黄芪多糖对分泌白细胞介素12树突细胞亚群的免疫调控效应与机制

目的 观察黄芪多糖(APS)对分泌IL-12树突细胞(DC)亚群CD11chighCD45RBlowDC功能的影响.方法磁珠分选技术获得BALB/c小鼠脾脏CD11chighCD45RBlowDC和CD4+T淋巴细胞.在CD11 chighCD45RBlowDC中加入不同浓度APS(50、100、200μg/mL)处理,以不加APS的细胞作为对照,应用ELISA法检测细胞培养上清液中IL-12水平,流式细胞仪检测细胞表面分子CD40、CD80、CD86、I-A/E及Toll样受体4(TLR4)的表达.将CD4+T淋巴细胞分为正常对照组(未行任何处理)、未刺激组(加入未经APS处理的CD11chighCD45RBlowDC与CD4+T淋巴细胞混合培养)、高浓度APS刺激组(加入经200μg/mL APS处理后的CD11chighCD45RBlowDC与CD4+T淋巴细胞混合培养)、高浓度APS刺激+抗体1组(加入经200μg/mL APS处理后的CD11chighCD45RBlowDC、IL-12抗体与CD4+T淋巴细胞混合培养)和高浓度APS刺激+抗体2组(加入经200 μg/mL APS处理后的CD11chighCD45RBlowDC、IL-12同型对照抗体与CD4+T淋巴细胞混合培养).采用噻唑蓝法测定CD4+T淋巴细胞增殖能力,流式细胞仪检测细胞培养液中IL-4和γ干扰素水平.对数据行多组间单因素方差分析.结果与未加APS刺激相比,3种浓度APS均显著增强CD11chighCD45RBlowDC表面分子CD40、CD80、I-A/E及TLR4表达及IL-12分泌,其中IL-12分泌呈APS浓度依赖性;CD86表达无明显变化.高浓度APS刺激组CD4+T淋巴细胞增殖能力高于未刺激组(F=13.438,P＜0.05);高浓度APS刺激组细胞γ干扰素水平为(2784±137)pg/mL,高于未刺激组[(1952±101)pg/mL,F=12.177,P＜0.05];高浓度APS刺激组细胞IL-4水平为(172±20)pg/mL,明显低于未刺激组[(193±19)pg/mL,F=11.963,P＜0.05].高浓度APS刺激+抗体1组前述3项指标表达水平较未刺激组明显改善,高浓度APS刺激+抗体2组前述3项指标表达水平与高浓度APS刺激组接近.结论 APS能够通过促进CD11chighCD45RBlowDC中IL-12的表达,诱导CD4+T淋巴细胞向Th1型反应分化,通过激活CD11chighCD45RBlowDC增强免疫活性.

Abstract：

Objective To investigate immunomodulatory effect of Astragalus polysaccharides (APS) on IL-12-secreting dendritic cell (DC) subset CD11chigh CD45RBlow DC. Methods Spleen CD11chighCD45RBlow DC and CD4 +T lymphocytes in BALB/c mice were purified by magnetic beads sorting,and were treated with 0 (as control), 50, 100, 200 μg/mL APS. Immunofluorescence staining and flow cytometry were used to determine expressions of CD11chighCD45RBlow DC surface molecules, including CD40,CD80, CD86, I-A/E, and Toll-like receptor (TLR) 4. IL-12 level in CD11chighCD45RBlow DC culture supernatant was determined by ELISA. The CD4+ T lymphocytes were divided into: normal control group,non-stimulation group ( CD4 + T lymphocytes cocultured with APS-unstimulated CD11 chigh CD45RBlow DC ) ,high-dose APS stimulation group (CD4+T lymphocytes cocultured with 200 μg/mL APS-stimulated CD11ch'ghCD45RBlow DC) , high-dose APS stimulation + antibody 1 group ( CD4 + T lymphocytes cocultured with 200 μg/mL APS-stimulated CD11chighCD45RBlow DC and IL-12 antibody), high-dose APS stimulation +antibody 2 group (CD4 +T lymphocytes cocultured with 200 μg/mL APS-stimulated CD11chigh CD45RBlow DC and IL-12 antibody isotype). Proliferation ability of CD4 + T lymphocytes was determined with MTT method.IL-4 level as well as IFN-γ level in CD4 + T lymphocyte culture supernatant was determined by flow cytometry. Data were processed with one-way analysis of variance. Results Compared with those in control, the expressions of CD 11 chigh CD45 RBlow DC surface molecules ( except for CD86 ) on CD 11 chigh CD45RBlow DC surface, as well as IL-12-secreting level with dose-dependence were increased in cells stimulated with 50,100, 200 μg/mL APS. Proliferation ability of CD4 +T lymphocytes in high-dose APS stimulation group was higher as compared with that in non-stimulation group ( F = 13. 438, P ＜0.05). IFN-γlevel in high-dose APS stimulation group [(2784 ± 137 ) pg/mL] was higher than that in non-stimulation group [(1952 ±101 ) pg/mL, F = 12. 177, P ＜0.05]. IL-4 level in high-dose APS stimulation group was (172 t 20) pg/mL,which was lower than that in non-stimulation group [( 193 ± 19) pg/mL, F = 11.963, P ＜0.05]. Proliferation ability of CD4+ T lymphocytes, IFN-γ level, and IL-4 level in high-dose APS stimulation + antibody 1 group were all ameliorated when compared with those in non-stimulation group; while levels of the 3 indexes in high-dose APS stimulation + antibody 2 group were similar to those in high-dose APS stimulation group.Conclusions APS can activate IL-12-producing CD11 chighCD45RBlowDC, and further induce the activation of immune function of T lymphocyte with shifting of Th2 to Th1 in vitro. APS can enhance the immune response via promoting the phenotypic and functional maturation of CD11 chighCD45RBlow DC.     

