腺病毒介导CD40Ig基因转染联合骨髓细胞输注诱导大鼠心脏移植物耐受的研究

目的　研究CD4 0Ig基因转染联合骨髓细胞输注对大鼠心脏移植免疫耐受诱导的影响。方法　构建可表达CD4 0Ig的腺病毒载体Ad CD4 0Ig。建立大鼠心脏移植模型 ,将实验动物分为 5组 :A ,对照组 ,无任何处理 ;B组 ,单纯输注供者骨髓细胞 ;C ,单纯输注Ad CD4 0Ig ;D ,Ad CD4 0Ig和供者的骨髓细胞联合输注 ;E :输注对照腺病毒Ad Lacz。观察心脏移植物的存活时间、并MLR检测及移植物组织学检查。结果　 5组移植物的存活时间分别为 :8 34± 0 35天、9 2 6± 0 84天、18 73± 1 5 7天、36 91± 4 2 0天和 7 87± 0 4 1天。D组移植物的存活时间显著延长 ,MLR表现出供者特异的低反应性 ,组织切片检查淋巴细胞浸润情况也明显减轻。结论　腺病毒介导CD4 0Ig基因转染联合骨髓细胞输注 ,可诱导一定程度的免疫耐受。     

肝移植受体免疫耐受的诱导及CD4^＋CD25^＋T细胞的重要作用

背景:解决肝移植排斥反应的惟一方法是诱导免疫耐受,而环孢素A对诱导鼠肝移植免疫耐受及T细胞都存在一定影响,可为各种免疫抑制剂的合理使用提供依据.目的:探讨环孢素A诱导肝移植后免疫耐受的可行性及方法,分析CD4+CD25+调节性T细胞在诱导耐受中的作用.设计、时间及地点:随机分组,动物实验观察,2007-01/2008-04在中山大学医学实验动物中心和深圳市第三人民医院肝病研究所完成.材料:健康LEW大鼠66只,BN大鼠78只,CD4、CD25抗体和Foxp3抗体(克隆号PCH101)由美国eBioscience公司生产,环孢素A针剂由北京诺华制药提供.方法:根据用药情况建立6组肝移植模型:同基因对照组:BN大鼠进行同种异体肝移植,移植后不用药.急性排斥组:LEW大鼠作为供体,BN大鼠作为受体,移植后不用药.环孢素A小、中、大剂量组:LEW大鼠作为供体,BN大鼠作为受体,移植后分别给予环孢素A1.0,1.5,2.0 mg/(kg·d),疗程均为5 d.环孢素A中剂量延期组:LEW大鼠作为供体,BN大鼠作为受体,移植后给予环孢素A1.5 mg/(kg·d),疗程7 d.除急性排斥组和环孢素A小剂量组各24只外,其他6只/组.主要观察指标:观察各组大鼠移植后生存时间及外周血变化,并检测急性排斥组和组肝、环孢素A小剂量组脾组织中CD4+CD25+Foxp3+Treg的含量.结果:同基因对照组存活时间>100 d,而不发生排斥反应.环孢素A小、中、大剂量组存活时间分别为(51.5±2.4),(53.6±3.6).(23.2±2.1)d,环孢素A中剂量延期组和急性排斥组分别为(57.8±7.2),(20.6±3.2)d,除同基因对照组外,各组间差异均有统计性意义(F=114.82,P<0.01).各组外周血CD4+CD25+Foxp3+Treg的比例无明显差别及增加(P>0.05).环孢素A小剂量组肝组织中CD4+CD25+Foxp3+Treg的含量明显增加,且高于急性排斥组(P<0.05).结论:小剂量环孢素A可以诱导免疫耐受,大剂量环孢素A突然停药会导致加速性排斥.CD4+CD25+Foxp3+Treg能促进移植肝受体的免疫耐受,但其增加只存在于移植的肝内,外周血、脾脏未见增加.     

