Protective immunity elicited by distinct polysaccharide antigens of classical and hypervirulent Klebsiella

经典和高毒力克雷伯氏菌的不同多糖抗原引发的保护性免疫

• 批准号: 10795212
• 负责人: David A. Rosen
• 金额: $ 66.9万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2028-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10795212
• 关键词: Animals; Antibiotic Resistance; Antibodies; Antibody Response; Antigens; Bacteremia; Bacteria; Bacteriology; Binding; Biological Assay; Carrier Proteins; Cells; Cessation of life; Communities; Complement; Conjugate Vaccines; DNA Sequence Alteration; Data; Dependence; Development; Dose; Effectiveness; Encapsulated; Engineering; Enrollment; Enzyme-Linked Immunosorbent Assay; Escherichia coli; Europe; Exhibits; Goals; Hospitalization; Human; Humoral Immunities; Immune Sera; Immune response; Immune system; Immunity; Immunization; Immunize; Immunoelectron Microscopy; Immunofluorescence Microscopy; Immunoglobulin G; Infection; Infection prevention; Interferometry; Klebsiella; Klebsiella pneumoniae; Licensing; Link; Liver Abscess; Measures; Meningitis; Modeling; Monitor; Multi-Drug Resistance; Mus; Names; O Antigens; Organism; Ozone; Parents; Pathogenesis; Patients; Pneumonia; Polysaccharides; Pulmonary Challenge; Recombinants; Research Personnel; Sepsis; Serum; Specificity; Structure; Surface; Techniques; Testing; Time; Transmission Electron Microscopy; Urinary tract infection; Vaccinated; Vaccination; Vaccines; Virulent; Work; adaptive immune response; bactericidal immunity; bactericide; capsule; carbapenem resistance; chemical conjugate; cross immunity; efficacy evaluation; experimental study; healthcare-associated infections; human pathogen; in vivo; inhibiting antibody; inhibitor; longitudinal human study; manufacturing process; mouse model; mutant; novel; participant enrollment; pathogen; prevent; relative effectiveness; resistant Klebsiella pneumoniae; response; sugar; transmission process; vaccine access; vaccine development; vaccine failure; vaccine formulation

PROJECT SUMMARY This project will enhance our understanding of the humoral immune response to Klebsiella pneumoniae (Kp) and its polysaccharide antigens with the long-term goal of guiding and optimizing broad vaccine development. Kp infections, including pneumonia, urinary tract infection, and bacteremia, are sharply on the rise among hospitalized patients; CDC has declared infections with Kp and other carbapenem-resistant Enterobacteriales (CRE) demand a threat level of urgent. Beyond classical Kp typically seen in the US, emerging hypervirulent Kp strains, capable of causing liver abscess, bacteremia, and meningitis in healthy hosts, are spreading globally. This work builds on the PI's background in bacteriology, Gram-negative bacterial pathogenesis, and modeling of host adaptive immune responses, to investigate antibodies targeting Kp's polysaccharide capsule (K-type) and O-antigen. We have found that, while mice are able to produce antibodies targeting Kp capsule and O- antigen, capsule may directly interfere with O-antibody binding and killing of Kp. With our collaborators at Omniose, we have developed and are testing novel bioconjugate vaccines targeting the most prevalent K- and O-types. Bioconjugation is an alternative manufacturing process that uses recombinant E. coli strains to concurrently produce the capsule or O-antigen and an engineered carrier protein, and to enzymatically link the two. We have produced multiple K- and O-bioconjugates that have demonstrated promising efficacy in mice. As both O- and K- vaccines are under development, we will use our novel bioconjugate vaccines in murine protection experiments to determine the relative effectiveness of O-antigen or K-antigen bioconjugates against classical and hypervirulent Kp isolates. Further, we will challenge O-immunized mice with strains of closely related O-antigen structural subtypes that have not been included to date in vaccine formulations being developed commercially. Potential masking of O-antigen by capsule will be determined through mouse serum IgG ELISAs. Serum bactericidal assays (SBAs) and opsonophagocytic killing assays (OPKAs) will be developed and correlated with murine protection. Further, with bacterial mutants, complemented strains, and capsule inhibitors, we will determine the specificity of Kp O-antibody inhibition by capsule, utilizing multiple techniques including biolayer interferometry, immunofluorescence microscopy, and transmission immunoelectron microscopy. Finally, we will perform a first-ever longitudinal study of human patients with Kp infection, analyzing their sera for antibodies specific to Kp polysaccharides and their functional activity against the inciting Kp strain. At the conclusion of these studies, the relative efficacy of both K- and O-type bioconjugate vaccines will be determined, cross-protection among O-antigen subtypes will be resolved, correlates of protective immunity will be established, and mechanisms of O-antigen masking will be defined. Our results will illuminate human antibody responses to Kp infection and guide vaccine development to target this worrisome pathogen.

项目概要 该项目将增强我们对肺炎克雷伯菌 (Kp) 和体液免疫反应的了解 其多糖抗原的长期目标是指导和优化广泛的疫苗开发。钾 感染，包括肺炎、尿路感染和菌血症，在人群中急剧上升 住院病人； CDC 已宣布感染 Kp 和其他耐碳青霉烯类肠杆菌 (CRE) 要求威胁级别为紧急。除了美国常见的经典 Kp 之外，新兴的高毒力 Kp 能够在健康宿主中引起肝脓肿、菌血症和脑膜炎的菌株正在全球传播。 这项工作建立在 PI 在细菌学、革兰氏阴性细菌发病机制和建模方面的背景基础上 宿主适应性免疫反应，研究针对 Kp 多糖胶囊（K 型）的抗体 和O-抗原。我们发现，虽然小鼠能够产生针对 Kp 胶囊和 O- 抗原、荚膜可直接干扰O-抗体结合并杀伤Kp。与我们的合作者 Omniose，我们已经开发并正在测试针对最流行的 K-和 O型。生物共轭是一种替代制造工艺，使用重组大肠杆菌菌株来 同时产生荚膜或O-抗原和工程载体蛋白，并通过酶促连接 二。我们已经生产了多种 K-和 O-生物结合物，并在小鼠中证明了有希望的功效。 由于 O 疫苗和 K 疫苗都在开发中，我们将在小鼠中使用我们的新型生物结合疫苗 保护实验以确定 O 抗原或 K 抗原生物结合物的相对有效性 经典和高毒力 Kp 分离株。此外，我们将用密切相关的菌株来挑战 O 免疫小鼠。 迄今为止尚未包含在疫苗配方中的相关 O 抗原结构亚型 商业化开发。胶囊对 O 抗原的潜在掩蔽将通过小鼠血清测定 IgG ELISA。将开发血清杀菌测定（SBA）和调理吞噬杀灭测定（OPKA） 并与小鼠保护相关。此外，利用细菌突变体、补充菌株和荚膜 抑制剂，我们将利用多种技术确定胶囊对 Kp O 抗体抑制的特异性 包括生物层干涉测量、免疫荧光显微镜和透射免疫电子 显微镜。最后，我们将对 Kp 感染人类患者进行首次纵向研究，分析 他们的血清中含有针对 Kp 多糖的特异性抗体及其针对刺激性 Kp 菌株的功能活性。 根据这些研究的结论，K 型和 O 型生物结合疫苗的相对功效将是 一旦确定，O抗原亚型之间的交叉保护将得到解决，保护性免疫的相关性将得到解决 建立，并定义 O 抗原掩蔽机制。我们的结果将阐明人类抗体 对 Kp 感染的反应并指导针对这种令人担忧的病原体的疫苗开发。