T细胞免疫球蛋白粘蛋白分子-3与免疫调节的研究进展

T细胞免疫球蛋白粘蛋白分子3(Tim3)是一种Ⅰ型膜表面蛋白分子,属于新近发现的T细胞免疫球蛋白粘蛋白分子家族的一员。Tim3分子只选择性表达在分化的Th1细胞而不是Th2细胞上,可以作为新的区分Th1和Th2细胞的表面标志。Tim3分子通过与CD4 CD25 调节性T细胞和或抗原提呈细胞上表达的Tim3配体相互作用,抑制Th1免疫应答,在自身和异体免疫性疾病以及免疫耐受中起着重要作用。     

Tim家族在免疫应答中的作用

Tim(T-cell immunoglobulin and mucin-domain-containing molecule)家族是最近发现的基因家族,主要表达在免疫细胞表面,调节Th1和Th2细胞介导的免疫应答,在一些变态反应和自身免疫性疾病的发生和发展中发挥着重要的作用。当前研究主要集中在该家族中已发现的4个成员:Tim-1,表达在Th2细胞和活化的初始T细胞表面,为T细胞的活化提供协同信号,并促进细胞因子的分泌;Tim-2,仅在动物中发现,选择性地表达在Th2细胞表面,负调节Th2的增殖分化及细胞因子的产生;Tim-3,选择性地表达在Th1细胞表面,负调节Th1介导的免疫应答;Tim-4是Tim-1的天然配体,主要表达在活化的抗原提呈细胞(APC)表面。     

T细胞免疫球蛋白粘蛋白分子-4在免疫应答中的作用以及与相关疾病的关系

T细胞免疫球蛋白粘蛋白分子（T-cell immunoglobulin and mucin-domain-containing molecule, TIM）基因是近年来发现的新基因家族,其在调节免疫应答中发挥重要的作用。 TIM-4是TIM家族成员之一,仅表达在巨噬细胞和活化的树突状细胞（ dendritic cell, DC）表面,能够调节T细胞,抑制初始CD4＋T细胞和Th17细胞,增加Th2细胞。 TIM-1与TIM-4相互作用可调节T细胞活化增殖,调节Th1／Th2细胞平衡。此外, TIM-4可与磷脂酰丝氨酸结合,促进巨噬细胞对凋亡细胞的吞噬作用。已经发现TIM-4的调节异常与自身免疫性疾病、过敏性疾病以及肿瘤等有关。因此,了解TIM-4作用于相关受体的机制,可能为免疫介导性疾病调控治疗提供更多的靶点和途径。     

Tim3 和BAT3 在再生障碍性贫血中免疫机制的研究进展

再生障碍性贫血(AA)是一种骨髓造血功能降低的自身免疫性疾病。研究发现异常免疫机制在AA的发病过程中起到调节作用。AA患者体内Th1细胞功能亢进,Th1/Th2细胞比例出现失衡,CD8~+T淋巴细胞比例增高,mDC细胞增多,M1/M2型巨噬细胞比例失调,并且NK细胞数量也有一定程度下降。Tim3在AA等疾病中可以通过下游因子Gal9对机体适应性免疫反应进行保护,并在固有免疫系统的各个细胞中也起到调节作用。而BAT3抑制了Tim3在T淋巴细胞中的活性,同时也增强了AA疾病中DC细胞和巨噬细胞的摄取提呈作用,以及NK细胞杀伤抗原的功能。进一步了解Tim3和BAT3两种因子在AA疾病过程中适应性免疫应答和固有免疫应答中的作用机制,有望为AA等相关免疫疾病的治疗开拓新的方法和思路。     

CD28家族分子在疾病诊疗中的研究进展

机体免疫应答过程是由多种免疫细胞和免疫分子共同参与完成的,而免疫应答的核心是T淋巴细胞的活化。近年来的研究表明,T淋巴细胞活化、增殖及分化为效应细胞需要双重刺激信号：第一信号由T细胞受体（TCR）转导并由黏附分子增强;第二信号即协同刺激信号,由抗原提呈细胞（APCs）表面的协同刺激分子和T细胞的相应受体作用产生[1]。CD28/B7提供调节细胞迁移和Th1/Th2分化、     

T细胞免疫球蛋白及黏蛋白域蛋白4的生物学功能及其与过敏性疾病的关系

T细胞免疫球蛋白及黏蛋白域家族是一个影响Th1／Th2细胞分化的基因家族。T细胞免疫球蛋白及粘蛋白域蛋白4（TIM4）是TIM家族的一个成员,主要表达于树突状细胞和巨噬细胞。TIM4与TIM1结合后参与对Th2细胞的激活,影响机体的免疫功能：TIM4同时是一个黏附分子,其与磷脂酰丝氨酸结合后可介导巨噬细胞对凋亡细胞的吞噬。另外,TIM4与儿童过敏性鼻炎,过敏性哮喘之间存在着遗传相关性,     