供者淋巴细胞光化学疗法处理后预输注对小鼠心脏移植预后的影响

[目的]探讨经体外光化学疗法(extracorporeal photopheresis,ECP)处理后的供者淋巴细胞预输注对小鼠心脏移植后移植物存活的影响.[方法]采用小鼠腹部异位心脏移植模型,供者为BALB/C小鼠,受者为C57BL/6小鼠.实验分为两组:对照组直接行心脏移植手术,ECP组于术前7d分离供者脾脏淋巴细胞,给予ECP处理后回输给受者,移植后观察移植物存活情况;部分受者于术后7d获取脾脏用于流式细胞术检测,移植心脏者行HE染色观察其组织学特点,并用免疫组化法检测组织T淋巴细胞浸润.[结果]ECP组移植心脏存活时间延长(20±4.67dvs7.5±0.70 d,P＜0.001),伴有移植物排斥反应减轻,淋巴细胞浸润减少,以及外周效应性T细胞生成减少,CD4+ CD25+ Foxp-3+调节性T细胞增加.[结论]供者淋巴细胞ECP处理后预输注能延长小鼠移植心脏存活时间,其机制可能在于ECP诱导的凋亡淋巴细胞预输注减少了效应性T细胞的数量,并且增加了调节性T细胞的产生.     

输注同基因骨髓间充质干细胞联合脾组织移植诱导肝移植大鼠的免疫耐受

背景:有研究显示在免疫抑制剂的作用下,同种脾脏细胞移植可诱导免疫耐受,使移植物长期存活.另有研究还显示异种骨髓间充质干细胞移植可延长移植肝存活时间.目的:观察输注与受体同基因骨髓间充质干细胞联合脾组织移植对诱导大鼠肝移植后免疫耐受的作用.方法:将受体Lewis大鼠以数字表法随机分为4组:急性排斥组行DA-Lewis大鼠原位肝移植;环孢素A组行DA-Lewis大鼠原位肝移植后灌胃给予环孢素A;干细胞组行DA-Lewis大鼠原位肝移植,同期输注异体Lewis大鼠骨髓间充质干细胞;脾组织移植组在干细胞移植组的基础上同期移植DA大鼠脾组织.观察各组生存期,肝功能情况,血清细胞因子水平,嵌合体的形成情况及肝脏病理变化.结果与结论:与其他各组相比,脾组织移植组大鼠存活时间明显延长,术后血清丙氨酸氨基转移酶、天冬氨酸氨基转移酶、总胆红索、白细胞介素2、干扰素Y水平明显降低(P<0.05),白细胞介素6、白细胞介素10明显升高(P<0.05),30 d后受体脾脏中供体阳性细胞明显升高(P<0.05).肝脏病理显示,环孢素A组和于细胞组移植肝仅呈急性轻度排斥反应,急性排斥组呈急性重度排斥反应,脾组织移植组未见明显排斥反应.说明大鼠肝脏、脾组织移植后输注同基因骨髓间充质干细胞町减轻移植肝的排斥作用,甚至诱导免疫耐受.     

氨基胍与环孢素A联用对大鼠心脏移植后细胞凋亡的影响

目的: 探讨诱导型一氧化氮合酶抑制剂氨基胍与环孢素A联合应用对同种大鼠心脏移植后急性排斥期细胞凋亡的影响.方法:采用Ono大鼠心脏移植模型,将Wistar大鼠心脏移植入SD大鼠腹腔内,分为四组.(1)对照组:术后不作处理;(2)环孢素A组:术后每日腹腔注射环孢素A 5mg/(kg·d);(3)氨基胍组:术后每日皮下注射AG 600mg/(kg·d);(4)环孢素A加氨基胍组:术后每日腹腔注射环孢素A 5mg/(kg·d)并皮下注射AG600mg/(kg·d).术后4 d用TUNEL法测定心肌细胞凋亡指数(AI),并观察移植心肌存活时间.结果:与单独使用环孢素A和氨基胍相比,环孢素A与氨基胍联合应用显著减少急性排斥期移植心肌细胞凋亡数目,凋亡指数与其他组比较有显著性差异(P<0.05),并延长了移植心脏的存活时间(P<0.05).结论:环孢素A与氨基胍合用可协同移植心肌细胞凋亡,延长移植物存活时间.     

