外周血循环滤泡辅助性T 细胞及IL-21 在银屑病中的表达及意义

目的:探讨外周血循环滤泡辅助性T 细胞(Follicular helper T cells,Tfh)及相关细胞因子IL-21 在银屑病患者中的表达水平及其与疾病活动度的关系。方法:收集38 例银屑病患者及32 例健康对照者,流式细胞术检测外周血循环CD4+CXCR5+ Tfh 和CD4+ CXCR5+ ICOS+ Tfh 细胞比例以及Th17 细胞比例;ELISA 检测血清IL-21 浓度;分析这些指标间及与银屑病疾病活动度评分PASI 间的相关性。结果:与健康对照者相比,银屑病患者外周血循环CD4+ CXCR5+ Tfh 和CD4+ CXCR5+ ICOS+Tfh 细胞比例更高,血清IL-21 浓度和Th17 细胞比例亦显著高于对照组(P<0.05);IL-21 浓度与CD4+ CXCR5+ Tfh 和CD4+CXCR5+ ICOS+ Tfh 细胞比例均显著正相关,而与Th17 细胞比例间无显著相关性(P>0.05);且CD4+ CXCR5+ ICOS+ Tfh 细胞比例和血清IL-21 与银屑病疾病活动度PASI 评分显著正相关,而CD4+ CXCR5+ Tfh 则与之无显著相关性(P>0.05)。结论:银屑病患者外周血循环Tfh 比例、IL-21 浓度上调与银屑病患者疾病活动度密切相关,提示Tfh 可能参与银屑病的发生发展过程,这一效应可能是通过分泌高水平IL-21 实现;IL-21 浓度与Tfh 细胞比例相关,而与Th17 细胞比例无相关性提示银屑病患者IL-21可能主要由Tfh 细胞分泌。     

类风湿性关节炎患者外周血CD3~+CD8~+效应记忆T细胞和滤泡辅助性T细胞ICOS、 PD-1表达上调且与病情相关

目的研究类风湿性关节炎(RA)患者外周血T淋巴细胞程序性死亡蛋白1(PD-1)和可诱导共刺激分子(ICOS)的表达,并确定其与疾病活动度之间的关系。方法募集RA患者30例、健康对照26例。流式细胞术检测外周血CD3~+CD8~+的效应记忆T细胞(Tem)和滤泡辅助性T(Tfh)细胞比例,而后检测淋巴细胞亚群中PD-1和ICOS阳性的细胞比例;通过Spearman相关性分析评估其与28个关节疾病活动度评分(DAS28)之间的相关性。结果与健康对照组相比, RA组患者外周血Tem和Tfh细胞绝对数增高, Tem和Tfh细胞的ICOS与PD-1表达增加; RA组患者外周血CD3~+CD8~+ Tem和Tfh细胞ICOS和PD-1表达水平与DAS28之间呈正相关。结论外周血CD3~+CD8~+ Tem和Tfh细胞PD-1和ICOS可能参与RA的发生发展,并可能作为RA活动度的评价指标。     

微小RNA-7敲减对小鼠脾脏中T淋巴细胞体外功能的影响

观察微小RNA-7(microRNA-7,miR-7)敲减(Knock down,KD)对小鼠脾脏T淋巴细胞体外功能的影响并探讨其意义。常规分离野生型(wild type,WT)小鼠脾脏T淋巴细胞,经CD3和CD28抗体刺激后,Real-time PCR检测不同时间点(0h;24h;48h)细胞中miR-7的表达变化;进一步用Con A、CD3和CD28抗体刺激miR-7KD小鼠脾脏T淋巴细胞,CCK8检测细胞增殖率;Real-time PCR检测miR-7KD小鼠脾脏T淋巴细胞IL-12、IL-4、IL-6、TNF-α、IFN-γ和IL-10表达的变化;FACS检测CD4+T和CD8+T细胞的数量变化及CD4+T细胞膜分子CD44、CD62L和IL-4、IFN-γ的表达变化。结果显示,WT小鼠脾脏T淋巴细胞活化后,miR-7的表达水平显著上调(P0.05);与WT小鼠相比,在Con A、CD3和CD28抗体作用下miR-7KD小鼠脾脏T淋巴细胞增殖明显增加(P0.05);miR-7KD小鼠脾脏T淋巴细胞IL-12、IL-4、IL-6、TNF-α和IFN-γ水平均明显上调(P0.05),而IL-10表达显著下调(P0.05);FACS检测结果显示CD4+T细胞比例明显上调(P0.05),而CD8+T细胞的比例变化不显著(P0.05);CD4+T细胞膜分子CD62L水平显著下降,CD69及IL-4、IFN-γ的表达水平均显著上调(P0.05)。结果表明,miR-7敲减以后可显著影响小鼠脾脏T淋巴细胞的功能,本实验为后续深入探讨其在T淋巴细胞功能调控中的作用提供实验依据。     

