联合应用CTLA-4Ig及抗ICOS单克隆抗体延长小鼠移植胰岛存活时间

目的探讨共刺激信号阻断剂细胞毒T淋巴细胞相关抗原4免疫球蛋白（CTLA-4Ig）及抗共同刺激分子ICOS单克隆抗体（ICOSmAb）对移植胰岛功能的影响。方法以BALB／c小鼠为供者，C57BL／6糖尿病小鼠为受者，进行同种胰岛细胞移植。将移植后的小鼠随机分成4组，每组10只。ICOS组：移植后1、3、5d腹腔内注射ICOSmAb 100μg／kg；CTLA4组：移植后0、2、4d腹腔内注射CTLA-4Ig50μg／kg；联合阻断组：移植后腹腔注射CTLA-4Ig和ICOSmAb，用法同CTLA4组和ICOS组；对照组：单纯胰岛移植，不注射CTLA-4Ig和ICOSmAb。观察术后移植物存活时间和移植胰岛的病理改变；逆转录聚合酶链法（RT-PCR）检测移植胰岛组织中白细胞介素2（IL-2）、白细胞介素10（IL-10）mRNA的表达情况；应用流式细胞仪检测CD4^＋、CD8^＋T淋巴细胞表达情况。结果联合阻断组的小鼠移植胰岛存活时间较其它3组明显延长，移植胰岛的细胞形态经光镜检查接近正常。联合阻断组与其它3组比较，IL-2mRNA表达减少，差异有统计学意义（P〈0．05），IL-10mRNA的表达差异无统计学意义（P〉0．05）；移植术后21d，CD4^＋、CD8^＋T淋巴细胞表达上调不明显。结论应用CTLA-4Ig和ICOSmAb联合阻断CD28和共同刺激分子ICOS，可以明显的抑制排斥反应，延长移植胰岛的存活时间及存活率。     

应用羟基荧光素二醋酸琥珀酰亚胺脂探讨新型免疫抑制剂J2作用机制

目的探讨基于CIM立体构型设计的新型免疫抑制剂（J2）在小鼠体内的免疫抑制作用以及其作用机制。方法将羧基荧光素二醋酸琥珀酰亚胺酯（CFSE）标记的C57BL／6（H-2b）小鼠的淋巴细胞4×10^6～6×10^6经尾静脉注入经印钴照射（900拉德）后的DBA／2（H-2d）小鼠体内构建模型。将DBA／2小鼠随机分为5组，每组5只，模型建立后即刻腹腔注射J2，每天1次。对照组注射生理盐水、CsA组注射环孢素A（10mg／kg体重）；实验组J2A组（1mg／kg体重）、J2B组（4mg／kg体重）、J2C组（8mg／kg体重）。给药3d后分组处死DBA／2小鼠取脾制备淋巴细胞，用CD3、CD4、CD8单抗分别标记受检T细胞，FACS流式细胞仪检测CD4^＋T细胞和CD8^＋T细胞在小鼠体内分裂增殖的情况，并检测CD4^＋T细胞的凋亡情况。结果CFSE标记C57BL/6小鼠的脾淋巴细胞着染率大于99％。对照组分裂的CD4^＋T细胞（75．34±1．58）％、分裂的CD8^＋T细胞（83．48±1．25）％明显多于CsA组和实验组（P〈0．01）。J2B组和J2C组分裂的细胞数分别与CsA组比较差异无统计学意义（P〉0．05），但J2A组多于CsA组（P〈0．05）。对照组CD4^＋T细胞早期凋亡的比例（41．1±3．4）％明显高于其他各组（P〈0．01）。J2A组（35．6±4．1）％、J2B组（24．0±3．7）％和J2C组（13．6±2．3）％CD4^＋T细胞早期凋亡的比例显著高于CsA组（7．4±1．9）％（P〈0．05）。结论J2可能抑制T细胞亚群CD4^＋T细胞的活化，从而进一步抑制CD8^＋T细胞的分裂增殖而具有免疫抑制作用。     

CD4-CD8-双阴性T细胞在移植免疫耐受形成中的作用

体内移植物抗宿主反应和宿主抗移植物反应主要是由T淋巴细胞介导。在同种异体移植时,因移植物的组织相容性抗原与受者不符,而刺激受者免疫系统发生排斥反应。由于移植物的细胞构成不同,触发的免疫反应会有所差异。去除T细胞或抑制T细胞的功能均能使移植物的存活时间延长。最近研究发现一种T细胞亚群——αβTCR^＋CD3^＋CD4^- CD8^-双阴性T细胞（double-nega-tiveTcell,DNT）可通过抑制同系基因型CD4^＋ T细胞或CD8^＋ T细胞从而抑制移植物排斥反应的发生,因此研究DNT细胞在移植免疫耐受形成中的作用将有重要意义。     