他克莫司处理供者树突状细胞在诱导大鼠同种心脏移植免疫耐受中的作用(英文)

背景:诱导供者特异性免疫耐受被认为是最终克服器官移植后排斥反应的有效途径,近年来关于未成熟树突状细胞在诱导免疫耐受中的重要作用日益受到关注。目的:观察他克莫司处理的供者未成熟树突状细胞对大鼠同种异体心脏移植免疫耐受的影响,分析未成熟树突状细胞诱导免疫耐受的作用途径。设计:随机对照动物实验。材料:实验于2006-04/2006-12在青岛大学医学院附属医院动物实验中心完成。以45只Wistar大鼠为供体,45只SD大鼠为受体,行颈部心脏移植45例次。按随机数字表法分为3组,每组15例次,进行不同的预处理。方法:对照组、未经他克莫司处理组及他克莫司处理组移植前7d分别经尾静脉注射生理盐水、供者未成熟树突状细胞和他克莫司处理的未成熟树突状细胞。分别测定移植后SD大鼠与Wistar大鼠及第3品系Lewis大鼠的单向混合淋巴细胞反应。主要观察指标:各组受体大鼠移植心脏存活时间、心肌病理及血清白细胞介素2、白细胞介素4、白细胞介素10、γ-干扰素含量变化。结果:①未经他克莫司处理组大鼠的移植心脏存活时间较对照组明显延长(P<0.01),他克莫司处理组大鼠的移植心脏存活时间进一步延长(P<0.05)。②混合淋巴细胞培养结果显示为供者特异性。③各组大鼠血清白细胞介素2、γ-干扰素、白细胞介素4、白细胞介素10含量差异具有显著性意义(P<0.01)。代表Th1的白细胞介素2、γ-干扰素水平明显降低,代表Th2的白细胞介素4、白细胞介素10水平明显增高。结论:未成熟树突状细胞能够诱导同种异体大鼠心脏移植免疫耐受;他克莫司处理的未成熟树突状细胞能够加强这种免疫耐受,且这种耐受是供者特异性的。其可能主要通过调节T细胞免疫应答类型(Th1至Th2的免疫偏移)、诱导调节性T细胞和诱导T细胞失能等途径来参与免疫耐受的形成。     

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.     

NKT细胞通过IL-10参与诱导小鼠心脏移植免疫耐受

目的探讨NKT细胞在诱导小鼠心脏移植免疫耐受中的作用机制。方法 BALB/c小鼠作为供体,C57BL/6小鼠作为受体,建立小鼠腹部异位心脏移植模型。排斥组:单纯行心脏移植,无其他处理;耐受组:受鼠于术前7天接受BALB/c来源脾细胞(1×107个/只)尾静脉注射,并分别于术前7天、5天、3天,接受抗CD40L抗体腹腔注射(250μg/只/次)。术后通过腹部移植心触诊,观察移植心存活情况;分别取排斥组术后10天及耐受组术后50天的受鼠脾脏,分离NKT细胞,通过混合淋巴细胞反应(Mixed lymphocyte reaction,MLR)检测NKT细胞的免疫抑制功能;通过ELISA法检测NKT细胞的细胞因子分泌情况。结果 NKT细胞可以抑制供体抗原特异性淋巴细胞增殖,并可通过IL-10参与诱导免疫耐受。结论 NKT在诱导小鼠心脏移植免疫耐受过程中起重要作用。     

输注TGF-β1基因修饰的供体脾细胞诱导同种大鼠移植心脏耐受的实验研究

目的:研究TGF-β1修饰的供者脾细胞特异性输注对同种大鼠移植心脏耐受的诱导及效果。方法:建立同种大鼠异位心脏移植模型,用脂质体转染TGF-β1基因修饰供者脾细胞;观察TGF-β1修饰的脾细胞输注组,单纯脾细胞输注组和假处理组移植心脏存活天数和病理改变。结果:建立了稳定转染TGF-β1基因的脾细胞;TGF-β1修饰的脾细胞特异性输注可明显延长移植心脏存活时间(17.0±3.3)d,与单纯脾细胞输注组(7.0±1.1)d和假处理组(6.3±1.0)d比较,差异有显著性(P<0.05);而且可明显减轻同种移植心脏的病理损伤。结论:输注TGF-β1基因修饰的供体脾细胞可诱导同种大鼠移植心脏的耐受产生。     

