FOXP3蛋白复合体及调节性T细胞功能研究进展

 FOXP3⁺CD4⁺CD25⁺调节性T 细胞（FOXP3⁺Tregs）负责正常机体免疫稳态的维持。人类许多重大免疫性疾病均与调节性T 细胞的功能异常相关。叉头状家族转录蛋白FOXP3 是调节性T 细胞中特异性表达的关键转录因子,对调节性T 细胞的发育与功能有着重要作用。近年来的研究表明,FOXP3 蛋白转录调控复合体的装配及其翻译后修饰调节对调节性T 细胞的功能至关重要,相关生理过程受到各种炎症微环境的动态调节。深入研究FOXP3⁺Tregs 活性调节的分子机制将为攻克人类重大免疫及相关性疾病提供创新性线索。     

有氧和力竭游泳运动对DNA疫苗免疫效果的影响及机制研究

将48只雌性C57BL/6小鼠随机分成对照组(16只),有氧游泳运动组(16只)和力竭游泳运动组(16只).在小鼠分别进行6周有氧和力竭游泳运动后,肌肉注射DNA疫苗3次,每次间隔14d.末次免疫后14d,处死小鼠,收集血液和脾细胞,检测抗原特异性的体液和细胞免疫反应.为了进一步研究不同强度有氧运动影响疫苗的免疫效果的作用机理,小鼠运动6周后,处死小鼠,收集脾细胞分析CD4⁺CD25+CD25⁺调节性T细胞(Treg)的数量及其抑制功能和IL-2的变化.结果显示:和对照组比,有氧运动增强了抗原特异性的细胞免疫反应和细胞毒T淋巴细胞反应(CTL);与之相反,力竭运动抑制抗原特异性的细胞免疫反应和CTL反应.但两种不同强度的游泳运动都不影响血清中抗体的产生.机理研究发现,力竭运动增加Treg细胞的数量及抑制功能,而有氧运动并不影响Treg的数量和功能,但增加脾细胞IL-2的表达.以上结果表明:1)有氧和力竭运动不影响DNA疫苗的体液免疫效果;2)有氧运动可能通过增加脾细胞中IL-2的产生而增强DNA疫苗的细胞免疫效果;3)力竭游泳运动可能通过改变Treg的数量及其抑制功能而削弱DNA疫苗的细胞免疫效果.     

低剂量Activin A通过激活CD8+T细胞发挥抗肿瘤效应

Activin A属于转化生长因子-β(transforming growth factor-β,TGF-β)超家族中的多功能细胞因子,存在于多种免疫细胞中.CD8⁺T细胞是发挥抗肿瘤活性的主要免疫细胞类型.以H22细胞移植瘤模型旨在探讨Activin A对CD8⁺T细胞功能的调控和作用机制.本研究首先在分离出的CD8⁺T细胞上发现Activin A受体及下游信号分子的表达.体外实验表明Activin A对小鼠H22肝癌细胞系的凋亡及增殖无显著影响.H22荷瘤鼠的体内研究发现低浓度Activin A抑制肿瘤生长,高浓度Activin A促进肿瘤生长.在Activin A对肿瘤CD8⁺T细胞作用的研究中,发现大剂量Activin A处理的肿瘤中CD8⁺T细胞含量减少,小剂量Activin A处理组中CD8⁺T细胞含量则增加.以上数据表明,不同剂量的Activin A可能通过调控CD8⁺T细胞的浸润对肿瘤的生长发挥双重作用.     

