结核杆菌Ag85B蛋白的表达及免疫特性的试验研究

正Ag85B是结核分枝杆菌最主要的分泌蛋白,参与结核分枝杆菌细胞壁的合成,能与人纤维连蛋白结合,参与结核病的形成,且在T细胞上有多个表位能诱导机体产生保护性免疫应答。因此,本研究对结核杆菌Ag85B蛋白的细胞免疫特性、体液免疫特性以及免疫应答进行研究,以找到诊断和控制结核病的有效方法。1资料与方法1.1实验材料大肠杆菌DH5α和BL21、p ET-30a载体、BCG丹麦株、结核分枝杆菌H37Rv、李斯特重组     

CD4^＋CD25^＋调节性T细胞调控结核分枝杆菌感染的机制和意义

机体免疫反应有助于控制慢性结核分枝杆菌感染,但不能将其清除。细胞免疫在清除结核分枝杆菌感染中起着重要作用,包括CD4^＋Th细胞和CD8^＋T细胞以及高水平Th1类细胞因子。近年研究表明,在慢性病原体感染中存在具有调节功能的CD4^＋CD25^＋T细胞亚群,剔除这群细胞能够增加机体的免疫反应,它们在结核分枝杆菌慢性感染的发病机制中也起着重要作用。此文就目前有关调节性T细胞的分化和功能,及其在结核分枝杆菌感染中的意义和作用机制等研究进展作一综述。     

结核菌素试验临床应用的研究进展

人类感染结核分枝杆菌后,产生免疫力的同时也会发生迟发型超敏反应。将一定量的结核菌素注入皮内,如受试者曾感染结核分枝杆菌,则在注射部位出现迟发型超敏反应炎症,判为阳性,未感染结核分枝杆菌的则为阴性。此法可用于检测可疑患者是否曾感染过结核分枝杆菌,接种卡介苗（BCG）后是否阳转以及检测机体细胞免疫功能。     

潜伏感染者实施预防性治疗面临的几个科学问题

世界卫生组织在2014年底提出了有关结核潜伏感染管理的指南性文件,其中预防性治疗引人关注,具有重要的现实意义。随着现代生物学技术的快速发展,结核分枝杆菌的潜伏感染得到更深入的认识。最近的研究表明:确定潜伏感染者的检测技术具有一定的局限性,而存在于干细胞内的潜伏感染结核分枝杆菌不容易被清除,并且体内潜伏感染结核分枝杆菌与活动性结核分枝杆菌存在相同的突变率,加之我们对抗结核药物之间的关系还缺乏深入了解,一种药物的耐药性可能导致其它药物的最低抑菌浓度(MIC)值升高。上述这些发现提示我们潜伏感染结核分枝杆菌的预防性治疗仍然存在一些基础科学问题有待进一步研究。     

巨噬细胞在抗结核免疫中的作用及其研究进展

据估计世界上有1/3人口感染了结核分枝杆菌。在大多数情况下,结核分枝杆菌感染者是无症状和没有传染性的,即潜伏性结核感染。为何机体免疫反应可使绝大多数人免患活动性结核病,而又不能完全清除这种感染呢？研究表明,巨噬细胞在控制结核分枝杆菌感染中起着重要作用,而结核分枝杆菌本身也已产生了逃避巨噬细胞杀灭的机制。本文就以上方面的研究进展综述如下。     

PCR法鉴定结核分枝杆菌复合群亚种的研究

结核分枝杆菌复合群中各菌型致病性和药物敏感性不尽相同,在临床治疗前需要进行菌种鉴定,目前临床使用的生化方法耗时长,给治疗带来不便,本研究采用PCR法可快速鉴定结核分枝杆菌复合群亚种,具有快速、准确的优点,现将研究结果报道如下。1材料和方法1.1材料1.1.1菌株人结核分枝杆菌标准株(H37Rv,CMCC(B)95053)和牛结核分枝杆菌标准株(CMCC(B)93006),非洲分枝杆菌标准株(M.africanum,CMCC(B)95049)购自国家菌种保存中心。19株牛结核分枝杆菌分离株(M.bovis),PNB培养生长试验阴性,TCH培养生长试验为阴性;20株人结核分枝杆菌分离株(M.tb) 更多还原     