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.     

可诱导共刺激分子与人IgG Fc融合蛋白诱导同种免疫低应答的体内外实验

目的 探讨真核表达人可诱导共刺激分子(ICOS)与人IgG Fc融合蛋白(ICOS-Ig融合蛋白)在体内外对同种免疫应答的影响.方法 构建ICOS-Ig融合蛋白表达载体,在CHO细胞中表达并纯化ICXIS-Ig融合蛋白.以Balb/c小鼠脾细胞为反应细胞,经Co60照射灭活的(257BL/6小鼠脾细胞为刺激细胞,进行初次混合淋巴细胞反应(MLR),MLR体系中分别加入50μ,/ml IOOS-Ig融合蛋白(ICOS-Ig组)或对照IgG(IgG组),采用氚标记胸腺嘧啶脱氧核苷(3H-TdR)掺入法检测反应细胞的增殖情况,酶联免疫吸附试验(ELSA)检测培养上清液中自细胞介素(IL)2、4、10以及γ干扰素(IFN-γ)的含量.收集初次MLR细胞,与灭活的C57BL/6小鼠脾细胞或C3H小鼠脾细胞共培养,进行再次MLR,检测指标同初次MLR.以Co60照射Balb/c小鼠,经尾静脉输注用羟基荧光素二醋酸盐琥珀酰亚胺脂(CFSE)标记的C57BL/6小鼠脾细胞,每天腹腔注射ICOS-Ig融合蛋白0.2 mg(IOOS-Ig组)、IgG(对照IgG组)或环孢素A(CsA组),3 d后取Balb/c小鼠脾细胞,流式细胞仪测定CFSE荧光强度以判断同种T淋巴细胞的体内增殖情况.结果 初次MLR显示,ICOS-Ig组同种T淋巴细胞活化增殖的抑制率为(58±8)%,其培养上清液中IFN-γ的水平明显高于IgG组(P<0.05).再次MLR显示,IOOS-Ig融合蛋白能特异性抑制C57BL/6小鼠脾细胞所致的细胞增殖,抑制率为(42±8)%,IL-4和Ⅱ-10的分泌受到抑制,而IFN-γ7的分泌增加;ICOS-Ig融合蛋白并不抑制第三方细胞所致的细胞增殖.体内实验显示,ICOS-Ig组和CsA组的CFSE荧光强度明显强于空白对照组和对照IgG组(P<0.05),而联合处理组CFSE荧光强度强于ICOS-Ig组和CsA组(P<0.05).结论 ICOS-Ig融合蛋白在体内外均可抑制同种T淋巴细胞的活化增殖,且这种作用具有特异性.     

CD4+CD25-T淋巴细胞转化为CD4-CD8-调节T细胞的体外实验研究

目的 探讨体外诱导和纯化CD4+ CD25-T淋巴细胞(effector T cell,Teff)转化为CD4-CD8-双阴性调节T细胞(double negative regulatory T cell,DN Treg)的最适条件.方法 采用免疫磁珠分选方法提取C57BL/6小鼠的CD4+ CD25-T淋巴细胞、DBA/2小鼠的成熟树突状细胞共培养,加入不同剂量的IL-2,通过流式细胞检测CD4-CD8-T细胞的转化比例并确定最适条件,免疫磁珠阴性选择分选提纯转化的CD3+ CI4-CD8-T细胞,流式细胞仪检测转化的CD4-CD8-调节T细胞对CD4+ CD25-效应T细胞增殖抑制情况.结果 CD4+ CD25-T淋巴细胞与DBA/2小鼠的树突状细胞共培养6d后检测CD4-CD8-调节T细胞的转化比率为6.21％ ±2.03％,实验组加入不同浓度IL-2的转化率:A组(25 ng/ml)为14.77％±2.15％,B组(50 ng/ml)为21.29％±2.68％,C组(75 ng/ml)为43.45％ ±4.45％,D组(100 ng/ml)为28.59％±3.05％,IL-2浓度在75 ng/ml时,转化获得率最高(C组与对照组、实验A、B、D组比较分别t=10.700,8.288,6.158,3.932,均P＜0.05);分离提纯CD4-CD8-双阴性调节细胞纯度达到98.10％,CD4-CD8-双阴性调节细胞与CFSE染色的CD4+ CD25-T淋巴细胞、小鼠树突状细胞共培养6d,实验组增殖指数为1.15明显低于对照组2.07.结论 小鼠CD4+ CW25-T淋巴细胞在体外,成熟树突状细胞刺激下可转化为CD4-CD8-双阴性调节T细胞,IL-2可显著提高其转化率.     