人参皂苷Rg3联合阿帕替尼促进可诱导共刺激分子(ICOS)上调的肺癌细胞免疫应答

目的研究人参皂苷Rg3联合阿帕替尼在可诱导共刺激分子(ICOS)上调的肺癌的细胞免疫应答中的作用。方法建立Lewis肺癌小鼠模型后,随机分为8组,将人参皂苷Rg3或/和阿帕替尼联合ICOS激动剂单克隆抗体作用于小鼠体内,观察各组肿瘤生长、肿瘤组织中CD8~+T淋巴细胞富集和细胞因子IFN-γ、IL-4和TNF-α变化,以及其表面ICOS表达情况。结果人参皂苷Rg3和阿帕替尼联合应用,显著增强ICOS激动剂单克隆抗体显著抑制肿瘤的生长;促进CD8~+T淋巴细胞在肿瘤组织中的富集,上调IFN-γ、IL-4和TNF-α分泌;ICOS激动剂单克隆抗体促进CD8~+T淋巴细胞表面的ICOS表达,但其表达量不受Rg3和阿帕替尼的影响。结论人参皂苷Rg3联用阿帕替尼能增强ICOS促进的肺癌模型动物内细胞免疫应答。     

滤泡辅助性T细胞及其相关因子在HIV疾病进展中的变化研究北大核心CSCD

目的通过对不同疾病进展阶段的HIV感染者外周血滤泡辅助性T细胞（follicular helper T cell, Tfh）进行分析,探讨Tfh及其相关因子对HIV感染疾病进程的影响,为进一步研究Tfh在HIV抗病毒治疗和疫苗研究提供科学依据。方法本研究招募HIV-1感染者33例,根据疾病进展情况分为HIV-1长期不进展者（long-term nonprogressors, LTNP）11例、快速进展者（rapid progressors, RP）10例、HIV典型进展者（typical progressors, TP）12例,同时招募11名健康人（normal control, NC）作为对照。分离受试者外周血单个核细胞,用多色流式的方法检测CD4＋CD45RA－CXCR5＋Tfh和CD4＋CD45RA－CXCR3－CXCR5＋PD-1＋Tfh及其表达ICOS、IFN-γ、IL-21因子的水平。此外,对血浆IL-10和CD19＋B细胞频数也进行分析,探讨Tfh与CD4、B细胞的关系。结果两个Tfh亚群比例在HIV-1感染人群均比正常对照高,CD4＋CD45RA－CXCR5＋Tfh在LTNP人群最高,与正常对照比较差异有统计学意义（P〈0.05）。Tfh相关因子ICOS、IFN-γ、IL-21在T细胞刺激剂作用下均有明显升高,ICOS＋Tfh与HIV-1疾病进展呈负相关,与CD19＋B细胞呈正相关（r＝－0.49,P〈0.01;r＝0.60,P〈0.05）。血浆IL-10的浓度在HIV-1感染者中有明显升高,TP组最高,其次为RP组（TP组vs NC组,P〈0.01;RP组vs NC组,P〈0.05）。结论外周血Tfh及其相关因子的表达在HIV-1感染者与健康对照者间差异有统计学意义,特定亚群Tfh与HIV-1疾病进展和B细胞功能密切相关。     

