转FasL基因的树突状细胞诱导大鼠肝移植免疫耐受的实验研究

目的 观察转FasL基因的树突状细胞（DC）体内注射诱导大鼠肝移植免疫耐受作用,并研究其机制。方法 用“二袖套法”行受体为Wistar大鼠肝移植36例,并随机分为3组：（1）对照组（n＝12）;（2）环孢霉素治疗组（n=12）;（3）转FasL基因治疗组（n=12）,腹腔注射转FasL基因的树突状细胞。手术后7d分别杀死各组4只大鼠,用原位末端标记法及透射电镜观察移植肝细胞及肝脏内淋巴细胞凋亡,其余大鼠用于观察生存期。结果 对照组大鼠在9－15d迅速死亡,TUNEL及电镜观察发现肝细胞变性坏死明显;而环孢霉素治疗组及转FasL基因治疗组免疫排斥以应轻微,移植后大鼠已存活超过6个月,原位末端标记法及电镜均发现FasL基因治疗组肝脏内浸润淋巴细胞凋亡明显。结论 转FasL基因DC细胞治疗能有效地诱导肝移植免疫耐受,其机制是诱导了肝脏内浸润淋巴细胞凋亡。     

未成熟树突状细胞诱导大鼠免疫低反应性

目的观察供者来源的未成熟树突状细胞(imDCs)联合骨髓移植(BMT)对大鼠移植肾的保护作用,并探讨其机制.方法DA(RT1a)大鼠为供者,Lewis(RT11)大鼠为受者,Wistar大鼠为无关第三品系.将实验动物随机分为5组,每组8只,进行不同的预处理后进行肾移植.(1)阴性对照组受者不接受任何预处理;(2)imDCs诱导组受者术前7d经尾静脉注射经60Co照射(30 Gy)灭活的、供者来源的未成熟树突状细胞2×107/只;(3)BMT诱导组受者术前4 d经尾静脉注射供者来源的新鲜骨髓细胞2×108/只;(4)imDCs+BMT联合诱导组受者术前7 d经尾静脉注射经60Co照射(30 Gy)灭活的、供者来源的未成熟树突状细胞2×107/只,术前4 d经尾静脉注射供者来源的新鲜骨髓细胞2×108/只;(5)第三品系组预处理与imDCs+BMT联合诱导组相同,但供者肾脏来自Wistar大鼠.术后进行单向混合淋巴细胞反应(MLR);白细胞介素2(IL-2)逆转实验;体内细胞转移实验(DTH);流式细胞仪检测RT1a阳性细胞百分率.结果各组大鼠肾移植后平均存活时间分别为阴性对照组(7.12±1.25)d;imDCs诱导组(24.38±3.20)d;BMT诱导组(7.87±2.10)d;第三品系组(6.63±1.06)d;而imDCs+BMT联合诱导组延长到(80.75±16.88)d;后者与上述4组比较,差异均有统计学意义(P＜0.01).免疫耐受的大鼠脾细胞增殖程度(SI值,3.41)明显低于对照组(7.56),P＜0.01;转移耐受的Lewis大鼠(FI值,0.55)明显低于对照大鼠(0.93),P＜0.01;在免疫耐受的受者体内检测到RT1a阳性细胞.结论术前输注供者来源的未成熟树突状细胞联合骨髓移植,可成功诱导受者产生免疫耐受,显著延长肾移植大鼠的存活时间.可能机制为特异性T细胞克隆无能、T细胞的负向免疫调节以及嵌合体的形成.     