RNAi对大鼠T淋巴细胞CD28和OX40基因表达的联合抑制作用

目的 通过RNAi技术干扰T细胞CD28、CD134基因表达后,诱导获得抑制性T细胞(Ts);探讨Ts免疫学特性.方法 设计针对目标基因的siRNA,转染大鼠T淋巴细胞,FCM检测CD28、CD134水平,混合淋巴细胞反应(MLR)检测转染后的T淋巴细胞对异体淋巴细胞的增殖能力的影响,逆转录-聚合酶链反应(RT-PCR)及酶联免疫吸附试验(ELISA)法检测细胞因子水平.结果 siRNA转染大鼠T淋巴细胞后,抑制CD28、CD134分子的表达,siRNA转染24 h后,siRNA组CD28、CD134表达受到抑制[转染后及转染前表达分别为(22.35±4.37)%及(34.76±3.51)%(P<0.05)],T淋巴细胞分泌细胞因子IL-10水平增高,转染组及未转染组表达分别为(77.15±12.60)ng/L及(37.56±5.93)ng/L(P<0.01).而转染组及未转染组的IL-2表达分别为(2.79±0.51)及(4.35±1.11)ng/L(P<0.05);干扰素(IFN)-γ表达分别为(277.15±14.8)、(682.7±53.5)ng/L(P<0.05).结论 siRNA可以特异性抑制大鼠T淋巴细胞共刺激分子CD28、CD134基因表达,抑制了IL-2、IFN-γ的表达,提高了IL-10细胞因子表达水平,从而产生了免疫耐受效应.Ts细胞具有抗原特异性,而且在外源性rrIL-2存在时,不能逆转Ts细胞的功能.     

混合培养的供、受者骨髓细胞过继回输延长小鼠移植心脏存活时间

目的 将供、受者骨髓细胞经混合培养后过继回输,以观察其对同种异体移植心脏存活时间和受者免疫功能的影响.方法 取Balb/c小鼠和C57BL/6J小鼠的骨髓细胞,进行混合培养.配制含Balb/c小鼠和C57BL/6J小鼠脾淋巴细胞的混合淋巴细胞反应体系(MLR)以及含Balb/c小鼠和C3H小鼠脾淋巴细胞的MLR,分别加入混合培养的骨髓细胞,观察其对MLR中细胞增殖的影响.以C57BL/6J小鼠为供者,Balb/c小鼠为受者行腹腔异位心脏移植,实验分为4组:(1)移植对照组,受者仅进行心脏移植,不作其他处理;(2)实验对照组,心脏移植后给予西罗莫司灌胃;(3)实验组,移植手术结束前注射混合培养的骨髓细胞1×10~7个,术后给予西罗莫司;(4)第三方对照组,受者接受C3H小鼠的移植心脏,手术结束前注射混合培养的骨髓细胞1×10~7个,术后给予西罗莫司.记录移植心脏存活时间;移植心脏停跳当日,取受者外周血,检测CD4~+ CD25~+ T淋巴细胞的比例及供者来源的H-2K~b细胞的比例.结果 加入混合培养的骨髓细胞后,Balb/c和C57BL/6J的MLR的淋巴细胞增殖率低于Balb/c和C3H的MLR.实验组移植心脏的存活时间长于其他3组(P<0.05).实验组CD4~+CD25~+T淋巴细胞的百分率高于其他3组(P<0.05).实验组外周血中H-2K~b细胞的比例高于其他3组(P<0.05).结论 受者输注混合培养的供、受者骨髓细胞可在一定程度上调节免疫应答,延长小鼠移植心脏的存活时间,该作用具有供者抗原特异性.     