人外周血和扁桃体中Tfh细胞与其他Th细胞亚群之间的关系

目的比较观察人外周血和扁桃体Tfh细胞的表型以及与Th1、Th17、Th22细胞亚群之间的关系。方法分离正常人PBMC及扁桃体单个核细胞,利用anti-CD3+anti-CD28或PMA+ionomycin刺激后,采用ELISA和流式细胞术(FCM)检测其细胞因子的产生,分析Tfh与Th1、Th17、Th22细胞亚群之间的关系。结果与PBMC中CD4+T细胞不同,扁桃体CD4+T细胞高表达CXCR5和CD45RO,低表达CCR7和CD62L;与PBMC中CD4+T细胞相比,扁桃体CD4+T细胞IL-21和IL-17产生水平较高,IFN-γ产生水平较低,IL-22水平无显著差异;外周血和扁桃体CD4+T细胞中均存在一定比例的IL-21+IL-17+双阳性、IL-21+IL-22+双阳性、IL-21+IFN-γ+双阳性细胞,IL-21单阳性细胞在扁桃体CD4+T细胞中所占比例明显高于外周血;外周血和扁桃体CD4+CXCR5+细胞除表达IL-21外,还表达IL-17、IL-22和IFN-γ。结论扁桃体中存在较多数量的Tfh细胞,大多数Tfh细胞是不同于Th1、Th17和Th22的细胞亚群。     

细粒棘球蚴早期感染促进小鼠体内IL-22的产生

目的探讨小鼠腹腔细粒棘球蚴感染早期主要产生IL-22的CD4~+T细胞Th1、Th17和Th22细胞以及IL-22R1的表达情况。方法建立小鼠腹腔细粒棘球蚴感染模型,分别在感染后第3、6、9、12天收集外周血、小鼠脾淋巴细胞以及肝脏和肠管组织。ELISA检测外周血IFN-γ和IL-17、IL-22的蛋白表达量;qRT-PCR检测脾淋巴细胞中Th1细胞相关因子(Ifng、Tbx21基因)、Th17细胞相关因子(IL-17、Rorc基因)、Th22细胞相关因子(IL-22、Ahr基因)以及肝脏和肠管组织中IL-22R1的mRNA表达水平;流式细胞术检测脾淋巴细胞中Th1细胞(CD4~+IFN-γ~+)、Th17细胞(CD4~+IFN-γ~-IL-22~+IL-17~+)及Th22细胞(CD4~+IFN-γ~-IL-22~+IL-17~-)的百分比情况。结果与对照组相比,ELISA、qRT-PCR和流式细胞术检测细粒棘球蚴感染后Th1细胞、Th17细胞、Th22细胞增高:qRT-PCR检测细粒棘球蚴感染后肝脏和肠管IL-22R1的表达增高。结论细粒棘球蚴感染小鼠早期,主要产生IL-22的CD4~+T细胞Th1、Th17、Th22细胞比例以及IL-22R1表达增加,可能参与了宿主的免疫防御反应。     

急性MCMV感染对小鼠脾Th1/Th2/Th17细胞亚群分化的影响

目的:在整体水平观察小鼠巨细胞病毒(MCMV)感染对小鼠脾Th1/Th2/Th17细胞亚群分化及其主要的效应性细胞因子(IFN-γ、IL-4、IL-17A)表达的影响.方法:建立MCMV感染模型,8只BALB/c小鼠分别于接种MCMV Smith株后3天和14天各处死4只;另设8只接种唾液腺匀浆的模拟感染小鼠作为对照.用空斑形成试验测定肝、脾和唾液腺组织病毒滴度;流式细胞术检测脾T淋巴细胞中Th1(CD4+ IFN-γ+)、Th2(CD4+ IL-4+)、Th17(CD4+IL-17A+)细胞比例,双抗体夹心ELISA法检测脾细胞培养上清中病毒特异性IFN-γ、IL-4、IL-17A水平.结果:MCMV感染早期肝、脾和唾液腺组织中病毒呈低水平复制,而感染后14天仅在唾液腺组织呈高水平复制;Th1细胞比例及病毒特异性IFN-γ主要在MCMV感染早期呈显著升高(P ＜0.01);Th2细胞及IL-4均无明显表达及改变;Th17细胞及病毒特异性IL-17A则主要在感染后14天升高(P＜0.05).结论:MCMV感染早期,机体通过上调Th1细胞分化比例及IFN-γ的表达发挥抗病毒效应,而MCMV诱导Th17细胞分化及IL-17A的高表达可能是MCMV感染致宿主特异性细胞免疫功能失调并逃避机体特异性细胞免疫攻击的原因之一.     