人胸腺基质淋巴细胞生成素与过敏性疾病的研究进展

人胸腺基质淋巴细胞生成素（TSLP）是新近发现的具有IL-7样功能的细胞因子。它能够强烈诱导DC表达MHCⅡ类分子以及协同刺激分子CD40、CD80，促进DC产生招募Th2型细胞的趋化因子CCL17和CCL22，诱导初始T细胞分化为分泌IL-4、IL-5、IL-13的变应原特异性CD^4和CD8^＋效应T细胞，调节机体免疫应答向Th2型偏移，从而参与遗传过敏性皮炎、哮喘等多种过敏性疾病的发生过程。     

Th17细胞与肝脏疾病的研究进展

机体免疫系统是抵抗外来病原体和各种损害的防御系统,根据CD4^＋T细胞的功能经典地分为辅助性T细胞（Th1、Th2）、细胞毒性T细胞以及调节性T细胞（Treg）3个亚群。Th1介导细胞免疫,Th2介导体液免疫,而Treg则在维护机体免疫平衡中发挥重要作用。然而随着对自身免疫性疾病的研究,发现一群不同于Th1、Th2、Treg的新型CD4^＋T细胞亚群——Th17细胞。已证实Th17细胞与清除胞外病原体、炎症、自身免疫性疾病和肿瘤的发生发展有密切联系。随着人们对肝炎、肝纤维化和肝癌等肝病认识不断加深,这种新型的Th17细胞在这些疾病中发生发展的作用机制也不断的被研究者所关注。     

Tim家族的研究进展及与哮喘的关系

T细胞免疫球蛋白域粘蛋白域蛋白(Tim)基因是新近发现的一类基因家族,研究表明Tim家族与T细胞免疫反应及Th1和Th2细胞分化有关,可能对哮喘和自身免疫病的发生与发展起重要作用,本文拟就有关内容作一综述。     

Th17细胞分化的转录调控网络

初始T细胞通过其表面的T细胞抗原受体识别病原微生物,受不同共刺激分子的调节,活化各种信号转导通路,最终分化为多种效应性T细胞,发挥抗炎、调节免疫等作用.经典的根据初始T细胞所分泌细胞因子种类和功能的不同,将其分为辅助性T细胞1型(T help cell 1,Th1)、2型(T help cell 2,Th2)和调节性T(Treg)细胞,Th1和Th2细胞分别参与细胞和体液介导的免疫应答,Treg细胞可以抑制免疫反应.近来,研究报道一种新的T细胞系,因其能特异性的分泌产生IL-17细胞而被称为Th17细胞,Th17细胞通过孤核受体γt(Retinoic acid receptor-related orphan receptor γ t,RORγt)介导的IL-17的产生调节炎症性自身免疫性疾病[1].     

Acute stimulation generates Tim‐3‐expressing T helper type 1 CD4 T cells that persist in vivo and show enhanced effector function

T‐cell immunoglobulin and mucin domain 3 (Tim‐3) is a surface receptor expressed by T helper type 1 (Th1) effector CD4 T cells, which are critical for defence against intracellular pathogens and have been implicated in autoimmune disease. Previous studies showed that Tim‐3 expression makes Th1 cells more susceptible to apoptosis and also marks functionally impaired T cells that arise due to chronic stimulation. However, other studies suggested that Tim‐3‐expressing Th1 cells do not always have these properties. To further define the relationship between Tim‐3 and Th1 cell function, we analysed the characteristics of Th1 cells that expressed Tim‐3 in response to brief stimulation in vitro or an acute viral infection in vivo. As expected, cultured CD4 T cells began expressing Tim‐3 during Th1 differentiation and secondary stimulation generated Tim‐3^? and Tim‐3⁺ fractions that were separated and further analysed. When injected into naive mice, Tim‐3⁺ cells down‐regulated Tim‐3 and survived equally well compared with Tim‐3^‐ cells. Further, Tim‐3^? and Tim‐3⁺ Th1 cells had similar functional responses when transferred into naive mice that were subsequently infected with lymphocytic choriomeningitis virus (LCMV). Cultured Th1 cells that expressed Tim‐3 following T‐cell receptor stimulation had a greater capacity to express signature Th1 cytokines than their Tim‐3^? counterparts and showed differential expression of genes that regulate CD4 T‐cell function. Consistent with these findings, Tim‐3⁺ Th1 cells generated in response to LCMV infection displayed augmented effector function relative to Tim‐3^? cells. These results suggest that Tim‐3 expression by Th1 cells responding to acute stimulation can mark cells that are functionally competent and have an augmented ability to produce cytokines.     