树突状细胞诱导大鼠肝移植免疫耐受的研究

目的 观察大鼠骨髓来源的树突状细胞(DC)对同种异体肝移植大鼠免疫耐受的影响.方法 用不同细胞因子诱导培养大鼠骨髓来源的成熟DC(mDC)和不成熟DC(imDC),采用形态学观察、表型分析和功能学实验对培养细胞进行鉴定,构建Wistar大鼠和SD大鼠肝移植模型,并于移植前5 d注射到受体大鼠内,研究它们对移植后大鼠肝脏病理及存活时间的影响情况.结果 DC细胞形态不规则,大多数细胞表面有细长树枝状突起,mDC和imDC表面均表达表面分子OX62,而表面分子CD86在imDC表面低表达,在mDC表面高表达.imDC和mDC与淋巴细胞相互作用,发现imDC对淋巴细胞的增殖无明显作用,相反mDC对淋巴细胞的增殖有明显的促进作用.注射imDC的受体大鼠的存活时间显著长于注射mDC的受体大鼠,注射mDC的肝移植大鼠在移植后较早且出现较强的急性排斥反应,而注射mDC的大鼠在移植后16 d才开始出现轻度急性排斥反应.结论 建立了在体外大量扩增大鼠骨髓来源DC的方法,imDC能显著延长受体大鼠肝移植的存活时间.     

未成熟树突状细胞诱导肝移植免疫耐受作用机制的研究进展

作为肝脏终末期疾病和急性肝衰竭的有效治疗手段,肝脏移植已愈发体现出其不可替代的临床价值.但由于同种异体肝移植术后的排斥反应,使其成为左右移植器官功能的关键.因此, 针对排斥反应机制及相关治疗的探讨一直是各国移植工作者研究的重点之一.作为目前已知最为强大的抗原提呈细胞(APCs)-树突状细胞(DCs)在肝移植术后对维系免疫耐受状态所起的重要作用,已经成为科研人员研究的焦点问题.本文就树突状细胞在肝移植术后诱导免疫耐受的机制,以及近年来相关的研究进展概述如下.     

FcγRIIb基因修饰树突状细胞对大鼠原位肝移植排斥反应的影响

目的:研究FcγRIIb基因修饰树突状细胞对大鼠原位肝移植术后肝功能及病理排斥反应的影响。方法:利用基因克隆技术构建含Lewis大鼠FcγRIIb基因的重组慢病毒表达载体TRE-FcγRIIb。分别包装TRE-FcγRIIb表达病毒与TET-on可诱导病毒,用其共感染DA大鼠骨髓来源未成熟树突状细胞并检测FcγRIIb...     

供者未成熟树突状细胞联合西罗莫司诱导大鼠皮肤移植物免疫耐受研究

目的：观察大鼠骨髓来源的未成熟树突状细胞（i mDCs）联合西罗莫司（SRL）在诱导大鼠同种异体皮肤移植免疫耐受中的协同作用。方法：以雄性Lewis大鼠为供者、Brown-Norway大鼠为受者,建立大鼠同种异体皮肤移植模型。对照（control）组术前不给予任何干预;未成熟树突状细胞（imDCs）组于术前7天经尾静脉注射供者骨髓来源的未成熟树突状细胞;西罗莫司（SRL）组于术后连续7天经胃管灌注西罗莫司;联合（imDCs＋SRL）组于术前7天经尾静脉注射供者骨髓来源的未成熟树突状细胞,并于术后连续7天经胃管灌注西罗莫司。结果：对照组、未成熟树突状细胞（imDC）组、西罗莫司（SRL）组、联合（imDCs＋SRL）组大鼠同种异体皮肤移植物术后存活时间分别为（8.25±1.75）（、10.25±1.91）（、10.64±2.50）（、21.38±2.97）天。方差分析提示组间差异有统计学意义（P〈0.05）;S-N-K检验提示除单独应用未成熟DC组与单独应用SRL组外,各组间的差异均有统计学意义（P〈0.05）。结论：供者骨髓来源未成熟树突状细胞可诱导大鼠同种异体皮肤移植免疫耐受;联合使用西罗莫司可延长移植皮片成活时间。     

