巨噬细胞替代激活及调控

巨噬细胞作为机体天然免疫系统的重要组成部分,在生物体内发挥多种免疫功能,包括吞噬细菌、病毒等微生物,递呈并处理抗原和参与免疫应答。这些免疫功能的发挥依赖于巨噬细胞的激活。巨噬细胞的激活有多种形式,包括经典激活与替代激活。研究表明,替代激活的巨噬细胞参与了组织修复、血管新生、肿瘤发展侵袭与转移、炎症干预等多种生理病理过程。本文将根据近年来的研究进展,就巨噬细胞替代激活的亚型、分子特征、相关信号转导通路及重要调控分子作一综述。     

Lymph Node Stromal Cells Generate Antigen-Specific Regulatory T Cells and Control Autoreactive T and B Cell Responses

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Participation of NK1.1+ T Cells in the Rejection of lpr αβT Cells When Bone Marrow Cells of Ipr Mice Are Transplanted into B6 Mice

When C57BL/6 (B6) mice were irradiated (9 Gy) and received bone marrow (BM) cells of B6-lpr/lpr mouse origin (i.e., lpr→B6), all mice died within 6 days. In the irradiated B6 mice, radioresistant CD3^? IL-2Rβ⁺ NK cells and IL-2Rβ CD3^int cells (i.e., CD3^int cells of extrathymic origin) remained, especially in the liver. There were two subsets, NK1.1⁺ and NK1.1^?, among the IL-2Rβ⁺ CD3^int cells. However, the NK1.1⁺ subset (i.e., NK1.1⁺ T cells) was much more radioresistant, and the majority of CD3^int cells belonged to this subset in irradiated mice. The expansion of lymphocytes from injected BM cells did not occur in the irradiated B6 mice. However, such expansion did take place in irradiated B6-lpr/lpr mice injected with both BM cells of B6-lpr/lpr and B6 origin. As a result, the mice subjected to BM cells survived. Irradiated B6 mice were treated in vivo with anti-NK1.1 mAb or anti-asialoGM₁ antibody to eliminate NK cells alone or both NK cells and NK1.1⁺ T cells. When irradiated B6 mice were pretreated with anti-NK1.1 mAb, the mice could survive. These results suggest that intact NK1.1⁺ T cells of extrathymic origin may recognize abnormal BM cells with the lpr gene and inhibit the expansion of lymphocytes, including abnormal double-negative CD4^?8^? cells, in B6-lpr/lpr mice. To inhibit the expansion of lymphocytes, mechanisms other than Fas ligand/Fas molecules on extrathymic T cells may be responsible.     

巨噬细胞凋亡及其调控

巨噬细胞通过介导和调控自身及其他细胞凋亡而实现其免疫调节和效应细胞功能.引起巨噬细胞凋亡的原因有生物、化学、病理、自身等因素.不仅巨噬细胞自身凋亡和凋亡调控有其特点,更为有趣的是,巨噬细胞可根据需要：介导或抑制自身凋亡;介导或抑制其他细胞凋亡;抑制自身凋亡,介导其他细胞凋亡.这可能是巨噬细胞在免疫调节,特别是肿瘤免疫中发挥重要作用的基础.     

机械应力对巨噬细胞的功能调节作用及机制

巨噬细胞作为先天免疫系统识别外界环境刺激的先锋,能够响应环境细微变化对自身功能实现适应性调节,在维持体内稳态和抵抗感染方面起关键作用。生理或病理组织微环境存在多种机械应力刺激,对巨噬细胞的免疫功能具有重要影响。本文围绕机械应力对巨噬细胞的功能调节,从影响细胞行为和极化的角度综述,总结巨噬细胞机械应力感知及转导的分子机制,展望巨噬细胞力学生物学研究在组织工程、再生医学以及肿瘤免疫治疗领域的应用前景,为深入理解巨噬细胞功能可塑性提供有力支持。     

调节性T细胞与自身免疫性疾病

自身免疫性疾病是由于机体正常免疫耐受功能受损导致免疫系统对自身组织结构和功能的破坏,并出现一定临床表现的一类疾病.调节性T细胞作为一类具有负向免疫调节功能的淋巴细胞亚群在免疫自稳和免疫耐受中起关键作用,既能抑制不恰当的免疫反应,又能限制免疫应答的范围、程度及作用时间,对效应性T细胞的增殖及免疫活性的发挥产生抑制,因此在许多自身免疫性疾病的发病中扮演重要角色.近年来的研究表明调节性T细胞可以通过细胞接触、分泌细胞因子、基因调控等多种途径发挥作用,在不同的疾病,不同的内环境因素作用下可以表现出不同的特点,转录因子Foxp3作为调节性T细胞的特异性标志是其分化成熟及功能维持的根本.     

