Serogroup 19 capsule maleability leading to vaccine failure

血清群 19 胶囊的雄性能力导致疫苗失败

• 批准号: 10723991
• 负责人: Moon H. Nahm
• 金额: $ 18.56万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-17 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10723991
• 关键词: Affect; Alleles; Amino Acid Substitution; Amino Acids; Anabolism; Antibodies; Antibody Response; Appearance; Bacteria; Bacterial Capsules; Binding; Biochemical; Bioinformatics; Biological; Carbohydrates; Cell surface; Cessation of life; Clinical; Conjugate Vaccines; Cytoplasm; Databases; Disease; Effectiveness; Foundations; Future; Genetic; Genetic Polymorphism; Genomics; Goals; Human; Immune response; Immunity; Immunization; Immunize; Immunologics; In Vitro; Individual; Infection; Integration Host Factors; Investigation; Length; Link; Lipopolysaccharides; Mediating; Medical; Membrane; Methods; Modeling; Molecular; Mutagenesis; Mutation; Outcome; Pathway interactions; Persons; Play; Polymerase; Polysaccharides; Population; Property; Proteins; Reporting; Research; Role; Serotyping; Site; Specificity; Streptococcus pneumoniae; Structure; Surface; Testing; Trisaccharides; Vaccinee; Vaccines; Variant; Virulence; breakthrough infection; burden of illness; capsule; clinically relevant; design; experience; fitness; gene function; genetic variant; improved; microbial; novel; pathogen; pathogenic bacteria; preservation; success; tool; trait; vaccine evaluation; vaccine failure; vaccine-induced immunity; Affect; Alleles; Amino Acid Substitution; Amino Acids; Anabolism; Antibodies; Antibody Response; Appearance; Bacteria; Bacterial Capsules; Binding; Biochemical; Bioinformatics; Biological; Carbohydrates; Cell surface; Cessation of life; Clinical; Conjugate Vaccines; Cytoplasm; Databases; Disease; Effectiveness; Foundations; Future; Genetic; Genetic Polymorphism; Genomics; Goals; Human; Immune response; Immunity; Immunization; Immunize; Immunologics; In Vitro; Individual; Infection; Integration Host Factors; Investigation; Length; Link; Lipopolysaccharides; Mediating; Medical; Membrane; Methods; Modeling; Molecular; Mutagenesis; Mutation; Outcome; Pathway interactions; Persons; Play; Polymerase; Polysaccharides; Population; Property; Proteins; Reporting; Research; Role; Serotyping; Site; Specificity; Streptococcus pneumoniae; Structure; Surface; Testing; Trisaccharides; Vaccinee; Vaccines; Variant; Virulence; breakthrough infection; burden of illness; capsule; clinically relevant; design; experience; fitness; gene function; genetic variant; improved; microbial; novel; pathogen; pathogenic bacteria; preservation; success; tool; trait; vaccine evaluation; vaccine failure; vaccine-induced immunity

