CD4+CD25+调节性T细胞对小鼠肝脏移植自发性免疫耐受的影响

目的 研究CD4+CD25+调节性T细胞在诱导自发性肝脏免疫耐受中的作用.方法 向受体和供体注射抗CD25抗体(PC61)后进行小鼠原位肝脏移植,观测其生存时间.术后20～30 d切取移植肝脏行HE染色,同时观察CD4+CD25+T细胞对CD4+T细胞和CD8+T细胞功能的影响.结果 去除受体而不是供体小鼠的CD4+CD25+T细胞可以导致肝移植排斥反应.而且,去除CD4+CD25+T细胞使移植物的白细胞浸润明显增多,组织损伤加重.同时,去除CD4+CD25+T细胞导致CD4+T细胞的增殖活性和CD8+T细胞的细胞毒活性明显增强.结论 受体来源的CD4+CD25+调节性T细胞在小鼠肝脏移植免疫耐受诱导中起重要作用.

Abstract：

Objective To examine the contribution of CD4+ CD25+ regulatory T cells to liver transplant tolerance. Methods After injection of anti-CD25 monoclonal antibody (mAb, PC61), mouse orthotopic liver transplantation was performed and survivals were determined. The paraffin-embedded sections of hepatic allografts were cut and stained with hematoxylin and eosin (HE). Furthermore, the effect of CD4+ CD25+ regulatory T cells on proliferative response of CD4+ T cells and cytotoxicity of CD8+ T cells was examined by depleting these regulatory T cells. Results Depletion of these cells in the recipients but not in the donors before liver transplantation caused rejection. Histological analyses of hepatic allografts with PC61 treatment showed extensive leukocyte infiltration and tissue destruction, whereas those in the control group showed minimal changes. Moreover, elimination of CD4+CD25+ T cells resulted in the enhancement of both proliferative response of CD4+ T cells and cytotoxicity of CD8+ T cells against donor-type alloantigen. Conclusions These results suggest that CD4+CD25+ regulatory T cells were important for tolerance induction to hepatic allografts.     

全身照射预处理供体对异基因大鼠肝移植的作用及对受体内CD4~+CD25~+调节性T细胞的影响

目的 探讨全身照射(TBI)预处理诱导大鼠肝移植术后急性排斥反应的发生机制,及CD4~+ CD25~+调节性T细胞的变化在诱导免疫耐受中的作用.方法 以雄性Lewis、DA大鼠为供、受体,随机分为正常对照组、同种肝移植组、自发免疫耐受组、急性排斥反应组.观察各组受体的生存时间及生存率,检测受体术后外周血中ALT、TB含量、Foxp3~+ CD4~+ CD25~+ 调节性T细胞和T细胞亚群上GITR的表达,检测受体术后第14天移植肝的病理变化和受体脾脏CTL杀伤活性.结果 自发免疫耐受组,术后经历短暂排斥反应最终获得免疫耐受并长期存活.急性排斥反应组,在术后第17～21天死亡,与其他组相比,外周血血清中ALT、TB含量明显升高,而Foxp3~+ CD4~+ CD25~+调节性T细胞比例明显降低.TBI预处理大鼠供肝致受体外周血中CD3~+ CD4~+ T细胞上GITR表达降低,CD3~+CD8~+T细胞上GITR表达增加,提高CTL的杀伤活性.结论 通过TBI清除供体大鼠肝移植物中携带的旁路淋巴细胞,致受体外周血中Foxp3~+ CD4~+ CD25~+调节性T细胞表达降低,而使CD3~+ CD8~+T细胞上GITR表达增加,共同诱导大鼠肝移植术后急性排斥反应发生和耐受障碍.     

