CD4+效应T细胞的新成员——Th17细胞

在抗原的刺激下，初始CD4^＋T细胞被诱导分化为效应或调节T细胞，传统上CD4^＋效应T细胞因产生的细胞因子的不同被分为两个亚群：Th1细胞——主要促进细胞内感染的病原体的清除，由IL-12诱导分化，产生的主要细胞因子是IFN-γ；和Th2细胞——主要促进寄生虫感染的清除（如蠕虫），由IL-4诱导分化，主要产生IL-4、IL-5、IL-13。     

羟氯喹抑制系统性红斑狼疮Th17细胞的分化研究

目的:研究羟氯喹对体外和SLE患者Th17细胞分化的影响。方法:将30例SLE患者依据用药不同分为两组进行治疗:分别为强的松组和羟氯喹+强的松组,采用ELISA和RT-PCR检测IL-17的表达,采用流式细胞仪方法测定羟氯喹治疗前后SLE患者Th17的变化;在体外实验中,将Th0在诱导Th17分化的条件下,加或不加HCQ进行培养,检测Th17细胞分化和IL-17表达情况。结果:SLE患者检测结果发现,与强的松组比较,羟氯喹+强的松组IL-17的水平、基因表达和Th17细胞比例显著降低。体外实验发现,羟氯喹可抑制Th17细胞的增殖和分化以及IL-17的产生。结论:羟氯喹可抑制SLE患者Th17细胞分化和IL-17的产生,为羟氯喹治疗SLE提供了依据。     

CD4~+CD25~+调节性T细胞/Th17细胞失衡与婴幼儿脓毒症

目的 观察不同免疫状态下婴幼儿脓毒症CD4~+CD25~+Foxp3~(high)岫调节性T细胞(Tr)/Th17细胞的变化,探讨婴幼儿脓毒症适应性免疫紊乱可能的机制.方法 婴幼儿脓毒症48例,健康同龄儿童对照组26例.用流式细胞术榆测CD14~+单核细胞HLA-DR表达率,CD4~+CD25~+Foxp3~(high)Tr 比例及Th17细胞比例;用ELISA法检测细胞因子IL-1β、IL-6、IL-10、TNF-α、TGF-β及IL-17A等浓度,计算IL-10/TNF-α比值;实时荧光定量PCR(real-time PCR)检测CD4~+T细胞Foxp3、ROR-γt mRNA表达及IL-17A mRNA表达.以CD14~+单核细胞HLA-DR表达＞或＜30%为阈值,将患儿分为免疫激活组(DR-H组)和免疫抑制组(DR-L组).结果 DR-L组IL-10/TNF-α比值明显高于DR-H组(P＜0.05)及对照组(P＜0.05).CD4~+CD25~+Foxp3~(high) Tr细胞比例及转录因子Foxp3基因表达DR-L组明显高于对照组及DR-H组(P＜O.05).Th17细胞比例、IL-17A血浓度、Th17细胞IL-17A基因表达及转录因子ROR-γt基因表达DR-H组及DR-L组均明显高于对照组(P＜0.05),两组之间差异无统计学意义(P＞0.05).DR-H组和DR-L组Th17细胞主要分化调控因子IL-6、IL-1β血清浓度明显高于正常对照组(P＜0.05),两组问IL-6、IL-1β浓度差异无统计学意义(P＞0.05),DB-L组CD4~+CD25~+Foxp3~(high) Tr细胞主要调节因子TGF-β血浓度明显高于DR-H组及对照组(P＜0.05).结论 Th17持续过度活化可能是导致脓毒症前炎症细胞因子/趋化因子持续增高的原因之一;CD4~+CD25~+Foxp3~(high) Tr细胞/Th17细胞失衡可能参与脓毒症混合性拮抗反应综合征(MARS)的发生发展,婴幼儿脓毒症细胞因子微环境变化可能是导致CD4~+CD25~+Foxp3~(high) Tr细胞/Thl7细胞失衡的原因之一.     