小鼠不成熟CD8α+树突状细胞的免疫抑制功能的体外实验

目的 观察不成熟CD8α+树突状细胞(DC)的体外免疫抑制功能.方法 取C57BL/6(H-2b)小鼠和Balb/c(H-2d)小鼠的骨髓和脾脏,制备不成熟CD8α+DC和脾淋巴细胞,并经丝裂霉素处理.采用甲基噻唑基四唑(MTT)法,实验设混合淋巴细胞反应(MLR)组(阳性对照组)、MLR加不同密度的同系CD8α+DC组、MLR加不同密度同种异型CD8α+DC组、MLR加不同密度CD8α+DC的培养上清组、CD8α+DC加同系T淋巴细胞组及阴性对照组.MLR组按刺激细胞/反应细胞10∶1建立.CD8α+DC按与反应细胞比例0.2∶1、0.5∶1、0.8∶1和1∶1的梯度加入MLR中分别建立同系CD8α+D组和同种异型CD8α+D组;MLR中加入不同密度(1×105/ml～5×106/ml)CD8α+DC的培养上清液建立CD8α+DC上清组;CD8α+DC与同系淋巴细胞共培养建立CD8α+DC加同系T淋巴细胞组;以反应细胞2×105/孔作为阴性对照.采用酶联免疫吸附试验法检测MLR加同系CD8α+DC组(1∶1)上清液中γ干扰素(IF-γ)和白细胞介素10(IL-10)的浓度.结果 同系和同种异型不成熟CD8α+DC对MLR均有抑制作用(P＜0.05),二者间差异无统计学意义(P＞0.05).抑制作用随DC比例的增加而增强,当CD8α+DC/反应细胞比例大于0.2时显示抑制作用(P＜0.05),比例为1时抑制作用最强.CD8α+DC体外刺激同系淋巴细胞增殖的能力较弱,当DC与T淋巴细胞的比值大于2时,显示出一定的刺激作用(P＜0.05),其培养上清液对MLR也有抑制作用(P＜0.05),其中密度5×105/ml的细胞培养上清液抑制作用最强.MLR加同系CD8α+DC组(1∶1)上清液中IL-10的含量为(451.9±12.2)pg/ml,IFN-γ的含量为(1.0±1.2)pg/ml.结论 不成熟CD8α+DC体外具有免疫抑制或诱导免疫耐受的功能,可产生较高水平的IL-10,CD8α+DC及其培养上清液均可抑制MLR.

Abstract：

Objective To observe the function of immature CD8α+ dentritic cells (DCs) in vitro. Methods The bone marrow and spleen of C57BL/6(H-2b) and Balb/c (H-2d) mice were got to prepare immature CD8α+ DCs and spleen lymphocytes,and treated by mytomycin. MTT test was used.MLR group, MLR plus variable density syngeneic CD8α+ DC group, MLR plus variable density allogeneic CD8α+ DC group,MLR plus variable density CD8α+ DC supernatant group,CD8α+ DC plus syngeneic T cell group and negative control group were established. MLR group was set up by responder cell ratio of 0.2,0.5,0.8,1.0,to build the MLR plus syngeneic and allogeneic CD8α+ DC experimental groups. Culture supernatant from different density (1 × 105/ml - 5 × 106/ml) of CD8α+DCs was added into MLR to build CD8α+ DC supernatant group. CD8α+ DCs were co-cultured with syngeneic T cells to build CD8α+ DCs plus syngeneic T cells group. 2 × 105/well responder cells served as the negative control group. ELISA was used to detect the concentrations of IFN-γ and IL-10 in the DCs could both suppress MLR (P＜0. 05), and the difference was not statistically significant (P＞0. 05). When CD8α+ DCs were increased, the suppressive effect was enhanced. When CD8α+ DC/responder cell ratio ＞0. 2, the inhibitory effect could be observed, and this effect reached the peak when the ratio was 1.0. The CD8α+ DCs had weak ability to stimulate syngeneic lymphocyte proliferation in vitro, and certain stimulating effect could be seen only when CD8α+ DC/responder cell ratio ＞2 (P＜0. 05). Its culture supernatant also showed suppressive effect (P＜0. 05), and the supernatant with a cell density of 5 × 105/ml showed the maximum effect. IL-10 concentration in the concentration was 1.0 ± 1.2 pg/ml. Conclusion The in vitro function of immature CD8α+ DCs was immunosuppression/tolerance,and they could secret high level of IL-10. The CD8α+ DCs and their culture supernatant could suppress MLR in vitro.     

活化的脐血T淋巴细胞胞内细胞因子特性研究

目的通过对人脐血中CD4+和CD8+T淋巴细胞经特异抗原刺激后,胞内细胞因子γ-IFN和IL-4分泌水平的研究,探讨人脐血干细胞移植后急、慢性移植物抗宿主病(GVHD)发生低下的可能机制.方法15份脐血和15份健康成人外周血中T淋巴细胞在莫能霉素存在的情况下,体外经十四烷酰拂波醇乙脂和离子霉素刺激后,分别进行CD4-FITC、CD8-FITC荧光单抗染色和γ-IFN-PE、IL-4-PE荧光单抗胞内染色,最后进行流式细胞仪分析.结果脐血中CD4+Th细胞和CD8+Tc细胞胞内γ-IFN分泌水平均明显低于成人外周血中CD4+和CD8+T细胞,而脐血CD8+T细胞胞内IL-4分泌水平与成人外周同类细胞差异无显著性.结论人脐血中T淋巴细胞受特异抗原刺激后,胞内不能产生正常的Th1/Tc1样细胞因子谱,即活化的脐血T淋巴细胞Th1/Tc1样反应低下,这可能是脐血移植后GVHD发生低下的原因之一.     