胡桃楸树皮抗肿瘤有效成分对H22荷瘤小鼠T细胞亚群的影响

 为测定胡桃楸树皮提取物(HT)抗肿瘤有效成分对H₂₂荷瘤小鼠T细胞亚群的影响,将昆明小鼠随机分为HT高剂量组、HT低剂量组、阳性药环磷酰胺组、模型组和正常组,采用接种法复制H₂₂肿瘤移植模型。利用荧光标记抗体-流式细胞术检测HT对建立的H₂₂荷瘤小鼠模型外周血中CD4⁺/CD8⁺细胞亚群比值变化; ELISA法检测CD4⁺细胞所分泌细胞因子IL-4和IFN-γ的含量,以测定Th1/Th2细胞亚群比例。结果显示,与阳性药注射用环磷酰胺(CTX)相比,HT高、低剂量组能显著降低机体CD8⁺亚群比例(P<0.01),HT低剂量组可明显提高CD4⁺/CD8⁺比值(P<0.05)。HT高、低剂量组的IL-4含量显著低于阳性药CTX组(P<0.001),明显低于模型组(P<0.05)。HT高剂量组的IFN-γ/IL-4水平明显高于阳性药CTX组(P<0.05)。研究表明,胡桃楸树皮提取物具有明显的抑瘤作用,能保护胸腺和脾脏,能减轻荷瘤机体的T细胞免疫功能的损伤。     

胃癌小鼠模型中T淋巴细胞检测及初步分析

为建立胃癌小鼠模型,检测T淋巴细胞在免疫系统的水平变化,探讨其在胃癌免疫系统中的作用。采用在615近交系小鼠皮下注射MFC胃癌细胞建立胃癌小鼠模型。流式细胞仪检测胃癌小鼠(n=20)及正常小鼠(n=20)脾脏CD4+CD25+Treg及T细胞亚群水平。结果显示,胃癌实验组小鼠脾CD3+T(42.87±4.33)%和CD8+T(36.55±3.15)%细胞较正常组升高(P0.01);CD4+T(55.02±2.64)%细胞及CD4+T/CD8+T(1.48±0.13)细胞比值较正常组降低(P0.01);胃癌实验组小鼠脾CD4+CD25+Treg(2.14±0.91)%细胞较正常组升高(P0.01)。由此可知,胃癌小鼠脾Treg细胞水平升高,CD4+T降低,CD3+T、CD8+T升高,CD4+T/CD8+T比值降低,可能在胃癌细胞免疫逃逸过程中发挥一定作用。     

基于胆固醇代谢调控的肿瘤免疫治疗新方法

 免疫检测点阻断疗法等肿瘤免疫疗法近年在临床上取得了重大突破,但仍存在响应率低等显著缺点,需开发新的肿瘤免疫疗法以使更多肿瘤患者受益。胆固醇作为细胞质膜脂质的重要组成成分,其代谢可以影响T细胞的质膜环境及效应功能。本研究发现,通过调控胆固醇代谢可以增强CD8⁺ T细胞的抗肿瘤免疫反应。抑制关键胆固醇酯化酶ACAT1的活性,CD8⁺ T细胞质膜游离胆固醇水平上调,细胞的抗肿瘤免疫应答显著增强,这为肿瘤免疫治疗提供了新思路和新方法。     

调节性T细胞与白塞病

调节性T细胞(Treg细胞)在机体保持自身免疫耐受,达到免疫平衡中发挥重要作用.Treg细胞在感染、肿瘤、自身免疫性疾病等各种免疫紊乱相关性疾病中起重要调节作用.近年来对Treg细胞的研究比较广泛,但其在白塞病(Behcet disease,BD)的发病机制中作用尚不清楚.现有人体和动物研究表明BD活动期Treg细胞及其分泌的功能因子增高,但仍存在争议,另外Treg作用于BD的靶点亦不明确,需要进一步研究.     

树突状细胞在肿瘤免疫中作用的初步研究

树突状细胞(DC)是体内最重要的专职抗原呈递细胞,是连接天然免疫和获得免疫的桥梁.cDC由于其强大的提呈抗原的能力在肿瘤免疫中发挥重要的作用.利用CD11c-DTR小鼠,检测了cDC清除(ConventionalDendritic cell)对肿瘤生长的影响,分析了cDC敲除后荷瘤小鼠肿瘤微环境的改变.结果表明,cDC减少后Treg的浸润增多.即cDC对肿瘤微环境中的Treg有抑制作用.同时,cDC清除后CD4+和CD8+T细胞抗肿瘤的Th1反应降低.我们的工作加深了对于树突状细胞在肿瘤免疫作用中的理解.     