IL-21在不同乙型肝炎病毒感染者外周血CD4~+T细胞中表达的初步研究

目的:探讨乙肝病毒感染不同临床表现患者外周血CD4+T细胞中IL-21表达的差异及其在发病机制中的作用。方法:分离乙肝病毒感染不同临床表现患者及健康人外周血单个核细胞(PBMC),使用PMA+ionomycin进行刺激,同时每份标本未加PMA+ionomycin刺激做阴性对照,流式细胞术(FCM)检测IL-21的表达情况及其与Th17细胞亚群的关系。结果:PMA+ionomycin刺激能够诱导IL-21的产生,产生IL-21的主要为CD4+T细胞,IL-17A+IL-21+CD4+T细胞几乎检测不到,IL-21+CD4+T细胞比例在急性乙型肝炎组、乙肝病毒携带组中较正常对照组和慢重肝组有所升高,Th17细胞亚群比例在各组中没有统计学差异;除急性乙型肝炎组外,其余各组中IL-21+CD4+T细胞比例与Th17细胞亚群比例均有较好的相关性。结论:IL-21在HBV感染不同临床表现患者外周血CD4+T的表达有一定差异,并且其与Th17细胞亚群有相关性,提示IL-21在HBV感染的发病机制可能发挥一定作用。     

强直性脊柱炎患者Th17细胞与CD4+CD25+FoxP3+调节性T细胞的变化及意义

目的 探讨强直性脊柱炎( ankylosing spondylitis,AS)患者Th17和CD4+ CD25+ FoxP3+调节性T细胞比例及相关细胞因子水平的变化及意义.方法 强直性脊柱炎患者40例,正常同年龄对照37例.采用流式细胞术检测外周血Th17与调节性T细胞的比例,双抗体夹心酶联免疫吸附法( ELISA)检测血清IL-6、IL-23、IL-17和TGF-β水平.结果 AS组患者外周血Th17细胞比例明显高于对照组[(1.02±0.34)％vs(0.68:±0.29)％,P＜0.05],CD+ CD25+ FoxP3+细胞比例明显低于对照组[(3.77±0.81)％ vs (4.69±1.23)％,P＜0.05].AS患者血清中IL-6、IL-23、IL-17水平明显高于对照组[ (6.15±2.71) ng/L vs(3.31±1.65) ng/L; (9.44±3.12) ng/ml vs (5.82±2.61) ng/ml;( 10.53±4.97) ng/L vs (6.78±3、26) ng/L,P均＜0.01];差异有统计学意义.与对照组相比,AS组TGF-β水平有下降的趋势[(4,76±2.15) ng/ml vs(5.16±2.02) ng/ml,P＞0.05],但差异无统计学意义.AS患者血清各细胞因子含量与临床及实验室指标无相关性.结论 强直性脊柱炎患者Th17与CD4+CD35+FoxP3+调节性T细胞比例失衡,血清IL-6、IL-23、IL-17和TGF-β水平变化,这些原因可能参与强直性脊柱炎免疫发病过程.     

原发性肾病综合征患儿外周血Th17与CD4~+ CD25~+ Foxp3~+调节性T细胞的水平

目的:观察原发性肾病综合征(PNS)患儿外周血Th17细胞和CD4+ CD25+ Foxp3+调节性T细胞(Treg)及其相关因子的水平和功能,初步探讨其在儿童PNS发病中的作用。方法:PNS患儿分为单纯型肾病(SNS)20例、肾炎性肾病(NNS)15例;同时以20例健康体检儿童作为对照组。采用流式细胞术(FCM)检测外周血单个核细胞(PBMC)中Th17细胞和Treg细胞比例;Real-time PCR法检测PBMC中RORC、IL-23p19和Foxp3 mRNA的表达;ELISA分别检测血清中IL-1β、IL-6、TGF-β1的水平。结果:SNS、NNS组患儿Th17细胞及RORC、IL-23p19 mRNA、IL-1β、IL-6的水平均明显高于正常组(P0.05),且NNS组患儿以上指标明显高于SNS组(P0.05);SNS、NNS组患儿Treg细胞、Foxp3 mRNA和TGF-β1水平的表达明显低于正常组(P0.05),其中两组疾病患儿血清TGF-β1的水平无统计学意义(P0.05),其余指标NNS患儿均明显低于SNS组(P0.05)。结论:Th17/Treg细胞功能失衡可能在儿童PNS的发病中起到重要作用,其失调程度可能与PNS的临床表现、对激素的敏感性、病理类型、及预后有关。     

