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.

项目概要 该研究项目将增强我们对 O 抗原引发的免疫反应的理解 肺炎克雷伯菌 (Kp)，假定疫苗开发的重要目标。本次活动的长远目标 该提案是为了进一步了解由两种亚型引起的先天性和适应性免疫反应 常见血清群O2为Kp、O2v1和O2v2。我们试图了解如何添加单个 相对于 O2v1，O2v2 的支链半乳糖改变了其细菌适应性和宿主免疫敏感性。 此外，我们将确定这两种亚型之间的交叉反应性以及是否感染或接种疫苗 一种亚型具有针对另一种亚型的交叉保护作用，这些信息对于疫苗的设计至关重要 广泛针对这种日益耐药的生物体。 Kp 感染，包括肺炎、尿路感染 住院患者中感染和血流感染急剧上升；美国疾病控制与预防中心 (CDC) 已宣布 Kp 和其他碳青霉烯类耐药肠杆菌感染需要紧急威胁级别。 该项目以 PI 在细菌学、感染小鼠模型和发病机制研究方面的背景为基础 革兰氏阴性菌，特别关注 Kp 毒力因子 O 抗原和宿主 免疫原性反应。我们之前已经证明，使用针对 Kp 的生物结合疫苗是 有益于预防疾病，并寻求增加我们对未来的理解和覆盖范围 疫苗。 Kp 历史上有十一个已知的 O 抗原血清群。最近，额外的 O 抗原亚型 这些血清群中的病毒已被鉴定。然而，致病适应性、免疫原性、功能性方面的差异 抗体反应和相关亚型之间的交叉保护尚不清楚。 我们构建了表达 O 抗原亚型 O2v2 的经典 Kp 菌株的突变体，以产生 表达 O2v1 的其他等基因菌株。我们将测试这些细菌是否表现出相似的表型表达 通过测量荚膜、高粘膜粘度、菌毛和生物膜来确定毒力因子。一个完善的小鼠 将利用肺炎模型来确定肺部健康状况并描绘宿主先天免疫 对每种病原体的反应。中性粒细胞和补体介导的细菌杀灭测定将用于 进一步探索细菌对先天免疫攻击的抵抗力，文献表明这种抵抗力可能会增强 O2v2 菌株。接下来，我们将进行一系列实验来测试O2v1和O2v2是否具有交叉保护作用。使用 经典免疫学技术，包括 ELISA 和流式细胞术，我们将确定 IgG 亚类 以及由这些病原体呼吸道感染引起的效应细胞因子。最后，使用新颖的 O2v1 或 O2v2 生物结合疫苗，然后用 O2v1 或 O2v2 菌株进行攻击，我们将评估交叉保护 对抗肺炎引起的体重减轻和死亡。我们将使用血清进一步表征抗体功能 杀菌和调理吞噬杀灭试验。这些研究将极大地增进我们对 对 Kp O 抗原的免疫反应，有助于设计对抗这种病原体的疫苗。