移植大鼠心脏局部CD134表达与急性排斥反应的相关性研究

目的探讨大鼠浸润淋巴细胞CD134表达与移植心脏生存时间的关系。方法建立大鼠异位心脏移植模型，术中静脉应用CD45单克隆抗体（CD45mAb）及供体脾细胞。术后切取移植心脏，检测局部浸润细胞CD134表达情况。结果在正常大鼠心脏，CD134阳性细胞很少；在CD45mAb及联合应用供体脾细胞组，CD134阳性细胞较单用脾细胞组和不用药组均明显减少。结论排斥反应与浸润淋巴细胞的CD134表达呈正相关。     

Anti-interleukin 2 receptor monoclonal antibodies spare phenotypically distinct T suppressor cells in vivo and exert synergistic biological effects

The therapeutic efficacies of ART-18, ART-65, and OX-39, mouse antibodies of IgG1 isotype recognizing distinct epitopes of the p55 beta chain of the rat IL-2-R molecule, were probed in LEW rat recipients of (LEW X BN)F1 heterotopic cardiac allografts (acute rejection in untreated hosts occurs within 8 d). A 10-d course with ART-18 prolongs graft survival to approximately 21 d (p less than 0.001). Therapy with ART-65, but not with OX-39, was effective (graft survival approximately 16 and 8 d, respectively). Anti-IL-2-R mAb treatment selectively spared T cells with donor-specific suppressor functions; the CD8+ (OX8+ W3/25-) fraction from ART-18-modified recipients, and primarily the CD4+ (W3/25+ OX8-) subset from ART-65-treated hosts conferred unresponsiveness to naive syngeneic rats after adoptive transfer, increasing test graft survival to approximately 16 and 45 d, respectively. Concomitant administration of ART-18 and ART-65 to recipient animals in relatively low doses exerted a strikingly synergistic effect, with 30% of the transplants surviving indefinitely and 50% undergoing late rejection over 50 d. These studies provide evidence that anti-IL-2-R mAbs selectively spare phenotypically distinct T cells with suppressor functions. The data also suggest that in vivo targeting of functionally different IL-2-R epitopes may produce synergistic biological effects.     

高压氧预处理对小鼠皮肤移植术后脾淋巴细胞及其黏附分子的影响(英文)

本研究探讨高压氧预处理对同种异体小鼠皮肤移植排斥反应的影响及其分子机制。BALB/c供鼠与C57BL/6受鼠,各自或共同接受高压氧预处理;受鼠在皮肤移植术后,腹腔注射常规免疫抑制剂环孢素A。采用免疫荧光染色技术和流式细胞术,观察不同处理方案对小鼠脾淋巴细胞CD3+、CD4+、CD8+细胞百分率及淋巴细胞表面黏附因子LFA-1(CD11a/CD18)表达的影响。结果表明,与对照组相比,HBO预处理组小鼠脾淋巴细胞CD3+、CD4+、CD8+及其表面黏附分子CD4+CD11a+、CD4+CD18+、CD8+CD11a+、CD8+CD18+的表达均下降,以供鼠和受鼠都接受HBO预处理同时与环孢素A联合应用组下降最明显(p0.05);HBO预处理与环孢素A联合应用组小鼠一般状态好于单独应用HBO预处理或环孢素A组。结论:高压氧预处理与环孢素A联合应用较单独应用高压氧预处理和环孢素A可更好地降低皮肤移植术后的免疫排斥反应,其保护作用的分子机制与调节淋巴细胞的活性并抑制其表面黏附因子的表达作用相关。     