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。     

Th17细胞的分化调控与自身免疫性疾病

Th17细胞是最近发现的一种在分化和功能上均不同于Th1和Th2的新型CD4＋T细胞亚群.该群细胞以主要分泌细胞因子IL-17而得名.IL-6、TGF-β、IL-21及IL-23等对Th17细胞的分化调控发挥重要作用.研究表明,Th17细胞可参与多种自身免疫性疾病的发生、发展与转归.     

Th17细胞分化的调节

Th17细胞是一群分泌IL-17的CD4+T细胞,它在分化发育及功能上不同于Th1细胞和Th2细胞。目前认为Th17细胞与自身免疫性疾病的发生发展密切相关,Th17细胞在病灶部位高表达,并与疾病的严重程度相一致。研究发现:CD4+CD25+Treg和Th17细胞的分化均需要TGF-β,并通过IL-6决定两者的分化比例,CD4+CD25+Treg和Th17细胞的动态平衡在机体免疫防御、免疫自稳中起着重要作用;RORγt是Th17细胞分化的关键转录因子,RORγt的表达依赖于IL-6和TGF-β;IL-23及其受体能上调Th17细胞的表达,而IL-12、IFN-γ、IL-4、T-bet抑制其表达。对Th17细胞的深入研究将有助于我们对自身免疫性疾病发病机制的深入了解。     

红霉素可抑制弹性蛋白肽诱导的CD4~+T细胞向Th17细胞分化

目的探讨红霉素对弹性蛋白肽暴露下CD4+T细胞向Th17细胞分化的影响。方法从小鼠脾脏经免疫磁珠分选出CD4+T细胞,随机分为空白对照组、弹性蛋白肽组和弹性蛋白肽加红霉素干预组。弹性蛋白肽组和弹性蛋白肽联合红霉素处理组加入终浓度30μg/mL的弹性蛋白肽,弹性蛋白肽联合红霉素处理组在弹性蛋白肽处理的基础上,另外加入100μg/mL的红霉素。3组细胞在无血清培养液培养24h,用流式细胞术检测Th17的百分比,荧光定量PCR检测维甲酸相关孤儿核受体γt(RORγt)mRNA表达,Western blot法检测核因子κB(p65)[NF-κB(p65)]及信号转导子和转录激活子3(STAT3)蛋白相对含量。结果弹性蛋白肽组CD4+IL-17+细胞的百分比为(11.32±2.34)%、对照组为(5.21±1.36)%;qRT-PCR发现RORγt mRNA表达比对照组明显增加,Western blot法检测发现NF-κB(p65)和STAT3蛋白表达比对照组增强。与弹性蛋白肽组比较,弹性蛋白肽联合红霉素处理组的CD4+IL-17+细胞的百分比、RORγt mRNA表达、NF-κB(p65)和STAT3蛋白表达明显减少。结论红霉素可抑制弹性蛋白肽诱导CD4+T细胞向Th17分化。     

Interleukin-16 aggravates ovalbumin-induced allergic inflammation by enhancing Th2 and Th17 cytokine production in a mouse model

Asthma is a chronic inflammatory disease that involves a variety of cytokines and cells. Interleukin-16 (IL-16) is highly expressed during allergic airway inflammation and is involved in its development. However, its specific mechanism of action remains unclear. In the present study, we used an animal model of ovalbumin (OVA)-induced allergic asthma with mice harboring an IL-16 gene deletion to investigate the role of this cytokine in asthma, in addition to its underlying mechanism. Increased IL-16 expression was observed during OVA-induced asthma in C57BL/6J mice. However, when OVA was used to induce asthma in IL-16^−/− mice, a diminished inflammatory reaction, decreased bronchoalveolar lavage fluid (BALF) eosinophil numbers, and the suppression of OVA-specific IgE levels in the serum and BALF were observed. The results also demonstrated decreased levels of T helper type 2 (Th2) and Th17 cytokines upon OVA-induced asthma in IL-16^−/− mice. Hence, we confirmed that IL-16 enhances the lung allergic inflammatory response and suggest a mechanism possibly associated with the up-regulation of IgE and the promotion of Th2 and Th17 cytokine production. This work explored the mechanism underlying the regulation of IL-16 in asthma and provides a new target for the clinical treatment of asthma.     