结核分枝杆菌潜伏感染相关抗原的研究进展

结核病是全世界范围内危害人类健康的主要传染病之一。结核分枝杆菌潜伏感染者是结核病的主要来源,早期发现、诊断并有效治疗潜伏感染是有效控制结核病蔓延的重要措施之一。目前,结核分枝杆菌潜伏感染抗原主要包括与结核分枝杆菌缺氧、营养缺乏及与结核分枝杆菌复苏、再激活相关的蛋白。有些潜伏感染相关抗原具有良好的T细胞免疫能力,尤其更易在被潜伏感染人群中识别,有望成为新型的结核分枝杆菌潜伏感染诊断标志物及潜伏感染候选疫苗;有些潜伏感染相关抗原对B淋巴细胞具有较强免疫原性,在结核病体液免疫诊断方面有潜在诊断价值。这些潜伏感染相关蛋白在未来结核分枝杆菌潜伏疫苗及诊断试剂开发中具有良好的应用前景。     

非结核分枝杆菌相关研究新进展

非结核分枝杆菌在自然界中广泛存在,部分可引起人类疾病.因非结核分枝杆菌对多种抗结核药物耐药,且诊断困难、患者预后较差,使非结核分枝杆菌感染性疾病逐渐成为医学界十分关注的研究课题.作者从非结核分枝杆菌种类及感染率、非结核分枝杆菌耐药情况及耐药机制研究、非结核分枝杆菌感染特点及治疗方案、非结核分枝杆菌检测方法及环境水非结核分枝杆菌污染研究等方面综述了非结核分枝杆菌相关的研究进展.其耐药机制及传播机制尚未阐明,需要进行深入研究.     

HIV和结核分枝杆菌共同感染的免疫学机制

人类免疫缺陷病毒(HIV)和结核分枝杆菌共感染是全球性公共卫生重大问题,结核分枝杆菌和HIV均是在细胞内复制的病原体,通过损伤细胞免疫而造成持续感染。随着免疫学的进展,人们逐渐了解HIV和结核分枝杆菌共感染的一些临床特点及免疫学机制。树突状细胞(DCs)通过高水平表达主要组织相容性复合物II(MHC II)类分子、协同分子及黏附分子,诱导免疫激活,促使T细胞增殖。HIV和结核分枝杆菌感染后树突状细胞功能受损,导致Th1/Th2及Treg/Th17(help T cell,辅助性T细胞;Regulatery T cell,调节性T细胞)平衡打破,进一步降低了细胞毒性T细胞(CTL)清除结核分枝杆菌和HIV的能力。随着HIV和结核分枝杆菌共感染免疫机制研究的不断深入,人们对HIV合并结核分枝杆菌感染的诊治水平将不断提高。     

巨噬细胞在抗结核免疫中的作用及其研究进展

据估计世界上有1／3人口感染了结核分枝杆菌。在大多数情况下，结核分枝杆菌感染者是无症状和没有传染性的，即潜伏性结核感染。为何机体免疫反应可使绝大多数人免患活动性结核病，而又不能完全清除这种感染呢?研究表明，巨噬细胞在控制结核分枝杆菌感染中起着重要作用，而结核分枝杆菌本身也已产生了逃避巨噬细胞杀灭的机制。本文就以上方面的研究进展综述如下。     

Reactive oxygen and nitrogen intermediates in the relationship between mammalian hosts and microbial pathogens

