树突状细胞与肿瘤免疫系统相互作用研究进展

树突状细胞(dendritic cells, DCs)是功能最强的专职抗原呈递细胞。DCs能够摄取和呈递抗原表达共刺激分子,并迁移到淋巴器官激活T细胞,进而启动免疫反应。在肿瘤发展过程中,DCs不仅能诱导抗肿瘤免疫反应,还可以诱导免疫耐受。现对树突状细胞的生物学特性、树突状细胞与肿瘤免疫系统的相互作用等方面的最新研究进展进行综述,并介绍免疫治疗中基于树突状细胞疫苗的多种治疗方法。相关研究对于更好地理解肿瘤微环境中树突状细胞在肿瘤演化中的作用、寻找新的治疗策略以及改进治疗方法至关重要。     

单核细胞与未成熟树突状细胞粘附相关差异表达基因筛选及相互作用分析

本研究目的是分析单核细胞(monocytes,mon)与未成熟树突状细胞(immature DCs,im DCs)两个不同发育阶段间差异表达基因的功能及其编码蛋白的相互作用,筛选出粘附相关的关键基因,并进行生物信息学分析。我们从NCBI(美国国立生物技术信息中心)公共数据平台GEO(Gene Expression Omnibus)下载基因芯片数据GSE15076,使用perl语言将探针id转换成gene symbol。利用R Bioconducto软件(RGui 3.3.1)解析原始数据并筛选差异基因。进一步利用STRING online工具筛选核心差异基因(可信度≥0.4),Cytoscape软件构造蛋白质相互作用网络图。对STRING online工具筛选核心差异基因进行京都基因与基因组百科全书(kyotoencyclopedia of genes and genomes,KEGG)分析。im DCs相对于mon表达的差异基因,过滤条件为Log FC2和adj.p.val0.01。通过分析,我们共找到1 223个差异基因,其中567个上调基因,656个下调基因,通过进一步筛选,在网络中的上调基因有399个,下调基因458个,主要涉及m TOR信号通路、细胞代谢、细胞粘附等功能。其中上调基因中CDH1,CD274等差异基因与细胞粘附密切相关,而下调基因中SELL、IL-6、TNF等差异基因与细胞粘附改变密切相关。因此,在单核细胞发育分化到未成熟树突细胞阶段,粘附相关基因的表达变化,对进一步深入理解im DCs独特的生物物理学特性和免疫学功能来说具有重要意义。为进一步研究DCs细胞粘附功能的分子机制提供指导。     

自然杀伤细胞免疫功能相关糖结合蛋白的研究进展

自然杀伤(NK)细胞是固有免疫系统的重要组成,其作为抵抗病原体和癌变细胞的第一道机体防线,通过释放穿孔素、颗粒酶等介导的细胞毒作用杀伤靶细胞.随着糖组学的飞速发展,大量研究报道糖基化异常往往与细胞的病变相关,这为免疫学研究及疾病的治疗策略提供了全新的研究角度.NK细胞作为固有免疫系统的主要效应细胞之一,其活性及功能受细胞表面糖基化修饰及相关糖结合蛋白(例如siglec、selectin及galectin)的影响较大,siglec通过与肿瘤细胞表面上调的唾液酸化糖链结合以抑制NK细胞活化,selectin与其配体相互作用促进NK细胞的免疫功能,galectin结合β-半乳糖苷介导NK细胞免疫进程.因此,本文从糖组学的角度概述与NK细胞免疫功能相关的糖结合蛋白及与其相互作用糖链的最新研究进展,并且讨论了病变过程中糖结合蛋白异常对肿瘤进程的影响,以及其在疾病治疗策略方面的应用前景.     

