CXC趋化因子受体6在小鼠心脏移植排斥反应中的表达及意义

目的 研究CXC趋化因子受体6(CXCR6)在同种异体小鼠心脏移植中的表达及CXC趋化因子配体16(CXCL16)与CXCR6相互作用对移植物存活时间的影响.方法 以野生型Balb/c小鼠(H-2d)为供者(同种移植组),或以野生型C57BL/6小鼠(H-2b)为供者(同系移植组),以野生型C57BL/6小鼠为受者分别行小鼠腹腔异位心脏移植.测定同系和同种移植组小鼠移植心脏CXCR6mRNA的表达,并测定受者脾脏CD8+T淋巴细胞CXCR6的表达.另制作小鼠同种异位心脏移植模型(Balb/c小鼠为供者,C57BL/6小鼠为受者),将其分为实验组和对照组,实验组受者移植当天至发生排斥反应时腹腔注射抗CXCL16抗体,对照组受者同期注射对照抗体.记录两组移植心脏存活时间.进行CD8+T淋巴细胞的细胞毒试验,即用Balb/c小鼠脾细胞免疫C57BL/6小鼠后,获取C57BL/6小鼠脾脏CD8+T淋巴细胞,将Balb/c小鼠脾细胞与C57BL/6小鼠CD8+T淋巴细胞混合培养,分别加入抗CXCL16抗体、小鼠IgG(对照抗体)和抗CD40L抗体.结果 同种移植组移植心脏中CXCR6 mRNA的表达以及脾脏CD8+T淋巴细胞上CXCR6的表达均高于同系移植组和正常对照组.抗CXCL16抗体对CD8+T淋巴细胞的细胞毒活性无影响.与对照组相比较,实验组小鼠移植心脏存活时间并未明显延长.结论 小鼠心脏移植排斥反应中CD8+T淋巴细胞CXCR6的表达上升,阻断CXCL16/CXCR6相互作用并不能延长移植心脏的存活时间.     

CXC趋化因子受体6在小鼠心脏移植排斥反应中的表达及意义

目的 研究CXC趋化因子受体6(CXCR6)在同种异体小鼠心脏移植中的表达及CXC趋化因子配体16(CXCL16)与CXCR6相互作用对移植物存活时间的影响.方法 以野生型Balb/c小鼠(H-2d)为供者(同种移植组),或以野生型C57BL/6小鼠(H-2b)为供者(同系移植组),以野生型C57BL/6小鼠为受者分别行小鼠腹腔异位心脏移植.测定同系和同种移植组小鼠移植心脏CXCR6mRNA的表达,并测定受者脾脏CD8+T淋巴细胞CXCR6的表达.另制作小鼠同种异位心脏移植模型(Balb/c小鼠为供者,C57BL/6小鼠为受者),将其分为实验组和对照组,实验组受者移植当天至发生排斥反应时腹腔注射抗CXCL16抗体,对照组受者同期注射对照抗体.记录两组移植心脏存活时间.进行CD8+T淋巴细胞的细胞毒试验,即用Balb/c小鼠脾细胞免疫C57BL/6小鼠后,获取C57BL/6小鼠脾脏CD8+T淋巴细胞,将Balb/c小鼠脾细胞与C57BL/6小鼠CD8+T淋巴细胞混合培养,分别加入抗CXCL16抗体、小鼠IgG(对照抗体)和抗CD40L抗体.结果 同种移植组移植心脏中CXCR6 mRNA的表达以及脾脏CD8+T淋巴细胞上CXCR6的表达均高于同系移植组和正常对照组.抗CXCL16抗体对CD8+T淋巴细胞的细胞毒活性无影响.与对照组相比较,实验组小鼠移植心脏存活时间并未明显延长.结论 小鼠心脏移植排斥反应中CD8+T淋巴细胞CXCR6的表达上升,阻断CXCL16/CXCR6相互作用并不能延长移植心脏的存活时间.     