PD-L1.Ig与1,25(OH)2D3联合应用对异基因大鼠胰腺移植后急性排斥反应的影响

目的 探讨PD-L1.Ig联合1,25(OH)2D3对大鼠胰腺移植急性排斥反应的免疫调控作用以及对大鼠移植胰腺存活时间的影响.方法 以F344大鼠为供体,Lewis大鼠为受体,建立4组原位胰腺移植模型.每组12例,共48例.A组:对照组、B组:PD-L1.Ig组、C组:1,25(OH)2D3组、D组:PD-L1.Ig+1,25(OH)2D3组;观察术后各组血糖变化,移植物存活以及组织病理学改变;流式细胞检测受体血、脾以及移植胰CD4+T细胞、CD8+T细胞、CD4+CD25+T细胞表达水平;酶联免疫吸附试验(ELISA)检测移植物局部白细胞介素(IL)-2、-4、-10、-12表达水平;于术后第7天分别杀死各组受体和供体鼠各2只,取受体脾细胞与供体作混合淋巴细胞反应(MLR).结果 与A比较,PD-L1.Ig组并未显著延长移植胰腺存活时间(P＞0.05),C、D组对改善血糖水平和延长移植胰腺存活时间作用明显(P＜0.01),其中,D组移植胰腺存活时间最长(23.9±0.8)d;与A组比较,B组无明显改善,C组排斥反应较A组明显减弱,而D组几乎未发生排斥反应;CD3+CD8+T细胞计数D、C、B与A组比较均有减少,差异有统计学意义(P＜0.01).CD4+T细胞D、C、B与A组的差异有统计学意义(P＜0.05).CD4+CD25+调节性T细胞A、B、C、D组逐渐升高,差异有统计学意义(P＜0.01),且以D组较为明显(C组比A组P＜0.01);D组明显抑制移植物局部Th1型细胞因子IL-2、IL-12的产生,显著提高Th2型细胞因子IL-4、10的水平;与对照组比较,各治疗组受体T淋巴细胞在MLR中表现对供体淋巴细胞特异性低反应性,能有效抑制T细胞对同种异体抗原的反应.结论 共刺激阻断剂PD-L1.Ig联合1,25(OH)2D3可有效抑制细胞免疫应答,干预急性排斥反应,显著延长大鼠移植胰腺存活时间.     

腺苷2A受体激活抑制大鼠T淋巴细胞功能

目的研究激活腺苷2A受体对大鼠T淋巴细胞体外活化、增殖及细胞毒效应的影响。方法植物血凝素(phytohemagglutinin,PHA)刺激小鼠脾脏来源的T淋巴细胞,并以终浓度为0.01μmol/L、0.1μmol/L、1μmol/L及10μmol/L的腺苷2A受体激动剂CGS21680与其共培养。荧光抗体染色结合流式细胞术检测T淋巴细胞活化抗原CD69及CD25的表达及细胞增殖情况,ELISA法检测T淋巴细胞分泌IL-2及INF-γ的水平。结果各浓度的CGS21680均可明显抑制T淋巴细胞表面CD25及CD69分子的表达(P0.05,P0.01),抑制T淋巴细胞增殖(P0.01),也对IL-2及INF-γ的分泌产生明显抑制作用(P0.01)。结论激活腺苷2A受体能有效地抑制小鼠T淋巴细胞的体外活化、增殖及细胞毒作用。     

血必净促进内毒素/脂多糖刺激调节性T淋巴细胞凋亡并介导辅助性T淋巴细胞漂移的作用

目的 了解血必净注射液促进LPS刺激CD4+CD25+调节性T淋巴细胞(Treg细胞)凋亡过程及介导辅助性T淋巴细胞(Th)漂移的调节作用.方法 免疫磁珠法分选获得大鼠脾脏CD4+CD25+Treg细胞,分为常规培养对照组、抗CD3/CD28组、抗CD3/CD28+LPS组、抗CD3/CD28+血必净组和抗CD3/CD28+LPS+血必净组,培养3 d后应用流式细胞术检测Treg细胞凋亡率及叉头翼状螺旋转录因子3(Foxp3)表达.将CD4+CD25+Treg细胞与CD4+CD25+T淋巴细胞1:1培养,伴刀豆球蛋白A刺激68 h,检测上清液中Th1分泌的γ干扰素(IFN-γ)、Th2分泌的IL-4、Th17分泌的IL-17水平.结果 抗CD3/CD28+LPS+血必净组Treg细胞凋亡率为(45.1±2.7)%,明显高于抗CD3/CD28+LPS组[(29.4±1.6)%,P＜0.01];2组Foxp3平均荧光强度分别为95±9、140±18,差异有统计学意义(P＜0.01).同时,抗CD3/CD28+LPS+血必净组IFN-γ分泌水平显著高于抗CD3/CD28+LPS组(P＜0.01),IL-4则呈相反变化(P＜0.05),抗CD3/CD28+LPS+血必净组IFN-γ/IL-4较对照组升高(P＜0.01);抗CD3/CD28+血必净组IL-17分泌水平较抗CD3/CD28组明显下降(P＜0.05).结论 CD4+CD25+Treg细胞活化介导了Th1向Th2功能性极化;血必净对LPS诱导的T淋巴细胞免疫功能有重要调节作用,可促进CD4+CD25+Treg细胞凋亡并介导Th2向Th1漂移,从而缓解细胞免疫抑制状态.     