流感病毒利用其神经氨酸酶蛋白逃避NK细胞激活受体的识别

<正>自然杀伤(NK)细胞在抗病毒感染和消灭转化细胞的过程中发挥核心作用。通过抑制和激活受体控制病原体感染细胞和肿瘤细胞的识别。曾表明NK细胞激活(杀伤)受体中的天然细胞毒性受体NKp44和NKP46,可与流感病毒感染的细胞表面表达的病毒血凝素(HA)蛋白相互作用。我们进一步发现,NKp44/NKP46和病毒的HA之间的相互作用     

单核细胞与未成熟树突细胞的细胞骨架相关的核心差异基因表达的生物信息学分析

为进一步深入理解不同分化阶段树突状细胞(dendritic cells,DCs)的生物物理学特性和免疫学功能的差异。从CEO数据库获得CD14~+单核细胞(monocytes,mon)及其诱导而成的未成熟DCs(immature DCs,im DCs)的m RNA表达数据(芯片编号:GSE15076),利用R语言软件(RGui 3.2.3)解析原始数据并筛选差异基因。进一步利用STRING online工具筛选核心差异基因(可信度≥0.4),Cytoscape软件构造蛋白质相互作用网络图。对STRING online工具筛选核心差异基因进行京都基因与基因组百科全书(kyoto encyclopedia of genes and genomes,KEGG)分析。实时荧光定量PCR技术检测mon及im DCs部分核心差异基因CCNB1、CDK5、IL-6和TNF在基因水平上的表达情况。im DCs相对于mon表达的差异的基因共3 371个(im DCs与mon对比,表达变化倍数≥2,p值0.05),其中上调基因为2 396个,下调基因为975个,通过进一步筛选后获得上调基因655个,下调基因110个,主要涉及m TOR信号通路、细胞代谢、细胞粘附等功能。其中上调基因中CDK5、CCNB1等差异基因与细胞骨架改变密切相关,而下调基因中IL-6、TNF、CXCR4等差异基因与细胞骨架改变密切相关,这对进一步深入理解im DCs独特的生物物理学特性和免疫学功能来说具有重要意义。     

Toll样受体与树突状细胞介导的天然免疫和获得性免疫

树突状细胞(dendritic cells,DCs)作为迄今所发现的抗原提呈功能最强的一类抗原提呈细胞,是联结天然免疫和获得性免疫的桥梁。Toll样受体(Toll-like receptors,TLRs)是一类进化保守的胚系编码的模式识别受体,在DCs的抗原识别、递呈及激活T细胞等方面具有重要作用,是机体受外来抗原入侵后作出适当免疫反应的调控点。现就TLRs在不同DCs亚群中的分布、与DCs介导的天然免疫和获得性免疫的关系及DCs功能可塑性的分子基础作一综述。     

未成熟树突状细胞与成熟树突状细胞的细胞骨架调控相关基因表达的差异分析

分析未成熟树突状细胞(immature dendritic cells,im DCs)向成熟的树突状细胞(mature dendritic cells,m DCs)分化的过程中,细胞骨架的调控相关基因及信号通路的表达变化,为进一步理解不同分化阶段树突状细胞(dendritic cells,DCs)的生物物理学特性、迁移能力和免疫学相关功能的改变。利用CEO数据库获得经CD14+单核细胞(monocytos,monos)诱导而成的im DCs和m DCs的m RNA的表达数据(芯片编号:GSE15076),通过R语言软件对原始数据进行处理,筛选差异表达基因(Log|FC|≥2,p0.05),利用STRING online-工具对差异表达基因进一步筛选(可信度≥0.4);Cytoscape软件构建蛋白质相互作用网络图(protein-protein interaction network,PPI),通过Cluster ONE对筛选后的差异表达基因进行聚类分析,筛选功能相关性密切的差异表达基因,并利用DAVID在线分析进一步进行GO分析和KEGG信号通路分析。m DCs相对于im DCs差异表达的基因共3 351个,上调基因1 801个,下调基因1 550个,其中C-C趋化因子受体活性、G-蛋白偶联的嘌呤核苷酸受体活性和异源三聚体G蛋白复合物等与细胞骨架调控密切相关。主要涉及的信号通路包括趋化因子/趋化因子受体信号通路、Rap1信号通路、Jak-STAT信号通路和PI3K-Akt信号通路等,其中的相关基因与细胞骨架的调控关系密切。这对进一步深入理解DCs的生物物理学特性、迁移能力和免疫学功能有一定的帮助。     