CD4+CD25+调节性T细胞、Foxp3 mRNA及可溶性白细胞介素2受体检测在肾移植中的意义

目的 观察肾移植患者外周血中CD4+CD25+调节性T细胞水平及其表面特异性标志物Foxp3和可溶性白细胞介素2受体（sIL-2R）的变化，探讨其在诊断移植肾急性排斥反应中的作用和价值。 方法 选取42例维持性血液透析接受同种异体肾移植治疗的患者及30例健康体检对照者。在患者移植前、移植后1、2、4、8周或发生排斥反应时，以流式细胞仪检测外周血中CD4+CD25+调节性T细胞水平；荧光定量PCR检测Foxp3 mRNA表达；双抗体夹心酶联免疫吸附法（ELISB）检测血浆中sIL-2R水平。 结果 (1)移植后第1、2、4、8周急性排斥反应组CD4+CD25+调节性T细胞、Foxp3 mRNA水平明显低于同期未发生排斥的肾功能稳定组，而sIL-2R水平却显著高于肾功能稳定组。(2)血液透析患者外周血CD4+CD25+调节性T细胞[(9.22±3.53)%]、Foxp3 mRNA[（0.82±0.36）×10-3]及sIL-2R[（856.30±108.24） U/ml]水平与健康对照组[分别为(6.09±1.99)%、(0.50±0.28)×10-3、(247.35±11.24) U/ml]比较，差异均有统计学意义(P < 0.01)。(3)肾移植后随着肾功能的恢复，外周血CD4+CD25+调节性T细胞[(16.53±4.14)%]、Foxp3 mRNA[(4.97±1.94)×10-3]显著升高(P < 0.01)，而sIL-2R[（463.72±31.23）U/ml]水平明显降低(P < 0.01)。(4)当发生急性排斥反应时，CD4+CD25+调节性T细胞[(12.18±2.86)%]、Foxp3 mRNA[(3.15±1.22)×10-3]显著降低(P < 0.01)，而sIL-2R[(748.36±115.41) U/ml]水平明显升高(P < 0.01)，并且这些变化早于Scr的变化。(5)患者移植前后外周血CD4+CD25+调节性T细胞百分率与Foxp3 mRNA水平均呈正相关（分别为r ＝ 0.904、0.932，P < 0.01），但与sIL-2R水平无相关。 结论 外周血CD4+CD25+调节性T细胞、Foxp3 mRNA及sIL-2R水平的测定均可以作为肾移植患者移植后发生急性排斥反应的早期预测指标，并可判断预后。     

骨髓或外周血中CD4+CD25+Foxp3+调节性T淋巴细胞与aGVHD的关系

目的 研究患者异基因造血干细胞移植(allo-HSCT)前后骨髓或外周血单个核细胞中CD4+CD25+Foxp3+调节性T淋巴细胞(以下简称CD4+CD25+Foxp3+T细胞)的比率、Foxp3 mRNA和Foxp3蛋白的表达与急性移植物抗宿主病(aGVHD)的关系.方法 选择37例行HIA相合异基因造血干细胞移植(allo-HSCT))的患者作为研究对象.采用流式细胞术检测患者allo-HSCT前7天(-7 d)、移植当天(0 d)、移植后30天(+30d)、+60 d和+90 d时骨髓或外周血单个核细胞中CD4+CD25+Foxp3+T细胞所占的比率;定量聚合酶链反应(PCR)检测Foxp3 mRNA相对表达量;蛋白印迹(Western blot)法检测Foxp3的蛋白表达水平.结果 37例患者存移植后100 d内发生aGVHD 13例(aGVHD组),未发生aGVHD 24例(无aGVHD组).CD4+CD25+Foxp3+T细胞的比率在0 d时最低,与-7、+30、+60、+90d时比较.差异均有统计学意义(P<0.01);与aGVHD组比较,无aGVHD组患者的CD4+CD25+Foxp3+T细胞的比率明显升高,差异有统计学意义(P<0.01).aGVHD组患者移植后Foxp3的表达水平逐渐升高,但明显低于无aGVHD组,尤其在+60和+90 d时的差异有统计学意义(P<0.01).Western blot法检测结果 表明,aGVHD组受者的Foxp3蛋白表达也明显低于无aGVHD组.结论 CD4+CD25+Foxp3+T细胞对防止发生aGVHD具有重要作用,监测患者骨髓或外周血中CD4+CD25+Foxp3+T细胞的比率可以预测aGVHD的发生.     

