BOG初次免疫联合结核分枝杆菌Ag85A DNA疫苗加强免疫效果的研究

为探讨BCG初次免疫,结核分枝杆菌Ag85A DNA疫苗加强免疫的序贯免疫策略对小鼠的免疫效果。采用BCG及结核分枝杆菌Ag85A DNA疫苗依次免疫小鼠,在末次免疫后的4、6、8周通过检测小鼠血清总IgG抗体、特异性淋巴细胞增殖．细胞因子的水平,观测BCG初次免疫,Ag85A DNA疫苗加强免疫的策略对小鼠的免疫效果。结果显示,采用BCG初次免疫,结核分枝杆菌Ag85A DNA疫苗加强免疫的策略组的小鼠与其它免疫方式组相比,IgG明显升高（P〈0．05）、特异性淋巴细胞明显增殖、IFN7、IL-2、IL-4水平明显增高（P〈0．05）。由此可知,在采用BCG初次免疫,结核分枝杆菌Ag85A DNA疫苗加强的免疫策略后,能增强对小鼠的免疫效应,尤其是Thl型细胞免疫反应增强明显,为进一步在动物体内进行保护性效应试验的研究提供了实验依据。     

树突状细胞在抗结核分枝杆菌感染中的作用

树突状细胞（Dendritic cells,DCs）是最有效的抗原呈递细胞.DCs能够摄取外来物质,包括结核分枝杆菌（Mycobacterium tuberculosis,MTB）,并将其呈递给效应性淋巴细胞,激发宿主对抗病原微生物感染的免疫反应.因此,树突状细胞与结核分枝杆菌的相互作用在感染初期机体发动免疫应答中十分重要.研究树突状细胞和结核分枝杆菌间的相互作用,有利于从根本上了解细菌-宿主作用机理,为阐明结核分枝杆菌逃避免疫的机制提供依据.     

前脑啡肽原和热休克蛋白参与宿主对结核分枝杆菌感染的应答

利用双向电泳比较了由临床分离的结核分枝杆菌感染离体巨噬细胞U937前后的全细胞蛋白组表达差异，肽指纹鉴定和生物信息学分析2个表达明显上调的斑点．确定它们分别为热休克蛋白HSP105β和前脑啡肽原．比较蛋白质组学和转录组学研究发现，热休克蛋白表达提高可能源于转录增加．提出了从神经免疫学角度研究结核分枝杆菌致病和宿主免疫机理的新思路，为解释吸毒人群中结核病高发病率提供了基础。     

表达HBHA和hIL-12融合蛋白的重组耻垢分枝杆菌对结核分枝杆菌感染小鼠的免疫治疗作用

评价表达HBHA和hIL12融合蛋白的重组耻垢分枝杆菌用于结核分枝杆菌感染小鼠的免疫治疗效果.结核分枝杆菌H37Rv感染小鼠4周后,用表达HBHA和hIL12融合蛋白的重组耻垢分枝杆菌免疫治疗,检测免疫小鼠肺部荷菌量和组织病理变化.重组耻垢分枝杆菌可有效控制感染小鼠肺部结核分枝杆菌的荷菌量,减轻病理损伤.但在降低肺部荷菌量方面不如化疗药物.表达HBHA和hIL12融合蛋白的重组耻垢分枝杆菌可有效控制结核分枝杆菌在小鼠体内的增殖,可能成为联合化疗药物控制结核病的有效候选疫苗.     

抗结核分枝杆菌感染的免疫机制

对宿主利用体内各种细胞与结核分支杆菌的相互作用进行了综述.机体抵抗结核分枝杆菌感染的机制包括特异性免疫和非特异性免疫,参与非特异性免疫的主要有巨噬细胞和γδT细胞,另外,树突状细胞在引发T细胞免疫方面起着关键的作用.由于结核分支杆菌是胞内寄生菌,特异性免疫以细胞免疫为主,主要包括CD4+T细胞免疫和CD8+T细胞免疫.     