不同分化阶段的树突状细胞的细胞膜生物物理特性变化

DCs是迄今所知最有效的抗原呈递细胞,在体外可以用CD14 的单核细胞诱导分化而得到.imDCs能够主动地摄取抗原和病原体,产生MHC-抗原肽复合物,并且从抗原获取位点向二级淋巴组织迁移,逐渐分化成mDCs,mDCs与幼稚的T细胞相互作用,从而导致免疫应答或耐受.在这些过程中,DCs必须经历数次变形和转位以通过基底膜和血管壁等屏障,并且在二级淋巴组织内与幼稚的T细胞发生直接的物理性接触.为了更好地理解DCs从外周组织向二级淋巴组织迁移的过程和启动免疫应答的机制,通过研究体外DCs分化过程中细胞膜的生物物理特性,包括细胞膜的粘弹性、表面电荷及其分布和流动性,结果发现DCs细胞膜粘弹性逐渐增加,mDCs的电泳率最大,表面电荷分布出现明显的不对称现象,并且膜流动性也逐渐增加,说明DCs的细胞膜生物物理特性在其行使生理功能的过程中发挥着重要的作用,这对更深入地理解DCs的迁移和与幼稚T细胞相互作用以及免疫应答的启动过程具有非常重要的意义.     

小反刍兽疫病毒Nigeria75/1疫苗毒及其N蛋白对山羊PBMCs免疫效应的影响

小反刍兽疫(PPR)是羊、骆驼等小反刍动物的一种急性、烈性、接触性A类传染病,发病率和致死率极高.目前,PPR在全球仍呈现区域性流行和多地散发势态.为探讨PPRV及N蛋白体外诱导山羊外周血单个核细胞(PBMCs)在不同时间对PBMCs免疫应答效应的影响.本研究将PPRVNigeria75/1疫苗毒(1 MOI)、重组N蛋白(10μg/mL)和RPMI 1640(阴性对照)体外刺激PBMCs 48h、72h、96h.采用CCK-8法检测PBMCs细胞增殖情况;qRT-PCR及ELISA检测炎症因子包括IL-1β、IL-6、IL-10、TNF-a和IFN-γ的mRNA表达水平及分泌情况;流式细胞术检测T细胞CD4+和CD8+的表达、及单核来源树突状细胞(DCs)表面分子CD40、CD86、CD80的表达、以及检测PPRV感染PBMCs引起的细胞凋亡.研究发现:与对照组相比,PPRV能够抑制PBMCs的体外增殖,显著促进炎症因子IL-1β、IL-6、IL-10、TNF-α、IFN-γ的表达(P＜0.05).并且PPRV感染PBMCs产生细胞凋亡,促进CD4+T细胞和CD8+T细胞表达.另外PPRV体外刺激DCs,CD40、CD86、CD80的表达显著升高(P＜0.05),提示PPRV具有刺激DCs细胞成熟与分化的功能.进一步研究发现PPRV N蛋白体外刺激PBMCs能引起与PPRV作用相同的免疫效应.本研究表明PPRV Nigeria75/1疫苗毒体外感染PBMCs主要引起炎症反应与细胞凋亡、促进单核来源DCs成熟与分化,并且N蛋白参与PPRV引起的各项免疫功能.     