This review summarizes recent evidence from knock-out mice on the role of reactive oxygen intermediates and reactive nitrogen intermediates (RNI) in mammalian immunity. Reflections on redundancy in immunity help explain an apparent paradox: the phagocyte oxidase and inducible nitric oxide synthase are each nonredundant, and yet also mutually redundant, in host defense. In combination, the contribution of these two enzymes appears to be greater than previously appreciated. The remainder of this review focuses on a relatively new field, the basis of microbial resistance to RNI. Experimental tuberculosis provides an important example of an extended, dynamic balance between host and pathogen in which RNI play a major role. In diseases such as tuberculosis, a molecular understanding of host-pathogen interactions requires characterization of the defenses used by microbes against RNI, analogous to our understanding of defenses against reactive oxygen intermediates. Genetic and biochemical approaches have identified candidates for RNI-resistance genes in Mycobacterium tuberculosis and other pathogens.     

结核病黏膜疫苗的研究进展北大核心CSCD

呼吸道黏膜免疫是机体抵御结核分枝杆菌(Mycobacterium tuberculosis,MTB)感染的第一道防线,是重要的抗MTB感染的保护性免疫,如何通过黏膜免疫,诱导黏膜免疫系统产生抗MTB感染的特异性免疫,是目前结核病疫苗研究的新方向。本文基于近年来结核病黏膜疫苗的研究,总结了不同类型疫苗的特点、黏膜免疫后的免疫学特性和免疫保护效果,展望了未来结核病黏膜疫苗的研究方向,希望能够对研发更加高效的结核病黏膜疫苗有所启示。     

Protective immunity against Mycobacterium tuberculosis

Mycobacterium tuberculosis (MTB) is a facultative intracellular pathogen with which over a billion people have been infected and 3 million people die annually. The bacterium induces vigorous immune responses, yet evades host immunity, persisting within phagosomes of the infected macrophages. Thus, it is necessary to delineate that the virulence-related intracellular survival mechanism and the host immune responses to eradicate M. tuberculosis on the molecular basis. In this regard, recent findings clearly indicated that Toll-like receptors (TLRs) play an essential role in the recognition of MTB components by macrophages and dendritic cells, resulting in not only activation of innate immunity but also development of antigen-specific adaptive immunity. It has been also reported that induction of early death of the infected cells may be one of the strategy of host defense against MTB because macrophages go into apoptosis upon infection with MTB, resulting in suppression of the intracellular replication. Furthermore, recent report has shown that autophagy is induced by IFN-gamma and suppress intracellular survival of mycobacteria, suggesting that activation of autophagy pathway is required to overcome phagosome maturation arrest induced by MTB. In addition, it is known that IFN-gamma plays an important role in protection. The cytokine that is produced from NK cells and dendritic cells at the early period of infection strongly induces not only macrophage activation but also development of antigen-specific IFN-gamma-producing CD4+T cells. Since antigen-specific CD8+ T cells and CD1-restricted T cells are also reported to contribute to the protective immunity, cooperation of these T cells is essential for the host resistance. In this paper, I am going to summarize the recent progress of the understanding of protective immunity against MTB.     

Innate immunity and tuberculosis

The immune system is divided into innate and adaptive immunity. The innate immune system provides the first line of host defense against invading microorganisms before the development of adaptive immune responses. Innate immune responses are initiated by germline-encoded pattern recognition receptors (PRRs), which recognize specific structures of microorganisms. Toll-like receptors (TLRs) are one of the family of pattern-recognition receptors to sense a wide range of microorganisms, such as bacteria, fungi, protozoa and viruses. Recognition of Mycobacterium tuberculosis components by TLRs triggers activation of signal transduction pathways, which then induces dendritic cell maturation and cytokine production, resulting in development of adaptive immunity. TLRs are critically involved in the induction of host defense to M. tuberculosis.     