NOD小鼠人源化后CD4~+T和CD8~+T细胞及其分泌IFN-γ与IL-17的频率变化及意义

目的 观察分析NOD小鼠和NOD.β2mnullHHD小鼠Ⅰ型糖尿病(Type1 diabetes,T1D)发病情况以及脾T细胞亚群的频率及功能差异,揭示CD4+T和CD8+T细胞亚群在HLA-A*0201转基因NOD小鼠和NOD小鼠的T1D发病中作用的异同。方法采用测量血糖的方法观察2种小鼠的发病情况,采用流式细胞术分析小鼠脾淋巴细胞CD3+CD4+T、CD3+CD8+T细胞亚群频率以及这2群细胞分泌IL-17和IFN-γ频率的差异。结果 NOD.β2mnullHHD小鼠较NOD小鼠发病早且严重;NOD.β2mnullHHD小鼠脾淋巴细胞的CD3+CD4+T细胞亚群显著高于NOD小鼠,NOD.β2mnullHHD小鼠脾淋巴细胞的CD3+CD8+T细胞亚群显著低于NOD小鼠;2种小鼠的脾淋巴细胞中CD3+CD4+IL-17+T细胞亚群与CD3+CD8+IL17+T细胞频率无差异;NOD.β2mnullHHD小鼠脾淋巴细胞的CD3+CD4+IFN-γ+T和CD3+CD8+IFN-γ+T细胞亚群频率显著高于NOD小鼠。结论 HLA-2.1分子转入NOD小鼠后HLA-2.1分子加速了HLA-A*0201转基因NOD小鼠T1D的发病进程;NOD.β2mnullHHD小鼠相对NOD小鼠的T1D发病更早、病情更重,这与CD3+CD4+T和CD3+CD8+T细胞分泌的IFN-γ显著相关,而与IL-17无关,为T1D防治的临床转化基础研究提供实验数据。     

小鼠接种HBV疫苗引起的特异性细胞免疫反应

目的：研究小鼠免疫接种基因重组乙型肝炎表面抗原疫苗(rHBs)产生的特异性细胞免疫反应。 方法： 40只BALB/c小鼠随机分为0.65、1.25、2.5、5 μg 4组，腹腔分别接种0.65、1.25、2.5、5 μg的rHBs 1次或2次。初次免疫后4周或加强免疫后2周分离小鼠脾T淋巴细胞；分别进行以下实验：实验组用rHBs(10 mg/L)刺激脾T淋巴细胞，对照组用PBS代替rHBs刺激脾T淋巴细胞；3 d后用［3H］掺入法检测脾T淋巴细胞特异性增殖反应，以［3H］掺入的同位素counts·min-1值及刺激指数(SI, 实验组counts·min-1值/对照组counts·min-1值)表示。同时用ELISA方法检测培养液中白细胞介素-2(IL-2)及γ-干扰素(IFN-γ)的浓度。 结果：只接受单次免疫的0.65、1.25、2.5、5 μg组小鼠脾T淋巴细胞特异性增殖反应SI分别为1.55、1.93、2.41、2.811；小鼠脾T淋巴细胞释放的IL-2分别为(5.48±8.88)、(9.28±6.98)、(28.53±14.32)、(64.69±20.88)ng/L，释放的IFN-γ分别为(8.22±8.61)、(9.89±9.34)、(20.27±15.50)、(30.77±22.12)ng/L。接受加强免疫的0.65、1.25、2.5、5 μg组小鼠脾T淋巴细胞特异性增殖反应SI分别为1.61、2.05、3.74、3.62；小鼠脾T淋巴细胞释放的IL-2分别为(5.75±5.04)、(102.53±67.52)、(177.13±91.12)、(332.10±124.31)ng/L，释放的γ-干扰素分别为(3.63±4.42)、(28.33±13.04)、(59.66±25.75)、(80.73±19.30)ng/L。 结论： 小鼠接种rHBs后, 脾T淋巴细胞产生特异性增殖反应，并特异性分泌IL-2、γ-干扰素，反应强度与是否加强免疫及接种的剂量密切相关。     