Fgr Expression Restricted to Subpopulation of Monocyte/Macrophage Lineage in Resting Conditions Is Induced in Various Hematopoietic Cells after Activation or Transformation

The c-fgr gene product (Fgr) is a member of the src-family of protein tyrosine kinases. We have established a monoclonal antibody (2H2) which recognizes the unique N-terminal domain of the murine Fgr. In the present study, using immunohistochemical analysis and immune complex kinase assay with the 2H2, we investigated expression of Fgr in various cell populations and tissues in a murine system. In resting conditions, Fgr expression was confined to subsets of a monocyte/macrophage lineage. Thus, Fgr⁺ cells were detected in paracortical areas and medullas of lymph nodes, but seen only in marginal zones of the spleen and the medulla of the thymus. No Fgr⁺ macrophage was detected in other tissues, Peyer's patches, brain, heart, lung, liver, pancreas, kidney and peritoneal cavity. However, immune complex kinase assay revealed that, upon stimulation, T and B cells as well as peritoneal macrophages expressed significant levels of Fgr molecules. Transformed cell lines of lymphoid origin, EL-4 and LK35.2, which are T and B lineage lymphomas, respectively, also expressed Fgr molecules. Thus, various cells of hematopoietic origin appeared to possess a potentiality to express Fgr following activation or transformation. The present findings may help elucidate the functional significance of Fgr in immunologically committed cells in either activated or non-activated conditions.     

记忆性T细胞的形成与特点

免疫记忆是在缺乏抗原存在的情况下,免疫系统所具有的一个特殊警觉时期.关于记忆细胞的产生和维持机理以及体内的功能调控因子如何发挥功效等方面一直以来都存在着争论.随着生物化学和基因组学的发展,记忆性T细胞的形成及特点在分子水平方面已得到了良好的解释.     

天然调节T 细胞与诱导调节T 细胞的生物学特性

CD4+CD25+FOXP3+的调节T细胞(regulatory T cells,Treg)在维持机体免疫平衡方面起着重要的作用。体外扩增Treg细胞用于治疗自身免疫病、哮喘及诱导器官移植免疫耐受引起人们极大的兴趣。Treg细胞可分为2个亚群,分别为nTreg和iTreg,两者有不同的生物学特性。nTreg在特定条件下,可以分泌具有促进炎症的IL-17;iTreg在体内可丢失FOXP3,失去其免疫抑制功能。Treg细胞用于临床治疗,还有许多问题需要研究解决。     

人生长激素基因逆转录病毒载体的构建及其对3T3和ES细胞的转化与表达

为了研究生长激素基因在异源细胞中的表达,构建了携带人生长激素基因（ｈＧＨ）的逆转录病毒载体ｐＩＮＳ－ＧＨ,并将其导入小鼠成纤维细胞３Ｔ３和小鼠胚胎干细胞（ＥＳ细胞）ＣＣＥ中。ｐＩＮＳ－ＧＨ转化３Ｔ３细胞,获得了高效表达的克隆,即用放射免疫法检测到克隆培养基中有大量的人生长激素蛋白富积,如ＧＨＳＮＣ２０,富积率高达３７８４ｎｇ／ｍｌ,而且外源基因的整合很稳定。不同的３Ｔ３转化克隆的表达率有显著的差异,Ｓｏｕｔｈｅｒｎ杂交的结果表明,这种差异与外源基因整合的拷贝数无关。ｐＩＮＳ－ＧＨ转化ＣＣＥ细胞没有获得明显表达的克隆,而且外源基因的整合也不稳定。转化的ＥＳ细胞克隆总ＤＮＡ的Ｓｏｕｔｈｅｒｎ杂交结果表明,ｈＧＨ基因的确整合到细胞基因组中。目前尚未发现明显的外源ＤＮＡ重排的迹象。     

CD4+CD25+调节性T细胞的外周维持

CD4 CD25 调节性T细胞作为一种抑制性T细胞功能亚群,在维持机体的免疫自稳和免疫耐受方面发挥了关键作用。该作用的发挥与其外周细胞库的维持密切相关。新近的研究显示CD4 CD25 调节性T细胞主要通过两种机制来维持其外周细胞库,一些功能分子参与其中。     