树突状细胞诱导肝移植免疫耐受新进展

肝移植的最终目标是要达到移植肝和受体之间的免疫耐受,树突状细胞在肝移植免疫耐受的诱导中起着举足轻重的作用。现就树突状细胞在肝移植免疫耐受诱导中的作用进行综述。     

转化生长因子-β1基因修饰未成熟树突状细胞诱导大鼠肝移植免疫耐受

目的 观察转化生长因子-β1 (TGF-β1)基因转染未成熟树突状细胞(imDC)对大鼠肝移植免疫耐受的诱导作用.方法 利用大鼠骨髓细胞诱导培养imDC,以脂质体介导的pIRES2-EGFP-hTGF-β1转染imDC,于移植前5d输注受体Lewis大鼠体内,移植后分别于3、7、10d抽血检测肝功能[总胆红素( TBIL)和谷丙转氨酶(ALT)]、酶联免疫吸附试验(ELISA)法检测白细胞介素-12(IL-12)水平、肝组织苏木素-伊红(HE)染色急性排斥反应病理评分、原位末端转移酶标记(TUNEL)法检测肝脏淋巴细胞的凋亡及观察各组大鼠肝移植后的生存时间.结果 TGF-β1组移植后肝功能(TBIL和ALT)优于各对照组(P＜0.05);TGF-β1组移植后3、7d血清IL-12浓度分别为71.03±10.70、80.88±14.23均低于各对照组(P＜0.05);TGF-β1组移植后7d出现交界性排斥反应,移植10 d后出现轻度排斥反应(P＜0.05);TGF-β1基因转染组移植后3、7、10d汇管区淋巴细胞凋亡指数分别为6.75±1.93、14.00±2.19、18.25±1.38,较各对照组均明显增高(P＜0.05);TGF-β1组大鼠移植后中位生存期为58 d,明显长于各对照组.结论 TGF-β1基因改造的imDC能诱导大鼠移植免疫耐受,在诱导器官移植耐受中有良好的应用前景.     

大鼠胰腺癌微环境诱导未成熟树突状细胞功能的变化

目的 观察胰腺癌微环境对树突状细胞(DC)成熟的影响及功能变化并探讨胰腺肿瘤细胞免疫逃逸的机制.方法 培养树突状细胞,加入粒细胞巨噬细胞集落刺激因子(rmGM-CSF)40μg/L、白细胞介素(IL)-4 40μg/L,培养到第6天时得到大量的未成熟树突状细胞(imDC),加入大鼠胰腺癌细胞(AR42J cell)培养上清液诱导,流式细胞术检测DC的表面分子CD86、CD80的表达(n=6),观察能否延缓或阻断imDC的成熟及其在脂多糖(LPS)刺激后这种作用能否被逆转.并观察AR42J细胞培养上清诱导的Dc对同种异体混合淋巴细胞增殖.结果 加入胰腺癌癌细胞上清液培养的DC,与正常成熟的DC比较,CD80+CD86+阳性率由(70.88±3.60)%降至(7.15±0.71)%,LPS刺激后DC细胞的表面分子CD80+CD86+表达仍然较低(7.43±1.05)%,表明胰腺癌细胞培养上清液对DC的成熟有阻断作用.AR42J细胞上清诱导培养的imDC组刺激同种异体混合淋巴细胞增殖的强度显著低于正常培养的imDC组刺激同种异体混合淋巴细胞增殖的强度.结论 体外大鼠胰腺癌细胞培养上清液可以诱导DC处于不成熟状态,且这种不成熟状态不容易被逆转.     

