后12,24,72 h实验组均有急性排斥反应发生,其中实验组丙氨酸氨基转移酶、天冬氨酸氨基转移酶、总胆红素在24 h和72 h表达水平明显高于对照组(P < 0.05);实验组72 h组织学表现重于对照组,Banff评分高于对照组(P < 0.05);实验组中血清、肝组织的白细胞介素6水平在肝移植后12,24,72 h明显高于对照组(P < 0.05),并以72 h最为明显。结果表明白细胞介素6可能参与肝移植后排斥反应的发生,其表达可能在恒河猴原位肝移植后急性排斥反应的早期诊断中有一定意义。 中国组织工程研究杂志出版内容重点：肾移植;肝移植;移植;心脏移植;组织移植;皮肤移植;皮瓣移植;血管移植;器官移植;组织工程全文链接：     

Mechanism of Immune Hyporesponsiveness Induced by Recipient-derived Immature Dendritic Cells in Rat Liver Transplantation

Objective: The use of donor-derived immature dendritic cells (imDC) has become a promising approach to induce immune tolerance or immune hyporesponsiveness. However, donor-derived imDC needs to be harvested for a few days and transfused into the recipient in 5-10 days before transplantation, which is practically impossible in a clinical setting where donor organs are mainly harvested from cadavers. Moreover, donor-derived imDC might be cleared by allogeneic reaction offsetting induced immune tolerance or immune hyporesponsiveness. In our study, we further explored the underlying mechanism of immune hyporesponsiveness induced by donor-antigen-unloaded recipient-derived imDC by transfusing these imDC into rats in 1 day before liver transplantation. This paper is to study the mechanism of immune hyporesponsiveness induced by donor-antigen-unloaded recipient-derived imDC and its protection of liver grafts in rats. Methods: 40 SD rats (donor) and 40 male Wistar rats (recipient) were randomly divided into 4 groups: control, cyclosporine A(CsA), mature DC (mDC), and imDC; with 10 SD rats and 10 Wistar rats for each group. Animal models of acute graft rejection were established with these rats. Corresponding treatments were given before or after transplantation. In the control group, Wistar rats received no treatment other than liver transplantation. In the CsA group, Wistar rats underwent liver transplantation plus CsA treatment (10 mg/kg·d) in the starting day 2 after transplantation. For the mDC group, recipient-derived mDC(1×106/rat) were infused intravenously via the dorsal vein of the penis to recipient rats. For the imDC group, imDC (1×106/rat) were injected into recipient rats via the dorsal vein of the penis. In each group, 5 recipients were executed at 10 days after transplantation; the remaining five recipients were kept for the observation of survival time. Blood samples were collected for the measurement of ALT and TBIL; IL-2, IFN-γ, IL-4 and IL-10 and levels were measured with double-antibody sandwich ELISA. Liver tissue was harvested for HE staining and the observation of histological features. Acute rejection was evaluated with Banff classification. Expression levels of Fas-L/Fas in the grafts were detected by immunohistochemical staining; and western blot was used to detect the expression level of Scurfin. Results: The median survival times (MST) of the liver allografts in the CsA and imDC group were significantly longer than those in the control or mDC group (P<0.05). The serum levels of ALT and TBIL in the control and mDC groups were significantly higher than those of the CsA or imDC group(P<0.05). Compared with the CsA and imDC group, the levels of IL-2 and IFN-γ were higher but the levels of IL-4 and IL-10 were lower than those of the control and mDC groups(P<0.01). Slight or no rejection reaction was found in the CsA and imDC groups (P<0.05). The expression level of Scurfin protein in CD4+ CD25+ T cells of the imDC group was significantly higher than that of three other groups(P<0.05). Conclusion: Donor-antigen-unloaded recipient-derived imDC is an effective treatment in inducing immune hyporesponsiveness by blocking indirect recognition in rat liver transplantation model. Survival span was significantly prolonged by its protective effect. The mechanism of immune hyporesponsiveness induced by imDC transfusion may involve the preprocesses of T cell apoptosis induction, immune tolerance or hyporesponsiveness in T cells, induction of the shift in THl/TH2 balance, selection activation of Th2 subset, or induction of regulatory T cell.     

复合组织及血清肿瘤坏死因子α、白细胞介素10表达与大鼠喉移植急性排斥反应的相关性

背景：喉移植后致炎细胞因子(肿瘤坏死因子α、γ-干扰素等)和抗炎细胞因子(白细胞介素10、白细胞介素4等)之间的相互作用会发生哪些变化呢？ 目的：观察肿瘤坏死因子α、白细胞介素10在大鼠喉移植急性排斥反应期移植喉组织的不同部位和血清中的表达变化,评价其血清水平在预测急性排斥反应中的作用。 方法：进行Wistar→SD大鼠喉移植,移植后依照注射环孢霉素A剂量不同随机分为3组：0 mg组、5 mg组及10 mg组,以未进行喉移植的SD大鼠为正常对照组。 结果与结论：各组移植后第3,7,11天肿瘤坏死因子α、白细胞介素10血清浓度的变化与移植后各相应时间点黏膜上皮及黏膜下层组织中其表达水平的变化均呈正相关。提示,供体喉的高抗原性主要集中于喉的黏膜上皮层及黏膜下层组织;血清肿瘤坏死因子α和白细胞介素10的浓度可以作为预测喉移植术后急性排斥反应的指标。     

A CIITA-independent pathway that promotes expression of endogenous rather than exogenous peptides in immune-privileged sites

A CIITA-independent pathway of MHC class II expression has been found in the eye and the brain, both immune-privileged sites. Although corneal endothelial cells were unable to express MHC class II in response to IFN-gamma alone, these cells readily expressed MHC class II molecules via a CIITA-independent pathway when triggered by simultaneous exposure to IFN-gamma and TNF-alpha. CIITA-independent expression of MHCclass II molecules enabled corneal endothelial cells to present cytosolic, but not endosomal, ovalbumin (OVA) to OVA-primed T cells. To determine whether CIITA-independent expression of MHC class II is relevant in vivo, minor H-only-incompatible corneal allografts prepared from CIITA knockout (KO) mice, MHC class II KO mice or wild-type donors were placed in eyes of normal mice. Cornea allografts from wild-type and CIITA KO mice suffered similar rejection fates, whereas far fewer class II-deficient corneas were rejected. In addition, MHC class II-bearing macrophages were observed in cuprizone-induced inflammatory and demyelinating brain lesions of CIITA KO mice. We conclude that class II expression via the CIITA-independent pathway enhances the vulnerability to rejection of corneal grafts expressing minor antigens. The potential relevance of CIITA-independent MHC class II expression at immune-privileged sites is discussed in relation to tolerance to strong autoantigens.