联合阻断CD28和可诱导共刺激分子对小鼠同种异体胰岛移植物急性排斥反应的影响

目的 在小鼠同种异体胰岛移植模型上，通过联合阻断CD28和可诱导共刺激分子（ICOS），观察CTLA-4Ig及ICOS单克隆抗体（ICOSmAb）对胰岛移植物功能的影响。方法将小鼠随机分成4组，每组10只。联合阻断组：分别于移植后0．2、4d和1、3、5d腹腔内注射CTLA-4Ig50μg／kg和ICOSmAb100μg／kg体重组。ICOS组：移植后1、3．5d腹腔内注射ICOSmAb100μg/kg体重组。CTLA4组：移植后0、2、4d腹腔内注射CTLA-4Ig50μg/kg体重组。对照组：单纯胰岛移植，不做CT-LA-4Ig和ICOSmAb处理组。观察术后移植物存活时间和病理改变，RT-PCR检测移植组织中IL-2、IL-10mRNA表达，流式细胞仪检测CD4^＋、CD8^＋T淋巴细胞表达。结果 联合阻断组小鼠移植物存活时间平均为（31．00±6．57）d，较其他3组延长，差异有统计学意义（P〈0．05）；IL-2和IL-10mRNA表达水平分别为（44．23±6．24）和（65．23±11．02），与其他3组比较，IL-2mRNA表达差异有统计学意义（P〈0．05），而IL-10mRNA表达差异无统计学意义（P〉0．05）；CD4^＋、CD8^＋T淋巴细胞荧光阳性百分率分别为（13．73±0．49）％和（14．56±0．31）％，表达上调均不明显；移植胰岛光镜检查接近正常。结论 应用CTLA-4Ig和ICOSmAb联合阻断CD28和ICOS，可以明显抑制胰岛移植物排斥反应。     

抗原特异性CD4+CD25+T细胞对同种异体胰岛移植影响及作用机制研究

目的:探讨抗原特异性CD4+CD25+Treg细胞免疫对同种异体胰岛急性移植排斥反应的影响和机制。方法:用MACS分选供体抗原特异性CD4+CD25+Treg细胞免疫糖尿病BALB/cByJ受体小鼠，以ICR小鼠胰岛为供体行同种异体胰岛移植。观察移植后小鼠的存活时间、移植前后外周血CD4+和CD8+T细胞亚群的变化和移植物中Th1/Th2细胞因子mRNA表达水平的变化。结果:抗原特异性Treg细胞联合胰岛移植组(C组)胰岛移植物平均生存期为(34.57±17.15)d，显著长于单纯胰岛移植组(B组)的(10.6±1.82) d (P<0.01)；移植后第3天，C组外周血CD4+/CD8+的值显著低于B组(P<0.01)；C组移植物中IL-10,TGF-β mRNA表达比B组显著增强。B组移植物中IL-1β，IL-2及IFN-γ mRNA表达明显强于C组。结论:抗原特异性CD4+CD25+ Treg细胞可通过调节Th2/Th1之间的反应平衡而延长同种异体胰岛移植物的存活时间。     

反义细胞外信号调节激酶对移植物血管的保护作用

目的探讨反义细胞外信号调节激酶（ERK1／2）基因治疗对移植物血管的保护作用及可能的保护机制。方法建立BN至Lewis大鼠的腹主动脉移植模型。反义ERK1／2治疗组移植前取供者动脉血管段给予经脂质体包装的反义ERK1／2基因转染；腹主动脉移植术后1个月内受者每日从尾静脉或阴茎背静脉注入经脂质体包装的反义ERK1／2寡核苷酸100μl。对照组移植未经任何处理的血管段，移植后也无特殊处理。移植术后60d取移植段主动脉进行组织病理学观察内膜和胶原纤维变化；免疫组织化学法观察移植段血管ERK1／2基因的表达和CD4^＋、CD8^＋T淋巴细胞的浸润情况；ELISA法检测血清中细胞间粘附分子（ICAM-1）的变化。结果移植术后60d，对照组的移植动脉呈慢性移植物血管病表现，血管内膜显著增厚，移植血管中ERK1／2基因高表达，CD4^＋、CD8^＋T淋巴细胞大量浸润；反义ERK1／2基因治疗组移植动脉呈血管内膜炎改变，ERK1／2基因表达不明显，内膜有少量CD4^＋、CD8^＋T淋巴细胞；对照组ICAM-1表达显著高于反义ERK1／2治疗组（P〈0．05）。结论反义ERK1／2基因治疗对移植物血管具有保护作用，可以减缓慢性移植物血管病的发生，这种保护机制可能和减少ICAM-1的表达以及减少移植血管T淋巴细胞的浸润有关。     