弓形虫可溶性抗原混合液延长小鼠移植心脏存活时间

目的 探讨弓形虫可溶性抗原混合液(STAgs)延长小鼠移植心脏存活时间的作用及其作用机制.方法 通过在冰浴中超声粉碎弓形虫速殖子制备弓形虫STAgs.实验分为3组,每组受者9只.STAgs组和急性排斥反应(AR)组:供者为Balb/c小鼠,受者为C57BL/6小鼠,移植前4 d两组受者分别皮下注射STAgs 5μg和磷酸盐缓冲液100μl,同系对照组供、受者均为C57BL/6小鼠,术前未进行任何处理.分组后建立小鼠颈部异位心脏移植模型.术后观察移植心脏存活时间,术后第7天每组处死3只受者,获取移植心脏行病理学检查观察排斥反应,采用免疫组织化学检测移植心中CD4+和CD8+T淋巴细胞.结果 同系移植组在观察终点100 d时均存活,AR组和STAgs组移植心脏存活时间分别为(6.7±0.5)和(70.8±3.5)d,3组间两两比较,差异均有统计学意义(P＜0.05).术后第7天,同系移植组、AR组和STAgs组移植心排斥反应分级分别为0级、Ⅲ～Ⅳ级和0～Ⅰ级;免疫组织化学检测显示STAgs组CD4+和CD8+T淋巴细胞比例明显少于AR组,差异有统计学意义(P＜0.05).结论 弓形虫STAgs能显著延长小鼠移植心脏的存活时间,减轻移植心脏的排斥反应,县体机制可能与弓形虫STAgs可影响TH1/TH2比例相关,也可能通过刺激机体产生脂氧素A4抑制树突状细胞活化发挥作用.

Abstract：

Objective To investigate the effects of T. gondii soluble tachyzoite antigen (STAgs) on the survival time of mouse heart allograft and the possible mechanism. Methods The STAgs were prepared by pulverizing T. gondii tachyzoite with ultrasound on ice. Cervical heterotopic heart transplantations were done by using Balb/c mice as donors, and C57BL/6 mice as recipients.The recipients were classified randomly into three groups: syngeneic group, acute rejection group and STAgs-treated group. The recipients in acute rejection group and STAgs-treated group were injected subcutaneously with 0. 1 ml PBS and 0. 1 ml (5 μg) STAgs at the 4th day before transplantation respectively, and those in syngeneic group were not subjected to any treatment. The grafts were observed daily by cervical palpation, and the total cessation of cardiac contraction was defined as the endpoint. The heart allografts were harvested at the 7th day after transplantation for pathological examination and immunohistochemical staining for CD4+ T, CD8+ T. Results The recipients in syngeneic group were all alive at the 100th day after transplantation. The average survival time in acute rejection group and STAgs-treated group was (6.7± 0.5) days and (70.8± 3.5) days,respectively (P＜0.05). HE staining showed that the rejection on the 7th day after transplantation in syngeneic group, acute rejection group and STAgs-treated group was fallen into 0 degree, Ⅲ-Ⅳ degree and 0- Ⅰ degree, respectively. Immunohistochemical staining revealed that the CD4+ T and CD8+T were markedly down-regulated in STAgs-treated group as compared with those in acute rejection group. Conclusion T. gondii STAgs can significantly prolong the survival time of mouse heart allograft and inhibit the rejection probably by changing the ratio of TH1/TH2, or inhibiting the effect of dendritic cells by inducing the lipoxin A4.     