他克莫司对小鼠T_H17型细胞分化增殖的影响及其机制

目的 观察在T_H17型细胞极化环境下,他克莫司(Tac)对小鼠T_H17型细胞分化增殖的影响及机制.方法 将小鼠脾脏初始CD4+CD25+T淋巴细胞使用抗CD3抗体及抗CD28抗体进行活化,使用转化生长因子β_1,(TGF-β_1,)和白细胞介素6(IL-6)等细胞因子进行诱导,促使其向T_H17型细胞方向分化.将体外培养的T_H 17型细胞分为4组,分别用不同剂量的Tac进行干预,即:Tac0 ng/ml组(对照组)、Tac 0.1 ng/ml组、Tac 1 ng/ml组和Tae 10 ng/ml组.应用流式细胞术检测各组T_H 17型细胞亚群纯度,使用逆转录聚合酶链反应(RT.PCR)检测各组IL-17 mRNA相对表达量.结果 Tac可抑制小鼠T_H17型细胞亚群的分化增殖,降低IL-17 mRNA的表达量,且呈剂量依赖性,各组间比较,差异均有统计学意义(P<0.05).结论 Tac通过抑制T_H17型细胞胞浆内的钙调磷酸酶,抑制T_H17型细胞亚群的分化增殖,抑制IL-17 mRNA产生并减轻炎症进程,从而抑制排斥反应.     

Aggressive skin allograft rejection in CD28-/- mice independent of the CD40/CD40L costimulatory pathway.

CD28-/- mice have been utilized to study the role of B7/CD28 and B7-CTLA4 interactions. There is evidence that CTLA4 ligation may be critical for tolerance induction. The aim of the current study is to further investigate rejection responses of CD28-/- mice and to define the role of B7-CTLA4 interactions in the absence of the CD40 and CD28 pathways. Balb/c skin allografts were transplanted onto C57BL/6 (B6) wild type or CD28-/- mice treated with anti-CD40L, CTLA4-Ig, or combination blockade. To investigate the cellular mechanism of rejection in CD28-/- recipients, mice were treated with anti-CD4 or anti-CD8 antibodies prior to treatment with costimulation blockade. The fluoroscein dye CFSE was utilized to study T cell expansion in vivo. Surprisingly, treatment of B6 CD28-/- mice with CTLA4-Ig alone (MST 12d), anti-CD40L alone (MST 13d), or combined blockade (MST 13d) had no effect on allograft survival compared to untreated B6 CD28 mice (MST 11d). CD28-/- recipients depleted of CD4+ cells and treated with CTLA4-Ig, anti-CD40L, or combination blockade also did not have prolonged survival compared with untreated mice (MST 10d). In contrast, CD28-/- recipients depleted of CD8+ cells had markedly prolonged allograft survival when treated with either anti-CD40L alone (MST 49d) or with combination blockade (MST 57d). Studies utilizing CFSE demonstrated that CD28-/- CD8+ T cells are not defective in in vivo proliferation responses compared with wild type CD8 cells. Thus, CD28-/- CD8+ T cells are responsible for aggressive rejection responses of CD28-/- mice independent of the CD40 pathway. In addition, CD40L blockade does not result in CD4+ T cell tolerance in CD28 recipients, despite an intact B7-CTLA4 pathway.     

Costimulatory blockade induces hyporesponsiveness in T cells that recognize alloantigen via indirect antigen presentation

BACKGROUND: Blockade of T cell costimulation by treatment with donor-specific transfusion (DST) and anti-CD154 monoclonal antibody (mAb) induces prolonged allograft survival in mice. This effect is due in part to deletion of host CD8 and CD4 T cells that recognize alloantigen by direct presentation. The fate of host CD4 T cells that recognize alloantigen by indirect presentation, however, is unclear. METHODS: We studied Tg361 TCR transgenic CD4 T cells that recognize alloantigen by indirect presentation. Carboxyfluorescein diacetate, succinimidyl ester-labeled Tg361 cells were adoptively transferred into syngeneic nontransgenic recipients and their fate in the peripheral blood, spleen, and lymph nodes following treatment with DST and anti-CD154 was analyzed. RESULTS: Treatment of mice with DST plus anti-CD154 mAb does not delete Tg361 CD4 T cells, but instead renders them hyporesponsive to rechallenge with alloantigen. Mice circulating hyporesponsive CD4 T cells also fail to reject skin allografts. The hyporesponsive state of the T cells is not reversed by the addition of interleukin-2, anti-CD28 mAb, or an agonistic anti-CD134 mAb in the presence of antigen. These T cells are capable of activation, however, as evidenced by in vitro proliferation in response to anti-CD3 mAb. CONCLUSIONS: These results demonstrate that costimulation blockade can induce hyporesponsiveness of host CD4 T cells recognizing alloantigens by indirect presentation, thus prolonging graft survival by a mechanism that does not involve deletion of alloreactive T cells.     