CD4+ CD25+ Tr细胞与大鼠肝移植自发免疫耐受关系的研究

目的研究CD4^＋CD25^＋Tr细胞及其相关基因Foxp3与大鼠肝移植自发免疫耐受的关系。方法双袖套法建立大鼠原位肝移植模型;密度梯度离心法分离肝内淋巴细胞;免疫磁性分离法（MACS）分选CD4^＋CD25^＋Tr细胞,流式细胞术（FCM）检测所得细胞纯度。体外细胞增殖试验研究CD4^＋CD25^＋Tr细胞的免疫抑制作用。Western蛋白印迹法检测CD4^＋CD25^＋Tr细胞Scurfin蛋白表达。结果自发耐受组大鼠移植肝内CD4^＋CD25^＋Tr细胞含量显著高于急性排斥组。混合淋巴细胞反应中,LEW大鼠的脾细胞比DA大鼠自身的脾细胞更能刺激CD4^＋CD25^＋T细胞的增殖。CD4^＋CD25^-T细胞能抑制CD4^＋CD25^-T细胞的增殖,当加入外源性IL-2（200U／ml）时,该抑制作用被逆转。结论转录因子Foxp3介导的CD4^＋CD25^＋Tr细胞的免疫抑制作用可能是诱导大鼠肝脏移植自发免疫耐受的机制之一。     

可诱导性共刺激分子单抗联合细胞毒T淋巴细胞4Ig在大鼠胰腺移植中的作用

目的 探讨可诱导性共刺激分子（ICOS）单抗、细胞毒T淋巴细胞4ig（CTLA41g）阻断共刺激通路对于异基因大鼠胰腺移植的作用及其机制。方法 建立胰腺移植模型，分A组（对照组），B组（CTLA4Ig组），C组（抗ICOS单抗组），D组（联合CTLA4Ig和抗ICOS单抗组）。术后1、4,7d监测血糖，第7天取胰腺做苏木素-伊红染色，脾脏做流式细胞检测CD3^＋CD8^＋T细胞、CD4^＋T细胞、CD4^＋CD25^＋T细胞。结果 与A组比较：B、C、D组排斥反应较A组明显减弱，显著延长了移植物的存活时间。CD3^＋CD8^＋T细胞计数B、C、D与A组比较均有减少，差异有统计学意义（P〈0．01）。CD4^＋T细胞B、D与A组的差异有统计学意义（P〈0．05）。CD4^＋CD25^＋T细胞各组间逐渐升高，差异有统计学意义（P〈0．01）。结论 抗ICOS单抗和CTLA4Ig能有效地抑制大鼠胰腺移植排斥反应，延长移植物存活时间，且联合应用比单一应用更有效。其可能机制为诱导了CD4^＋CD25^＋T细胞的产生。     

阻断OX40和CD40协同共刺激信号延长小鼠胰岛移植物存活时间

目的 研究阻断OX40/OX40L和CD40/CD154L协同共刺激通路对小鼠胰岛移植物存活的影响及其机制.方法 以DBA/2小鼠为供者,C57BL/6小鼠为受者,制作胰岛移植模型.受鼠分为4组.(1)对照组,注射IgG; (2)抗OX40组,注射抗OX40L单克隆抗体;(3)抗CD154组,注射抗CD154单克隆抗体;(4)联合治疗组,注射抗OX40L单克隆抗体和抗CD1 54单克隆抗体.记录各组胰岛移植物平均存活时间(MST).将CD154敲除小鼠处死,取其脾脏T淋巴细胞,体外检测活化T淋巴细胞表面OX40的表达;在活化T淋巴细胞中加入不同浓度的抗OX40L单克隆抗体,体外检测T淋巴细胞增殖情况.结果 对照组胰岛移植物MST为19 d,抗CD154组胰岛移植物MST为48 d(P＜0.05);抗OX40组胰岛移植物MST为22 d,与前两组相比较,差异无统计学意义(P＞0.05);联合治疗组胰岛移植物MST＞ 150 d,高于另外3组(P＜0.05).66％的胞表达OX40,较初始T淋巴细胞的表达率高(2％,P＜0.05);加入抗OX40L单克隆抗体后,T淋巴细胞增殖受抑制且呈剂量依赖性.结论 阻断OX40/OX40L和CD40/CD154L双通路可诱导小鼠胰岛移植物长期存活, 其发挥作用的关键机制是抑制了T淋巴细胞的增殖.     