树突细胞的免疫耐受及其在Ⅰ型糖尿病中的作用

树突细胞(dendritic cells,DCs)通过将抗原提呈给初始T淋巴细胞(native T lymphocyte),从而诱导CD8~+细胞毒性T细胞(cytotoxic T cell,CTL)和CD4~+效应T细胞的分化并启动获得性免疫应答。此外DCs在诱导并维持免疫耐受方面也具有重要作用。现就DCs的免疫耐受机制及其在I型糖尿病(type 1 diabetes mellitus,T1DM)中的作用的研究进展作一综述,为T1DM等自身免疫性疾病及移植免疫疾病的细胞免疫治疗提供新思路。     

Distinctive lack of CD48 expression in subsets of human dendritic cells tunes NK cell activation

CD48 is a glycosyl phosphatidylinositol anchor protein known to be virtually expressed by all human leukocytes. Its ligand, 2B4, is a signaling lymphocyte activation molecule-related receptor involved in NK cell activation. Because dendritic cells (DCs) are strong inducers of NK cell functions, we analyzed the expression of CD48 in different human DC subsets. We observed that monocytes differentiating in DCs promptly down-regulate CD48. Similarly, DCs isolated from inflamed lymph nodes generally do not express CD48. Plasmocytoid DCs do not express CD48 either, whereas myeloid DCs harbored in blood, bone marrow, and thymus express it. In addition, we showed that CD48 expression in DCs affects NK cell functions during NK/DC cross-talk, because NK cells obtained from normal donors and from X-linked lymphoproliferative disease patients are, respectively, triggered or inhibited by DCs expressing surface CD48. Remarkably, IFN-gamma production by lymph node NK cells, in contrast to blood NK cells, can be negatively modulated by 2B4/CD48 interactions, indicating a 2B4 inhibitory pathway in lymph node NK cells. Therefore, the CD48 deficiency of DCs harbored in inflamed lymph nodes that we report in this study might be relevant to successfully activate lymph node NK cells in the early phase of the immune response. Our results show that distinct subsets of human DCs, differently from all other mononuclear hemopoietic cells, specifically do not express CD48. Moreover, the expression of CD48 depends on the anatomic location of DCs and might be related to the tissue-specific 2B4 function (activating or inhibitory) of the NK cells with which they interact.     

Interleukin-15 Dendritic Cells Harness NK Cell Cytotoxic Effector Function in a Contact- and IL-15-Dependent Manner

The contribution of natural killer (NK) cells to the treatment efficacy of dendritic cell (DC)-based cancer vaccines is being increasingly recognized. Much current efforts to optimize this form of immunotherapy are therefore geared towards harnessing the NK cell-stimulatory ability of DCs. In this study, we investigated whether generation of human monocyte-derived DCs with interleukin (IL)-15 followed by activation with a Toll-like receptor stimulus endows these DCs, commonly referred to as “IL-15 DCs”, with the capacity to stimulate NK cells. In a head-to-head comparison with “IL-4 DCs” used routinely for clinical studies, IL-15 DCs were found to induce a more activated, cytotoxic effector phenotype in NK cells, in particular in the CD56^bright NK cell subset. With the exception of GM-CSF, no significant enhancement of cytokine/chemokine secretion was observed following co-culture of NK cells with IL-15 DCs. IL-15 DCs, but not IL-4 DCs, promoted NK cell tumoricidal activity towards both NK-sensitive and NK-resistant targets. This effect was found to require cell-to-cell contact and to be mediated by DC surface-bound IL-15. This study shows that DCs can express a membrane-bound form of IL-15 through which they enhance NK cell cytotoxic function. The observed lack of membrane-bound IL-15 on “gold-standard” IL-4 DCs and their consequent inability to effectively promote NK cell cytotoxicity may have important implications for the future design of DC-based cancer vaccine studies.     