CXC趋化因子受体6在小鼠心脏移植排斥反应中的表达及意义

目的 研究CXC趋化因子受体6(CXCR6)在同种异体小鼠心脏移植中的表达及CXC趋化因子配体16(CXCL16)与CXCR6相互作用对移植物存活时间的影响.方法 以野生型Balb/c小鼠(H-2d)为供者(同种移植组),或以野生型C57BL/6小鼠(H-2b)为供者(同系移植组),以野生型C57BL/6小鼠为受者分别行小鼠腹腔异位心脏移植.测定同系和同种移植组小鼠移植心脏CXCR6mRNA的表达,并测定受者脾脏CD8+T淋巴细胞CXCR6的表达.另制作小鼠同种异位心脏移植模型(Balb/c小鼠为供者,C57BL/6小鼠为受者),将其分为实验组和对照组,实验组受者移植当天至发生排斥反应时腹腔注射抗CXCL16抗体,对照组受者同期注射对照抗体.记录两组移植心脏存活时间.进行CD8+T淋巴细胞的细胞毒试验,即用Balb/c小鼠脾细胞免疫C57BL/6小鼠后,获取C57BL/6小鼠脾脏CD8+T淋巴细胞,将Balb/c小鼠脾细胞与C57BL/6小鼠CD8+T淋巴细胞混合培养,分别加入抗CXCL16抗体、小鼠IgG(对照抗体)和抗CD40L抗体.结果 同种移植组移植心脏中CXCR6 mRNA的表达以及脾脏CD8+T淋巴细胞上CXCR6的表达均高于同系移植组和正常对照组.抗CXCL16抗体对CD8+T淋巴细胞的细胞毒活性无影响.与对照组相比较,实验组小鼠移植心脏存活时间并未明显延长.结论 小鼠心脏移植排斥反应中CD8+T淋巴细胞CXCR6的表达上升,阻断CXCL16/CXCR6相互作用并不能延长移植心脏的存活时间.     

大鼠肝移植排斥反应时γ干扰素及白细胞介素10的表达及意义

目的 探讨大鼠肝移植排斥反应时γ干扰素(IFN-γ)及白细胞介素10(IL-10)的表达及意义.方法 采用改良的Kamada"二袖套法"制备大鼠原位肝移植模型,同系移植组供、受者均为SD大鼠;同种异体移植组的供者为Wistar大鼠,受者为SD大鼠;另设假手术组.术后7 d处死动物,观察移植肝脏的组织学变化,检测血清IFN-γ和IL-10的含量,以及移植肝脏内IFN-γ和IL-10 mRNA的表达.结果 同种异体移植组移植肝脏有较多坏死肝细胞,汇管区及中央静脉周围可见以淋巴细胞为主的炎症细胞浸润,胆管上皮细胞可见胞浆空泡变性、核固缩或碎裂,整个肝小叶结构紊乱.同系移植组肝脏组织结构仅有轻度缺血再灌注损伤表现,汇管区有较少炎症细胞浸润,胆管上皮细胞结构和肝小叶结构基本正常.同种异体移植组血清IFN-γ为(386.7±14.4)Pg/ml,明显高于同系移植组的(159.8±16.5)pg/ml(P<0.05);同种异体移植组血清IL-10为(126.3±13.1)pg/ml,明显低于同系移植组的(288.3±17.1)pg/ml(P<0.05).同种异体移植组移植肝组织内IF-γ mRNA表达水平明显高于同系移植组(P<0.05),而IL-10 rnRNA表达水平明显低于同系移植组(P<0.05).结论 大鼠肝移植排斥反应时IFN-γ表达明显升高,IL-10表达明显降低;T_H1/T_H2型细胞因子的动态平衡可能在大鼠肝移植排斥反应中起着重要作用.     