结核分枝杆菌对宿主细胞凋亡效应的调控研究

由结核分枝杆菌（MTB）引起的结核病是严重危害人类健康的重大传染病,全世界约有1/3的人口潜伏感染MTB。近几年随着耐多药MTB和HIV混合感染的流行,使结核病控制形势更加严峻。细胞凋亡是生物有机体一种古老的免疫防御反应,在帮助机体清除胞内菌过程中发挥关键作用。已有研究结果表明,结核分枝杆菌对宿主细胞凋亡的调控过程非常复杂,即表现为有双重性：有些基因能促进凋亡,而有些则表现为抑制效应,且本研究组初步的研究结果表明细菌的毒力与凋亡有一定的内在联系,但是相关的分子机制还很不清楚。因此,鉴定MTB基因组中与凋亡相关的基因可以为研究细菌和宿主细胞之间的相互作用奠定基础,并且有助于研发新的药物靶标和候选疫苗。     

包虫病基因工程疫苗免疫效果考核试验

包虫病基因工程疫苗完全可抗我国细粒棘球绦虫犬——绵羊株对中间宿主(绵羊)的侵袭。在包虫病流行区免疫羊可获得保护。免疫期约半年新疆细毛羊免疫保护率为88．1％；蒙古黑头羊为83．6％。     

树突细胞免疫应答结核分枝杆菌基因调控网络的构建与分析

目的 探讨结核分枝杆菌感染树突细胞(dendritic cells,DCs)后宿主DCs基因表达谱的变化,并构建免疫应答基因调控网络,筛选出特征基因模块.方法 通过NCBI GEO datasets数据库,收集结核分枝杆菌感染DCs的芯片表达谱数据,运用R语言分析筛选出差异表达的基因,并对差异表达特征进行统计学分析;基于筛选出的差异基因,整合转录调控元件(TRED)数据库,构建结核分枝杆菌感染DCs中的免疫应答基因调控网络,并筛选出显著功能模块,通过注释及可视化整合分析工具(DAVID)整合KEGG数据库对网络基因进行功能分析(GO analysis)、信号通路分析(Pathway analysis)及疾病相关性分析;对网络基因进一步行蛋白相互作用(PPI)网络分析,并挖掘出关键子网络,筛选高节点度基因;结合基因调控网络中显著功能模块与PPI关键子网络,筛选出结核分枝杆菌感染DCs中的特征基因,并进行ROC曲线分析.结果 构建了DCs免疫应答结核分枝杆菌过程中异常表达的基因调控网络,并提取了包括CREB1、IL6、CEBPA和CCND14个差异表达基因在内的显著功能模块,网络中差异基因与保护性免疫过程或信号通路相关性较大,且在结核通路中有显著功能模块基因CREB1与IL6的分布.PPI网络分析基因调控其节点度Degree最显著的基因为IL6,且在显著功能与通路(inflammatory response与TNF signaling pathway)上均有IL6的分布信息.通过ROC曲线分析CREB1和IL6与DCs免疫应答结核分枝杆菌临床病理特征相关性,其ROC曲线下面积(AUC)分别为0.9114和0.9636.结论 筛选出CREB1与IL6不仅有预测调控关系,且DCs免疫应答结核分枝杆菌的特征基因集特异性强、灵敏度高,可作为表征DCs免疫应答结核分枝杆菌过程的候选标志物,可能成为先天免疫应答向适应性免疫应答的过渡信号.     

结核分枝杆菌FurB（Zur）研究进展

在结核分枝杆菌中存在与铁的代谢相关的基因．铁是多种酶的辅因子，在结核分枝杆菌的生长过程中发挥了重要作用．Fur是结核分枝杆菌中存在的铁依赖调节因子，包括FurA和FurB两种类似蛋白，其中FurB被认为还具有锌依赖性．对近年来FurB的相关研究进展情况进行综述．     

研究发现结核杆菌抑制宿主免疫机制

<正>中科院微生物所研究员刘翠华与中国科学院院士高福、北京师范大学教授邱小波及其团队合作的一项研究揭示,结核分枝杆菌(Mtb)中分泌性酪氨酸磷酸酶(Ptp A)可通过抑制宿主天然免疫相关信号通路而促进结核分枝杆菌在巨噬细胞内的存活。研究人员还发现,结核分枝     