CTLA4-Ig和抗CD40L单克隆抗体抑制大鼠胰腺移植急性排斥反应的机制

目的探讨细胞毒T淋巴细胞相关抗原4免疫球蛋白（CTLA4-Ig）和抗CD40L单克隆抗体对异基因大鼠胰腺移植后急性排斥反应的作用及其相关机制。方法建立大鼠的胰十二指肠移植模型，供者为F344大鼠，受者为经链尿佐菌素诱导为糖尿病模型的Lewis大鼠，受者移植后分为4组，每组12只。A组：为应用生理盐水对照组；B组：应用CTLA4-Ig200μg；C组：应用抗CD40L单克隆抗体200μg；D组：联合应用CTLA4-Ig和抗CD40L单克隆抗体各200μg。各组分别于术后第2d腹腔注射相应的药物。术后1、4、7、10d分别取各组的移植胰腺，进行常规病理检测；采用逆转录聚合酶链（RT-PCR）法检测移植物白细胞介素2（IL-2）、白细胞介素4（IL-4）、白细胞介素10（IL-10）、γ干扰素（IFN-γ）的表达；术后第1、4、7、10d取受者外周血，采用流式细胞术计数T细胞亚群CD3^＋、CD4^＋和CD8^＋；术后第4d取移植胰计数CD4^＋CD25^＋T细胞。结果病理检测显示：与A组相比，B、C组排斥反应明显减弱，D组几乎未发生排斥反应；B、C、D组IL-2的表达高峰延迟，且表达水平较A组有不同程度的降低，D组又较B、C组表达水平下降，差异有统计学意义；B、C、D组IFN-γ的表达水平较A组有不同程度的降低，但D组与B、C组的差异不显著；B、C组IL-4的表达水平较A组有不同程度的升高，D组较A、B、C组表达水平下降，差异有统计学意义；B、C组IL-10的表达水平较A组有不同程度的升高，D组与A组差异不显著；B、C、D组CD3^＋、CD4^＋和CD8^＋T细胞数均相对减少，CD4^＋CD25^＋T细胞数有不同程度升高，与A组比较，D组的差异最为显著。结论联合应用CTLA4-Ig和抗CD40L单克隆抗体能更有效地抑制大鼠胰腺移植后排斥反应，其机制可能与Th1／Th2型细胞因子偏移及CD4^＋CD25^＋调节性T细胞增多等有关。     

T-cell activation, proliferation, and memory after cardiac transplantation in vivo

OBJECTIVE: To study the response of alloantigen (H2Kb)-specific T cells to a H2b+ cardiac allograft in vivo. SUMMARY BACKGROUND DATA: The response of T cells to alloantigen has been well characterized in vitro but has proved more difficult to assess in vivo. The aim of these experiments was to develop a model of T-cell-mediated rejection where the response of T cells after transplantation of a cardiac allograft could be followed in vivo. METHODS: Purified CD8+ T cells from H2Kb-specific TCR transgenic mice (BM3; H2k) were adoptively transferred into thymectomized, T-cell-depleted CBA/Ca (H2k) mice. These mice were then transplanted with a H2Kb+ cardiac allograft. Using four-color flow cytometry, the proliferative response, modulation of activation markers, and potential cytokine production of the H2Kb-specific T cells was assessed after transplantation. RESULTS: Consistent rejection of H2Kb+ cardiac allografts required the transfer of at least 6 x 10(6) CD8+ H2Kb-specific T cells. Short-term analyses revealed that the transgenic-TCR+/ CD8+ T cells proliferated and became activated after transplantation of an H2Kb+ cardiac allograft. Fifty days after transplantation, the transgenic-TCR+/CD8+ T cells remained readily detectable, bore a predominantly memory phenotype (CD44hi), and rapidly produced interleukin 2 and interferon-gamma on in vitro restimulation. CONCLUSIONS: These data show that the activation of alloantigen-specific T cells can be followed in vivo in short-term and long-term experiments, thereby providing a unique opportunity to study the mechanisms by which T cells respond to allografts in vivo.     