T细胞疫苗抗异品系大鼠肝移植排斥反应的实验研究

目的 研究特异性T细胞疫苗接种对大鼠肝移植后排斥反应的影响。方法 利用LOU/CN大鼠的脾细胞免疫CHN大鼠,取后者脾细胞活化制备T细胞疫苗,对肝移植受者CHN大鼠进行免疫。测定T细胞疫苗接种与未接种组的混合淋巴细胞培养cpm值。采用三袖套法进行大鼠原位肝移植。按移植前后处理方法不同分为3组:（1）T细胞疫苗接种组:用T细胞疫苗接种后7～9d的CHN大鼠进行原位肝移植;（2）环孢素A（CsA）组:未接种T细胞疫苗的CHN大鼠进行原位肝移植后,用CsA10mg·kg-1·d-1进行免疫抑制治疗;（3）阴性对照组:未接种T细胞疫苗的CHN大鼠进行原位肝移植后,用生理盐水作对照。分别测定各组的存活时间、微量细胞毒反应。结果T细胞疫苗接种组与未接种组外周血淋巴细胞cpm值分别为:9804±1182和22386±2117,二者比较,差异有显著性（P<0.01）。异品系大鼠肝移植后,T细胞疫苗接种组存活时间为（17.1±2.8）d,CsA组为（14.2±3.1）d,阴性对照组为（11.6±2.4）d。三组比较,（P<0.01）。微量细胞毒测定死细胞百分率:T细胞疫苗接种组为（26.4±9.3）％,CsA组为（43.7±10.4）％,阴性对照组为（62.4±8.1 ％。三组比较,差异有显著性（P<0.01）。结论T细胞疫苗接种能显著延长异品系大鼠肝移植的存活期,有显著的抗排斥反应作用。     

Primary Alloproliferative TH1 Response Induced by Immature Plasmacytoid Dendritic Cells in Collaboration with Myeloid DCs

The role played by dendritic cell (DC) subsets in the immune response to alloantigens is not well defined. In vitro experiments have extensively shown that freshly isolated myeloid (M)DCs induce a strong T lymphocyte proliferation whereas plasmacytoid (P)DCs do not, unless activated by CD40 ligation. The aim of these studies was to explore whether the interplay among PDCs, MDCs and T cells modulates alloresponse. Freshly isolated MDCs and PDCs were merged in different proportions and used as antigen presenting cells (APCs) in mixed lymphocyte cultures (MLC). As described, isolated PDCs only induced a mild alloresponse, while MDCs were potent inducers of alloproliferation. Unexpectedly, when PDCs were merged with even low numbers of MDCs (down to 100 cells) and used as APCs, a potent Th1 cell proliferation was detected. Survival and maturation of PDCs was increased in these MLC conditions, which could partially explain the magnitude of the T-cell response. Interestingly, the proportion of IFNgamma-producing cells generated in such cultures was higher compared to MDC-stimulated cultures. These data suggest that the interaction between both DC subsets is determinant to generate a potent Th1 response, at least in an allogeneic situation, and may be relevant to the outcome of allogeneic stem cell transplantation.     

Transplantation of Bioengineered Lungs Created From Recipient-Derived Cells Into a Large Animal Model

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用MyD88 siRNA制备半成熟树突状细胞致免疫耐受的实验研究

目的 探讨利用Toll样受体关键蛋白转录水平抑制剂髓细胞样分化标记物（myeloid differentiation marker 88，MyD88）siRNA，制备半成熟树突状细胞（dendritic cell，DC）的表型和致耐受功能。方法 取BALB／c小鼠骨髓接种、培养，加入浓度为10ng／ml的重组小鼠粒细胞巨噬细胞集落刺激因子（rmGM—CSF）诱导，培养至第8d将DC分为3组，空白对照组：于培养过程中不加其它任何物质；LPS组：加入终浓度为1μg／ml的LPS；实验组：加入MyD88 siRNA4h后，再加入1μg／ml的LPS。采用流式细胞术检测3组DC的表型，用酶联免疫吸附测定（ELISA）检测培养上清的白细胞介素10（IL-10）、白细胞介素12（IL-12）的含量，初次和再次混合淋巴细胞实验检测DC刺激T细胞增殖能力，并观察术后鼠移植心存活时间。结果 空白对照组DC表型为CD11c^＋、CD25、CD40^low、CD80^low、CD86^low和MHC-Ⅱ^low未成熟表型DC，再经LPS刺激后成为成熟表型DC；而实验组DC表型为CD11c^＋、CD25^-、CD40^mid、CD80^low、CD86^low和MHC-Ⅱ^mid。半成熟表型，其IL-10／IL-12比率明显增高；可诱导同种异型T细胞无反应性，并能延长移植心存活时间。结论 MyD88siRNA转染结合LPS刺激可使未成熟DC进一步分化为一种半成熟DC，较未成熟DC拥有更稳定有效的致耐受特性。     

