Humoral immunity against the M. tuberculosis kasB persistent mutant

针对结核分枝杆菌 kasB 持久突变体的体液免疫

• 批准号: 9624948
• 负责人: John R. Chan
• 金额: $ 8.94万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE, INC
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-15 至 2018-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9624948
• 关键词: Acid Fast Bacillae Staining Method; Antibodies; Antibody Response; Antigen Targeting; Antigens; Antitubercular Agents; Aspartate; Bacillus (bacterium); Bacteria; Biology; Carbohydrates; Cell Wall; Chronic; Clinical; Collaborations; Cues; Development; Disease; Drug Tolerance; Exposure to; Expression Profiling; Family; Gene Expression; Gene Expression Profile; Goals; Humoral Immunities; Hypoxia; Immune Evasion; Immune response; Immunization; Immunotherapeutic agent; In Vitro; Infection; Inhalation; Joints; Laboratories; Lead; Life Cycle Stages; Link; Lipids; Manuscripts; Masks; Monoclonal Antibodies; Mus; Mycobacterium tuberculosis; Mycobacterium tuberculosis antigens; Mycolic Acid; Organism; Outcome; Pathway interactions; Persons; Phenotype; Phosphorylation; Phosphorylation Site; Physiological; Play; Population; Process; Proteins; Protocols documentation; Publishing; Reagent; Regimen; Research; Role; Starvation; Structure; Surface; Testing; Threonine; Tuberculosis; Tuberculosis Vaccines; Vaccines; base; cell envelope; design; differential expression; holo-(acyl-carrier-protein) synthase; in vivo; interest; macromolecule; macrophage; meetings; mutant; mycobacterial; nitrosative stress; novel; novel strategies; programs; response; tool; tuberculosis immunity; vaccine development; vaccine efficacy

Abstract Mycobacterium tuberculosis (Mtb) is remarkably adept to establishing in an infected host a clinically silent latent state that can subsequently reactivates, posing a formidable hindrance to tuberculosis (TB) control. It is generally thought that the majority of the one-third of the world's population estimated to be infected with Mtb harbor latent bacilli. This latter population affords a large reservoir for the perpetuation of Mtb. The latent persistent form of Mtb is often drug-tolerant and thus difficult to treat. Given the propensity of Mtb to enter dormancy, it is likely that the infectious inoculum inhaled by a susceptible host contains latent form of bacilli in addition to those that are actively replicating. Ample evidence support the notion that Mtb, when exposed to conditions conducive to the establishment of a latent state, displays a gene expression profile distinct from that of actively replicating bacilli. Thus, it is likely that the antigenic profile of a latent persister is different than that of its rapidly growing counterpart. Indeed, loss of acid fastness has been demonstrated in Mtb existing in a chronic persistent state, which is thought to be, at least in part, the result of an aberrant cell envelope structure in dormant bacilli. Based on the above, it stands to reason that an effective TB vaccine should elicit an immune response that can target both actively replicating and latent persistent bacilli. In fact, BCG, the only anti-TB vaccine currently available and generated in conditions unrelated to those conducive to promote persistence (and therefore likely not expressing antigens (Ags) unique to latent tubercle bacilli), may not be capable of inducing an immune response that optimally protects against persistent organisms. The Jacobs group has recently characterized a set of mutants of Mtb kasB, which encodes a -ketoacyl-acyl carrier protein synthase involved in the biosynthetic pathway of mycolic acids (a major family of mycobacterial cell envelope lipids). The study has revealed that KasB activity is regulated via phosphorylation at two threonine residues, and that specific KasB-deficient mutants display phenotypes consistent with features of persisters, including a loss of acid fastness and inability to replicate when inoculated into mice. Importantly, immunization protocol that includes an acid-fast negative kasB persistent mutant -- which phosphorylation sites at the two aforementioned threonine residues have each been replaced by an asaparte (kasB-DD) -- protects against Mtb better than regimens that use BCG alone. The acid-fast negative kasB-DD strain displays an aberrant lipid profile involving species beyond mycolic acids. Aberrant packing of the cell envelope due to abnormal surface lipids such as mycolic acids may expose other macromolecules, including proteins and carbohydraes, that are otherwise masked. Collectively, these observations support the notion that persistent Mtb can express distinct Ags and that targeting such moieties, in addition to those typically present in actively replicating bacilli, might lead to enhanced vaccine efficacy. We therefore hypothesize that targeting Ags differentially expressed by and/or distinct to Mtb persisters represents an effective approach to developing anti- TB strategies including immunotherapeutics and vaccines. To begin testing this hypothesis, we propose to characterize the humoral immune response elicited by the acid-fast negative kasB-DD persister. The choice of this approach is based on emerging evidence suggesting antibodies (Abs) play a significant role in protection against Mtb and in modulating infection outcome. In addition, rigorous characterization of the Ab response to kasB-DD (and in the process, that of the control WT Mtb) can be expected to generate an extensive set of Mtb Ag-specific monoclonal Abs (mAbs) that constitutes a most valuable set of tools for advancing our understanding of three important aspects of Mtb research: (i) the humoral response of WT and persister tubercle bacilli, (ii) the biology of the difficult-to-track persistent Mtb, and (iii) the mechanisms that regulate tuberculous latency. Thus, the information yielded by these studies have the potential to lead to the development of novel strategies for better control of Mtb, including efficacious vaccines.