Molecular variations in the promoter and coding regions of human Tim-1 gene and their association in Koreans with asthma

The family of T-cell immunoglobulin domain and mucin domain (TIM) proteins is identified to be expressed on T cells. A member of Tim family, TIM-1, was considered as a membrane protein that is associated with the development of helper T cell (Th2) biased immune responses, and may be selectively expressed on Th2 cells. In the present study we performed single nucleotide polymorphism (SNP) scanning of the coding and promoter regions of human Tim-1 gene. We identified a total of ten SNPs including five novel SNPs (-1166C>G, -416G>C, -232A>G, 5365C>T, and 5529A>G) in the coding and promoter regions, one novel variation site (-2278_-2276dupATT) in the promoter region and three variations (5383_5397del, 5387_5389insAAC, and 5509_5511delCAA) in exon 4 of human Tim-1 gene. Our results suggest that the exon 4 variation site in human Tim-1 gene is associated with the susceptibility of allergic disease.     

Tim-2 up-regulation and galectin-9-Tim-3 pathway activation in Th2-biased response in Schistosoma japonicum infection in mice

T cell immunoglobulin domain and mucin domain (Tim) family, a new gene that expresses on the surface of T cells, plays a critical role in regulation of T cells response. Previous data have shown that Tim-3 expressed on Th1 cells promotes itself apoptosis. Tim-2 is preferentially up-regulated during Th2 differentiation and functions as a potent costimulatory molecule for T-cell immunity. The present study aims to learn whether Tims are responsible for Th2-biased response evoked by Schistosoma japonicum infection. The expressions of Tim-2 and Tim-3 in spleen lymphocytes from S. japonicum-infected mice were examined, and the possible role of galectin-9-Tim-3 pathway in Th2-biased response triggered by schistosome infection was discussed. Our results showed that Tim-2 mRNAs were up-regulated in the spleen of schistosome-infected mice, which coincided with elevated IL-4 gene expression. Administration of galectin-9 significantly induced apoptosis of na?ve spleen lymphocytes with down-regulation IFN-γexpression in vitro. Additionally, Tim-3-Fc fusion protein notably enhanced Th1 cells and decreased Th2 cells in vitro. Thus, we concluded that pro-apoptotic effects on Th1 population through galectin-9-Tim-3 pathway and the up-regulation of Tim-2 on Th2 cells might be critical to Th2-biased response of host with schistosomiasis japonica.     

Tim‐3 regulates inflammatory cytokine expression and Th17 cell response induced by monocytes from patients with chronic hepatitis B

Tim‐3 is expressed on monocytes/macrophages and is involved in the regulation of inflammatory responses. The aim of this study was to determine the effect of Tim‐3 on inflammatory response triggered by peripheral monocytes from patients with chronic hepatitis B (CHB). Tim‐3 expression on peripheral monocytes and frequency of Th17 cells in peripheral blood mononuclear cells (PBMCs) derived from CHB patients were detected. Followed by lipopolysaccharides (LPS) activation of circulating monocytes from CHB patients, expression of inflammatory cytokines including TNF‐α，IL‐1β and IL‐6 were examined in the presence and absence of Galectin‐9 which is the ligand for Tim‐3. Subsequently, after purified CD4+T cells were cocultured with LPS‐activated monocytes from CHB patients in the presence of anti‐Tim‐3 antibody, percentage of Th17 cells and production of IL‐17 were measured. Tim‐3 expression was significantly upregulated and closely correlated to the frequency of Th17 cells in patients with CHB. Expression of TNF‐α，IL‐1β and IL‐6 increased significantly in monocytes stimulated with LPS and Galectin‐9, compared to LPS stimulation alone. LPS‐activated monocytes from CHB patients could drive differentiation of memory CD4+T cells to Th17 cells. However, under the blockade of Tim‐3 signalling by anti‐Tim‐3 antibody, percentage of Th17 cells and production of IL‐17 decreased significantly. Our results demonstrate that upregulated expression of Tim‐3 on circulating monocytes accelerates inflammatory response by promoting production of inflammatory cytokines and Th17 responses in CHB.     