Predominance of activated,clonally expanded T helper type 17 cells within the CD4+ T cell population in psoriatic lesions

Recent evidence points to the T helper type 17 (Th17) subset as key in the pathogenesis of psoriasis, but cells of this type in lesions remain to be fully characterized. Here we isolated, enumerated, functionally tested and clonotyped the CD4⁺ Th cell population ex vivo from lesional biopsies and paired peripheral blood samples from psoriasis patients. Th17 cells were over‐represented dramatically in lesions from all patients, representing 49–93% of CD4⁺ Th cells compared with 3–18% in blood. Most lesional Th17 cells produced interleukin (IL)‐17A ex vivo without further stimulation and expressed the CD45RO⁺ phenotype characteristic of activated or memory cells. There was no increase in ‘natural’ [CD25^hiforkhead box protein 3 (FoxP3⁺)] regulatory T cells in lesions versus peripheral blood, but there was enrichment of ‘induced’ IL‐10⁺ regulatory T cell numbers in biopsies from some patients. The lesional Th17 cells exhibited a bias in T cell receptor Vβ chain usage, suggestive of specific expansion by antigen. The therapeutic challenge is to overcome the dominance of overwhelming numbers of such antigen‐specific Th17 cells in psoriatic lesions.     

Th17 cells: new players in asthma pathogenesis

CD4+ T effector lymphocytes are distinguished in different subsets on the basis of their patterns of cytokine secretion. Th1 cells, thank to IFN-γ production, are responsible for cell-mediated immunity against intracellular pathogens, Th2 cells, through the production of IL-4, provide some degree of protection against helminthes, and Th17 cells, via IL-17, promote neutrophils recruitment for the clearance of bacteria and fungi. However, beyond their protective role, these T-helper subsets can also be involved in the pathogenesis of several inflammatory diseases. Asthma is an inflammatory disease characterized by different clinical phenotypes. Allergic asthma is the result of an inflammatory process driven by allergen-specific Th2 lymphocytes, whereas Th17 cells are mainly involved in those forms of asthma, where neutrophils more than eosinophils, contribute to the inflammation. The identification in allergic asthma of Th17/Th2 cells, able to produce both IL-4 and IL-17, is in keeping with the observation that different clinical phenotypes can coexist in the same patient. In conclusion, a picture in which different T-cell subpopulations are active in different phase of bronchial asthma is emerging, and the wide spectrum of clinical phenotypes is probably the expression of different cellular characters playing a role in lung inflammation.     

The cytokine milieu in the interplay of pathogenic Th1/Th17 cells and regulatory T cells in autoimmune disease

The propagation and regulation of an immune response is driven by a network of effector and regulatory T (Treg) cells. The interplay of effector T and Treg cells determines the direction of the immune response towards inflammation or its resolution in an autoimmune disease setting. In autoimmune diseases, this interplay shifts the balance in favor of the development of autoreactive effector T cells, resulting in inflammatory pathology. The objective of an effective therapeutic approach for autoimmune disease is to restore this balance. In this review, we describe the characteristics and development of pathogenic T helper 1 (Th1) and Th17 cells and the beneficial Treg cells in autoimmune diseases and the crucial roles of the cytokine milieu in influencing the balance of these T-cell subsets. Given the importance of cytokines, we discuss current immunotherapeutic strategies using cytokine or cytokine receptor antibodies for the treatment of autoimmune diseases.     