门静脉输注供者脾细胞诱导的供者特异性免疫低反应性

目的 探讨经门静脉输注供者脾细胞能否诱导皮肤移植小鼠产生供者特异性的免疫低反应性及其可能机制.方法 取Balb/c小鼠,随机分为空白对照组(经小鼠门静脉输注RPMI 1640培养液)、受者脾细胞组(经小鼠门静脉输注Balb/c小鼠脾细胞)、供者脾细胞组(经小鼠门静脉输注C57BL/6小鼠脾细胞)、空白移植对照组(经小鼠门静脉输注RPMI 1640培养液,7 d后移植C57BL/6小鼠的皮肤)、实验对照组(经小鼠门静脉输注Balb/c小鼠脾细胞,7 d后移植C57BL/6小鼠的皮肤)、实验组(经小鼠门静脉输注C57BL/6小鼠脾细胞,7 d后移植C57BL/6小鼠的皮肤)以及第三方移植组(经小鼠门静脉输注C57BL/6小鼠脾细胞,7 d后移植C3H小鼠的皮肤).记录空白移植对照组、实验对照组、实验组和第三方移植组移植皮肤的存活时间,并观察移植皮肤的病理学变化;脾细胞输注后7 d,分别获取空白对照组、受者脾细胞组和供者脾细胞组小鼠的外周血、脾脏和肝脏,用流式细胞仪测定样本中CD4+CD25+Foxp3+调节性T淋巴细胞(CD4+CD25+Foxp3+Treg细胞)的比例.结果 实验组移植皮肤的存活时间为(19.8±4.6)d,明显长于空白移植对照组、实验对照组和第三方移植组,但仍未达到长期存活.皮肤移植后7 d,空白移植对照组和实验对照组的移植皮肤呈现重度急性排斥反应的病理学改变,而实验组移植皮肤呈现中度急性排斥反应的病理学改变.供者脾细胞组外周血、肝脏和脾脏中CD4+CD25+Foxp3+Treg细胞比例明显高于空白对照组和受者脾细胞组.结论 门静脉输注供者脾细胞可特异性地延长供者皮肤移植物的存活时间,减轻移植物的排斥反应,该效应可能与受者体内的CD4+CD25+Foxp3+Treg细胞增加有关.     

输注负载胎盘滋养层细胞抗原的受者aaDC延长小鼠移植心的存活时间

目的 探讨输注负载供者胎盘滋养层细胞抗原的受者耐受性选择性激活树突状细胞(aaDC)对小鼠移植心存活时间的影响.方法 雌性Balb/c小鼠和雄性C57BL/6小鼠合笼后,获取雌鼠胎盘滋养层细胞,并提取其抗原.体外制备Balb/c小鼠的aaDC,分别与滋养层细胞抗原或者C57BL/6小鼠脾细胞抗原共培养,获得负载滋养层细胞抗原或者C57BL/6小鼠脾细胞抗原的aaDC,测定培养液中白细胞介素10(IL-10)和IL-12的含量以及aaDC表面CD40、CD80、CD86和主要组织相容性复合物(MHC)Ⅱ类分子的表达.取Balb/c小鼠,分别接受负载滋养层细胞抗原或者C57BL/6小鼠脾细胞抗原的aaDC输注(滋养层细胞抗原组和脾细胞抗原组),7 d后接受C57BL/6小鼠心脏异位移植,以注射生理盐水者为对照组,输注负载滋养层细胞抗原aaDC后接受昆明小鼠心脏移植者为第三供者对照组.术后记录移植心存活时间,并检测受者脾脏和移植心组织中IL-2、IL-10和γ干扰素(IFN-7)mRNA的表达.结果 负载脾细胞抗原的aaDC,CD86和MHCⅡ类分子的表达明显升高,而负载滋养层细胞抗原的aaDC,仅MHCⅡ类分子表达升高.滋养层细胞抗原aalDC的培养液中,IL-10为(122.6±15.4)ng/L,IL-12为(232.8±25.4)ng/L,空白对照aaDC的IL-10和IL-12分别为(35.4±8.5)ng/L和(267.3±12.5)ng/L,二者间IL-10的差异有统计学意义(P<0.05),而IL-12的差异无统计学意义(P>0.05).脾细胞抗原aaDC培养液中的IL-10和IL-12与空白对照aaDC相近,差异均无统计学意义(P>0.05).对照组移植心存活时间为(6.73±0.58)d,脾细胞抗原组为(12.28±0.76)d,滋养层细胞抗原组为(38.83±2.79)d,第三供者对照组为(6.68±0.62)d.滋养层细胞抗原组移植心存活时间明显长于脾细胞抗原组和对照组(P<0.01),而第三供者对照组和对照组间移植心存活时间的差异无统计学意义(P>0.05).结论 预先输注负载供者胎盘滋养层细胞抗原的受者aaDC,可延长小鼠移植心的存活时间.     