The Strasburger Cells — Equivalents of Compagnion Cells

The Strasburger cells in the phloem rays of pine and larch show most prominent structural and physiological differences from ordinary ray parenchyma cells. Besides their particular one-sided sieve areas connecting them with the sieve cells, it is the absence of starch, the relative density in protoplast, and their premature death which makes these cells resemble true compagnion cells. Density in protoplast is primarily due to the missing of large vacuoles and the presence of numerous mitochondria while the ribosome population is not visibly increased. Strasburger cells in contact with mature sieve cells are distinguished by additional peculiarities, i.e. the highly elevated activity of mitochondrial enzymes and of acid phosphatases, the extraordinary prevalence of polysomes, the augmentation of nuclear surface and of the amount of decondensed chromatin, and by the increased nuclear RNA content, that all suggest an essentially increased metabolic activity of these cells. In DNA content, however, no significant difference is found from other ray cells. As these peculiar characteristics are not seen in Strasburger cells bordering immature sieve cells, they are taken to be not only of functional significance but to assure also the peculiar role Strasburger cells contiguous with mature sieve cells are playing in loading/unloading of sieve elements and/or in the sustaining of their metabolism.     

小鼠树突状细胞亚群与T细胞关系的研究进展

树突状细胞(dendritic cells,DCs)是目前已知机体内功能最强的专职性抗原提呈细胞,其最大特点是能够显著刺激初始型T细胞(naive T cells)增殖,是机体免疫反应的始动者。近年来,随着对小鼠DCs研究的不断深入开展,本文在此对DCs亚群与T细胞之间相互关系的研究取得的进展综述如下。     

Basic Blue 148: A Rapid Stain for T Helper Cells

After brief exposure to an aqueous solution of the oxazine textile dye C. I. basic blue 148 following fixation in 37% formalin, 95% ethanol and glacial acetic acid, T helper cell nuclei and cytoplasm in specimens of peripheral blood displayed a deep red-violet color. No other cell in normal blood or bone marrow specimens showed intense staining of this type. The total staining time is 1 min. Basic blue 148 stain is a promising technique for hematology and immunology laboratories as a rapid screening test for T helper cells in blood specimens using a microscopic slide and ordinary incandescent illumination.     

稳定表达小鼠CD40L的NIH3T3细胞系的建立及其在B细胞培养和激活中的应用

该研究构建小鼠CD40L真核表达重组质粒pcDNA3.1-mCD40L,通过电转法将重组质粒转至NIH3T3细胞中。利用G418对转染后细胞进行压力筛选,获得稳定转染细胞株。提取稳定转染细胞株RNA,通过RT-PCR法检测Neo基因的mRNA表达情况。分离稳定转染细胞上清,利用ELISA法检测小鼠CD40L蛋白水平的表达情况。RT-PCR结果显示,Neo基因能够在稳定转染细胞中表达,ELISA结果显示,获得的稳定转染细胞株NIH3T3-mCD40L细胞上清中CD40L的表达量高达1.286 ng/mL。进一步活性研究表明,该细胞系能够在体外与IL-2和IL-21共同作用培养B细胞至14天,并刺激B细胞产生特异性抗体。该细胞系的成功构建,为利用体外B细胞分离培养和活化法分离特异性单克隆抗体奠定了良好的基础。     

供体来源ImDex联合抗原特异性Treg保护大鼠肝脏移植物的研究

目的:探讨供体来源低剂量未成熟树突状细胞外来体(immature dendritic cells exosome,im Dex)联合供体抗原特异型调节性T细胞(regulatory t cells,Tregs)对于肝脏移植物的保护作用。方法:以BN-Lewis大鼠为供受体,建立大鼠原位肝移植模型。利用超高速梯度离心法获得im Dex,采用流式细胞术鉴定该im Dex的表型。不同剂量im Dex用于本移植模型,生存分析探究其对肝脏移植物的保护作用及该作用与剂量的相关关系。利用磁珠分选技术获得Treg,混合淋巴细胞培养获得供体抗原特异性Treg,将不同性质的Treg用于移植受体,验证抗原特异性Treg保护肝脏移植物。进一步探究两者联合使用的效果,应用免疫荧光、流式细胞术研究Treg在移植受体中的分布。结果:超高速梯度离心法分选出的im Dex具有im DC表型,其保护肝脏移植物的最佳作用剂量为20μg,Treg发挥保护移植物作用具有抗原特异性。两者联合应用组生存时间长于对照组(P0.05)。病理显示,输注的Treg分布于受体移植物。结论:Im Dex联合抗原特异性Treg可以有效保护大鼠肝脏移植物。     

调节性 T 细胞发育的一个关键转录因子 Foxp3

调节性 T 细胞是目前免疫学领域研究的热点,对于维持机体免疫耐受和免疫应答稳态具有非常重要的作用 . 对其发育和功能机制的深入认识,不但有助于了解错综复杂的免疫系统理论,而且在自身免疫性疾病、肿瘤和艾滋病的治疗以及移植耐受的诱导等方面具有广泛的应用前景 . 最近的研究发现,转录因子 Foxp3 对于调节性 T 细胞的发育具有重要的作用,是调节性 T 细胞发育的一个关键转录因子 .     