胰腺癌细胞与神经相互作用对MIA PaCa-2转移侵袭的影响及机制研究

为了探讨胰腺癌细胞MIAPaCa-2与神经的相互作用对MIAPaCa-2增殖、凋亡、转移和侵袭能力的影响,及其在上皮间质转化和嗜神经侵袭进程中的作用,建立了MIA PaCa-2和小鼠神经共培养模型,收集上清,用其处理MIAPa-Ca-2 细胞,通过流式细胞术观察 CD133⁺/CXCR4⁺双染比例变化;Transwell 实验检测 MIA PaCa-2/神经相互作用和CD133对胰腺癌细胞转移侵袭能力的影响; Western blotting 检测不同处理组相关蛋白的表达;CCK-8检测其对MIA Pa-Ca-2增殖能力的影响.结果显示共培养上清处理过的MIA PaCa-2细胞中CD133⁺/CXCR4⁺双阳性比例显著高于普通培养基组(P<0.05),MIA PaCa-2/神经相互作用和 CD133 促进MIA PaCa-2增殖、转移和侵袭,提高其抗凋亡能力,上调Vimentin和Slug的表达.表明MIA PaCa-2/神经相互作用可提高胰腺癌细胞中CD133⁺/CXCR4⁺双阳比例,促进细胞增殖,抑制凋亡,调控细胞上皮间质转化进程,并诱导其转移侵袭.     

QS412透性化细胞产海藻糖特性研究

透性化细胞中在麦芽寡糖基海藻糖合成酶和麦芽寡糖基海藻糖水解酶作用下由淀粉生产海藻糖,其使用可省略酶的纯化和胞内酶的固定化。本文研究了金属离子对透性化细胞产海藻糖活性的影响,观察到Mg²⁺对其活性有提高作用,Zn²⁺、Mn²⁺、Cu²⁺、Fe²⁺、Hg²⁺5种2价离子对其活性有明显抑制作用。其中,Hg²⁺的抑制作用最为明显,而Mn²⁺的作用未见报道。Zn²⁺在40mmol/L浓度以上能完全抑制体系中MTHase的活性,并且这种抑制作用可以通过添加EDTA消除,这就提供了制备MTHase底物及在两种酶存在下单独测定MTSase活性的可能。本征动力学和宏观动力学分析表明透性化细胞合成海藻糖的过程中外扩散影响可忽略,内扩散影响显著。通过对该过程作用特性的研究,为透性化细胞的研究和使用打下进一步的基础。     

大承气汤对支气管哮喘及肺肠合病Treg/TH17免疫机制的作用

目的 从“肺与大肠相表里”理论出发，以大承气汤通肠利肺作用为切入点，观察支气管哮喘（简称哮喘）及肺肠合病大鼠动物模型及在大承气汤方药干预下，肺与大肠之间共同免疫物质TH17/Treg的变化，探讨“肺与大肠相表里”的免疫机制.方法 建立哮喘组、肺肠合病组、大承气汤组哮喘干预组与肺肠合病干预组动物模型，检测各组大鼠外周血淋巴细胞中Th17/Treg亚群分布表达,及血清中 IL-17，IL-6，IL-2的水平.结果 与正常对照组比较，哮喘组及肺肠合病组大鼠外周血中Th17细胞比例升高，Treg细胞比例降低，血清中IL-6，IL-17水平升高，IL-2水平降低，有差异具有统计学意义（P＜0.005）；肺肠合病组大鼠组更明显（P＜0.005）.在大承气汤干预下，与哮喘组比较，哮喘干预组与肺肠合病干预组Th17细胞比例降低，Treg细胞比例升高，血清IL-6，IL-17水平下降，IL-2水平升高，差异有统计学意义（P＜0.005）.结论 哮喘发病时肠道功能的变化可能导致肺、肠TH17/Treg的免疫失衡，免疫反应向呼吸道粘膜等部位迁移，加重哮喘的发病.大承气汤是可以通过调节肠道TH17/Treg免疫，提高黏膜屏障功能，降低淋巴细胞的“归巢”作用，减轻哮喘发病.     