异基因大鼠心脏移植慢性排斥模型的建立

目的：探讨快速建立异基因大鼠心脏移植慢性排斥动物模型的方法。方法：以Lewis大鼠为供体，F344大鼠为受体，建立心脏移植模型共54只。随机分为3组，即空白对照组、CsA2mg·kg^-1组和CsA6mg·kg^-1组（每组18只）。空白对照组术后每天腹腔注射0．9％氯化钠溶液，试验组腹腔注射CsA2mg·kg^-1或CsA6mg·kg^-1，连续10d。术后20、40和60d时分批处死，取移植心脏行病理检查，时冠脉血管重塑和单核细胞浸润情况进行评分。结果：（1）对照组有7（39％）只大鼠出现移植心停跳，CsA6mg·kg^-1组有2（11％）只大鼠带心死亡。（2）术后40d各组都出现典型的冠脉内膜增生病变，术后60d病变更加明显。（3）各时段CsA组冠脉内膜增生程度与对照组相比无显著差异。单核细胞浸润程度较对照组减轻，术后20d有显著差异（P〈0．05）。结论：选用近交系的Lewis和F344大鼠建立心脏移植模型，移植后给予短程、小剂量CsA（2mg·kg^-1）干预，术后40d可以获得较为稳定的慢性排斥动物模型。     

CD28-B7 blockade after alloantigenic challenge in vivo inhibits Th1 cytokines but spares Th2

Blocking the CD28-B7 T cell costimulatory pathway with the fusion protein CTLA4Ig inhibits alloimmune responses in vitro and in vivo and induces tolerance to cardiac allografts in mice and rats, but the mechanisms mediating the tolerant state in vivo are unknown. Here, we report the effects and potential mechanisms of CTLA4Ig in the rat renal allograft model. LEW rats were nephrectomized and received renal allografts from major histocompatibility complex-incompatible WF rats. While all untreated and control immunoglobulin (Ig)-treated animals acutely rejected their allografts and died, 86% of rats that received a single injection of CTLA4Ig on day 2 after transplantation had prolonged survival (> 60-100 days) with preserved renal function. By contrast, only 29% of animals that received CTLA4Ig on the day of engraftment had prolonged survival. Long-term survivors (> 100 days) exhibited donor-specific tolerance, accepting donor-matched WF but acutely rejecting third-party BN cardiac allografts. Immunohistological analysis of grafts sampled at 1 week after transplantation showed that both control and CTLA4Ig-treated animals had mononuclear cell infiltrates, with a higher percentage of CD4+ cells in the CTLA4Ig- treated group. However, while this was associated with vasculitis and tubulitis in control grafts, there was no evidence of tissue injury in CTLA4Ig-treated animals. The immune response leading to graft rejection in control animals was characterized by expression of the T helper (Th) type 1 cytokines interleukin (IL)-2 and interferon-gamma. In contrast, the persistent CD4+ infiltrate without graft rejection in CTLA4Ig- treated animals was associated with increased staining for the Th2- related cytokines IL-4 and IL-10. Furthermore, grafts from CTLA4Ig- treated animals had marked upregulation of intragraft staining for IgG1, but not IgG2a or IgG2b. Administration of rIL-2 to CTLA4Ig- treated animals restored allograft rejection in 50% of animals tested. These results confirm that blockade of the CD28-B7 pathway after alloantigenic challenge induces donor-specific acceptance of vascularized organ allografts, and indicates in this model that CTLA4Ig inhibits Th1 but spares Th2 cytokines in vivo.     

The effects of chimeric cells following donor bone marrow infusions as detected by PCR-flow assays in kidney transplant recipients.