Activation and route of administration both determine the ability of bone marrow-derived dendritic cells to accumulate in secondary lymphoid organs and prime CD8<Superscript>+</Superscript> T cells against tumors

Aims

To examine the effects of route of administration and activation status on the ability of dendritic cells (DC) to accumulate in secondary lymphoid organs, and induce expansion of CD8⁺ T cells and anti-tumor activity.

Methods

DC from bone marrow (BM) cultures were labeled with fluorochromes and injected s.c. or i.v. into naïve mice to monitor their survival and accumulation in vivo. Percentages of specific CD8⁺ T cells in blood and delayed tumor growth were used as readouts of the immune response induced by DC immunization.

Results

The route of DC administration was critical in determining the site of DC accumulation and time of DC persistence in vivo. DC injected s.c. accumulated in the draining lymph node, and DC injected i.v. in the spleen. DC appeared in the lymph node by 24 h after s.c. injection, their numbers peaked at 48 h and declined at 96 h. DC that had spontaneously matured in vitro were better able to migrate compared to immature DC. DC were found in the spleen at 3 h and 24 h after i.v. injection, but their numbers were low and declined by 48 h. Depending on the tumor cell line used, DC injected s.c. were as effective or more effective than DC injected i.v. at inducing anti-tumor responses. Pre-treatment with LPS increased DC accumulation in lymph nodes, but had no detectable effect on accumulation in the spleen. Pre-treatment with LPS also improved the ability of DC to induce CD8⁺ T cell expansion and anti-tumor responses, regardless of the route of DC administration.

Conclusions

Injection route and activation by LPS independently determine the ability of DC to activate tumor-specific CD8⁺ T cells in vivo.

     

Laminin 5 Promotes Activation and Apoptosis of the T Cells Expressing α3β1 Integrin

By introducing an α3 gene-containing plasmid into a human T cell line Jurkat, we prepared the T cells, which express a high level of the α3β1 integrin, to assess the role of laminin 5 in the skin immune system. The α3β1-expressing T cells adhered to laminin 5 and exhibited spreading. These adhered T cells showed a significant tyrosine phosphorylation of intracellular proteins including p59^fynupon T-cell receptor (TCR) stimulation. Six hours after cross-linking TCR, these cells on laminin 5 secreted a three times higher level of IL-2 than those on a BSA-coated plate. Twenty hours after the stimulation, 48% of the α3β1-expressing T cells on laminin 5 caused apoptosis. The protein level of cyclin D3 and E decreased, while that of p53 increased in these T cells. These data suggest that laminin 5 may play at least two regulatory roles for T cell functions: augmentation of IL-2 production by antigen-stimulated T cells and induction of apoptosis in these T cells.     

γ射线对小鼠调节性T细胞功能及相关细胞因子的影响及其意义

调节性T细胞（regulatory T cells,Tregs）及相关细胞因子在机体免疫平衡的调节中发挥重要作用,而其在放射免疫损伤中的作用尚不明确.本实验以6Gyγ射线照射C57BL/6小鼠,于照射后1～28d不同时间,检测外周血、胸腺和脾脏Treg细胞亚群及血清中细胞因子IL-2,IL-10及TGF-γ含量的变化,以探讨其在放射免疫损伤中的作用机制.结果显示,小鼠经6Gyγ射线照射后各组织CD4＋CD25＋Treg细胞比例明显增加（P〈0.05或P〈0.01）,胸腺CD4＋CD25＋Foxp3＋Treg细胞比例于照后1d即明显增高（P〈0.01）,而在照后7d明显低于未照射组（P〈0.01）;血清抑制性细胞因子IL-10（7d）,TGF-γ（3d）含量明显增高（P〈0.05）,而IL-2浓度持续降低.本文揭示了Treg细胞及其相关细胞因子与辐射所致免疫功能受抑和免疫调节功能失衡密切相关,为进一步的辐射损伤机制研究奠定基础.