肝癌患者CD8+CD28-Foxp3+调节性T细胞的变化及意义

目的:探讨肝癌患者外周血和癌组织中CD8~+CD28~-Foxp3~+调节性T细胞(CD8~+CD28-Foxp3~+Tregs)的改变及意义。方法:采用流式细胞仪检测72例肝癌患者和22例健康对照人群外周血CD8~+CD28~-Foxp3~+T细与CD8~+T细胞比值(CD8~+CD28-Foxp3~+Tregs/CD8~+T),分析CD8~+CD28~-Foxp3~+Tregs/CD8~+T与肝癌患者临床病理因素的关系;分别用免疫组化和Western blot检测肝癌患者癌组织及癌旁组织中Foxp3阳性细胞与Foxp3蛋白表达水平。结果:与健康对照人群比较,肝癌患者外周血CD8~+CD28~-Foxp3~+Tregs/CD8~+T明显升高(P0.05);外周血CD8~+CD28~-Foxp3~+Tregs/CD8~+T与患者TNM分期、淋巴结转移、分化程度有关(均P0.05);肝癌组织中平均Foxp3阳性细胞数与Foxp3蛋白表达量均明显高于癌旁组织(均P0.05);外周血CD8~+CD28~-Foxp3~+Tregs/CD8~+T,肝癌组织Foxp3阳性细胞数与Foxp3蛋白表达量在高、中、低分化的肝癌中均呈依次升高趋势,但差异均无统计学意义(均P0.05)。结论:CD8~+CD28~-Foxp3~+Tregs在肝癌患者外周血及癌组织中增多,可能与肿瘤免疫抑制作用有关,其检测对肝癌患者病情有一定评估价值。     

不同分期前列腺癌患者外周血CD4~+ CD25~+ Foxp3~+调节性T细胞的变化及与胰岛素抵抗的相关性

目的 :观察不同分期前列腺癌患者外周血单个核细胞CD4+CD25+Foxp3+调节性T细胞的变化及与胰岛素抵抗的关系。方法:采用流式细胞术检测62例前列腺癌患者(患者组,临床TNM分期Ⅰ期5例、Ⅱ期16例、Ⅲ期21例、Ⅳ期20例)外周血单个核细胞(PBMC)中CD4+CD25+Foxp3+调节性T细胞数目,计算CD4+CD25+Foxp3+调节性T细胞占CD4+T淋巴细胞的百分率;并检测其空腹胰岛素及空腹血糖水平,计算胰岛素抵抗指数(HOMA-IR);采用ELISA法测定外周血胰岛素样生长因子1(IGF-1)水平,分析CD4+CD25+Foxp3+调节性T细胞与胰岛素抵抗的相关性,并与42例健康体检者进行对照。结果:与健康对照组相比,前列腺癌患者HOMAIR明显升高(6.68±1.66 vs 3.68±1.42),IGF-1水平明显下降[(96.39±21.21)ng/ml vs(164.56±30.58)ng/ml],PBMC CD4+CD25+Foxp3+Treg占CD4+T淋巴细胞的百分率[(13.88±0.96)%vs(5.33±0.65)%]及CD4+CD25+Foxp3+Treg绝对值[(3.55±0.29)×107vs(1.99±0.78)×107]明显升高(P0.05,P0.01)。患者PBMC CD4+CD25+Foxp3+Treg占CD4+T淋巴细胞的百分率及CD4+CD25+Foxp3+Treg绝对数﹑HOMA-IR均随TNM分期逐渐加重而增加,IGF-1逐渐下降;相关性分析表明:CD4+CD25+Foxp3+Treg/CD4+T及CD4+CD25+Foxp3+Treg绝对数均与HOMA-IR呈明显正相关(r分别为0.689、0.722,P0.01),与IGF-1呈明显负相关(r分别为-0.896、-0.747,P0.01)。结论:前列腺癌患者存在不同程度的胰岛素抵抗,且随着疾病程度的加重,外周血CD4+CD25+Foxp3+调节性T细胞数目和比例及胰岛素抵抗逐渐加重;CD4+CD25+Foxp3+调节性T细胞可能通过调节胰岛素抵抗参与其形成和发展。     

