Immune recognition of Klebsiella pneumoniae O2v1 and O2v2 O-antigen subtypes

肺炎克雷伯菌 O2v1 和 O2v2 O 抗原亚型的免疫识别

• 批准号: 10739041
• 负责人: David A. Rosen
• 金额: $ 23.33万
• 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: 2023-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10739041
• 关键词: Accounting; Acute; Affect; Antibiotic Resistance; Antibiotic-resistant organism; Antibiotics; Antibodies; Antibody Response; Antigens; Bacteria; Bacteriology; Biological Assay; Body Weight decreased; Cessation of life; Clinical; Complement; Conjugate Vaccines; Development; Disease; Enzyme-Linked Immunosorbent Assay; Europe; Exhibits; Flow Cytometry; Future; Galactans; Galactose; Glycosyltransferase Gene; Goals; Gram-Negative Bacteria; Hospitalization; Hospitals; Human; Humoral Immunities; Immune; Immune response; Immunization; Immunoglobulin G; Immunologic Techniques; In Vitro; Infection; Infection prevention; Innate Immune Response; Klebsiella pneumoniae; Knowledge; Lipopolysaccharides; Literature; Lung; Measures; Mediating; Microbial Biofilms; Monitor; Mus; Natural Immunity; O Antigens; Organism; Ozone; Pathogenesis; Pathogenicity; Patients; Phagocytosis; Phase I Clinical Trials; Phenotype; Pneumonia; Polysaccharides; Predisposition; Production; Research Project Grants; Research Project Summaries; Resistance; Respiratory System; Respiratory Tract Infections; Sepsis; Serum; Structure; Surface; Testing; Urinary tract infection; Vaccinated; Vaccination; Vaccine Design; Vaccines; Vertebral column; Virulence; Virulence Factors; Western Blotting; adaptive immune response; bacterial fitness; bacterial resistance; bactericide; capsule; carbapenem resistance; carbapenemase; combat; cross immunity; cross reactivity; cytokine; experimental study; fitness; healthcare-associated infections; immunogenic; immunogenicity; in vivo; innate immune function; interest; mortality; mouse model; mutant; neutrophil; novel; pathogen; pneumonia model; prevent; resistant Klebsiella pneumoniae; response; vaccine development

PROJECT SUMMARY This research project will enhance our understanding of the immune responses elicited by the O-antigen of Klebsiella pneumoniae (Kp), an important target in putative vaccine development. The long-term goal of this proposal is to further our knowledge of the innate and adaptive immune responses elicited by two subtypes of the common serogroup O2 of Kp, O2v1 and O2v2. We seek to understand how the addition of the single branched galactose of O2v2 changes its bacterial fitness and host immune susceptibility relative to O2v1. Further, we will determine cross-reactivity between these two subtypes and whether infection or vaccination with one subtype confers cross-protection against the other, information critical to the design of vaccines that can broadly target this increasingly antibiotic-resistant organism. Kp infections, including pneumonia, urinary tract infection, and bloodstream infection, are sharply on the rise among hospitalized patients; CDC has declared that infections with Kp and other carbapenem-resistant Enterobacteriales demand a threat level of urgent. This project builds on the PI's background in bacteriology, murine models of infection, and pathogenesis studies of Gram-negative bacteria, by focusing specifically on the Kp virulence factor O-antigen and the host immunogenic response. We have previously demonstrated that use of bioconjugate vaccines targeting Kp are beneficial in preventing disease and seek to increase our understanding and breadth of coverage of future vaccines. Kp historically has eleven known serogroups of O-antigen. Recently, additional O-antigen subtypes within these serogroups have been identified. Yet, differences in pathogenic fitness, immunogenicity, functional antibody response, and cross-protection between related subtypes are not well understood. We have constructed a mutant of a classical Kp strain expressing O-antigen subtype O2v2 to generate an otherwise isogenic strain expressing O2v1. We will test if these bacteria exhibit similar phenotypic expression of virulence factors by measuring capsule, hypermucoviscosity, fimbriae and biofilm. A well-established murine model of pneumonia will be leveraged to determine pulmonary fitness and delineate host innate immune response to each pathogen. Neutrophil and complement-mediated bacterial killing assays will be employed to further explore bacterial resistance to innate immune attack, which the literature indicates may be enhanced in O2v2 strains. Next, we will perform a range of experiments testing if O2v1 and O2v2 are cross-protective. Using classically immunological techniques including ELISA and flow cytometry, we will determine the IgG subclasses and effector cytokines elicited by respiratory tract infection with these pathogens. Lastly, using novel O2v1 or O2v2 bioconjugate vaccines followed by challenge with O2v1 or O2v2 strains, we will assess cross-protection against weight loss and mortality from pneumonia. We will further characterize antibody functionality using serum bactericidal and opsonophagocytic killing assays. These studies will significantly advance our understanding of immune response to Kp O-antigen and aid in vaccine design to combat this pathogen.

项目摘要 该研究项目将增强我们对O-antigen产生的免疫反应的理解 肺炎克雷伯菌（KP），推定疫苗开发的重要目标。这个长期目标 提议是为了进一步了解我们对两个亚型产生的先天和适应性免疫反应的了解 KP，O2V1和O2V2的常见血清群O2。我们试图了解单曲的添加方式 O2V2的分支半乳糖改变了其细菌适应性和相对于O2V1的宿主免疫敏感性。 此外，我们将确定这两种亚型之间的交叉反应性以及感染还是疫苗接种 一种亚型赋予另一个子类型，另一个子类型，对于可以设计的信息至关重要 广泛地针对这种日益抗生素的生物。 KP感染，包括肺炎，尿路 感染和血液感染急剧在住院的患者中急剧上升； CDC宣布 KP和其他耐碳青霉烯的感染需要紧急的威胁。 该项目建立在PI的细菌学，鼠类感染模型和发病机理研究的基础上 革兰氏阴性细菌的特殊聚焦于KP毒力因子O-抗原和宿主 免疫原性反应。我们以前已经证明，靶向KP的生物轭疫苗的使用是 有益于预防疾病并寻求提高我们对未来覆盖的理解和广度 疫苗。从历史上看，KP有11种已知的O-抗原血清群。最近，其他O-抗原亚型 在这些血清中，已经确定了。然而，致病能力，免疫原性，功能性差异 抗体反应和相关亚型之间的交叉保护尚不清楚。 我们已经构建了表达O-抗原亚型O2V2的经典KP菌株的突变体以生成一个 否则表达O2V1的同源菌株。我们将测试这些细菌是否表现出类似的表型表达 通过测量胶囊，超纤维粘度，纤维化和生物膜来毒力因子。一个公认的鼠 肺炎的模型将被利用以确定肺健身并描述宿主先天免疫 对每种病原体的反应。中性粒细胞和补体介导的细菌杀死测定法将用于 进一步探讨了对先天免疫攻击的细菌抗性，文献表明可能会增强 O2V2菌株。接下来，如果O2V1和O2V2是交叉保护，我们将执行一系列实验测试。使用 包括ELISA和流式细胞术在内的经典免疫学技术，我们将确定IgG亚类 和效应细胞因子通过这些病原体引起的呼吸道感染引起。最后，使用新颖的O2V1或 O2V2生物轭疫苗随后是O2V1或O2V2菌株的挑战，我们将评估交叉保护 反对肺炎的体重减轻和死亡率。我们将进一步表征使用血清的抗体功能 杀菌性和致吞杀虫剂杀伤测定法。这些研究将大大提高我们对 对KP O-抗原的免疫反应并有助于疫苗设计以对抗这种病原体。