Expression of Tim-1 and Tim-3 in Plasmodium berghei ANKA infection

Cerebral malaria (CM) is a serious and often fatal complication of Plasmodium falciparum infections; however, the precise mechanisms leading to CM is poorly understood. Mouse malaria models have provided insight into the key events in pathogenesis of CM. T-cell immune response is known to play an important role in malaria infection, and members of the T-cell immunoglobulin- and mucin-domain-containing molecule (Tim) family have roles in T-cell-mediated immune responses. Tim-1 and Tim-3 are expressed on terminally differentiated Th2 and Th1 cells, respectively, and participate in the regulation of Th immune response. Until now, the role of Tim family proteins in Plasmodium infection remains unclear. In the present study, the mRNA levels of Tim-1, Tim-3, and some key Th1 and Th2 cytokines in the spleen of Kunming outbred mice infected with Plasmodium berghei ANKA (PbANKA) were determined using real-time polymerase chain reaction (qRT-PCR). Compared with uninfected controls, Tim-1 expression was significantly decreased in infected mice with CM at day 10 postinfection (p.i.) but significantly increased in infected mice with non-CM at day 22 p.i.; in contrast, Tim-3 expression was significantly increased in infected mice both with CM at day 10 p.i. and with non-CM at day 22 p.i. The expressions of IFN-γ, TNF-α, IL-10, and IL-12 were significantly increased but IL-4 was significantly decreased in infected mice with CM at days 10 p.i., whereas the expressions of IFN-γ, TNF-α, IL-4, IL-10, and TGF-β were significantly increased but IL-12 was significantly decreased in infected mice with non-CM at days 22 p.i. Furthermore, the expression of Tim-1 and Tim-3 could reflect Th2 and Th1 immune response in the spleen of PbANKA-infected mice, respectively. Our data suggest that PbANKA infection could inhibit the differentiation of T lymphocytes toward Th2 cells, promote the Th1 cell differentiation, and induce Th1-biased immune response in the early infective stage, whereas the infection could promote Th2 cell differentiation and induce Th2-biased immune response in the late infective stage. Our data indicate that both Tim-1 and Tim-3 may play a role in the process of PbANKA infection, which may represent a potential therapeutic target.     

The expanding universe of T-cell subsets: Th1, Th2 and more

Since their discovery nearly ten years ago, T helper 1 (Th1) and Th2 subsets have been implicated in the regulation of many immune responses. In this article, Tim Mosmann and Subash Sad discuss the increasing number of T-cell subsets defined by cytokine patterns; the differentiation pathways of CD4⁺ and CD8⁺ T cells; the contribution of other cell types to these patterns; and the cytokine interactions during infection and pregnancy.     

Galectin-1 functions as a Th2 cytokine that selectively induces Th1 apoptosis and promotes Th2 function

Galectin-1 has been implicated in regulating T-cell survival, function, and Th1/Th2 balance in several mouse models, though the molecular and cellular basis of its immuno-modulatory activity has not been completely elucidated. Therefore, we examined galectin-1 expression and activity within differentiated murine Th1 and Th2 subsets. While recombinant galectin-1 specifically bound to both T-cell subsets, Th1 and Th2 T cells expressed distinct combinations of galectin-1-reactive epitopes and were differentially responsive to galectin-1 exposure. Indeed, Th1 cells were more susceptible to galectin-1-induced death than Th2 cells. Th2 protection from apoptosis was correlated with expression of anti-apoptotic galectin-3. Further, galectin-1 promoted TCR-induced type 2 cytokine production by Th2 cells. Differentiated Th2 cells constitutively expressed high levels of galectin-1 and can be induced to produce even higher levels of galectin-1 with restimulation, whereas comparable levels of galectin-1 in Th1 cells were only observed after restimulation. Co-culturing experiments using galectin-1(-/-) and galectin-1+/+ Th1 and Th2 T cells demonstrated that Th2-derived galectin-1 induced Th1 apoptosis, whereas Th1-derived galectin-1 promoted Th2 cytokine production. These studies identify galectin-1 as a cross-regulatory cytokine that selectively antagonizes Th1 survival, while promoting TCR-induced Th2 cytokine production.     

The CC-chemokine receptor 5 (CCR5) is a marker of, but not essential for the development of human Th1 cells

The CC-chemokine receptor 5 (CCR5) has recently been described as a surface marker of human T cells producing type 1 (Th1) cytokines. Here we confirm that CCR5 is expressed on human Th1 but not on Th2 T-cell clones. Using intracellular cytokine staining, we show that alloantigen specific CD4+ T-cell lines derived from a CCR5-deficient individual (delta32 allele homozygote) contain high numbers of both interferon gamma (IFN-gamma) and interleukin (IL)-2 producing cells, low numbers of IL-10 producing cells and no IL4 or IL-5 producing cells when stimulated with phorbol ester and ionomycin in vitro. These results were similar to those obtained from alloantigen specific CD4+ T-cell lines derived from CCR5 expressing individuals. An enzyme-linked immunoabsorbent assay (ELISA) confirmed that the Th1 cytokine-positive cells from the CCR5-deficient individual were able to produce equal amounts of cytokines when compared to T-cell lines from CCR5-expressing individuals, These results demonstrate that CCR5-negative T cells display the same capacity of Th1 T-cell differentiation as T cells derived from CCR5-expressing individuals. Thus, CCR5 expression is not essential for differentiation of human Th1 T cells.