酶联免疫斑点技术在心脏移植术后早期诊断急性排斥反应中的作用

目的 探讨酶联免疫斑点技术(ELISPOT)在心脏移植术后早期诊断急性排斥反应中的作用及在供者评估方面的应用价值.方法 采用小鼠腹部心脏移植模型,将实验小鼠分为3组,每组25对.(1)移植排斥组:供者为C57BL/6小鼠,受者为BALB/c小鼠,移植后无特殊处理;(2)实验处理组:供者为C57BL/6小鼠,受者为BALB/c小鼠,受者在移植术前1天经尾静脉输注特异性供者脾细胞,术前1 d及术后1周按每克体重应用环孢素A 5 μg;(3)同系移植组:供、受者均为BALB/c小鼠,移植术后无特殊处理.术后观察移植心存活时间及病理改变;应用ELISPOT技术检测受者脾细胞悬液中供者γ干扰素(IFN-γ)活性分泌细胞频数.结果 移植排斥组和实验处理组移植心平均存活时间分别为(7.8±0.77)d和(14.80±1.01)d,同系移植组存活时间均超过28 d,各组之间的差异有统计学意义(P＜0.05).移植排斥组与实验处理组和同系移植组相比较,移植心的心肌细胞变性坏死严重,并有大量炎性细胞浸润.移植术后第4天,移植排斥组、实验处理组和同系移植组受者脾细胞悬液中供者特异性IFN-γ活性分泌细胞频数分别为(288±16)个/2×105、(32±10)个/2×105和(6±2)个/2x105;第7天为(416±19)个/2×105、(44±8)个/2×105和(7±2)个/2×105;其与相应的移植心存活时间存在明显负相关,而与术后第7天病理分级存在明显正相关.结论 应用ELISPOT技术检测受者术后早期供者特异性IFN-γ活性分泌细胞频数可作为急性排斥反应的一个早期诊断指标.此技术具有较高的灵敏性与特异性,可用于术前供者配型.     

并发闭塞性细支气管炎的移植气管组织中核因子κB和肿瘤坏死因子的表达及意义

目的 探讨小鼠移植气管组织中核因子κB(NF-κB)和肿瘤坏死因子-α(TNF-α)的表达及其在闭塞性细支气管炎(OB)中的作用.方法 实验分为实验组和同系移植对照组,实验组受者为C57BL/6小鼠,同系移植对照组受者为Balb/c小鼠,供者均为Balb/c小鼠.将2支供者气管分别移植于受者两侧背部,术后7、14、21 d 2组分别处死受者7只,取移植气管,于光学显微镜下观察并计算移植气管截面的管腔闭塞率.用免疫组织化学法和Western印迹法检测移植气管组织中NF-κB和TNF-α的表达;用凝胶电泳迁移率改变法检测NF-κB的转录活性;用逆转录聚合酶链反应法检测TNF-α mRNA的表达.结果 实验组移植后14 d和21 d时的管腔闭塞率分别为(31±7)%和(80±17)%,并可见移植气管发生OB病理改变,而同系移植对照组未见此改变.免疫组织化学法和Western印迹法结果均显示.实验组各个时点移植气管组织中NF-κB和TNF-α的表达均高于同系移植对照组.实验组移植后7、14和21 d时,NF-κB基冈的转录活性分别为1.35±0.52、1.72±0.43和2.43±0.33,均高于同时点同系移植对照组的转录活性(P＜0.01,P＜0.05,P＜0.05);实验组各时点TNF-α mRNA的表达均高于同系移植对照组(P＜0.05,P＜0.05,P＜0.05).结论 发生OB的小鼠移植气管组织中NF-κB出及其下游靶基因TNF-α的表达升高.     