抽象的 结核分枝杆菌（MTB）非常擅长在感染的宿主中建立临床沉默 潜在状态可以随后重新激活，从而对结核病（TB）对照构成巨大的障碍。这是 通常认为，世界人口中三分之一的大多数人估计被MTB感染 港口潜伏细菌。后一个人口为MTB永存提供了庞大的预备役。潜在 MTB的持续形式通常是耐药的，因此很难治疗。鉴于MTB进入的承诺 休眠状态，易感宿主遗传的传染性接种物可能包含杆菌的潜在形式 补充那些积极复制的人。充分的证据支持MTB暴露于 导电到建立潜在状态，显示与此不同的基因表达谱 积极复制细菌。那是潜在毅力的抗原概况与此不同 其快速增长的对应物。实际上，在A中存在的MTB中已经证明了酸粘度的丧失 慢性持久状态，至少部分是一个异常的细胞信封结构的结果 在休眠的杆菌中。基于上述，有效的结核病疫苗应引起免疫力 可以针对积极复制和潜在持续性杆菌的反应。实际上，BCG，唯一的抗TB 目前可在与导电剂无关的条件下可用并生成的疫苗以促进持久性 （因此可能不表达潜在结节杆菌特有的抗原（AGS））可能无法 诱导了一种免疫反应，可以最佳地防止持续生物。 Jacobs组最近表征了MTB KASB的一组突变体，该突变体编码-Ketoacyl-acyl 粘液酸的生物合成途径（分枝杆菌的主要家族）载体蛋白合酶 细胞包络脂质）。该研究表明，KASB活性是通过磷酸化在两个处调节的 苏氨酸保留，并且特定的KASB缺陷突变体显示表型与 毅力，包括失去酸性腹部和无力在接种到小鼠中时复制。重要的是， 免疫协议，其中包括一个酸性负KASB持续突变体 - 哪个光谱位点 在两个关于苏氨酸的持有的情况下，苏氨酸保留均由Asaparte（KASB-DD）取代 - 保护 比单独使用BCG的治疗方案更好。酸性负KASB-DD菌株显示 异常的脂质谱涉及霉菌酸以外的物种。由于 异常表面脂质（例如霉菌酸）可能会暴露其他大分子，包括蛋白质和 碳水化合物，否则被掩盖了。总的来说，这些观察结果支持了持久的观念 MTB可以表达不同的AG和针对此类部分的AF，除了通常存在于 复制细菌，可能导致疫苗效率提高。因此，我们假设针对AGS 和/或与MTB持久者不同的表达和/或不同是一种有效的方法 结核病策略，包括免疫治疗和疫苗。为了开始检验这一假设，我们建议 表征由酸性负KASB-DD持久引起的体液免疫反应。选择 这种方法基于提示抗体（ABS）在保护中起重要作用的新兴证据 反对MTB并调节感染结果。另外，AB对AB响应的严格表征 可以预期，在此过程 Ag特异性的单克隆ABS（mAb）构成了最有价值的工具，用于推进我们 了解MTB研究的三个重要方面：（i）WT和毅力的体液反应 结节杆菌，（ii）难以传播的持续MTB的生物学以及（iii）调节的机制 结核潜伏期。这是这些研究所产生的信息有可能导致 制定新的策略，以更好地控制MTB，包括有效的疫苗。