Immune Evasion Mechanisms of Mycoplasma genitalium

生殖支原体的免疫逃避机制

• 批准号: 10078250
• 负责人: Gwendolyn Wood
• 金额: $ 19.25万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10078250
• 关键词: Adherence; Affect; Affinity; Alanine; Alleles; Antibiotic Resistance; Antibodies; Antibody Response; Antigen Targeting; Antigenic Variation; Archives; Awareness; Bacteria; Binding; Binding Sites; Biological; Biological Assay; Biology; C-terminal; Cell Culture Techniques; Cell surface; Cells; Chlamydia trachomatis; Chromosomes; Clinical; Collection; Complement; Crystallization; Diagnostic tests; Disease; Engineering; Enzyme-Linked Immunosorbent Assay; Epitopes; Exudate; Funding; Genes; Genome; Immune; Immune Evasion; Immune response; Immunoglobulin G; Immunoglobulin Variable Region; Immunoglobulin binding proteins; Immunoglobulins; Individual; Infection; Kinetics; Laboratories; Link; Measures; Mediating; Methods; Molecular Conformation; Mutation; Mycoplasma; Mycoplasma genitalium; Neisseria gonorrhoeae; Organelles; Oryctolagus cuniculus; Parasites; Pathogenesis; Patients; Phagocytes; Phagocytosis; Phase; Prevention strategy; Process; Proteins; Public Health; Recombinants; Regimen; Research; Role; Serology test; Sexual Transmission; Shapes; Sialic Acids; Site; Specimen; Structural Models; Structure; Surface; Surface Plasmon Resonance; System; Thermodynamics; Variant; Virulence; Woman; bactericide; cervicovaginal; combat; empowered; experimental study; flasks; homologous recombination; improved; inhibiting antibody; men; novel strategies; pathogen; polymeric IgA; prevent; protein structure; reproductive tract

PROJECT SUMMARY Mycoplasma genitalium (MG) is an emerging reproductive tract pathogen of significant public health concern. This sexually transmitted bacterium elicits a disease spectrum similar to Neisseria gonorrhoeae and Chlamydia trachomatis, yet may be more prevalent in certain clinical settings. Alarmingly, MG is becoming increasingly resistant to antibiotics with some infections totally untreatable with recommended regimens in the US. The recent FDA approval of an MG diagnostic test will certainly increase public awareness of MG, and demands for improved treatments. A hallmark of MG infection is long-term persistence despite the presence of specific antibodies in the genital tract. Over the past decade our laboratory has focused on the variability of the immunodominant MgpB and MgpC adherence proteins, and the local and systemic antibody response to these proteins during infection. We demonstrated that MgpB and MgpC undergo phase and antigenic variation via a unique system of homologous recombination between the mgpBC expression site and partial copies archived in the chromosome. We propose to extend these studies empowered by three recent advances: (1) the determination of the MgpC protein structure, which includes a sialic acid binding pocket, (2) our detailed analysis of antibody reactivity and antigenic variation in a collection of longitudinal specimens from MG-infected men, including evidence that the conserved C-terminal region of MgpC contains the dominant antigen targeted by patient antibodies, and (3) the discovery of the MG281 immunoglobulin binding protein whose role in pathogenesis is unexplored. MgpC C-terminal epitopes will be defined using engineered deletions and alanine substitutions analyzed by ELISA and surface plasmon resonance (SPR) to explore thermodynamics and kinetics of antibody binding. Complement killing and opsonophagocytosis assays will locate targets of bactericidal antibodies. Defining MgpC epitopes recognized by patient sera will inform improved serologic tests, essential to explore association of MG with serious upper reproductive tract sequelae in women. As the sialic acid binding pocket is embedded in the variable region of MgpC, we will measure changes in sialic acid binding affinity in different variants, and the effect of variant-specific antibodies on sialic acid binding and adherence. Understanding the role of MG281 in avoiding the biologic activity of anti-MG antibodies is a top priority in MG research especially as interactions of MG with innate immune effectors has not been defined. Therefore, our third aim will link the findings of Aims 1 and 2 to determine whether MG281 prevents killing by specific antibodies in sera of MG(+) men and in cervicovaginal exudates of MG(+) women. These experiments, along with our novel approaches pioneering experimental methods for the difficult field of mycoplasma research, will inspire improved prevention strategies to combat this increasingly antibiotic-resistant and important pathogen.

项目摘要 支原体生殖器（MG）是一种重要的公共卫生问题的新兴生殖道病原体。 这种性传播的细菌引起了类似于淋病和衣原体类似的疾病谱 气管机，但在某些临床环境中可能更普遍。令人震惊的是，MG越来越多 在美国，对抗生素具有完全不可治疗的抗生素。这 最近对MG诊断测试的FDA批准肯定会提高公众对MG的认识，并要求 用于改进治疗。 MG感染的标志是长期持久性，尽管存在特定 生殖道中的抗体。在过去的十年中，我们的实验室重点是 免疫主导MGPB和MGPC依从性蛋白，以及对这些局部抗体的反应 感染过程中的蛋白质。我们证明了MGP​​B和MGPC通过A进行相位和抗原变异 MGPBC表达站点和部分副本存档之间同源重组的独特系统 在染色体中。我们建议扩大这些研究的赋权，并获得了最近的三个进步：（1） MGPC蛋白结构的确定，其中包括唾液酸结合口袋，（2）我们的详细信息 分析来自MG感染的纵向标本集合中的抗体反应性和抗原变异 男性，包括证据表明MGPC保守的C末端区域包含针对的主要抗原 由患者抗体和（3）发现MG281免疫球蛋白结合蛋白的发现 发病机理未开发。 MGPC C末端表位将使用工程缺失和丙氨酸定义 通过ELISA和表面等离子体共振（SPR）分析的替换，以探索热力学和 抗体结合的动力学。补充杀戮和肠病毒细胞增多症测定法将定位 杀菌抗体。定义患者血清认可的MGPC表位将为改进的血清学检查提供信息， 探索妇女中MG与严重的上繁殖后遗症的关联至关重要。作为唾液 酸结合口袋嵌入了MGPC的可变区域中，我们将测量唾液酸结合的变化 不同变体的亲和力，以及变异特异性抗体对唾液酸结合和粘附的影响。 了解MG281在避免抗Mg抗体的生物学活性中的作用是MG的首要任务 研究尤其是MG与先天免疫效应子的相互作用尚未定义。因此，我们的 第三目的将链接目标1和2的发现，以确定MG281是否阻止了特定的杀戮 Mg（+）男性血清中的抗体以及Mg（+）女性的宫颈阴道渗出剂中的抗体。这些实验，沿着 借助我们的新方法，用于支原体研究困难领域的实验方法将 激发了改进的预防策略，以打击这种日益抗生素和重要病原体。