40 recipients of first cadaver kidney transplants were given perioperative donor vertebral bone marrow infusions (DBMC), compared with 100 controls who did not receive donor bone marrow. The immunosuppressive regimen included OKT3, Tacrolimus, and steroid maintenance therapy, and, in some patients, newly introduced mycophenolate mofetil. This report describes the 24-mo actuarial follow-up and several immunological monitoring studies including sequential measurements of donor bone marrow lineage subset chimerism by the recently reported PCR-flow assay. This is a sensitive in situ PCR detection system for donor versus recipient histocompatibility genes as well as cell surface CD epitope markers using flow cytometry. The results indicate (a) the stabilization of the donor CD3+ and CD34+ cells in recipient peripheral blood at levels below 1% between 6 mo and 1 yr postoperatively, with a 10-fold higher level of donor cell chimerism of these lineages in recipient iliac crest marrow; (b) significantly lower levels of chimerism in peripheral blood up to 6 mo postoperatively in patients who had early acute (reversible) rejection episodes compared with those who did not; (c) a higher degree of chimerism seen in patients who were class II MHC HLA DR identical with their donors; (d) the identification of a high proportion of the donor bone marrow derived CD3 dimly staining subset of T cells (to which regulatory functions have been ascribed) in recipient peripheral blood and especially in recipient bone marrow; and (e) an unexpectedly increased susceptibility to clinically significant infections (primarily viral), and even death in the DBMC-infused group, compared with controls, but no graft losses because of rejection in the DBMC-infused group. Mixed lymphocyte culture assays showed a trend toward a greater number of nonspecifically low reactors in the DBMC group, as well as a greater number of nonspecifically high reactors in the controls (P = 0.058). The autologous mixed lymphocyte reaction also indicated a trend towards nonspecific immune activation in the DBMC group. Finally, anti-cytomegaloviral IgG antibody reactivity was significantly inhibited in the DBMC group 4-6 mo postoperatively (P = < 0.05). In the controls, there were no donor cell lineages detected by PCR-flow in the peripheral blood. These rather unexpected findings, indicating a more depressed cellular and humoral immune capacity in the DBMC cadaver kidney transplant recipients in this relatively early follow-up period, are discussed relevant to chimerism, MHC restriction, and suppressor activity brought about by specialized DBMC subsets, which still need to be defined.     

不同CD34+干细胞移植途径对缺血性心肌病大鼠心功能影响的研究

目的 探讨同种异体CD34+干细胞不同移植途径对心肌梗死后心力衰竭大鼠心功能的影响,同时评价干细胞移植的有效途径和安全性.方法 Wistar雄性大鼠64只被随机分成3组:干细胞移植组(30只);急性心肌梗死模型组(20只);假手术组(14只).移植组和模型组结扎左冠状动脉(冠脉)前降支造成缺血性心肌病模型;假手术组只开胸,不结扎冠脉.另选同种异体大鼠30只,将粒细胞集落刺激因子(G-CSF)动员的外周血CD34+干细胞经免疫磁珠法分离纯化后制成干细胞悬液,在冠脉结扎后7 d分别经股静脉和心外膜注入到移植组大鼠体内,模型组和假手术组注入等量磷酸盐缓冲液(PBS).于制模前、干细胞移植术后1、2和4周分别行心脏超声检查,术后4周进行血流动力学测定.结果 与模型组比较,心肌梗死后4周移植组左室射血分数(LVEF)、左室短轴缩短率(ΔFS)、左室收缩期末压(LVESP)和左室内压最大上升速率(+dp/dt max)明显提高(P均＜0.01),左室收缩期末直径(LVESD)、左室舒张期末压(LVEDP)、左室内压最大下降速率(-dp/dt max)和左室等容舒张时间常数(Tc)均明显减小(P均＜0.01);股静脉移植和心外膜移植两种途径对心功能的影响差异无统计学意义(P均＞0.05).结论 经股静脉和心外膜两种途径移植外周血干细胞是安全可行的,二者均能有效地改善心功能,有助于梗死心肌的修复.     