Ipr1 gene mediates innate immunity to tuberculosis

An estimated eight million people are infected each year with the pathogen Mycobacterium tuberculosis, and more than two million die annually. Yet only about 10% of those infected develop tuberculosis. Genetic variation within host populations is known to be significant in humans and animals, but the nature of genetic control of host resistance to tuberculosis remains poorly understood. Previously we mapped a new genetic locus on mouse chromosome 1, designated sst1 (for supersusceptibility to tuberculosis 1). Here we show that this locus mediates innate immunity in sst1 congenic mouse strains and identify a candidate gene, Intracellular pathogen resistance 1 (Ipr1), within the sst1 locus. The Ipr1 gene is upregulated in the sst1 resistant macrophages after activation and infection, but it is not expressed in the sst1 susceptible macrophages. Expression of the Ipr1 transgene in the sst1 susceptible macrophages limits the multiplication not only of M. tuberculosis but also of Listeria monocytogenes and switches a cell death pathway of the infected macrophages from necrosis to apoptosis. Our data indicate that the Ipr1 gene product might have a previously undocumented function in integrating signals generated by intracellular pathogens with mechanisms controlling innate immunity, cell death and pathogenesis.     

Persistence of Mycobacterium tuberculosis in macrophages and mice requires the glyoxylate shunt enzyme isocitrate lyase

Mycobacterium tuberculosis claims more human lives each year than any other bacterial pathogen. Infection is maintained in spite of acquired immunity and resists eradication by antimicrobials. Despite an urgent need for new therapies targeting persistent bacteria, our knowledge of bacterial metabolism throughout the course of infection remains rudimentary. Here we report that persistence of M. tuberculosis in mice is facilitated by isocitrate lyase (ICL), an enzyme essential for the metabolism of fatty acids. Disruption of the icl gene attenuated bacterial persistence and virulence in immune-competent mice without affecting bacterial growth during the acute phase of infection. A link between the requirement for ICL and the immune status of the host was established by the restored virulence of delta icl bacteria in interferon-gamma knockout mice. This link was apparent at the level of the infected macrophage: Activation of infected macrophages increased expression of ICL, and the delta icl mutant was markedly attenuated for survival in activated but not resting macrophages. These data suggest that the metabolism of M. tuberculosis in vivo is profoundly influenced by the host response to infection, an observation with important implications for the treatment of chronic tuberculosis.     

A small-molecule nitroimidazopyran drug candidate for the treatment of tuberculosis

Mycobacterium tuberculosis, which causes tuberculosis, is the greatest single infectious cause of mortality worldwide, killing roughly two million people annually. Estimates indicate that one-third of the world population is infected with latent M. tuberculosis. The synergy between tuberculosis and the AIDS epidemic, and the surge of multidrug-resistant clinical isolates of M. tuberculosis have reaffirmed tuberculosis as a primary public health threat. However, new antitubercular drugs with new mechanisms of action have not been developed in over thirty years. Here we report a series of compounds containing a nitroimidazopyran nucleus that possess antitubercular activity. After activation by a mechanism dependent on M. tuberculosis F420 cofactor, nitroimidazopyrans inhibited the synthesis of protein and cell wall lipid. In contrast to current antitubercular drugs, nitroimidazopyrans exhibited bactericidal activity against both replicating and static M. tuberculosis. Lead compound PA-824 showed potent bactericidal activity against multidrugresistant M. tuberculosis and promising oral activity in animal infection models. We conclude that nitroimidazopyrans offer the practical qualities of a small molecule with the potential for the treatment of tuberculosis.     

结核分枝杆菌的抗逆性与致病性研究进展

结核病是由结核分枝杆菌(Mycobacterium tuberculosis,MTB)复合群感染导致的人畜共患传染病,在新型冠状病毒感染暴发前是全球死亡人数最多的单一传染病。结核病致死率高,主要原因是其致病菌结核分枝杆菌具有极强的毒力且可以抵御多种外界环境胁迫因子。本文主要介绍结核分枝杆菌对理化胁迫的耐受性,以及结核分枝杆菌的耐药性、致病性与免疫性,为深入研究结核病的发病机制和研发新型的抗结核药物提供理论指导。     

Complex lipid determines tissue-specific replication of Mycobacterium tuberculosis in mice