The role of B7 ligands (CD80 and CD86) in CD152-mediated allograft tolerance: a crosscheck hypothesis

BACKGROUND: The regulatory mechanism by which the B7 ligands (CD80 and CD86) direct the CD28/CD152 costimulatory pathways is unclear. This study investigated the role of CD80 and CD86 in a CD152-mediated allograft tolerance model. METHODS: A low-responding cardiac transplant model (BALB/c-->B10.A) with possible long-term acceptance was used. Immunocytochemical and flow cytometric analyses of the graft-infiltrating cells were conducted to characterize this transplant model. The influence of anti-CD80 and anti-CD86 treatments on the proliferation and interleukin (IL)-2 productions of the tolerated splenocytes (SC) was analyzed. The role of CD80 and CD86 in the induction and maintenance of the graft acceptance in this transplant model were also tested. RESULTS: B10.A mice could accept the BALA/c cardiac allografts (11/22), and an anti-CD152 antibody blocked the graft acceptance (10/10). Immunocytochemical and flow cytometric analyses showed that CD152+ cells were predominant among the CD4+ cells infiltrating the 100-day grafts of the B10.A recipients (B10.A-100). Either anti-CD80 or anti-CD86 treatment significantly enhanced polyclonal proliferation and IL-2 production of the B10.A-100 SC. Blockade of either CD80 or CD86 prohibited the tolerance transmitted by adoptive transfer, and anti-CD80 or anti-CD86 plus skin grafting undermined the established allograft tolerance. CONCLUSIONS: Both CD80 and CD86 were essential for the induction and maintenance of the CD152-mediated allograft tolerance.     

Glomerular complement regulation is overwhelmed in passive Heymann nephritis

BACKGROUND: An injection of anti-Fx1A antibodies in rats leads to passive Heymann nephritis (PHN), a model of membranous nephropathy. Fx1A is a crude extract of renal cortex that contains megalin as a principal component. However, when rats are given anti-megalin antibodies, abnormal proteinuria does not occur. Because of the established complement dependence of PHN, we hypothesized that antibodies neutralizing complement regulatory proteins in the rat glomerulus also were required to induce PHN. Two likely targets are Crry and CD59, proteins abundant on the rat podocyte and contained within Fx1A that inhibit the C3 convertase and C5b-9 assembly, respectively. METHODS: Rats were injected with anti-megalin monoclonal antibodies, followed by anti-Crry and/or anti-CD59 F(ab')(2) antibodies five days later. In a second group of experiments, rats were injected with anti-Fx1A or anti-Fx1A immunodepleted of reactivity against Crry and/or CD59. RESULTS: In the setting of podocyte-associated anti-megalin monoclonal antibodies, simultaneous neutralization of Crry and CD59 function led to the development of significant proteinuria (11.0 +/- 2.1 mg/day, P < 0.001 vs. all other groups). In contrast, animals that had neither or only one of these complement regulators inhibited had normal urinary protein excretion (< or =6 mg/day). In animals given anti-Fx1A depleted of anti-Crry and/or anti-CD59, all groups developed typical PHN, characterized by heavy proteinuria and extensive glomerular deposition of C3 and C5b-9. CONCLUSION: Crry and CD59 play an important role in restraining complement-mediated injury following subepithelial immune complex deposition; however, in PHN, their regulatory capacity is overwhelmed.     

高迁移率族蛋白B1对小鼠调节性T细胞与CD4+CD25-T细胞相互作用的影响

目的 观察高迁移率族蛋白B1(HMGB1)对调节性T细胞(Treg)与CD4+CD25-T细胞相互作用的影响,并初步探讨其影响Treg抑制功能的机制.方法 免疫磁珠法分离正常BALB/c小鼠脾脏CD4+CD25+Treg及CD4+CD25-T细胞.采用固相包被抗CD3/可溶性抗CD28进行辅助活化,以不同时间及浓度HMGB1刺激Treg,ELISA法分析HMGB1刺激对Treg分泌IL-10的影响.将HMGB1(1000μg/L)刺激后的Treg与CD4+CD25-T细胞共培养,MTT法观察其对Treg抑制CD4+CD25-T细胞反应的作用,并分析HMGB1刺激后的Treg对CD4+CD25-T细胞IL-2生成及细胞功能极化的影响.结果 经抗CD3/CD28辅助活化的CD4+CD25+Treg在HMGB1作用下IL-2生成无显著差异(P＞0.05),但随时间延长及剂量增加,IL-10生成明显减少(P＜0.05).经HMGB1刺激的Treg对CD4+CD25-T细胞增殖的抑制反应减弱,同时诱导CD4+CD25-T细胞IL-2产生及细胞功能极化的能力均下降(P＜0.05).结论 HMGB1可通过诱导Treg抑制功能的下调,从而影响CD4+CD25-T细胞功能,进而调节炎症反应过程.     