术前输注供者脾细胞联合应用西罗莫司延长小鼠移植心存活时间的机理

目的探讨移植术前输注供者脾细胞(DST)联合应用西罗莫司(SRL)延长小鼠移植心存活时间的机理。方法单向混合淋巴细胞培养中的刺激细胞及静脉输注的脾细胞均采用经丝裂霉素C处理后失去增殖活性的Balb/c(H-2~d)小鼠脾细胞(包括体外实验和体内实验)。(1)体外实验:分为3组,空白对照组:取正常C57BL/6(H-2~b)小鼠(B6小鼠)的脾细胞作为反应细胞;SRL组:取用SRL(1.5μl·g~(-1)·d~(-1))灌胃7 d后的B6小鼠脾细胞作为反应细胞;DST SRL组:取行脾细胞静脉输注8 d、次日予SRL(1.5μl·g~(-1)·d~(-1))灌胃7 d后的B6小鼠的脾细胞作为反应细胞。观察各组在单向混合培养中的脾细胞增殖能力。(2)体内实验:Balb/c小鼠为供者,B6小鼠为受者,建立颈部异位心脏移植模型。实验分为3组,空白对照组:单纯行心脏移植;DST组:受者移植前8 d给予供者脾细胞静脉输注;DST SRL组:受者移植前8 d给予供者脾细胞静脉输注,次日予以SRL灌胃7d(1.5μl·g~(-1)·d~(-1))。术后观察各组移植心的存活时间、病理表现、受者淋巴细胞中CD4~ CD25~ 调节性T细胞(Tr细胞)和凋亡细胞比例的改变及同种抗原刺激后增殖活性变化。结果体外实验中,DST SRL组反应细胞增殖活性平均为(13.76±2.81)%,明显低于空白对照组(28.14%±5.53%,P<0.05)。体内实验中,空白对照组、DST SRL组以及DST组移植心平均存活时间分别为(8.6±0.48)d、(35±14.4)d和(4.83±0.52)d,DST SRL组存活时间显著延长(P<0.05);流式细胞术(FACS)分析显示DST SRL组脾细胞中CD4~ CD25~ Tr细胞比例平均为(3.39±0.21)%,明显高于空白对照组(1.57%±0.3%,P<0.05)。结论移植术前输注供者脾细胞联合应用西罗莫司可通过清除同种反应性T细胞克隆,增加受者体内CD4~ CD25~ Tr细胞的比例,减低对同种抗原的应答能力,从而延长同种小鼠移植心存活时间。     

体内注射白细胞介素10和转化生长因子质粒延长小鼠移植皮肤存活时间

目的 探讨体内注射白细胞介素10(IL-10)和转化生长因子β1(TGF-β1)质粒对小鼠移植皮肤存活时间的影响.方法 构建含IL-10和TGF-β1基因的质粒,以Balb/c小鼠为受者、Balb/c小鼠与C57BL/6小鼠杂交的F1代小鼠为供者,行皮片移植.移植当天,经尾静脉分别给受者快速注射不含基因的空白质粒(空白组)、含IL-10基因质粒(IL-10组)、含TGF-β1基因质粒(TGF-β1组)以及含IL-10和TGF-β1双基因的质粒(联合组),以后每2天注射1次,20 μg/次,共注射6次,观察移植皮肤存活时间.另取Balb/c小鼠,在输注C57BL/6小鼠脾细胞后,按前述分组及方法接受质粒快速注射,注射5次后,分离其脾细胞,以流式细胞仪检测脾细胞中CD4+ CD25+ T淋巴细胞含量.结果 移植皮片存活时间,空白组为(13.50±1.04)d,IL-10组为(13.83±1.16)d,TGF-β1组为(15.33±1.50)d,联合组为(21.33±3.20)d,联合组移植皮片存活时间明显长于其他3组(P<0.01).脾细胞中CD4+ CD25+ T淋巴细胞的含量,空白组为(6.58±1.86)%,IL-10组为(10.52±1.13)%,TGF-β1组为(14.44±0.42)%,联合组为(14.25±1.24)%,TGF-β1组和联合组的CD4+ CD25+ T淋巴细胞含量明显高于空白组和IL-10组(P<0.01).结论 体内注射IL-10和TGF-β1质粒可延长小鼠移植皮肤存活时间,并能提高CD4+ CD25+ T淋巴细胞含量.     

