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.

项目总结 生殖支原体(MG)是一种新出现的生殖道病原体，具有重要的公共卫生意义。 这种性传播细菌会引起类似于淋球菌和衣原体的疾病谱。 沙眼，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 对抗生素产生抗药性，在美国，一些感染完全无法用推荐的疗法治疗。这个 最近FDA批准了MG诊断测试，这肯定会提高公众对MG的认识，并要求 以改善治疗方法。MG感染的一个特征是长期持续存在，尽管存在特定的 生殖道中的抗体。在过去的十年里，我们的实验室一直专注于 免疫优势的mgpB和mgpC黏附蛋白以及对它们的局部和系统抗体反应 在感染过程中的蛋白质。我们证明了mgpB和mgpC经历了相变和抗原变异 MgpBC表达位点和存档的部分拷贝之间的独特同源重组系统 在染色体上。我们建议把这些研究扩展至以下三项最新进展：(1) 确定了包括唾液酸结合口袋的镁蛋白结构，(2)我们详细的 MG感染者纵向标本抗体反应性和抗原性变异分析 男性，包括有证据表明，保守的MgpC C-末端区域包含靶向的主要抗原 通过患者抗体，以及(3)MG281免疫球蛋白结合蛋白的发现 发病机制尚不清楚。将使用工程缺失和丙氨酸来定义MgpC-末端表位 用ELISA法和表面等离子体子共振(SPR)分析取代，以探索热力学和 抗体结合的动力学。补体杀伤和吞噬细胞试验将定位靶点 杀菌抗体。定义患者血清识别的MgpC表位将有助于改进的血清学测试， 探讨MG与女性严重上生殖道后遗症的关系。作为唾液酸 酸结合口袋被嵌入在镁C的可变区，我们将测量唾液酸结合的变化 不同变异体之间的亲和力，以及变异体特异性抗体对唾液酸结合和黏附的影响。 了解MG281在避免抗MG抗体生物活性中的作用是MG的首要任务 尤其是在MG与天然免疫效应器的相互作用方面，研究尚未明确。因此，我们的 第三个目标将把目标1和目标2的发现联系起来，以确定MG281是否通过特定的 MG(+)男性血清和MG(+)女性宫颈阴道分泌物中的抗体。这些实验，沿着 凭借我们的新方法，在支原体研究的困难领域开创了实验方法，将 鼓励改进预防战略，以抗击这种日益抗药性和重要的病原体。