CD8+ T cell subsets TC1 and TC2 cause different histopathologic forms of murine cardiac allograft rejection

BACKGROUND: CD4+ T cell effector function is sufficient to mediate allograft rejection, and it is suggested that CD8+ T cell-mediated effects are dependent on CD4+ T cell help. CD8+ T cells can be classified into at least two functional subsets: Tc1, producing high amounts of interferon (IFN)-gamma and Tc2, producing interleukin (IL)-4, -5, -10, and -13 and low levels of IFN-gamma. Because these subsets express different chemokine receptors, they may have different capabilities of migrating into grafts. Once in the graft, each subset may perform different effector functions dependent on the cytokines it produces. We asked whether allospecific CD8+ T cells, in the absence of CD4+ T cells, are capable of mediating rejection of a primarily vascularized allograft, and if Tcl and Tc2 cells differ in their ability to mediate rejection. METHODS: Hearts from H-2d mice were transplanted into H-2b RAG 1-/- recipients. Without manipulation, these fully mismatched allografts would survive indefinitely due to the absence of mature T and B cells. We adoptively transferred allo-(H-2d)-reactive Tcl or Tc2 cells from H-2b mice into each recipient. Grafts were harvested and analyzed on predefined timepoints, rejection was graded on a modified ISHLT scale. RESULTS: On day 7, grafts from Tc1- or Tc2-injected animals showed grade 1-2 parenchymal rejection with stable phenotype and comparable distribution of graft infiltrating CD8+ T cells. Adoptive transfer of IFN-gammahigh Tc1, but not of IFN-gammalow Tc2 cells was followed by the development of graft vasculitis, as well as graft arteriopathy. Adoptive transfer of IL-4high IL-5high Tc2, but not of IL-4low IL-5low Tc1 cells lead to extensive infiltration of eosinophils and formation of giant cells. CONCLUSIONS: Both Tc1 and Tc2 cells can mediate murine cardiac allograft rejection in the absence of CD4+ T cell help, although each subset elicits a different type of inflammatory response. In this model, cytokine secretion of either functional CD8+ T effector cell subset is an important effector mechanism in the process of allograft rejection: IFN-gammahigh Tc1 cells are important in early graft vasculitis, although IL-4high IL-5high Tc2 cells promote recruitment of secondary effectors like eosinophils.     

A novel model of allograft rejection: immune reconstitution of Rag-1 recipients with 2C transgenic T-cell receptor lymphocytes

The complexity of allorejection (cell activation, homing, and effector function) makes detailed studies difficult. We have developed a model of allograft rejection using purified monoclonal alloreactive effector cells. Immunodeficient C57Bl/6-Rag-1 (H-2(b)) recipients of Balb/c (H-2(d)) islet or skin grafts were reconstituted via adoptive transfer of splenocytes from 2C transgenic mice containing CD8+ cytotoxic effector cells directed against L(d). Recipients were assessed for engraftment, activation and homing of effector cells, and ability to reject grafts. Both unpurified 2C splenocytes and purified 2C/CD8+ cells durably reconstitute immunodeficient mice. Naive 2C effector cells reject skin grafts, but not islet allografts. However, when effector cells are primed prior to reconstitution, islet allografts are rejected. Using this model, blockade of adhesion molecules LFA-1 and alpha4-integrin delayed infiltration of islet allografts and prolonged allograft survival. This model of allorejection may be useful to study the activation and homing of allospecific cells in vivo.     

Alloantigen-specific CD4+ regulatory T cells induced in vivo by ultraviolet irradiation after alloantigen immunization require interleukin-10 for their induction and activation,and flexibly mediate bystander immunosuppression of allograft rejection