供者脾细胞和环磷酰胺联合预处理对移植心脏存活的作用

目的　诱导同种异体心脏移植的免疫耐受 ,为心脏移植的抗排斥反应治疗提供依据。　方法　采用供者脾细胞和环磷酰胺联合预处理受者 ,诱导受者对移植心脏的免疫耐受 ,然后行大鼠颈部心脏移植术。将实验动物分成 5组。对照组 :受者不作任何预处理 ;组 1:预处理第 2天用环磷酰胺 5 0～ 80 mg/ kg预处理受者 ;组 2 :预处理当天用供者 5～ 10× 10 7个脾细胞预处理受者 ;组 3:受者不作任何预处理 ,手术当天开始用环孢菌素 A10 mg/ kg,每 2天 1次 ,共 8～ 10次 ,腹腔内注入 ;组 4:预处理当天用供者脾细胞 5～ 10× 10 7个和第 2天环磷酰胺 5 0～ 80 mg/ kg联合预处理受者。　结果　各组移植心脏的存活时间明显不同 ,5组移植心脏的存活时间差异有显著性 (P<0 .0 1)。供者脾细胞和环磷酰胺预处理受者的移植心脏存活时间明显延长。　结论　供者脾细胞和环磷酰胺联合预处理 ,可诱导受者对移植心脏的免疫耐受。     

The Immune Regulatory Effect of Apoptotic Cells and Exosomes on Dendritic Cells: Its Impact on Transplantation

Dendritic cells (DC) are professional antigen (Ag) presenting cells (APC) that trigger the anti-donor T-cell response that causes allograft rejection. During the past decade several laboratories have employed in vitro generated DC with tolerogenic potential for prolongation of allograft survival. This minireview describes the development of a second-generation of DC-based strategies for transplantation tolerance based on the delivery in situ of donor allogeneic (allo)-Ag to quiescent DC of graft recipients by means of donor-derived apoptotic cells or exosomes. Donor leukocytes in early apoptosis are rich in allo-Ag, are internalized efficiently by recipient DC in vivo and deliver immunosuppressive signals to DC. Administration (i.v.) of donor apoptotic leukocytes prolongs bone marrow engraftment and cardiac allografts survival in mice by exerting a profound down-regulatory effect on the anti-donor T-cell response. Exosomes are nanovesicles (<100 nm) produced by different cell types, including APC. DC-derived exosomes are rich in major histocompatibility complex (MHC) molecules that can be employed to target DC in situ. Once i.v. injected, exosomes carrying donor MHC molecules are captured by recipient's DC and prolong allograft survival in rodents. The use of the regulatory functions of apoptotic cells and exosomes may be useful tools to develop new strategies for transplantation tolerance.     

Hyporesponsiveness in Alloreactive T-cells by NF-κB Inhibitor-Treated Dendritic Cells: Resistance to Calcineurin Inhibition

Dendritic cells (DC) are the most potent antigen-presenting cells (APC) initiating primary T-cell responses. Beyond this immunostimulatory function, certain DC subsets have been shown to induce T-cell tolerance in vitro and in vivo. In this study, immature monocyte-derived DC were activated in the presence of the NF-kappaB inhibitor pyrrolidine dithiocarbamate (PDTC) and characterized with regard to phenotype, cytokine production and allostimulatory potential. Furthermore, the functional consequences of calcineurin inhibition were studied in T cells exposed to PDTC-modulated DC. We demonstrate that PDTC treatment of DC leads to an arrest in maturation as reflected by down-regulated major histocompatibility complex (MHC) antigens and costimulatory molecules, suppressed immunostimulatory cytokines and an impaired capability to support allogeneic T-cell activation. Allogeneic T cells challenged with PDTC-treated DC are refractory upon restimulation with alloantigens but not to polyclonal stimuli. Interestingly, the successful establishment of alloantigenic hyporesponsiveness is not prevented by concomitant calcineurin inhibition in vitro as well as in T cells from patients under cyclosporine A (CsA)-based immunosuppression ex vivo. These data may have important implications for the design of clinical regimens for the establishment of antidonor hyporeactivity in organ transplantation using in vitro-modulated DC.     