Inducible costimulator facilitates T-dependent B cell activation by augmenting IL-4 translation

The inducible costimulator (ICOS) is highly expressed in follicular helper T (Tfh) cells, a subset of CD4 T cells that migrate into the B cell zone and facilitate germinal center reactions. Although ICOS is known to play a critical role in forming the Tfh cell population during immune responses, its contribution to the effector functions of Tfh cells remains unclear. Using activated mouse splenic CD4 T cells we demonstrate that ICOS assists TCR-mediated signal transduction by potentiating the PI3K-AKT-mTOR signaling cascade that leads to hyper-phosphorylation of p70S6K and 4E-BP1, events that are known to augment cap-dependent mRNA translation. Consequently, ICOS costimulation promotes the formation of polysomes on IL-4 mRNA in a PI3K-dependent manner. Furthermore, we show that the supply of IL-4 becomes a limiting factor for T-dependent B cell activation during in vitro co-culture when the ICOS-PI3K signaling axis is disrupted in T cells. This ICOS costimulation-dependent translational control may ensure targeted delivery of IL-4 to cognate B cells during T–B collaborations in the germinal center.     

腺苷酸转位酶诱导自身免疫性心肌病小鼠的异常T细胞受体信号通路

目的：通过研究T细胞信号分子的表达, 探讨自身免疫性扩张型心肌病发生的分子机制。 方法： 以线粒体腺苷酸转位酶（ANT）合成肽免疫液免疫Balb/c小鼠，建立自身免疫性扩张型心肌病动物模型（DCM组），运用实时荧光定量PCR法检测其T细胞内P56lck的表达, 流式细胞术检测其Th细胞内IFN-γ和IL-4的含量, ELISA法检测其血清抗ANT自身抗体水平, 免疫组化法观察其T细胞表面CD45的表达。以不含ANT合成肽免疫液免疫小鼠作为对照组（control），试验期6个月。 结果： DCM组小鼠P56lck的基因表达(1 369.51±874.05 vs 47.93±10.21, P<0.01)、IFN-γ和IL-4的百分含量(尤其是IL-4)（8.27±1.29 vs 5.58±0.59, P<0.01; 9.93±1.53 vs 2.05±0.21, P<0.01）、抗ANT自身抗体的水平（0.105±0.015 vs 0.006±0.002, P<0.01）、CD45的表达强度(0.154±0.021 vs 0.026±0.008, P<0.01)均明显高于对照组。 结论： 异常的T细胞受体信号转导通路在ANT肽诱导扩张型心肌病发生中起着重要作用。     

The inducible costimulator (ICOS) is critical for the development of human T(H)17 cells

Human T helper 17 (T(H)17) cells regulate host defense, autoimmunity, and tumor immunity. Although cytokines that control human T(H)17 cell development have been identified, the costimulatory molecules important for T(H)17 cell generation are unknown. Here, we found that the inducible costimulator (ICOS) was critical for the differentiation and expansion of human T(H)17 cells. Human cord blood contained a subset of CD161(+)CD4(+) T cells that were recent emigrants from the thymus, expressed ICOS constitutively, and were imprinted as T(H)17 cells through ICOS signaling. ICOS stimulation induced c-MAF, RORC2, and T-bet expression in these cells, leading to increased secretion of interleukin-21 (IL-21), IL-17, and interferon-γ (IFN-γ) compared with cells stimulated with CD28. Conversely, CD28 ligation abrogated ICOS costimulation, dampening RORC2 expression while promoting the expression of the aryl hydrocarbon receptor, which led to reduced secretion of IL-17 and enhanced production of IL-22 compared with cells stimulated with ICOS. Moreover, ICOS promoted the robust expansion of IL-17(+)IFN-γ(+) human T cells, and the antitumor activity of these cells after adoptive transfer into mice bearing large human tumors was superior to that of cells expanded with CD28. The therapeutic effectiveness of ICOS-expanded cells was associated with enhanced functionality and engraftment in vivo. These findings reveal a vital role for ICOS signaling in the generation and maintenance of human T(H)17 cells and suggest that components of this pathway could be therapeutically targeted to treat cancer or chronic infection and, conversely, that interruption of this pathway may have utility in multiple sclerosis and other autoimmune syndromes. These findings have provided the rationale for designing new clinical trials for tumor immunotherapy.     