Streptococcus pneumoniae (the “pneumococcus”) is an important human commensal pathogen. A key determinant of pneumococcal fitness and virulence is its ability to produce a protective polysaccharide (PS) capsule which can take the form of >100 biochemically distinct “serotypes”. Pneumococcal capsule PS conjugate vaccines (PCVs) induce protective antibodies that mediate opsonophagocytic killing (OPK) of pneumococci and have effectively reduced the global burden of disease caused by serotypes included in vaccines. Despite this success, immunized people occasionally experience breakthrough infections by PCV serotypes, and the cause for these cases of “vaccine failure” remains unclear. Investigation of vaccine failure has largely focused on host factors and ineffective antibody response, while microbiological aspects have gone largely unaddressed. Furthermore, closely-related serotypes 19A and 19F are the serotypes most commonly implicated in vaccine failure cases, but few studies have evaluated their role in this phenomenon. Appreciating the breadth of capsule malleability and its impact on clinical outcomes, we are examining a potential link between serotype 19A/19F capsule variants, evasion of anti-capsule immune responses, and vaccine failure. Preliminary analyses identified multiple candidate mechanisms through which polymorphisms in the 19A/19F capsule polymerase Wzy can mediate considerable capsule variability while preserving most capsule features. We also found a strain that was serotyped as “19F” by conventional methods, but in fact produces a novel capsule PS structure, herein called 19x. Thus, the full diversity of 19A/19F-like capsule types is yet to be defined. As even small changes in capsule structure can abrogate cross-protective immunity, it is possible that some variants, which are indistinguishable from 19A/19F pneumococci in conventional serotyping methods, can nonetheless evade OPK by anti-19A/19F capsule antibodies in vaccinated individuals and, thus, spur the vaccine failure attributed to these serotypes. In this R21 proposal, we will perform directed mutagenesis to test the impact of Wzy polymorphisms on 19A/19F capsules structure and test the effect of these putative capsule changes on evading anti-capsule antibody-mediated OPK in vitro (Aim 1). We will also structurally/genetically/antigenically characterize the novel 19x capsule type and perform bioinformatics analysis of expansive genomic databases with the goal of identifying other putative capsule variants found among immunized populations (Aim 2). Importantly, tools and concepts developed here will fuel future investigation of the impact capsule PS malleability has in additional pneumococcal serotypes and other medically important bacterial pathogens that employ similar pathways for glycan synthesis. Independent of glycobiological advances, elucidation of the molecular basis of 19A/19F Wzy enzymatic specificity would immediately improve the precision of the molecular typing strategies.

肺炎链球菌（“肺炎球菌”）是一种重要的人类共生病原体。钥匙 肺炎球菌适应性和病毒的决定因素是其产生受保护的多糖（PS）的能力 胶囊可以采用> 100种生化不同的“血清型”的形式。肺炎球囊PS 共轭疫苗（PCV）诱导介导opsoponophocytic杀死（OPK）的受保护抗体 肺炎球菌，并有效地减少了由包括在 疫苗。尽管取得了成功，免疫抑制的人偶尔会经历PCV的突破性感染 血清型和这些“疫苗衰竭”病例的原因尚不清楚。疫苗衰竭的调查 主要集中在宿主因素和无效的抗体反应上，而微生物学方面已经消失了 在很大程度上没有解决。此外，密切相关的血清型19a和19f是最常见的血清型 在疫苗衰竭病例中实施，但很少有研究评估其在这种现象中的作用。 欣赏胶囊可延展性的广度及其对临床结果的影响，我们正在研究 血清型19a/19f胶囊变体之间的潜在联系，抗封装免疫反应的演变和 疫苗衰竭。初步分析确定了多种多态性的多种候选机制 在19a/19f胶囊聚合酶中，wzy可以介导相当大的胶囊变异性，同时保留大多数 胶囊特征。我们还发现了一种通过常规方法将血清型为“ 19f”的菌株，但实际上 产生一种新型的胶囊PS结构，称为19倍。这是19a/19f的胶囊类型的全部多样性 尚未定义。由于胶囊结构的微小变化也可以消除交叉保护 免疫力，有可能与19a/19f肺球无可分割的变体中的某些变体 传统的血清分型方法，尽管可以通过抗19a/19f胶囊抗体逃避OPK 接种疫苗的个体，因此刺激了归因于这些血清型的疫苗失败。 在此R21提案中，我们将执行定向诱变，以测试WZY多态性对 19a/19f胶囊结构并测试这些推定胶囊变化对逃避抗胶囊的影响 体外抗体介导的OPK（AIM 1）。我们还将在结构/遗传/抗原上表征 新颖的19x胶囊类型并对额外基因组数据库进行生物信息学分析，目的 识别免疫种群中发现的其他推定胶囊变体（AIM 2）。重要的是，工具和 此处开发的概念将推动对影响胶囊PS延纹性的未来投资。 肺炎球菌血清型和其他医学上重要的细菌病原体，这些病原体具有相似的途径 聚糖合成。独立于糖生物学进展，阐明19a/19f Wzy的分子基础 酶促特异性将立即提高分子型策略的精度。