PPAR-γ is a major driver of the accumulation and phenotype of adipose tissue Treg cells

Obesity and type-2 diabetes have increased markedly over the past few decades, in parallel. One of the major links between these two disorders is chronic, low-grade inflammation. Prolonged nutrient excess promotes the accumulation and activation of leukocytes in visceral adipose tissue (VAT) and ultimately other tissues, leading to metabolic abnormalities such as insulin resistance, type-2 diabetes and fatty-liver disease. Although invasion of VAT by pro-inflammatory macrophages is considered to be a key event driving adipose-tissue inflammation and insulin resistance, little is known about the roles of other immune system cell types in these processes. A unique population of VAT-resident regulatory T (Treg) cells was recently implicated in control of the inflammatory state of adipose tissue and, thereby, insulin sensitivity. Here we identify peroxisome proliferator-activated receptor (PPAR)-γ, the 'master regulator' of adipocyte differentiation, as a crucial molecular orchestrator of VAT Treg cell accumulation, phenotype and function. Unexpectedly, PPAR-γ expression by VAT Treg cells was necessary for complete restoration of insulin sensitivity in obese mice by the thiazolidinedione drug pioglitazone. These findings suggest a previously unknown cellular mechanism for this important class of thiazolidinedione drugs, and provide proof-of-principle that discrete populations of Treg cells with unique functions can be precisely targeted to therapeutic ends.     

Effect of polyvinyl butyrate nanoparticles incorporated with immune suppressing vitamins on alteration of population of intestinal immune cells

The nanoparticles (NPs) from polyvinyl butyrate (PVBu) which can work as an orally applicable donor of butyrate for intestine were prepared. Immunotolerance inducing molecules such as vitamin D₃ and all-trans retinoic acid (ATRA) were incorporated into PVBu NPs. The alteration in populations and numbers of DC103⁺ dendritic cells (DC) and regulatory T (Treg) cells in intestinal immune tissues were examined after oral administration of NPs. It was found that NPs reduced the population of CD103⁺ DC and Treg cells in Peyer’s patched in lower part of the intestine and inversely increased the population of CD103⁺ DC in mesenteric lymph node (MLN), while the population of Treg cells in MLN was unchanged. These observations indicate that NPs may enhance the immunotolerance at MLN and lamina propria toward luminal antigens, indicating the promising features of PVBu NPs as therapeutics of allergy and autoimmune diseases.     

大鼠口服免疫耐受与皮肤移植的研究

目的利用口服供者脾细胞延长受者大鼠皮肤存活时间,检测调节性T细胞在移植前后的变化,探讨口服免疫耐受的机制。方法以纯系SD大鼠为供者,纯系Wistar大鼠为受者,行异体皮肤移植,将24只受者大鼠随机分为A组（对照组,口服PBS）、B组（每日口服SD大鼠脾细胞1×10^7个）,C组（每日口服SD大鼠脾细胞5×10^7个）,对受体进行450Rad^60Co照射,然后检测受者外周血及脾脏CD4＋CD25＋、CD8＋CD28-调节性T细胞（Treg）,并对受者进行供者脾细胞导管灌胃,每次口服5×10^7个细胞,每日一次,7d后检查迟发型超敏反应（DTH）,并行皮肤移植,观察移植皮肤的存活时间,复查Treg两次。结果口服脾细胞后,DTH反应均出现明显的抗原特异性降低;C组的皮肤移植存活时间达到19．17d±1．94d,与前两组比较差异有显著性（P〈0．01）。在口服供体脾细胞延长皮肤移植存活大鼠（C组）的外周血及脾脏中CD8＋CD28-Treg均比口服前明显增高（P〈0．01）,并能维持2周以上。结论口服抗原可以引起受者对异基因抗原的特异性免疫反应降低,使受者的皮肤移植存活期延长,CD8＋CD28-Treg在口服免疫耐受的机制中发挥了重要作用。     