白细胞介素-15在心脏移植排斥反应中的表达及意义

目的 探讨白细胞介素-15（IL-15）在心脏移植排斥反应中的表达及其与排斥反应的关系。方法 采用小鼠颈部心脏移植模型，随机分为2组：同基因移植组，供、受体均为C57BL／6小鼠；异基因移植组，供、受体分别为BALB／C、C57BL／6小鼠。以pactin作内参照，分别于术后第1、3、5、7天取移植心脏，用逆转录-聚合酶链式反应（RT—PCR）法观察IL-15的表达情况。结果 随着术后天数的增加，异基因移植组IL-15表达逐渐升高，第5天达高峰（与同基因移植组相比，P〈0．01）。结论 IL-15的表达与心脏移植急性排斥反应的发生发展密切相关，可作为心脏移植急性排斥反应的监测指标，对急性排斥反应的早期诊断和移植物的预后估计具有重要的临床意义。     

Early increased chemokine expression and production in murine allogeneic skin grafts is mediated by natural killer cells

BACKGROUND: Increased expression of chemokine mRNA is observed in allogeneic but not syngeneic skin grafts 3-4 days after transplantation. The recipient cells mediating this early inflammatory response in allografts remain unidentified. METHODS: Isogeneic and allogeneic skin grafts were transplanted to euthymic and athymic nude mice. mRNA expression and protein production of macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-1beta, and the murine homolog of Gro(alpha), i.e. KC, from graft homogenates retrieved 3-4 days posttransplantation was tested by Northern blot hybridization and ELISA. To deplete NK cells, recipients were treated with antiasialo GM1 (ASGM1) antisera or with anti-NK1.1 mAb before transplantation. RESULTS: Expression of KC, MIP-1alpha, and MIP-1beta mRNA was equivalent in C57BL/6 allogeneic skin grafts and BALB/c isografts at day 2 posttransplant. At day 3 posttransplant, chemokine mRNA levels decreased in isografts but were maintained at high levels in the allografts. Increased early chemokine mRNA was also observed in C57BL/6, but not BALB/c++ grafts on BALB/c athymi(nu/nu) recipients. Treatment of allograft recipients with ASGM1 or with anti-NK1.1 antibody eliminated NK cells from the spleen and allograft infiltrating cell populations and decreased early chemokine mRNA levels in allografts 60-70%. Analyses of allograft homogenates indicated increased levels of KC, MIP-1alpha, and MIP-1beta protein at day 4 posttransplant that were decreased in recipients depleted of NK cells. Early chemokine mRNA levels were equivalent in isogeneic and semiallogeneic F1 grafts. CONCLUSIONS: Early chemokine mRNA expression and protein production in allogeneic skin grafts is amplified by recipient natural killer (NK) cells. These results indicate a novel function for infiltrating NK cells in mediating early increased intra-allograft chemokine production and inflammation during the initiation of acute rejection.     

Antigen-specific T-regulatory cells can extend skin graft survival time in mice

This study investigated the effects of donor antigen-specific CD4(+)CD25(+) T-regulatory cells (Tregs) on skin allografts in mice. An allogeneic skin transplant model was established using donor C57BL/6 or DBA and recipient BALB/c mice. Recipients were divided into 4 groups: control group without intervention (CON; C57BL/6 to BALB/c), rapamycin gavage group (RAP; C57BL/6 to BALB/c), CD4(+)CD25(+) Tregs-treated group (TRE; C57BL/6 to BALB/c), in which recipients received transfusions of CD4(+)CD25(+) Tregs stimulated with C57BL/6-derived immature dendritic cells, and the third-party donor group (DBA; DBA to BALB/c) in which recipients received transfusions of BALB/c CD4(+)CD25(+) Tregs stimulated with C57BL/6-derived immature dendritic cells. Mean (SD) survival time of the skin allografts in the TRE group was 17.0 (3.4) days, significantly longer than in the other groups: CON, 6.9 (1.9) days; RAP, 10.3 (3.0) days; and DBA, 10.8 (3.6) days. The TRE group demonstrated a significantly greater expression of transforming growth factor-β and interleukin (IL)-10. Donor antigen-specific CD4(+)CD25(+) Tregs effectively extend skin allograft survival in mice.     