A fundamental role for interleukin-21 in the generation of T follicular helper cells

T cell help to B cells is a fundamental property of adaptive immunity, yet only recently have many of the cellular and molecular mechanisms of T cell help emerged. T follicular helper (Tfh) cells are the CD4(+) T helper cells that provide cognate help to B cells for high-affinity antibody production in germinal centers (GC). Tfh cells produce interleukin-21 (IL-21), and we show that IL-21 was necessary for GC formation. However, the central role of IL-21 in GC formation reflected its effects on Tfh cell generation rather than on B cells. Expression of the inducible costimulator (ICOS) was necessary for optimal production of IL-21, indicative of interplay between these two Tfh cell-expressed molecules. Finally, we demonstrate that IL-21's costimulatory capacity for T helper cell differentiation operated at the level of the T cell receptor signalosome through Vav1, a signaling molecule that controls T cell helper function. This study reveals a previously unappreciated role for Tfh cells in the formation of the GC and isotype switching through a CD4(+) T cell-intrinsic requirement for IL-21.     

ICOS+ Th cells produce distinct cytokines in different mucosal immune responses

T cell activation, differentiation and effector functions depend on signals delivered through the antigen-specific TCR and non-clonal costimulatory receptors on the T cell. Activated T cells express the inducible costimulator (ICOS). We examined the co-expression of ICOS with Th cytokines in mucosal immune responses. ICOS+CD4+ Th cells expressed strikingly different cytokines depending on the type of infection encountered and the cells' anatomical localization. In the Th2-dominated response to Schistosoma mansoni, ICOS expression of CD4+ cells isolated from the liver was strongly associated with the expression of IL-5, IL-10, IL-13, and T1/ST2, but not with the chemokine receptor CXCR5, a pattern consistent with Th2 effector cells. In the secondary lymphatic organs of schistosome-infected mice, ICOS expression was randomly correlated with Th2 effector-cytokines, but positively correlated with CXCR5 expression; a pattern consistent with follicular Th cells. In Th cells isolated from gut or liver of mice infected with Toxoplasma gondii, ICOS expression was positively correlated with IFN-gamma production. Finally, in the severe combined immunodeficiency transfer colitis model, ICOS expression was strongly positively associated with IFN-gamma and IL-2. Thus, ICOS appears to costimulate distinct effector functions in different immune responses, depending on factors such as the nature of the antigen encountered and localization and chronicity of the immune response.     

IL-10 inhibits CD28 and ICOS costimulations of T cells via src homology 2 domain-containing protein tyrosine phosphatase 1

BACKGROUND: Specific T-cell activation requires T-cell receptor stimulation and the generation of costimulatory signals. Major costimulatory signals are delivered to T cells by the interaction of CD28 and inducible costimulator (ICOS). OBJECTIVE: To investigate the molecular pathways involved in direct T-cell suppression by IL-10. METHODS: T-cell proliferation analysis, immunoprecipitations, and Western blots were performed after T-cell receptor and CD28 and ICOS stimulations in the absence or presence of IL-10. Dominant-negative src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP-1) overexpression, small inhibitory RNA, and SHP-1-deficient and IL-10-deficient mice were used. RESULTS: IL-10 receptor-associated tyrosine kinase Tyk-2 acts as a constitutive reservoir for SHP-1 in resting T cells, and then tyrosine phosphorylates SHP-1 on IL-10 binding. SHP-1 rapidly binds to CD28 and ICOS costimulatory receptors and dephosphorylates them within minutes. In consequence, the binding of phosphatidylinositol 3-kinase to either costimulatory receptor no longer occurs, and downstream signaling is inhibited. Accordingly, spleen cells from SHP-1-deficient mice showed increased proliferation with CD28 and ICOS stimulation in comparison with wild-type mice, which was not suppressed by IL-10. Generation of dominant-negative SHP-1-overexpressing T cells or silencing of the SHP-1 gene by small inhibitory RNA both altered SHP-1 functions and abolished the T-cell suppressive effect of IL-10. CONCLUSION: The rapid inhibition of the CD28 or ICOS costimulatory pathways by SHP-1 represents a novel mechanism for direct T-cell suppression by IL-10. CLINICAL IMPLICATIONS: Molecular mechanisms of direct T-cell suppression by IL-10 may provide a novel target for therapy of allergy/asthma and autoimmune disease.     