不同免疫抑制方案对肾移植术受者CD4~+ Foxp3~+ 调节性T细胞的影响

目的 探讨不同免疫抑制剂方案对肾移植术受者外周血CD4~+ Foxp3~+调节性T细胞(regulatory T cells,Treg)表达水平的影响.方法 定群研究了2006年1月至2008年1月在本移植中心接受初次移植50例随访满1年肾移植受者,分为钙调神经蛋白抑制组(钙调神经蛋白抑制剂+吗替麦考酚酯+强的松)19例,其中环孢素组10例,他克莫司组9例;雷帕霉素组(雷帕霉素+吗替麦考酚酯+强的松)31例.另取20例行规律血液透析终末期肾病患者为对照组.采用流式细胞仪的方法检测3组外周血CD4~+ Foxp3~+ Treg占CD4~+ T细胞的比例,比较各组间表达水平与不同免疫抑制方案的关系.结果 钙调神经蛋白抑制剂组、雷帕霉素组和终末期肾病组3组年龄、性别比无统计学差异(P>0.05).钙调神经蛋白抑制剂组、雷帕霉素组2组冷缺血时间、HLA错配率、群体反应性抗体(PRA)和急性排斥反应发生率无统计学差异(P>0.05).雷帕霉素组和终末期肾病组CD4~+ Foxp3~+ T细胞占CD4~+ T细胞的比例均明显高于钙调神经蛋白抑制组,差异有统计学意义(P<0.01).使用环孢素患者和他克莫司患者外周血中CD4~+ Foxp3~+ T细胞占CD4~+ T细胞的比例之间无显著性差异(P>0.05).结论 肾移植术后服用雷帕霉素组患者外周血CD4~+ Foxp3~+ Treg占CD4~+ T细胞的比例显著高于服用钙调神经蛋白抑制组患者,提示雷帕霉素有助于诱导宿主对移植肾免疫耐受.     

肝移植术后血清降钙素原监测的临床意义

Objective To investigate the changes of procalcitonin (PCT) in patients after liver transplantation and explore their significance for diagnosis and differential diagnosis among bacterial infection, viral infection and acute rejection.Methods PCT was measured in serum of 25 liver trans-plant patients by immunofluorescence sandwich method and the patients were divided into the non-complication group, viral infection group, acute rejection group and bacterial infection group.Results The concentrations of PCT in the 1st, 2nd and 3rd day after transplantation were(24.50 ± 4.6)ng/ml, (21.40± 3.3)ng/ml and (12.25 ± 3.1)ng/ml, respectively and they presented a decreasing tendency.The concentrations of PCT in non-complication group, viral infection group and acute rejection group decreased gradually and were near the normal level of (0.51±0.11) ng/ml after 7～10 days.Moreo-ver, the concentrations of PCT in viral infection group and acute rejection group were (0.44 ± 0.16)ng/ml and(0.53±0.14)ng/ml when the patients were in fever.The concentration of PCT in the viral infection group were(15.70±5.1)ng/ml, which was significantly higher than that in other 3 groups (P<0.05) in the early days of fever.The statistical differences among the other three groups were not significant (P>0.05).Conclusion The concentration of PCT in serum is high in the 1st, 2nd and 3rd day then decreased gradually soon.The concentration of PCT is not high in viral infection or acute rejection while significantly high in bacterial infection, so it can be used to differentiate the bacterial infection from acute rejection and virus infection after liver transplantation.     

肝移植术后血清降钙素原监测的临床意义

Objective To investigate the changes of procalcitonin (PCT) in patients after liver transplantation and explore their significance for diagnosis and differential diagnosis among bacterial infection, viral infection and acute rejection.Methods PCT was measured in serum of 25 liver trans-plant patients by immunofluorescence sandwich method and the patients were divided into the non-complication group, viral infection group, acute rejection group and bacterial infection group.Results The concentrations of PCT in the 1st, 2nd and 3rd day after transplantation were(24.50 ± 4.6)ng/ml, (21.40± 3.3)ng/ml and (12.25 ± 3.1)ng/ml, respectively and they presented a decreasing tendency.The concentrations of PCT in non-complication group, viral infection group and acute rejection group decreased gradually and were near the normal level of (0.51±0.11) ng/ml after 7～10 days.Moreo-ver, the concentrations of PCT in viral infection group and acute rejection group were (0.44 ± 0.16)ng/ml and(0.53±0.14)ng/ml when the patients were in fever.The concentration of PCT in the viral infection group were(15.70±5.1)ng/ml, which was significantly higher than that in other 3 groups (P<0.05) in the early days of fever.The statistical differences among the other three groups were not significant (P>0.05).Conclusion The concentration of PCT in serum is high in the 1st, 2nd and 3rd day then decreased gradually soon.The concentration of PCT is not high in viral infection or acute rejection while significantly high in bacterial infection, so it can be used to differentiate the bacterial infection from acute rejection and virus infection after liver transplantation.     

