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.

项目概要 生殖支原体（MG）是一种新兴的生殖道病原体，引起重大公共卫生问题。 这种性传播细菌会引发类似于淋病奈瑟菌和衣原体的疾病谱 沙眼衣原体，但在某些临床环境中可能更为普遍。令人担忧的是，MG 正变得越来越 对抗生素有耐药性，某些感染在美国采用推荐的治疗方案是完全无法治疗的。这 FDA 最近批准了 MG 诊断测试，这肯定会提高公众对 MG 的认识，并要求 以改善治疗。 MG 感染的一个特点是尽管存在特定的病原体，但仍长期持续存在。 生殖道中的抗体。在过去的十年中，我们的实验室一直致力于研究 免疫显性 MgpB 和 MgpC 粘附蛋白，以及对这些蛋白的局部和全身抗体反应 感染期间的蛋白质。我们证明 MgpB 和 MgpC 通过以下方式经历相和抗原变异： mgpBC 表达位点和存档的部分副本之间独特的同源重组系统 在染色体中。我们建议通过最近的三项进展来扩展这些研究：（1） 确定 MgpC 蛋白质结构，其中包括唾液酸结合袋，(2) 我们详细 分析 MG 感染者纵向标本中的抗体反应性和抗原变异 男性，包括 MgpC 保守 C 末端区域含有靶向显性抗原的证据 (3) MG281 免疫球蛋白结合蛋白的发现，其作用 发病机制尚未探索。 MgpC C 末端表位将使用工程删除和丙氨酸来定义 通过 ELISA 和表面等离子共振 (SPR) 分析取代，以探索热力学和 抗体结合动力学。补体杀伤和调理吞噬作用测定将定位目标 杀菌抗体。定义患者血清识别的 MgpC 表位将为改进血清学测试提供信息， 对于探索 MG 与女性严重上生殖道后遗症的关系至关重要。由于唾液酸 酸结合袋嵌入 MgpC 的可变区，我们将测量唾液酸结合的变化 不同变体的亲和力，以及变体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 抗体生物活性方面的作用是 MG 治疗的首要任务 研究尤其是 MG 与先天免疫效应器的相互作用尚未明确。因此，我们的 第三个目标将把目标 1 和 2 的结果联系起来，以确定 MG281 是否可以通过特定的方式预防杀戮。 MG(+)男性血清和MG(+)女性宫颈阴道分泌物中存在抗体。这些实验，沿着 通过我们的新颖方法，为支原体研究这一困难领域开创性的实验方法，将 激发改进的预防策略来对抗这种日益耐药的重要病原体。