Suppression of hepatic allograft rejection in the rat by mitomycin C-treated donor splenocytes: analysis of the immune status

A single intraperitoneal injection of 3 x 10(6) donor splenocytes treated with mitomycin c (MMC) seven days before hepatic transplantation prolongs survival of hepatic allografts in the ACI (RT1a) to LEW (RT1l) rat combination. This effect is donor specific. An intravenous injection of the same dose of splenocytes treated with MMC seven days before transplantation also tends to prolong hepatic allograft survival. Furthermore, lymphocytotoxic antibody can be detected in rats 30 days after transplantation. Adoptive transfer of 5 x 10(7) splenocytes taken from long-term surviving hepatic allograft recipients pretreated with MMC-treated donor ACI splenocytes into irradiated (750 rads) LEW rats prolongs the survival of donor-type skin grafts, whereas third-party strain (BN) grafts are rejected. Similarly, prolonged survival of ACI cardiac allografts in irradiated (450 rads) LEW recipients is achieved following the transfer of spleen cells taken from longterm surviving hepatic allograft recipients pretreated with MMC-treated donor ACI splenocytes, whereas third-party (BN) cardiac allografts show rejection. These findings suggest the presence of donor-specific suppressor cells and indicate that a single injection of donor splenocytes treated with MMC to the recipient seven days before transplantation can induce specific suppression of rejection in a rat hepatic allograft model.     

CD40Ig treatment results in allograft acceptance mediated by CD8CD45RC T cells, IFN-gamma, and indoleamine 2,3-dioxygenase

Treatment with CD40Ig results in indefinite allograft survival in a complete MHC-mismatched heart allograft model in the rat. Here we show that serial second, third, and fourth adoptive transfers of total splenocytes from CD40Ig-treated recipients into secondary recipients led to indefinite donor-specific allograft acceptance. Purification of splenocyte subpopulations from CD40Ig-treated recipients demonstrated that only the adoptively transferred CD8(+)CD45RC(low) subset resulted in donor-specific long-term survival, whereas CD8(+)CD45RC(low) T cells from naive animals did not. Accepted grafts displayed increased indoleamine 2,3-dioxygenase (IDO) expression restricted in the graft to ECs. Coculture of donor ECs with CD8(+)CD45RC(low) T cells purified from CD40Ig-treated animals resulted in donor-specific IDO expression dependent on IFN-gamma. Neutralization of IFN-gamma or IDO triggered acute allograft rejection in both CD40Ig-treated and adoptively transferred recipients. This study demonstrates for what we believe to be the first time that interference in CD40-CD40 ligand (CD40-CD40L) interactions induces allospecific CD8(+) Tregs that maintain allograft survival. CD8(+)CD45RC(low) T cells act through IFN-gamma production, which in turn induces IDO expression by graft ECs. Thus, donor alloantigen-specific CD8(+) Tregs may promote local graft immune privilege through IDO expression.     

巨细胞病毒对小鼠心脏移植术后急性排斥反应的影响

目的观察巨细胞病毒（cytomegalovirus,CMV）感染对同种异基因小鼠腹腔异位移植心脏急性排斥反应的影响。方法 BALB/c小鼠80只,C57BL/6小鼠40只,按供、受鼠基因不同分为3组（每组20对）：同质移植组（A组,BALB/c→BALB/c）、环胞素A组（B组,C57BL/6→BALB/c）和小鼠巨细胞病毒联合环胞素A组（C组,C57BL/6→BALB/c）,施行小鼠腹腔异位心脏移植术。A组无药物干预,B组术后腹腔注射CsA 20mg/kg.d,C组除腹腔注射CsA 20mg/kg.d外,术后第1d腹腔接种104PFU小鼠巨细胞病毒（MCMV）0.2ml。术后观察移植鼠心脏跳动情况、移植心脏存活时间、移植心脏的病理组织学以及MCMV病毒滴度测定。结果术后10d,A组移植心脏几乎无排斥反应;B组移植心脏搏动有力,显微镜下观察移植心脏心肌间质内有局灶性炎症细胞浸润,心肌有变性;C组移植心脏搏动微弱,体积增大,重量增加,显微镜下见心内、外膜下及心肌间质有弥漫性淋巴细胞及单核细胞浸润;心肌细胞可发生变性、坏死。C组（12.4±1.3d）移植心脏存活时间明显低于B组（16.7±1.9d）（P〈0.01）,而A组移植心脏长期存活（观察60d）。结论巨细胞病毒感染加速小鼠腹腔异位移植心脏急性排斥反应。