大黄素对大鼠肝移植后CD4~+CD25~+调节性T细胞的影响

目的研究大黄素对大鼠肝移植后CD4+CD25+调节性T细胞的比例以及对其免疫抑制功能的影响。方法双袖套法建立大鼠原位肝移植模型,以大黄素和环孢素A(CsA)分别在术后腹腔给药,并以给予PBS作为模型对照组,观察不同药物移植后大鼠存活时间的影响,以及对移植术后大鼠外周血中CD4+CD25+调节性T细胞(Tregulatory cells,Treg)亚群的变化以及免疫功能的影响。结果大黄素能显著延长大鼠原位肝移植的术后成活时间,大黄素组大鼠的平均存活时间(17.4±2.5)d与肝移植模型对照组(8.8±1.9)d相比差异具有统计学意义;大鼠肝移植后大黄素给药可显著上调受体大鼠外周血以及肝内CD4+CD25+Treg的比例,并显著增强CD4+CD25+Treg抑制效应性T细胞的增殖能力(P0.05)。结论大黄素能够延长大鼠原位肝移植的术后成活时间,并可能通过上调外周血以及肝内CD4+CD25+Treg的数量及免疫抑制功能来实现移植后免疫排斥反应的抑制。     

脓毒症大鼠调节性T细胞凋亡对效应T细胞增殖和分泌功能的影响及血必净注射液的干预作用

目的 探讨血必净注射液对脓毒症大鼠CD+4CD+25调节性T细胞(Treg)凋亡的影响及与效应T细胞(Teff)增殖及分泌功能的关系.方法 Wister大鼠随机分为对照组、假于术组、肓肠结扎穿孔(CLP)组和血必净治疗组,每组8只;于第3天采用免疫磁珠法分选大鼠脾脏CD+4CD25+Treg和CD+4CD25-T细胞.CD+4CD25+Treg培养12 h后检测凋亡率、叉头翼状螺旋转录因子(Foxp3)和T淋巴细胞毒性相关抗原4(CTLA-4)表达及门细胞介素(IL)-10的分泌.将Treg与CD+4CD25-T细胞共培养,并以刀豆素A刺激后观察Treg对Teff增殖活性和细胞培养上清IL-2/可溶性IL-2受体α(slL-2Rα)含量的影响.结果 CLP组CD+4CD25+Treg细胞凋亡率<对照组和假于术组(P<0.01),而血必净治疗组明显>CLP组(P<0.01).与CLP组比较,血必净治疗组CD+4CD25+Treg细胞Foxp3、CTLA-4表达和IL-10分泌显著下降(P<0.01).同时,CLP组Teff增殖反应抑制率明显>对照组,而血必净组其抑制率CLP组,sll-2Rα低于CLP组(P<0.01).结论 脓毒症病理过程中CD+4CD25+Treg细胞对Teff抑制效应明显增强,而血必净注射液能诱导Treg细胞凋亡,减轻Treg对Teff的抑制作用.     