Ultraviolet (UV) irradiation prior to antigen immunization is employed to induce antigen-specific regulatory T cells (Tregs). UV-induced Tregs demonstrate unique bystander suppression, although antigen-specific activation is required initially. We previously reported the phenotype of alloantigen-specific transferable Tregs induced by UV-B irradiation after immunization was the same as T regulatory type 1-like CD4⁺ T cells, with antigen-specific interleukin (IL)-10 production. Here, by using semi-allogeneic transplantation models in vivo, we investigated the role of IL-10 in the induction and activation of these Tregs, and the possibility of bystander suppression of third-party allograft rejection. Naïve mice (H-2^b) were immunized with alloantigen (H-2^b/d), and received UV-B irradiation (40 kJ/m²) 1 week later. Four weeks afterwards, splenic CD4⁺ T cells were purified from the UV-irradiated immunized mice, and were transferred into naïve mice (H-2^b). Allografts expressing the same alloantigen as T-cell donors were immunized against (H-2^b/d) or an irrelevant alloantigen (H-2^b/k) were transplanted to CD4⁺ T-cell-transferred mice, and an alloantigen-specific prolongation of allograft survival observed. Experiments where IL-10 was neutralized by monoclonal antibody in the induction or effector phase revealed that IL-10 is critical, not only for induction but also for immunosuppressive function of CD4⁺ Tregs induced by UV irradiation after alloantigen immunization. Third-party allografts (H-2^d/k) were transplanted to CD4⁺ T-cell-transferred mice, and graft survival was also prolonged. Even a graft only partially compatible with immunized alloantigen worked well in vivo to activate CD4⁺ Tregs induced by UV irradiation after alloantigen immunization, which resulted in the bystander suppression of third-party allograft rejection.     

Allorecognition and effector pathways of islet allograft rejection in normal versus nonobese diabetic mice

Islet transplantation is becoming an accepted therapy to cure type I diabetes mellitus. The exact mechanisms of islet allograft rejection remain unclear, however. In vivo CD4(+) and CD8(+) T cell-depleting strategies and genetically altered mice that did not express MHC class I or class II antigens were used to study the allorecognition and effector pathways of islet allograft rejection in different strains of mice, including autoimmunity-prone nonobese diabetic (NOD) mice. In BALB/c mice, islet rejection depended on both CD4(+) and CD8(+) T cells. In C57BL/6 mice, CD8(+) T cells could eventually mediate islet rejection by themselves, but they produced rejection more efficiently with help from CD4(+) T cells stimulated through either the direct or indirect pathway. In C57BL/6 mice, CD4(+) T cells alone caused islet rejection when only the direct pathway was available but not when only the indirect pathway was available. In contrast, in NOD mice, CD4(+) T cells alone, with only the indirect pathway, could mediate islet and cardiac allograft rejection. These findings indicate that different mouse strains can make use of different pathways for T cell-mediated rejection of islet allografts. In addition, they demonstrate that NOD mice, which develop autoimmunity and are known to be resistant to tolerance induction, have an unusually powerful CD4(+) cell indirect mechanism that can cause rejection of both islet and cardiac allografts. These data shed light on the mechanisms of islet allograft rejection in different responder strains, including those with autoimmunity.     

CD103分子介导CD8+T淋巴细胞对同种胰岛移植物的损伤

目的 检验CD103分子是否介导了CD8+T淋巴细胞对同种移植胰岛的免疫损伤.方法 用流式细胞仪检测野生型C57BL/6小鼠外周血CD8+T淋巴细胞表达CD103的情况.以Balb/c小鼠为供者,C57BL/6小鼠为受者,制作同种胰岛移植模型.受者分为3组:M290-SAP组小鼠注射CD103免疫毒素M290-SAP;M290组小鼠注射抗CD103单克隆抗体M290;另以仅接受胰岛移植、不注射任何药物的小鼠为未处理组.检测移植胰岛CD3、CD8、CD44和CD103阳性细胞的表达,检测肠系膜淋巴结中CD3、CD8和CD103阳性细胞的表达.移植物功能丧失或观察期结束时获取移植胰岛,行HE染色和免疫组织化学染色.结果 野生型C57BL/6小鼠外周血的CD8+T淋巴细胞中有44.06%表达CD103.未处理组移植胰岛浸润的细胞成分中有29%的CD8+T淋巴细胞表达CD103.M290-SAP组小鼠淋巴细胞不仅丧失了CD103的表达,而且CD8+T淋巴细胞的绝对数量也减少,该组小鼠血糖稳定时间超过100 d(未处理组为13 d,P＜0.05),移植胰岛组织学形态良好.结论 CD8+T淋巴细胞免疫损伤同种移植胰岛必须表达CD103,CD103有可能成为胰岛移植抗排斥反应治疗的新靶点.