Frontier of mycobacterium research--host vs. mycobacterium

During the past decade, we have observed advance in tuberculosis research including novel vaccines, innate immunity (TLR), SNIP analysis and molecular mechanism of drug resistance. Worldwide genome project enabled the whole genome sequence of host resistant against tuberculosis as well as the whole genome sequence of M. tuberculosis H37Rv. DNA technology has also provided a great impact on the development of novel vaccine against TB. In this symposium, we have invited leading researchers in the field of the frontier study of Mycobacterium research in order to provide general overview of the cutting edge of frontier research. Molecular mechanism of drug resistance of M. tuberculosis has been clarified. On the other hand, molecular mechanism of host-defence (insusceptibility of host) against M. tuberculosis has not yet elucidated. Dr. Taro Shirakawa (Kyoto University) reviewed the susceptibility genes of host in TB infection and presented candidate genes associated with multi-drug resistant tuberculosis. Dr. Naoto Keicho (International Medical Center of Japan) tried to identify host genetic factors involved in susceptibility to pulmonary Mycobacterium avium complex (MAC) infection by candidate gene approach and genome-wide approach. In Japan, Dr. Masaji Okada (National Hospital Organization Kinki-Chuo Chest Medical Center) has been engaged actively in the development of new tuberculosis vaccines (HVJ-liposome/Hsp65 DNA + IL-12 DNA vaccine and recombinant 72f BCG vaccine). He showed basic strategy for construction of new candidate vaccines and also showed significant efficacy on the protection of tuberculosis infection using cynomolgus monkeys, which are very similar to human tuberculosis. Dr. Hatsumi Taniguchi (University of Occupational and Environmental Health) presented that M. tuberculosis mIHF and the neighbor genes went into a dormacy-like state of M. smegmatis in J774 macrophage cells. This study might provide a weapon for elucidating the mechanism of dormacy of M. tuberculosis and the development of novel therapy. Dr. Chiyoji Abe (Nippon Becton Dickinson Co.) reviewed the molecular basis of the resistance to anti-tuberculosis drugs. Most cases of resistance are related to simple nucleotide substitutions rather than to acquisition of new elements. Dr. Kiyoshi Takeda (Kyushu University) showed interesting finding. He analyzed whether Toll-like receptor (TLR)-mediated activation of innate immunity in host defense against mycobacterial infection. MyD88/TRIF double defi-indicating that innate immunity is involved in anti-mycobacterial infection. (1) SNP (single nucleotide polymorphism) analysis in association with Mycobacterium tuberculosis: Taro SHIRAKAWA (Department of Health Promotion & Human Behavior, Kyoto University Medical School, and RIKEN SRC Center) Candidate gene approach was made on 18 SNPs in 11 genes in association with M. tuberculosis. Patients with multi-drug resistance against M. tuberculosis are also subjected. SNPs in NRAMP1 gene were associated with the disease, and drug resistance, its mechanisms remain unknown. (2) Search for genes susceptible to pulmonary Mycobacterium avium complex infection: Naoto KEICHO (Department of Respiratory Diseases, Research Institute, International Medical Center of Japan) Interaction among pathogens and host factors is important for development of infectious diseases. We are trying to identify host genetic factors involved in susceptibility to nonimmunocompromized pulmonary Mycobacterium avium complex (MAC) infection by candidate gene approach and genome-wide approach. Elucidation of functional significance of susceptibility gene polymorphisms will lead to a new strategy for control and prevention of the disease. (3) T cell immunity against Tuberculosis in host and the establishment of novel vaccine: Masaji OKADA (Clinical Research Center, National Hospital Organization Kinki-Chuo Chest Medical Center) T cell (CTL, Th1) immunity including granulysin play an important role in host defense against tuberculosis (TB) in human. Patients with TB or Multi-drug resistant TB showed suppression of all these immunities. HVJ-liposome/Hsp65 DNA + IL-12 DNA vaccination was 100 fold more efficient than BCG on the elimination of Mycobacterium tuberculosis (M.TB) in the BALB/c mice. Cytotoxic T cells activity against M. TB was augmented. By using these new vaccines (Hsp 65 DNA + IL-12 DNA, recombinant 72f BCG) and the cynomolgus monkey models which are very similar to human tuberculosis, the prophylactic effect of vaccines was observed. Thus, these novel vaccines should provide a useful tool for the prevention of human TB infection. (4) Mycobacterium tuberculosis mIHF and the neighbor genes go into a dormancy-like state of M. smegmatis J15CS in J774 cells: Hatsumi TANIGUCHI (Department of Microbiology, School of Medicine, University of Occupational and Environmental Health) Mycobacterium smegmatis J15CS transformants harboring the mIHF gene or the mIHF-gmk-Rv1390 genes showed no difference in in vitro growth and acid-fastness. However, transformants harboring mIHF-gmk-Rv1390 formed short-rod cell morphology and decreased acid-fastness in the mouse macrophage-like cell line J774 compared to those of the other transformants, and the nuclei of the infected J774 cells also changed. Nevertheless, the colony forming units were similar. These indicate that mIHF and the neighbor genes of M. tuberculosis might regulate a growth of mycobacteria in macrophages. (5) Molecular basis of the resistance to anti-tuberculosis drugs: Chiyoji ABE (Nippon Becton Dickinson Company, Ltd.) Considerable progress has been made toward understanding the molecular basis of the resistance to anti-tuberculosis drugs. Most cases of resistance are related usually to simple nucleotide substitutions rather than to acquisition of new elements. Multi-drug resistant isolates of Mycobacterium tuberculosis arise a consequence of sequential accumulation of mutation conferring resistance to single therapeutic agents. The basis of resistance is not able to be explained yet in a substantial percentage of strains for other anti-tuberculosis drugs than rifampin and pyrazinamide. Further studies are required to fully understand the molecular mechanisms of resistance. (6) Toll-like receptors in anti-mycobacterial immune responses: Kiyoshi TAKEDA (Department of Molecular Genetics, Medical Institute of Bioregulation, Kyushu University) Toll-like receptors (TLRs) play an essential role in the recognition of specific patterns of microbial components. TLRs mediate activation of innate immunity and further development of antigen-specific adaptive immunity. In TLR signaling pathways, Toll/IL-1 receptor (TIR) domain-containing adaptors, such as MyD88, TIRAP, TRIF, and TRAM, have been shown to play pivotal roles. Thus, the molecular mechanisms for TLR-mediated activation of innate immunity have been largely understood. We analyzed whether TLR-mediated activation of innate immunity is involved in host defense against mycobacterial infection. MyD88/TRIF double deficient mice, in which TLR-dependent activation of innate immunity is abolished, showed high sensitivity to mycobacterial infection, indicating that innate immunity is critically involved in anti-mycobacterial responses.     