Hepatitis B Immunoglobulins Inhibit Dendritic Cells and T Cells and Protect Against Acute Rejection After Liver Transplantation

The efficacy of anti-viral intravenous immunogobulins (anti-HBs Ig and anti-CMV Ig) in preventing acute rejection after liver transplantation was assessed in a retrospective analysis, and correlated to their effects on immune cells in vitro. HBs Ag-positive liver graft recipients (n = 40) treated prophylactically with anti-HBs Ig had a significantly lower incidence of acute rejection compared with recipients without viral hepatitis (n = 147) (12% vs. 34%; p = 0.012), while the incidence of rejection in HCV-positive recipients (n = 29) was similar to that in the control group. Treatment with anti-CMV Ig (n = 18) did not protect against rejection. In vitro, anti-HBs Ig suppressed functional maturation of and cytokine production by human blood-derived dendritic cells (DC) at concentrations similar to the serum concentrations reached during anti-HBs Ig treatment of liver graft recipients. In addition, anti-HBs Ig inhibited allo-antigen- and lectin-stimulated proliferation of peripheral T cells. Anti-CMV Ig suppressed functional DC-maturation and alloantigen-stimulated T-cell proliferation, but not lectin-driven T-cell proliferation. In conclusion, anti-HBs Ig protects against acute rejection after liver transplantation, probably by functional inhibition of the two principal immune cells involved in allograft rejection, DC and T cells.     

无心跳供肝大鼠肝移植模型的手术操作技巧探讨

目的建立一个稳定的无心跳供肝大鼠原位肝移植模型。方法在Kamada"二袖套法"的基础上进行改良,根据供肝获取前经历无心跳热缺血时间不同分为10min(R10组)、20min(R20组)和30min(R30组)3组,比较各组术后1周大鼠存活率。结果供体手术时间约30min(不含热缺血时间)。供肝冷保存时间均为1h。肝上下腔静脉吻合时间12～22min(平均15min),门静脉和肝下下腔静脉套管分别约需2min和1min。无肝期时间14～24min(平均19min),受体总手术时间50～65min(平均60min)。大鼠术后24h内死亡视为手术失败,共计12例死亡。R10组、R20组和R30组手术成功率分别为95%(19/20)、80%(16/20)和65%(13/20),术后1周生存率分别为95%(18/19)、81%(13/16)和54%(7/13)。结论在Kamada"二袖套法"基础上进行改良的大鼠无心跳供肝肝移植模型能很好地模拟临床无心跳供肝肝移植。大鼠肝脏能耐受30min以内的热缺血时间,移植术后短期存活结果满意,长期存活率尚需进一步研究。     

通里攻下法对肝细胞溶酶体的保护作用

目的：观察内毒素刺激所致大鼠肝细胞溶酶体功能改变及下法对其影响。方法：通过对腹膜炎大鼠离体肝细胞溶酶体Ｎ－乙酰基－Ｂ－Ｄ－氨基葡萄糖苷酶（ＮＡＧ）等的测定,观察溶酶体功能,膜稳定性改变及通里攻下法对其的影响。结果：腹膜炎使溶酶体ＮＡＧ含量增加,而大承气汤可降低ＮＡＧ水平。结论：通里攻下法可增加溶酶体膜的稳定性。抑制肠源性内毒素血症发生时,溶酶体酶的合成及溢出活化。此可能为下法治疗肠源性内毒素血症的机制之一。