FasL is important in costimulation blockade-resistant skin graft rejection

BACKGROUND: Simultaneous blockade of the CD40 and CD28 costimulatory pathways is effective in prolonging allograft survival in murine and primate models. Recent data suggest that intact apoptotic pathways are crucial for the induction of hyporesponsiveness by costimulation blockade. We have studied the impact of fas/fasL signaling, an important T cell apoptotic pathway, on the effects of costimulation blockade. Methods. Wild type, lpr (fas deficient), and gld (fasL deficient), mice were used as donors and recipients in the murine skin graft model. Allograft survival was compared in untreated and costimulation blockade (500 microg anti-CD40L and 500 microg CTLA4-Ig, days 0, 2, 4, 6) treated recipients. In some recipients, CD4+ T cells were depleted using rat anti-murine CD4 (100 microg day -3, -2, -1, and weekly). RESULTS: gld mice treated with costimulation blockade enjoy a significantly greater increase in skin allograft survival than do wild-type mice. This effect is not replicated using lpr donors or recipients. Experiments in which CD4+ cells were depleted demonstrate that fasL is not necessary for CD8-mediated allograft rejection, and that depletion of CD4+ cells eliminates some of the survival advantage induced by costimulation blockade. CONCLUSIONS: FasL is not required for the establishment of costimulation blockade induced hyporesponsiveness, but rather appears to be required for normal costimulation blockade resistant rejection. Fas expression is not critical for costimulation blockade resistant rejection, suggesting that fasL may be interacting with other receptors. Further, it appears that CD4+ cells are important in the maintenance of allograft protection induced by costimulation blockade in this model.     

大面积烧伤脓毒症患者T淋巴细胞免疫功能的改变及临床意义

目的 了解大面积烧伤脓毒症患者T淋巴细胞免疫功能的变化，探讨其与脓毒症的关系。方法 选择59例烧伤面积≥30％TBSA的患者，分为脓毒症组43例和非脓毒症组16例。采集两组患者伤后1、3、5、7、14、21、28d的外周静脉血，检测T淋巴细胞增殖能力和白细胞介素2（IL-2）的分泌水平，并行相关性分析；通过流式细胞仪检测CD3^＋／CD4^＋ T淋巴细胞的百分率及其凋亡率，并行相关性分析。结果 与非脓毒症组比较，脓毒症组患者伤后l、14、2l、28dT淋巴细胞增殖能力和IL-2的分泌水平均显著下降（P〈0．05或P〈0.01），两指标呈显著正相关（r=0．82，P〈0．01）。伤后1、5、14、21、28d，脓毒症组患者CD3^＋／CD4^＋T淋巴细胞百分率明显低于非脓毒症组，而其凋亡率呈相反趋势（P〈0.05或P〈0．01），两指标呈显著负相关（r=-0.66，P〈0．05）。结论 大面积烧伤脓毒症患者T淋巴细胞免疫功能持续处于抑制状态，T淋巴细胞凋亡参与了脓毒症细胞免疫紊乱的病理生理过程。     

Anti-CD40L monoclonal antibody treatment induces long-term, tissue-specific, immunologic hyporesponsiveness to peripheral nerve allografts

The CD40/CD40L costimulatory pathway plays a crucial role in allograft rejection. The purpose of this study was to determine the effectiveness of anti-CD40L monoclonal antibody (mAb) treatment as a method to induce long-term, tissue-specific, immunologic hyporesponsiveness to peripheral nerve allografts. Sciatic nerve allografts were performed from BALB/c donor mice into C57BL/6 recipients. Anti-CD40L mAb (1 mg) was administered intraperitoneally to recipient mice on postoperative days 0, 1, and 2. After a 14-, 28-, or 60-day recovery period, the mice were rechallenged with either a BALB/c cardiac or peripheral nerve allograft. Rejection was assessed by measuring the production of interferon gamma (IFN-gamma), interleukin (IL)-2, -4, and -5, and alloantibodies immunoglobulin (Ig) M and IgG. IFN-gamma, IL-2, IL-4, IL-5, IgM, and IgG responses were much lower in the anti-CD40L mAb group compared with controls. Nerve allograft and nerve isograft rechallenge 60 days following the original nerve allotransplantation produced low cytokine responses, whereas cardiac allograft rechallenge produced high cytokine production, indicative of acute rejection. Short-term anti-CD40L treatment may cause long-term, tissue-specific, immunologic hyporesponsiveness. This may allow time for native axons to traverse the transplanted nerve allograft and replace the graft with autogenous peripheral nerve tissue.