GPIF对免疫损伤小鼠T淋巴细胞膜表面共刺激分子表达的影响

目的：分析羊胎盘免疫调节因子(GPIF)对BALB/c小鼠T淋巴细胞共刺激表面抗原分子表达及其细胞因子分泌的影响，探讨羊胎盘免疫调节因子免疫促进作用机理。方法: 60Coγ-ray辐射所致免疫抑制小鼠连续7 d腹腔注射GPIF，流式细胞分析术分析BALB/c小鼠脾细胞表达CD28+、CD152+单阳性细胞百分率，表达CD4+CD28+、CD8+CD28+、CD4+CD152+、CD8+CD152+双阳性细胞百分率；ELISA法检测小鼠血清IL-2、IFN-γ分泌水平。结果: 羊胎盘免疫调节因子显著提高免疫损伤小鼠脾淋巴细胞CD28+、CD4+CD28+、CD8+CD28+阳性细胞百分率(P<0.05，P<0.01)，降低CD152+、CD4+CD152+阳性细胞百分率(P<0.05，P<0.01)，提高小鼠血清IL-2、IFN-γ分泌水平(P<0.01)。结论: 羊胎盘免疫调节因子的免疫促进作用与其调节T淋巴细胞CD28、CD152共刺激分子通路的活化信号传递，降低T淋巴细胞的功能抑制，促进T淋巴细胞的活化有关。活化的T淋巴细胞分泌细胞因子IL-2、IFN-γ，参与细胞因子介导的免疫网络调节。     

Differential CD28 and inducible costimulatory molecule signaling requirements for protective CD4+ T-cell-mediated immunity against genital tract Chlamydia trachomatis infection

Th1 cells and gamma interferon (IFN-gamma) production play critical roles in protective immunity against genital tract infections by Chlamydia trachomatis. Here we show that inducible costimulatory molecule (ICOS)(-/-) mice develop greatly augmented host resistance against chlamydial infection. Protection following a primary infection was characterized by strong Th1 immunity with enhanced CD4(+) T-cell-mediated IFN-gamma production in the genital tract and high expression of T-bet in the draining para-aortic lymph node. This Th1 dominance was associated with low expression of interleukin 10 (IL-10) mRNA in the uteruses of protected ICOS(-/-) mice. By contrast, CD28(-/-) mice were severely impaired in their adaptive immune response, demonstrating a lack of CD4(+) T cells and IFN-gamma in the genital tract, with a substantial delay in bacterial elimination compared to that seen in wild-type (WT) mice. Upon reinfection, WT mice exhibited a transient local infection with evidence of regulatory T-cell (Treg)/Foxp3 mRNA and a more balanced Th1 and Th2 response in the genital tract than ICOS(-/-) mice, whereas 90% of the latter mice developed sterile immunity, poor expression of local Treg/Foxp3 mRNA, and macroscopic signs of enhanced local immunopathology. Therefore, different requirements for CD28 signaling and ICOS signaling clearly apply to host protection against a genital tract infection by C. trachomatis. Whereas, CD28 signaling is critical, ICOS appears to be dispensable and can have a dampening effect on Th1 development by driving Th2 immunity and anti-inflammation through IL-10 production and promotion of the Foxp3(+) Treg populations in the genital tract. Both the CD28-deficient and the ICOS-deficient mice demonstrated poor specific antibody production, supporting the fact that antibodies are not needed for protection against genital tract chlamydial infections.