IL-23 promotes tumour incidence and growth

Chronic inflammation has long been associated with increased incidence of malignancy and similarities in the regulatory mechanisms have been suggested for more than a century. Infiltration of innate immune cells, elevated activities of matrix metalloproteases and increased angiogenesis and vasculature density are a few examples of the similarities between chronic and tumour-associated inflammation. Conversely, the elimination of early malignant lesions by immune surveillance, which relies on the cytotoxic activity of tumour-infiltrating T cells or intra-epithelial lymphocytes, is thought to be rate-limiting for the risk to develop cancer. Here we show a molecular connection between the rise in tumour-associated inflammation and a lack of tumour immune surveillance. Expression of the heterodimeric cytokine interleukin (IL)-23, but not of its close relative IL-12, is increased in human tumours. Expression of these cytokines antagonistically regulates local inflammatory responses in the tumour microenvironment and infiltration of intra-epithelial lymphocytes. Whereas IL-12 promotes infiltration of cytotoxic T cells, IL-23 promotes inflammatory responses such as upregulation of the matrix metalloprotease MMP9, and increases angiogenesis but reduces CD8 T-cell infiltration. Genetic deletion or antibody-mediated elimination of IL-23 leads to increased infiltration of cytotoxic T cells into the transformed tissue, rendering a protective effect against chemically induced carcinogenesis. Finally, transplanted tumours are growth-restricted in hosts depleted for IL-23 or in IL-23-receptor-deficient mice. Although many strategies for immune therapy of cancer attempt to stimulate an immune response against solid tumours, infiltration of effector cells into the tumour tissue often appears to be a critical hurdle. We show that IL-23 is an important molecular link between tumour-promoting pro-inflammatory processes and the failure of the adaptive immune surveillance to infiltrate tumours.     

The myeloid cells of the central nervous system parenchyma

A microglial cell is both a glial cell of the central nervous system and a mononuclear phagocyte, which belongs to the haematopoietic system and is involved in inflammatory and immune responses. As such, microglia face a challenging task. The neurons of the central nervous system cannot divide and be replenished, and therefore need to be protected against pathogens, which is a key role of the immune system, but without collateral damage. In addition, after physical injury, neural cells need restorative support, which is provided by inflammatory responses. Excessive or chronic inflammatory responses can, however, be harmful. How microglia balance these demands, and how their behaviour can be modified to ameliorate disorders of the central nervous system, is becoming clear.     

T-cell-expressed proprotein convertase furin is essential for maintenance of peripheral immune tolerance

Furin is one of seven proprotein convertase family members that promote proteolytic maturation of proproteins. It is induced in activated T cells and is reported to process a variety of substrates including the anti-inflammatory cytokine transforming growth factor (TGF)-beta1 (refs 2-4), but the non-redundant functions of furin versus other proprotein convertases in T cells are unclear. Here we show that conditional deletion of furin in T cells allowed for normal T-cell development but impaired the function of regulatory and effector T cells, which produced less TGF-beta1. Furin-deficient T regulatory (Treg) cells were less protective in a T-cell transfer colitis model and failed to induce Foxp3 in normal T cells. Additionally, furin-deficient effector cells were inherently over-active and were resistant to suppressive activity of wild-type Treg cells. Thus, our results indicate that furin is indispensable in maintaining peripheral tolerance, which is due, at least in part, to its non-redundant, essential function in regulating TGF-beta1 production. Targeting furin has emerged as a strategy in malignant and infectious disease. Our results suggest that inhibiting furin might activate immune responses, but may result in a breakdown in peripheral tolerance.     

Intestinal homeostasis and its breakdown in inflammatory bowel disease

Intestinal homeostasis depends on complex interactions between the microbiota, the intestinal epithelium and the host immune system. Diverse regulatory mechanisms cooperate to maintain intestinal homeostasis, and a breakdown in these pathways may precipitate the chronic inflammatory pathology found in inflammatory bowel disease. It is now evident that immune effector modules that drive intestinal inflammation are conserved across innate and adaptive leukocytes and can be controlled by host regulatory cells. Recent evidence suggests that several factors may tip the balance between homeostasis and intestinal inflammation, presenting future challenges for the development of new therapies for inflammatory bowel disease.