Abstract：

Objective To test whether the CD103 molecule mediates CD8+ T lymphocytes on allogeneic islet graft immune injury. Methods By using flow cytometry, the expression of CD103 in peripheral CD8+ T lymphocytes in wild-type C57BL/6 mice was detected. Allogenic islet transplantation models were made using Balb/c donor mice and C57BL/6 recipient mice. Recipients were divided into 3 groups: M290-SAP-treated mice were injected with CD103 immunotoxin M290-SAP; M290-treated mice were injected with CD103 monoclonal antibody M290; untreated mice were only transplanted islet without any drug treatment. CD3, CD8, CD44 and CD103 positive cells were counted in islet allograft infiltrative lymphocytes. CD3, CD8, and CD103 positive cells were measured in the mesenteric lymph node. The islet allografts were removed and subjected to HE staining and immunohistochemical staining at the time of graft loss or the end of the observation period. Results 44. 06% peripheral CD8+ T cells expressed CD103 in wild-type C57BL/6 mice. 29 % CD8+ T cells expressed CD103 in the infiltrative lyrnphocytes of islet allografts in the untreated mice. In M290-SAP-treated mice, the lymphocytes had no CD103 expression and the absolute number of CD8+ lymphocytes was decreased as well The blood glucose was maintained stable for more than 100 days (13 days in untreated group, P＜0.05) in the M290-SAP-treated mice. Moreover, the transplanted islets retained intact. Conclusion CD103 expression is required for destruction of pancreatic islet allograft by CD8+ T cells. CD103 might provide a novel target for therapeutic intervention in islet allograft rejection.     

Mediation of skin allograft rejection in scid mice by CD4+ and CD8+ T cells.

We analyzed the role of CD4+ and CD8+ T cells in H-2-disparate skin allograft rejection in the mutant mouse strain C.B-17/Icr scid with severe combined immunodeficiency. On the day of skin allografting, scid mice were adoptively transferred with negatively selected CD4+ or CD8+ splenocytes from normal unsensitized C.B-17/Icr mice. These populations were obtained using a double-mAb--plus--complement elimination protocol using anti-CD4 or anti-CD8 mAb that resulted in no detectable CD4+ or CD8+ cells by FACS and negligible numbers of cytolytic T lymphocytes by limiting dilution analysis in anti-CD8 treated populations. Spleen cells were removed from grafted mice at the time of rejection and were tested in vitro for antidonor reactivity in several assays: mixed lymphocyte culture, cell-mediated lympholysis, and LDA for CTL and for IL-2-producing HTL. The presence of Thy 1.2+, CD4+, or CD8+ cells was determined by FACS. All control C.B-17 mice and scid mice adoptively transferred with nondepleted CD4+, and CD8+ cells rejected skin allografts with similar mean survival times (15.6 +/- 1.5, 18.8 +/- 3.4, 18.0 +/- 5.4, respectively), whereas control scid mice retain skin allografts indefinitely (all greater than 100 days). C.B-17 syngeneic grafts survived indefinitely in all groups. At the time of rejection, splenocytes from scid mice receiving CD4+ cells had negligible donor-specific cytotoxicity in CML and negligible numbers of CTL by LDA, but demonstrated a good proliferative response in MLC and IL-2-producing cells by LDA (frequency = 1/1764). There were no detectable CD8+ cells present by FACS analysis. Conversely, splenocytes from scid mice adoptively transferred with CD8+ cells had strong donor-specific cytotoxicity in CML (58.8% +/- 16.1%) and CTL by LDA (frequency = 1/3448), but no significant proliferation was detected in MLC. There were no detectable CD4+ cells by FACS, but there were small numbers of IL-2-producing cells by LDA (frequency = 1/10,204). These data demonstrate that CD4+ cells adoptively transferred into scid mice are capable of mediating skin allograft rejection in the absence of any detectable CD8+ cells or significant functional cytolytic activity. The adoptive transfer of CD8+ cells also results in skin allograft rejection in the absence of detectable CD4+ cells. The detection of small numbers of IL-2 secreting cells in these mice may indicate that CD(8+)-mediated allograft rejection in this model is dependent on IL-2-secreting CD8+ cells.     