Herpes simplex virus antigens directly activate NK cells via TLR2, thus facilitating their presentation to CD4 T lymphocytes

NK cells infiltrate human herpetic lesions, but their role has been underexplored. HSV can stimulate innate immune responses via surface TLR2, which is expressed on monocyte-derived dendritic cells (DCs) and NK cells. In this study, UV-inactivated HSV1/2 and immunodominant HSV2 glycoprotein D peptides conjugated to the TLR2 agonist dipalmitoyl-S-glyceryl cysteine stimulated CD4 T lymphocyte IFN-γ responses within PBMCs or in coculture with monocyte-derived DCs. NK cells contributed markedly to the PBMC responses. Furthermore, NK cells alone were activated directly by both Ags, also upregulating HLA-DR and HLA-DQ and then they activated autologous CD4 T lymphocytes. Using Transwells, Ag-stimulated NK cells and CD4 T lymphocytes were shown to interact through both cell-to-cell contact and cytokines, differing in relative importance in different donors. A distinct immunological synapse between Ag-stimulated NK cells and CD4 T lymphocytes was observed, indicating the significance of their cell-to-cell contact. A large proportion (57%) of NK cells was also in contact with CD4 T lymphocytes in the dermal infiltrate of human recurrent herpetic lesions. Thus, NK cells stimulated by TLR2-activating HSV Ags can present Ag alone or augment the role of DCs in vitro and perhaps in herpetic lesions or draining lymph nodes. In addition to DCs, NK cells should be considered as targets for adjuvants during HSV vaccine development.     

Pathogen-induced private conversations between natural killer and dendritic cells

Natural killer (NK) cells and dendritic cells (DCs) are recruited to inflammatory tissues in response to infection. Following priming by pathogen-derived products, their reciprocal interactions result in a potent activating crosstalk that regulates both the quality and the intensity of innate immune responses. Thus, pathogen-primed NK cells, in the presence of cytokines released by DCs, become activated. At this stage they favor DC maturation and also select the most suitable DCs for subsequent migration to lymph nodes and priming of T cells. In addition, a specialized subset of NK cells might directly participate in the process of T-cell priming via the release of interferon (IFN)gamma. Thus, the reciprocal crosstalk between NK cells and DCs that is induced by microbial products not only promotes rapid innate responses against pathogens but also favor the generation of appropriate downstream adaptive responses.     

CD83+CCR7+ NK cells induced by interleukin 18 by dendritic cells promote experimental autoimmune uveitis

Natural killer (NK) cells have been reported to play a pathological role in autoimmune uveitis. However, the mechanisms regarding NK cells in uveitis and factors that affect NK‐cell activation in this condition remain unclear. Here, we report that the number of CD3^‐NK1.1⁺CD83⁺CCR7⁺ cells is increased in the inflamed eyes within a mouse model of experimental autoimmune uveitis (EAU), and these cells express elevated levels of NKG2D, CD69 and IFN‐γ. Adoptively transferring CD83⁺CCR7⁺NK cells aggravates EAU symptoms and increases the number of CD4⁺IFN‐γ⁺T cells and dendritic cells (DCs) within the eye. These CD83⁺CCR7⁺NK cells then promote the maturation of DCs and IFN‐γ expression within T cells as demonstrated in vitro. Furthermore, IL‐18, as primarily secreted by DCs in the eyes, is detected to induce CD83⁺CCR7⁺NK cells. In EAU mice, anti‐IL‐18R antibody treatment also decreases retinal tissue damage, as well as the number of infiltrating CD83⁺CCR7⁺NK cells, T cells and DCs in the inflamed eyes and spleens of EAU mice. These results suggest that CD83⁺CCR7⁺NK cells, as induced by IL‐18 that primarily secreted by DCs, play a critical pathological role in EAU. Anti‐IL‐18R antibody might serve as a potential therapeutic agent for uveitis through its capacity to inhibit CD83⁺CCR7⁺NK cells infiltration.     