Donor IL-6 deficiency evidently reduces memory T cell responses in sensitized transplant recipients

BackgroundResistance of tolerance induction in sensitized transplantation is mainly caused by generation of memory T cells. It is unknown whether alteration of graft niche such as level of pro-inflammatory cytokines can affect generation of memory T cells.MethodsIL-6 deficient or wild-type (WT) C57BL/6 heart grafts were transplanted into pre-sensitized wild-type BALB/c recipients. Frequencies of memory T cells in the peripheral blood, grafts, and spleen were evaluated.ResultsWe revealed that deficiency of donor IL-6 could significant prolong sensitized allograft survival. Compared with counterpart of WT group, frequency of effector memory CD4 + T cells (CD4 + CD44 + CD62L-) in the peripheral blood was significantly lower in the IL-6 KO group (p = .026) at day 3 post-transplantation. Frequency of effector memory CD8 + T cells (CD8 + CD44 + CD62L-) in the peripheral blood was significantly lower in the IL-6 KO group (p < .0001) at day 3 post-transplant in comparison to that of WT group. No significant difference of central memory T cells was found between these groups. Histology demonstrated that deficiency of donor pro-inflammatory cytokine IL-6 (IL-6 KO group) preserved cardiac architecture with a mild infiltration of lymphocytes, whereas wild-type donor (control group) caused an evident lymphocytic infiltration within myocardial fibers of grafts and destruction of cardiac structure.ConclusionDeficiency of pro-inflammatory IL-6 of donor graft could effectively prolong sensitized allograft survival, which was caused by a remarkable decrease of peripheral memory T cells rather than central memory T cells. This unveiled mechanism of targeting IL-6 signaling pathway might provide a novel insight into preventing allograft rejection for sensitized transplant recipients.     

Allogeneic bronchoalveolar lavage cells induce the histology and immunology of lung allograft rejection in recipient murine lungs: role of intercellular adhesion molecule-1 on donor cells

BACKGROUND: Intercellular adhesion molecule (ICAM)-1 expressed on accessory cells has a key role in antigen presentation. The histology and immunology of lung allograft rejection is postulated to result from donor lung accessory cells presenting alloantigens to recipient lymphocytes, and, therefore, ICAM-1 may have a crucial role in the rejection process. We have previously reported that the instillation of allogeneic (C57BL/6, I-a(b)) bronchoalveolar lavage (BAL) cells (96% macrophages, 2% dendritic cells) into the lungs of recipient BALB/c mice (I-a(d)) induced the histology and immunology of acute lung allograft rejection. Using this model, the purpose of the current study was to determine the role of ICAM-1 on donor lung cells in lung allograft rejection. METHODS: BALB/c mice received allogeneic BAL cells from wild-type or ICAM-1 mutant (lacking ICAM-1 expression) C57BL/6 mice by nasal insufflation weekly for 4 weeks. Recipient mice underwent BAL and serum collection for the determination of T helper 1/T helper 2 cytokines and IgG subtypes. Lung histology was graded using standard criteria for allograft rejection. RESULTS: Although wild-type cells induced a lymphocytic vasculitis and bronchitis, ICAM-1 mutant allogeneic BAL cells only induced a lymphocytic vasculitis in recipient lungs. Both wild-type and ICAM-1 mutant cells induced up-regulated local interferon-gamma and IgG2a production, and deposition of IgG2a in recipient lungs. CONCLUSIONS: These data show that ICAM-1 on donor lung accessory cells mediates differential effects on the histology and immunology of acute lung allograft rejection.     

A new T-cell receptor transgenic model of the CD4+ direct pathway: level of priming determines acute versus chronic rejection