CD4+CD25+T细胞对同种异体小鼠心脏移植的免疫调节作用

目的 观察CD4+CD25+T细胞(Treg)对小鼠同种异体心脏移植的免疫调节作用.方法 流式细胞仪检测正常小鼠和胸腺切除+PC61小鼠淋巴结、脾脏和外周血的Treg的比例.将供体鼠BALB/C心脏移植到受体鼠B6腹腔内,观察对照组(n=6)、胸腺切除组(THY,n=8)、hCTLA4Ig组(n=8)、DST+hCTLA4Ig组(n=8)和THY+PC61+DST+hCTLA4Ig组(n=6)小鼠心脏移植后生存时间和移植心脏病理学检查.结果 正常B6小鼠淋巴结、脾脏和外周血的Treg的比例分别为5.1%、4.5%和1. 7%,明显高于胸腺切除+PC61处理组(1. 8%、1.7%、0.7%).移植心脏平均存活时间在对照组和胸腺切除组分别为(8.2±2.9)d和(7.6±3.0)d,两组间差异无统计学意义(P＞0.05);而在hCTLA4Ig组和DST+hCTLA4Ig组分别为(43.0±11.8)d和(135.0±29.7)d,均较对照组或胸腺切除组明显延长(P＜0.01);THY+PC61+DST+hCTLA4Ig组移植心脏平均存活时间(25.8±8.9)d,也明显较对照组明显延长,但短于hCTLA4Ig组和DST+hCTLA4Ig组(P＜0.01).DST+hCTLA4Ig组移植的心脏存活时间(135.0±29.7)d明显高于其他各组(P＜0.01),其病理组织学表现为间质内有较多的淋巴细胞浸润,伴毛细血管增生,管壁增厚,间质纤维化.结论 CD4+CD25+T细胞水平对同种异体心脏移植的免疫耐受具有免疫调节作用.

Abstract：

Objective To investigate the immunoregulation effects of CD4 + CD25 + T cells in mice heart allograft transplantation. Methods Flow cytometry was used to analyze the contents of CD4 + CD25 +T regulatory cells (Tregs) of the lymph nodes, spleen and blood in the normal mice group and the thymusectomy (THY) + PC61 group. BALB/C mice served as the donors and C57BL/6 (B6) mice as the recipients. Five groups were established, including control group ( n = 6 ), THY group ( n = 8 ), hCTLA4Ig group ( n = 8 ), DST ( donor-specific T-depleted spleen cells) + hCTLA4Ig group ( n = 8) and THY + PC61+ DST + hCTLA4Ig group (n = 6). The survival time after heart allograft transplantation was observed and pathological examination was done in different groups. Results In control group, the rate of Tregs in lymph nodes, spleen and blood was 5. 1%, 4. 5% and 1.7% respectively, which was significantly higher than in THY + PC61 group ( 1. 8% , 1. 7% and 0. 7% respectively). The average survival time of control and THY groups was 8. 2 ± 2.9 and 7.6 ± 3. 0 days respectively ( P ＞ 0. 05 ). The average survival time of hCTLA4Ig and DST + hCTLA4Ig groups was 43.0 ± 11.8 and 135.0 ± 29. 7 days respectively, which was significantly longer than in control group or THY group ( P ＜0. 01 ). The average survival time of THY +PC61 + DST + hCTLA4Ig group was 25.8 ± 8.9 days, which was significantly longer than in control group,but shorter than in hCTLA4Ig group or DST + hCTLA4Ig group ( P ＜ 0. 01 ). The survival time in DST +hCTLA4Ig group was 135.0 ± 29. 7 days, which was significantly longer than other groups ( P ＜ 0. 01 ).The pathological examination revealed that there were more lymphocytes infiltration and capillary vessel proliferation in the desmohemoblast in the transplanted heart of DST + hCTLA4Ig group. Conclusion CD4 +CD25 +T cells regulate the immune tolerance in the allograft transplantation.     

Bone Marrow–Derived Mesenchymal Stem Cells Inhibit Acute Rejection of Rat Liver Allografts in Association With Regulatory T-Cell Expansion

Bone marrow–derived mesenchymal stem cells (MSCs) exhibit immunosuppressive functions in vitro and in vivo. We investigated the immunoregulatory effects of rat MSCs in a model of allogeneic liver transplantation. Brown Norway rats received livers from inbred Lewis rats, and at designated intervals, infusions of MSCs derived from recipient, donor, or third-party rats. Allograft rejection and recipient survival rates were recorded. In particular, changes in circulating regulatory T cells (Tregs) were measured. After administration of MSCs derived from each of the 3 strains, allograft recipients demonstrated markedly longer survival compared with control animals. Histologic analysis revealed significant inhibition of allograft rejection. The MSCs induced generation of CD4+CD25+Foxp3+ Tregs. We concluded that MSCs inhibit acute rejection of allografts after liver transplantation, and propose that the immunoregulatory effects of MSCs are associated with expansion of Tregs.     