树突状细胞在抗感染免疫研究中的最新进展

树突状细胞(Dendritic cell,DC)是体内功能最强的抗原提呈细胞,也是介导机体固有免疫应答和适应性免疫应答的桥梁,其作用也越来越受到科研工作者的关注,而树突状细胞体外培养技术的发展成熟,为设计和发展DC依赖性疫苗提供了科学依据,也为感染性和肿瘤性疾病的预防和治疗展示了很好的应用前景。因此,对树突状细胞抗感染免疫方面研究的最新进展做一综述。     

自然杀伤细胞参与肝脏恶性肿瘤免疫逃逸研究进展

自然杀伤细胞是机体固有免疫系统重要组成部分,在肝脏等免疫器官中含量丰富,而且免疫表型、功能等表现出器官特异性。在正常情况下,靶细胞表面的配体与自然杀伤细胞表面的活化性受体直接结合并释放细胞毒性物质,诱导活化靶细胞凋亡程序,从而发挥抗感染、抗肿瘤作用。然而肿瘤细胞仍能够通过多种途径逃逸机体的免疫监视功能,研究认为肿瘤细胞抗原异常表达、肿瘤微环境中细胞因子及其他免疫细胞相互作用等因素所引起的自然杀伤细胞活性降低对于诱导肿瘤免疫逃逸起重要作用。本文综述了自然杀伤细胞在肝脏恶性肿瘤发生过程中参与免疫逃逸的机制及研究进展,以期为临床抗肿瘤免疫治疗的研究提供参考。     

CD117+ Dendritic and Mast Cells Are Dependent on RasGRP4 to Function as Accessory Cells for Optimal Natural Killer Cell-Mediated Responses to Lipopolysaccharide

Ras guanine nucleotide-releasing protein-4 (RasGRP4) is an evolutionarily conserved calcium-regulated, guanine nucleotide exchange factor and diacylglycerol/phorbol ester receptor. While an important intracellular signaling protein for CD117⁺ mast cells (MCs), its roles in other immune cells is less clear. In this study, we identified a subset of in vivo-differentiated splenic CD117⁺ dendritic cells (DCs) in wild-type (WT) C57BL/6 mice that unexpectedly contained RasGRP4 mRNA and protein. In regard to the biologic significance of these data to innate immunity, LPS-treated splenic CD117⁺ DCs from WT mice induced natural killer (NK) cells to produce much more interferon-γ (IFN-γ) than comparable DCs from RasGRP4-null mice. The ability of LPS-responsive MCs to cause NK cells to increase their expression of IFN-γ was also dependent on this intracellular signaling protein. The discovery that RasGRP4 is required for CD117⁺ MCs and DCs to optimally induce acute NK cell-dependent immune responses to LPS helps explain why this signaling protein has been conserved in evolution.     

Uptake and Intracellular Trafficking of Superantigens in Dendritic Cells

Bacterial superantigens (SAgs) are exotoxins produced mainly by Staphylococcus aureus and Streptococcus pyogenes that can cause toxic shock syndrome (TSS). According to current paradigm, SAgs interact directly and simultaneously with T cell receptor (TCR) on the T cell and MHC class II (MHC-II) on the antigen-presenting cell (APC), thereby circumventing intracellular processing to trigger T cell activation. Dendritic cells (DCs) are professional APCs that coat nearly all body surfaces and are the most probable candidate to interact with SAgs. We demonstrate that SAgs are taken up by mouse DCs without triggering DC maturation. SAgs were found in intracellular acidic compartment of DCs as biologically active molecules. Moreover, SAgs co-localized with EEA1, RAB-7 and LAMP-2, at different times, and were then recycled to the cell membrane. DCs loaded with SAgs are capable of triggering in vitro lymphocyte proliferation and, injected into mice, stimulate T cells bearing the proper TCR in draining lymph nodes. Transportation and trafficking of SAgs in DCs might increase the local concentration of these exotoxins where they will produce the highest effect by promoting their encounter with both MHC-II and TCR in lymph nodes, and may explain how just a few SAg molecules can induce the severe pathology associated with TSS.