Functional Antibody Repertoire Against S. aureus Leukocidins after Invasive Human Infection

人类侵袭性感染后针对金黄色葡萄球菌杀白细胞素的功能性抗体库

• 批准号: 10092085
• 负责人: Isaac P Thomsen
• 金额: $ 72.24万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-16 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10092085
• 关键词: Active Immunotherapy; Activities of Daily Living; Acute; Address; Affinity; Age; Animal Model; Antibiotic Resistance; Antibodies; Antibody Diversity; Antibody Repertoire; Antibody Response; Antigens; Binding Sites; Biological Assay; Blood; Cellular Immunity; Characteristics; Child; Childhood; Clinical; Complement; Deposition; Disease; Enrollment; Evaluation; Fc domain; Genus staphylococcus; Goals; Human; Humoral Immunities; ITGAM gene; Immune Evasion; Immune response; Immune system; In Vitro; Infection; Intervention; Investigation; Knowledge; Laboratories; Leucocidin; Mediating; Modeling; Monoclonal Antibodies; Organism; Passive Immunotherapy; Pediatric Hospitals; Phagocytes; Phagocytosis; Prospective cohort; Research Personnel; Role; Sepsis; Series; Specificity; Staphylococcal Infections; Staphylococcus aureus; Staphylococcus aureus infection; Targeted Toxins; Testing; Time; Tissues; Toxicity Tests; Toxin; Vaccines; Validation; Virulence; Virulence Factors; Whole Blood; Work; antitoxin; base; cohort; design; efficacy testing; experience; human disease; human monoclonal antibodies; leukotoxin; mouse model; neutralizing antibody; neutralizing monoclonal antibodies; new therapeutic target; novel; novel therapeutic intervention; pathogen; pathogenic bacteria; pre-clinical; preclinical study; prospective; response; tertiary care; therapeutic candidate; therapeutic target; vaccine candidate

PROJECT SUMMARY / ABSTRACT Staphylococcus aureus is now the most common invasive bacterial pathogen in children in the US, and antibiotic resistance rates continue to increase. Novel targets and approaches are needed if a safe and effective S. aureus vaccine is to become a reality. Optimal targets of intervention against S. aureus, a highly human-specific pathogen, may be identified most effectively by defining the antigens that contribute to invasive human infections. LukAB, a secreted leukotoxin, is produced by S. aureus in the setting of invasive human disease and is essential for immune evasion by the pathogen in a variety of models. We have purified a series of potently neutralizing human monoclonal antibodies (mAbs) targeting LukAB, which have broad neutralizing capacity, distinct binding sites and mechanisms of activity, and efficacy in a murine model of sepsis. The overall goals of this proposal are twofold: first, to test the hypothesis that key aspects of the human anti-leukocidin adaptive response include both mechanisms of toxin neutralization and the function of non-neutralizing antibodies targeting these toxins; second, to test the hypothesis that a selected combination of mAbs with distinct functions will most potently inhibit toxin-mediated staphylococcal immune evasion. Careful validation of the anti-leukocidin antibody response in rigorous models will allow for the evaluation of human mAbs as candidate agents of intervention against S. aureus. The proposed studies will define the diversity of the naturally occurring antibody repertoire to S. aureus leukocidins following natural human infection, given their importance in virulence and promise as targets of intervention. This will be accomplished by: 1) Characterizing the diversity and functional capacity of naturally occurring human antibodies targeting the staphylococcal leukocidins following invasive pediatric infection; 2) Elucidating the role of non-neutralizing antibodies specific to S. aureus leukocidins, including antibody-dependent complement deposition and phagocytosis; and 3) Determining the critical components of the anti-leukocidin adaptive response against S. aureus in human blood. We will leverage our existing workflow for the purification and characterization of neutralizing mAbs from prospectively enrolled children with invasive and non-invasive S. aureus infections at a major tertiary care children’s hospital. A panel of human mAbs will be created to allow the investigation of diverse mechanisms of neutralization, cross-toxin activity, and other important functions. The proposed aims will define, for the first time, the breadth of mechanisms by which the human host response targets and neutralizes S. aureus leukocidins during invasive human disease. Together these studies address a critical need for novel anti-S. aureus strategies. This work is designed to produce rationally selected candidates for anti-staphylococcal interventions based on our knowledge of important antigens expressed during human disease, obtained from children with S. aureus infections, to be tested for efficacy in humanized animal models in immediately subsequent work.

项目概要/摘要 金黄色葡萄球菌现在是美国儿童中最常见的侵入性细菌病原体，并且 如果安全且有效，则需要新的目标和方法。 有效的金黄色葡萄球菌疫苗将成为针对金黄色葡萄球菌干预的最佳目标。 人类特有的病原体，可以通过定义有助于侵入性的抗原来最有效地识别 LukAB 是一种分泌性白细胞毒素，由金黄色葡萄球菌在侵入人类的环境中产生。 我们已经纯化了一系列模型，并且对于病原体的免疫逃避至关重要。 靶向 LukAB 的强效中和人单克隆抗体 (mAb)，其具有广泛的中和作用 能力、不同的结合位点和活性机制，以及在败血症小鼠模型中的功效。 该提案的总体目标有两个：首先，检验以下假设：人类的关键方面 抗白细胞杀素适应性反应包括毒素中和机制和杀白细胞素功能 针对这些毒素的非中和抗体；第二，检验选定的假设 具有不同功能的单克隆抗体的组合将最有效地抑制毒素介导的葡萄球菌 在严格的模型中仔细验证抗白细胞杀素抗体反应将允许 人类单克隆抗体作为金黄色葡萄球菌干预候选药物的评估。 将定义自然发生的金黄色葡萄球菌杀白细胞素抗体库的多样性 考虑到它们的毒力和作为干预目标的前景，人类感染将成为可能。 通过以下方式完成： 1) 表征自然存在的人类的多样性和功能能力 侵袭性儿科感染后针对葡萄球菌杀白细胞素的抗体 2) 阐明其作用； 金黄色葡萄球菌杀白细胞素特异性的非中和抗体，包括抗体依赖性补体 3) 确定抗杀白细胞素适应性的关键成分 我们将利用现有的工作流程进行纯化和对抗人类血液中的金黄色葡萄球菌。 前瞻性入组的侵袭性和非侵袭性金黄色葡萄球菌儿童的中和单克隆抗体的表征 一家大型三级护理儿童医院将创建一组人类单克隆抗体，以应对金黄色葡萄球菌感染。 研究不同的中和机制、交叉毒素活性和其他重要功能。 拟议的目标将首次定义人类宿主反应机制的广度 这些研究共同解决了侵袭性人类疾病期间的金黄色葡萄球菌杀白细胞素的问题。 迫切需要新的抗金黄色葡萄球菌策略。 根据我们对表达的重要抗原的了解，提出抗葡萄球菌干预措施的候选者 在人类疾病期间，从金黄色葡萄球菌感染的儿童中获得，以测试人源化的功效 立即进行后续工作的动物模型。