Elevated circulating Th17 and follicular helper CD4+ T cells in patients with rheumatoid arthritis

It remains not fully elucidated the potential functions of Th17 cells and follicular helper T (Tfh) cells and secreting cytokines in the pathogenesis of rheumatoid arthritis (RA) and their association with disease activity. In this study, the frequencies of Th17 and Tfh cells were determined by flow cytometry, and the levels of interleukin (IL)‐17, IL‐21, and IL‐22 were measured by ELISA in RA patients with different disease activities. The dynamic changes of cell subsets were also detected in response to disease‐modify antirheumatic drugs (DMARDs) therapy. The percentages of CD3⁺CD4⁺IL‐17A⁺ (Th17) cells and CD3⁺CD4⁺CXCR5⁺ICOS^high (Tfh) cells, as well as the concentrations of IL‐17, IL‐21, and IL‐22 were significantly elevated in RA patients than those in healthy individuals. Furthermore, Tfh cells, IL‐21, and IL‐22 in the serum was positively correlated with the values of disease activity score. Concentrations of IL‐21 and IL‐22 in the serum were remarkably reduced following the DMARDs therapies. Our data suggested that Th17 cells, Tfh cells as well as the secreting cytokines may be involved in the pathogenesis of RA. The frequency of circulating Tfh cells and the productions of IL‐21 and IL‐22 were associated with the disease activity of RA patients, and might be potential therapeutic targets for treatment of RA.     

Altered Th1/Th2 commitment in human CD4+ T cells with ageing

The human immune system undergoes continuous remodelling with the advancement of age. Since age-associated functional alterations in the immune system could be caused by a possible change in helper T cell regulation in elderly subjects, we comparatively studied the function of CD4+ T cells in peripheral blood obtained from both young and old healthy volunteers. Upon cell activation by phorbol myristate acetate and ionomycin, the proportion of CD4+ T cells containing interferon-gamma (IFN-gamma) was found to be greater in the old subjects. Utilizing a co-culture system, which activated CD4+ T cells via the TCR/CD3 complex and CD28, we found that CD4+ T cells from the old subjects secreted more IFN-gamma and IL-2, but less IL-4, than those from the young subjects. Upon cell activation by co-culture, CD4+ T cells from the old subjects expressed more CD26, CD40L, and LFA-1, but less CD30, than those from the young. These results together suggest that the microenvironment in which CD4+ T cells develop in older people may cause production of more cells committed to Th1 than that in younger subjects.     

IL-4 influences the differentiation and the susceptibility to activation-induced cell death of human naive CD8+ T cells

It is now well established that the cytokine environment influences the activation, differentiation, proliferation and death of T lymphocytes during the primary response to antigen. Using an in vitro model, we investigated the influence of IL-4, added at the onset of TCR stimulation, on phenotypic and functional markers of naive CD8+ T cell activation including the up-regulation of activation markers, proliferation as well as the susceptibility to activation-induced cell death (AICD). We report that IL-4, unlike IL-2 added at the onset of repeated TCR stimulation of naive CD8+ T cells prevents AICD, in part due to its ability to maintain the level of the survival-related protein Bcl-2. Moreover, TCR-triggered activation of naive CD8+ T cells in the presence of IL-4 leads to the development of a CD8+ T cell subset that proliferates normally, but which fails to exhibit characteristic activation parameters such as the up-regulation of CD25 and Granzyme B. Taken together, these results demonstrate that exposure to IL-4 during primary activation influences CD8+ T cell differentiation by inducing the development of a sub-population of AICD-resistant, proliferation-competent cells that do not show some of the typical features of CD8+ T cell activation.     

CD4+ T helper 2 cells--microbial triggers, differentiation requirements and effector functions

Over the past 10 years we have made great strides in our understanding of T helper cell differentiation, expansion and effector functions. Within the context of T helper type 2 (Th2) cell development, novel innate‐like cells with the capacity to secrete large amounts of interleukin‐5 (IL‐5), IL‐13 and IL‐9 as well as IL‐4‐producing and antigen‐processing basophils have (re)‐emerged onto the type 2 scene. To what extent these new players influence αβ⁺ CD4⁺ Th2 cell differentiation is discussed throughout this appraisal of the current literature. We highlight the unique features of Th2 cell development, highlighting the three necessary signals, T‐cell receptor ligation, co‐stimulation and cytokine receptor ligation. Finally, putting these into context, microbial and allergenic properties that trigger Th2 cell differentiation and how these influence Th2 effector function are discussed and questioned.