CD4+ T-cell-independent rejection of corneal allografts

BACKGROUND: Several studies suggest that a significant number of corneal allografts undergo rejection in the absence of CD4 T cells. This study examined the role of CD4 T cell-independent mechanisms of corneal allograft rejection. METHODS: BALB/c corneal allografts were transplanted to C57BL/6 beige nude mice that received either CD8 or CD8 T cells from C57BL/6 CD4 knockout (KO) mice that had rejected BALB/c corneal allografts. Immune effector functions of CD8 or CD8 T cells from C57BL/6 CD4 KO mice were assessed using delayed-type hypersensitivity assays and Annexin V apoptosis assays respectively. RESULTS.: Both CD8 and CD8 T cells from CD4 KO corneal allograft rejector mice mediated corneal allograft rejection following adoptive transfer to nude mice. CD8 T cells, but not CD8 T cells, from CD4 KO mice adoptively transferred donor-specific DTH and induced apoptosis of BALB/c corneal endothelial cells in vitro. Apoptosis of BALB/c corneal endothelial cells was mediated by double negative (DN) T cells, as treatment of CD8 cells from CD4 KO mice with anti-Thy 1.2 plus complement abolished their effector function. CONCLUSION: The results support the proposition that CD4 T cell-independent rejection of corneal allografts can be mediated by either CD8 or CD8 T cells. The CD8 T cells represent a unique DN T cell population that might mediate rejection by either direct cytolysis or by inducing apoptosis of the donor corneal endothelium.     

CD8(+) T cells resistant to costimulatory blockade are controlled by an antagonist interleukin-15/Fc protein

BACKGROUND: Although permanent engraftment is often achieved with new therapeutics, chronic rejection and graft failure still occur. As the importance of CD8(+) T cells in rejection processes has been underlined in various transplant models, and as interleukin (IL)-15 is involved in the activation of CD8(+) T cells, we hypothesize that CD8(+) T cell "escape" from costimulation blockade might be a IL-15/IL-15R dependent process. METHODS: In a murine islet allograft model employing a fully major histocompatibility complex-mismatched strain combination of Balb/c donors to CD4 C57BL/6 recipients, a monotherapy with the IL-15 antagonist, IL-15 mutant/Fcgamma2a, or the costimulatory blockade molecule, CTLA4/Fc, was used. In addition to monitoring graft survival, infiltration of alloreactive immune cells was analyzed by histology and immunohistochemistry, and alloimmune response of proliferative CD8(+) T cells was measured in vivo. RESULTS: Sixty percent of the recipients treated with CTLA4/Fc acutely rejected their islet allograft, comparable to untreated control animals (50% survival). In contrast, the IL-15 antagonist proved to be highly effective, with 100% of recipients accepting their allograft. Immunohistology study demonstrated a remarkable decrease of CD8(+) T-cell intragraft infiltration in IL-15 mutant/Fcgamma2a treated animals with well-preserved islet architecture and a reduced frequency of proliferating alloreactive CD8(+) T cells in comparison with that of untreated and CTLA4/Fc treated groups. CONCLUSIONS: In this study, we determined the efficacy and potential therapeutic benefit of the IL-15 antagonist on CD4-independent CD8(+) T-cell responses to alloantigens. Targeting the IL-15/IL-15R pathway represents a potent strategy to prevent rejection driven by CD8(+) T cells resistant to costimulation blockade.     

Tim-3在小鼠心脏移植受者体内不同部位T淋巴细胞上表达的变化

目的 检测激活的T_H1类淋巴细胞标记分子"T淋巴细胞免疫球蛋白域及粘蛋白域蛋白-3(Tim-3)"在受者体内不同部位T淋巴细胞上表达的变化,探讨其与急性排斥反应的关系.方法 建立小鼠同基因和异基因心脏移植模型(简称:同基因组和异基因组);移植术后第3和第6天,分离和制备两组受者外周血、脾脏、引流淋巴结和移植心内淋巴细胞悬液,采用流式细胞仪检测Tim-3阳性细胞在CD4~+ 和CD8~+ T淋细胞中的比值.结果 两组受者术后外周血和脾脏内Tim-3~+/CD4~+以及Tim-3~+/CD8~+ 的比值比较,差异均无统计学意义(P>O.05).与同基因组比较,异基因组引流淋巴结内Tim-3~+/CD4~+ 比值轻度升高(P<0.05);但异基因组术后第6天与第3天比较,差异无统计学意义(P>0.05).与同基因组比较,移植心内Tim-3~+/CD4~+和TiM-3~+/CD8~+比值均显著升高(P<0.01);异基因组术后第6天与第3天比较.移植心TiM-3~+/CD4~+和Tim-3~+/CD8~+比值也显著升高(P<0.01).结论 小鼠异基因心脏移植受者引流淋巴结和移植心内T淋巴细胞上Tim-3的表达升高与急性排斥反应的进展动态相关.