Tuberculosis is the leading cause of death in the world resulting from a single bacterial infection. Despite its enormous burden on world health, little is known about the molecular mechanisms of pathogenesis of Mycobacterium tuberculosis. Bacterial multiplication and concomitant tissue damage within an infected host, including experimentally infected mice, occurs primarily in the lungs-the favoured niche of M. tuberculosis. Although it has been proposed that the distinctive cell wall of M. tuberculosis is important for virulence, rigorous genetic proof has been lacking. Here, using signature-tagged mutagenesis, we isolated three attenuated M. tuberculosis mutants that cannot synthesize or transport a complex, cell wall-associated lipid called phthiocerol dimycocerosate (PDIM) which is found only in pathogenic mycobacteria. Two mutants have transposon insertions affecting genes implicated in PDIM synthesis; the third has a disruption in a gene encoding a large transmembrane protein required for proper subcellular localization of PDIM. Synthesis and transport of this complex lipid is only required for growth in the lung; all three mutants are unaffected for growth in the liver and spleen. This clearly shows that a lipid is required for M. tuberculosis virulence.     

CD1b restricts the response of human CD4-8- T lymphocytes to a microbial antigen.

Molecules encoded by the human CD1 locus on chromosome 1 (ref. 33) are recognized by selected CD4-8- T-cell clones expressing either alpha beta or gamma delta T-cell antigen receptors. The known structural resemblance of CD1 molecules to antigen-presenting molecules encoded by major histocompatibility complex (MHC) genes on human chromosome 6 (refs 3, 4, 34, 35), suggested that CD1 may represent a family of antigen-presenting molecules separate from those encoded in the MHC. Here we report that the proliferative and cytotoxic responses of human CD4-8- alpha beta TCR+ T cells specific for Mycobacterium tuberculosis can be restricted by CD1b, one of the four identified protein products of the CD1 locus. The responses of these T cells to M. tuberculosis seemed not to involve MHC encoded molecules, but were absolutely dependent on the expression of CD1b by the antigen-presenting cell and involved an antigen processing requirement similar to that seen in MHC class II-restricted antigen presentation. These results provide, to our knowledge, the first direct evidence for the proposed antigen-presenting function of CD1 molecules and suggest that the CD1 family plays a role in cell-mediated immunity to microbial pathogens.     

Cloning of the mycobacterial epitope recognized by T lymphocytes in adjuvant arthritis

Adjuvant arthritis (AA) is a chronic disease inducible in rats by immunization with an antigen of Mycobacterium tuberculosis. After the isolation of arthritogenic T-cell lines and clones, it became possible to demonstrate that the critical M. tuberculosis antigen contained an epitope cross-reactive with a self-antigen in joint cartilage. Like AA rats, patients suffering from rheumatoid arthritis demonstrated specific T-lymphocyte reactivity to the M. tuberculosis fraction containing the cross-reactive epitope. To characterize the critical M. tuberculosis epitope we used AA T-cell clones to screen mycobacterial antigens expressed in Escherichia coli and genetically engineered truncated proteins and synthetic peptides. The AA T-cell clones recognized an epitope formed by the amino acids at positions 180-188 in the sequence of a Mycobacterium bovis BCG antigen. Administration of this antigen to rats induced resistance to subsequent attempts to produce AA.     

A glycolipid of hypervirulent tuberculosis strains that inhibits the innate immune response

Fifty million new infections with Mycobacterium tuberculosis occur annually, claiming 2-3 million lives from tuberculosis worldwide. Despite the apparent lack of significant genetic heterogeneity between strains of M. tuberculosis, there is mounting evidence that considerable heterogeneity exists in molecules important in disease pathogenesis. These differences may manifest in the ability of some isolates to modify the host cellular immune response, thereby contributing to the observed diversity of clinical outcomes. Here we describe the identification and functional relevance of a highly biologically active lipid species-a polyketide synthase-derived phenolic glycolipid (PGL) produced by a subset of M. tuberculosis isolates belonging to the W-Beijing family that show 'hyperlethality' in murine disease models. Disruption of PGL synthesis results in loss of this hypervirulent phenotype without significantly affecting bacterial load during disease. Loss of PGL was found to correlate with an increase in the release of the pro-inflammatory cytokines tumour-necrosis factor-alpha and interleukins 6 and 12 in vitro. Furthermore, the overproduction of PGL by M. tuberculosis or the addition of purified PGL to monocyte-derived macrophages was found to inhibit the release of these pro-inflammatory mediators in a dose-dependent manner.