Mycobacterial interaction with innate receptors: TLRs, C-type lectins, and NLRs

PURPOSE OF REVIEW: The recent discovery of novel classes of receptors, including toll-like receptors and nucleotide-binding oligomerization domain (NOD)-like receptors is challenging the crucial role of the innate immune system in the recognition of Mycobacterium tuberculosis. The present review is to focus on the roles and mechanisms of specific pattern-recognition receptor-microbial interaction for the host defense against mycobacterial infections. RECENT FINDINGS: Toll-like receptors, key players in innate immunity, are now known to be important for the initiation and coordination of host responses to Mycobacterium tuberculosis. The interaction of Mycobacterium tuberculosis with toll-like receptors triggers intracellular signaling cascades that culminate in a proinflammatory response, but can also trigger signals that dampen the innate immune response. Other membrane-bound pattern-recognition receptors, including the mannose receptor, DC-SIGN, and Dectin-1, contribute to the propagation of Mycobacterium tuberculosis inflammatory signals, and Nod-like receptors (cytosolic pattern-recognition receptors) also act in modulating host recognition of Mycobacterium tuberculosis. Interactions between toll-like receptors and other pattern-recognition receptors are also evident in responses to Mycobacterium tuberculosis, as are possible mechanisms for coordination of innate and adaptive immunity. SUMMARY: The complexity of Mycobacterium tuberculosis-pattern-recognition receptor interactions and their effects on host cell responses suggest key roles for innate immunity in controlling Mycobacterium tuberculosis, and the possibility of developing novel therapeutics for tuberculosis that target Mycobacterium tuberculosis-regulated innate immunity pathways.     