BACKGROUND: T-cell receptor transgenic (TCR-tg) mouse models with direct CD4 alloreactivity will help elucidate mechanisms of transplant rejection and tolerance in vivo. Although such models exist, they are limited by unusual strain combinations or are based on model antigens. METHODS: A TCR-tg mouse with direct CD4 specificity in the widely used BALB/c donor --> C57BL/6 host strain combination was created. This TCR-tg mouse, named 4C, was selected for reactivity against BALB/c dendritic cells in order to model early priming events after transplantation. The response of 4C T cells to skin and heart transplants were characterized. RESULTS: The alloantigen is restricted by I-A and appears to be widely distributed in mouse tissues. 4C T cells are able to acutely reject skin but not heart allografts. Paradoxically, heart grafts elicited a stronger proliferation and effector function of TCR-tg T cells than skin grafts. 4C T cells caused cardiac allograft vasculopathy in the absence of other T cells and alloantibodies, suggesting a role for the direct pathway in chronic rejection. Augmentation of priming with an infusion of donor-derived dendritic cells resulted in acute heart allograft rejection by 4C T cells, demonstrating that the level of priming can play a role in determining acute versus chronic rejection by the CD4 direct pathway. CONCLUSIONS: Rejection of a graft by the direct CD4 pathway is determined by graft susceptibility to rejection, as well as the degree of T-cell priming caused by the graft. Grafts that are not acutely rejected can develop transplant vasculopathy mediated by the direct CD4 T cells.     

Infusion of Lin- bone marrow cells results in multilineage macrochimerism and skin allograft tolerance in minimally conditioned recipient mice

Donor-specific immunological tolerance using high doses of donor bone marrow cells (BMC) has been demonstrated in mixed chimerism-based tolerance induction protocols; however, the development of graft versus host disease (GVHD) remains a risk. In the present study, we demonstrate that the infusion of low numbers of donor Lin(-) bone marrow cells (Lin(-) BMC) 7 days post allograft transplantation facilitates high level macrochimerism induction and graft tolerance. Full-thickness BALB/c skin allografts were transplanted onto C57BL/6 mice. Mice were treated with anti-CD4 and anti-CD8 mAbs on day 0, +2, +5, +7 and +14 along with low dose busulfan on day +5. A low dose of highly purified Lin(-) BMC from BALB/c donor mice was infused on day +7. Chimerism and clonal cell deletion were evaluated using flow cytometry. Donor-specific tolerance was tested by donor and third-party skin grafting and mixed leukocyte reaction (MLR). Lin(-) BMC infusion with minimal immunosuppression led to stable, mixed, multilineage macrochimerism and long-term allograft survival (>300 days). Mixed donor-recipient macrochimerism was observed. Donor-reactive T cells were clonally deleted and a 130% increase in CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) was observed in the spleen. Tolerant mice subsequently accepted second donor, but not third-party (C3H), skin grafts and recipient splenocytes failed to react with allogeneic donor cells indicating donor-specific immunological tolerance was achieved. We conclude that the infusion of donor Lin(-) BMC without cytoreductive recipient conditioning can induce indefinite survival of skin allografts via mechanisms involving the establishment of a multilineage macrochimeric state principally through clonal deletion of alloreactive T cells and peripherally induced CD4(+)Foxp3(+) Tregs.     

Factors influencing the regulation of cytokine balance during islet transplantation in mice

Many experimental islet studies compare the effect of allogeneic transplantations with either syngeneically transplanted or sham-operated animals. Presently we examined multiple "control" treatments to be able to distinguish effects by the operating procedures themselves versus reactions induced by islet graft rejection. Herein, we have studied untreated, sham-operated, syngeneically or allogeneically (C57BL/6) islet transplanted BALB/c mice, and subsequently examined cytokine production (TNFalpha, IFNgamma, IL-4, IL-10, IL-17 and TGF-beta) in vitro by RT-PCR and ELISA in spleen cells and transplants. To investigate if the strain of the recipient mice influences cytokine production we also performed allogeneic islet transplantations in the reverse direction. So-called control treatments such as sham operations and syngeneic transplantations had a distinct effect on cytokines in spleen cells, possibly induced by surgery and/or anaesthesia. This seems to decrease the regulatory T cells, thereby leading to increased cytokine expression. Furthermore, spleen cells from surgically manipulated animals seem to have a decreased responsive capacity to con A stimulation in culture. Cytokine generation, FoxP3 mRNA expression and COX-2 mRNA expression in the two investigated mouse strains were sometimes altered in opposite directions by the treatments. In conclusion, the genetic background of both the islet donor and recipient has a major impact on both the magnitude and skewing of a cytokine response. Moreover, factors not directly related to allorejection influences systemic cytokine production in connection to islet transplantation.