Requirement of CD28 signaling in homeostasis/survival of TGF-beta converted CD4+CD25+ Tregs from thymic CD4+CD25- single positive T cells

BACKGROUND: The thymus is a major organ that generates "natural" CD4+CD25+ T regulatory cells (Tregs). However, the detailed pathway(s) by which Tregs are developed remain a mystery. CD28-/- mice have profound decrease in Tregs, but the underlying molecular events remain largely undefined. METHODS: CD4+CD25+ thymocytes from wildtype and CD28-/- mice were cultured with T-cell receptor (TCR) and transforming growth factor (TGF)-beta stimulation to generate CD25+ Tregs and their phenotype and function were studied in vitro and in vivo. RESULTS: TGF-beta induced Foxp3 expression in thymic CD4+CD25+ cells and converted them to CD25+ Tregs. The converted Tregs expressed high levels of CD25, whereas the non-suppressive CD4+ T cells from the control cultures expressed CD25(low). CD28-/- thymic CD4+CD25+ cells showed transit lower levels of Foxp3 upon TCR and TGF-beta stimulation early in culture, but the defect in Foxp3 expression was restored to normal levels after 60-72 hr. Consequently, TGF-beta converted CD28-/- CD25+ cells to CD25+ Tregs that were indistinguishable from those of the wildtype mice. However, the total number of TGF-beta converted CD28-/- Tregs was significantly lower than that of wildtype mice. In vivo, TGF-beta converted CD28-/- CD25+ Tregs were less viable than those from the wildtype mice. Importantly, TGF-beta induced alloantigen specific CD4+CD25+ Tregs from thymic CD25-SP cells which also required CD28 to maintain their survival. CONCLUSIONS: TGF-beta and TCR co-stimulation converts thymic CD4+CD25+ T cells into CD4+CD25+ Tregs by inducing Foxp3, and the contribution of CD28 stimulation to this process is mainly through maintaining survival of the induced Tregs.     

Reduced CD4+ CD25++ CD45RA− Foxp3hi activated regulatory T cells and its association with acute rejection in patients with kidney transplantation

BackgroundIt was found that regulatory T cells (Tregs) importantly affect the maintenance of the kidney graft. However, Tregs are a heterogeneous population with less to more suppressive activity. The aim of this study was to determine the effects of different subsets of Tregs, as well as their ratio to effector T cells (Teff), on kidney transplantation outcomes.MethodsA total of 58 participants were enrolled in this study and divided into four groups: (i) first kidney transplant recipients (stable 1); (ii) second kidney transplant recipients (stable 2); (iii) transplant recipients with acute rejection (AR); and (iv) healthy control subjects. By using flow cytometer, the frequencies of CD4⁺ CD25⁺⁺ CD45RA⁻ Foxp3^hi activated Tregs (aTregs), CD4⁺ CD25⁺ CD45RA⁺ Foxp3^lo resting Tregs (rTregs), CD4⁺ CD25⁺ CD45RA⁻ Foxp3^lo non-suppressive T cells, CD4⁺ CD25⁺ Foxp3⁻ cells Teff, and total Tregs were analyzed in all subjects.ResultsThe frequency of aTregs (as well as the ratio of aTregs/Tregs) was significantly lower in the AR patients than the other three groups. In contrast to AR patients, stables 1 and 2 had a higher aTreg/Treg ratio than those in the control group. Although patients with AR had a significantly lower total Tregs than the other three groups, the balance of total Tregs and Teff was similar between patients with and without AR.ConclusionPatients with AR had poorer immunoregulatory properties than those with normal graft functioning, as well as those in the control group. These reduced immunoregulatory properties in patients with AR could lead to graft rejection.