The effect of mycobacterial virulence and viability on MAP kinase signalling and TNF alpha production by human monocytes

SETTING: The success of Mycobacterium tuberculosis as a human pathogen depends on its ability to tolerate and perhaps manipulate host defense mechanisms. OBJECTIVE: To determine the induction of tumour necrosis factor-alpha (TNF alpha), a central mediator of immunity, by human monocytes infected with virulent M. tuberculosis, M. leprae and attenuated M. bovis BCG. DESIGN: Mycobacteria-induced cellular activation pathways of TNF alpha production was investigated using an inhibitor of protein tyrosine kinase (PTKs) and an inhibitor of mitogen-activated protein (MAP) kinases. RESULTS: TNF alpha production was significantly lower during infection with virulent M. tuberculosis than with BCG and this differential response was independent of mycobacterial viability. TNF alpha production involved the PTK and MAP kinase pathways. Reduced TNF alpha induction by M. tuberculosis was associated with a reduction in the extent and duration of phosphorylation of extracellular-signal regulated kinases (ERK 1/2). Infection with M. leprae triggered low and transient ERK 1/2 activation as well as low TNF alpha production. CONCLUSION: Maintenance of the differential response in both live and heat-killed preparations suggests that the reduced TNF alpha response associated with virulent mycobacteria is due to differences in the presence of components capable of triggering host pattern recognition receptors, rather than events associated with phagosome trafficking or the active release of intracellular modulators.     

Immune response to postprimary tuberculosis in mice: Mycobacterium tuberculosis and Miycobacterium bovis bacille Calmette-Guérin induce equal protection

We addressed the question of whether protective immunity induced by natural infection with Mycobacterium tuberculosis and that induced by vaccination with Mycobacterium bovis bacille Calmette-Guerin (BCG) differ in the murine model. We infected mice with M. tuberculosis Erdman, cured them by chemotherapy, and subsequently reinfected them with a low dose of M. tuberculosis H37Rv. The course of tuberculosis was compared with that in mice previously vaccinated with BCG Danish 1331. Protection against postprimary M. tuberculosis infection did not differ significantly between the 2 groups. After challenge infection, numbers of interferon- gamma -positive splenocytes did not differ between mice with primary infection and vaccinated mice. Splenocytes from primary M. tuberculosis-infected mice conferred marginally higher protection than did those from BCG-vaccinated mice. Serum transfer did not protect against reinfection in either group. Our data emphasize that natural infection with M. tuberculosis and vaccination with BCG do not differ in their capacity to induce protective immunity against tuberculosis and support the notions that reinfection contributes to the development of active disease and that any novel vaccine against tuberculosis has to perform better than both vaccination with BCG and immunity evoked by natural infection.     

Fatal disseminated adenovirus 11 pneumonia in an agammaglobulinemic patient

Adenovirus type 11, an organism not previously associated with pneumonia, caused the death of a patient with infantile x-linked agammaglobulinemia who had normal cell-mediated immunity. Despite long-standing, regular therapy with immune globulin, his serum lacked neutralizing antibody to the virus. This case confronts the conventional view that viral infections are primarily resisted by cellular immune reactions and reemphasizes the importance of antibody in the host defense against adenoviruses. It further demonstrates the continued vulnerability of such patients to certain pathogens in the presence of presumably adequate standard-dose passive immunization.