Protective antibody in streptococcal infection models

链球菌感染模型中的保护性抗体

• 批准号: 10576491
• 负责人: Debra E BESSEN
• 金额: $ 59.39万
• 依托单位: NEW YORK MEDICAL COLLEGE
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-12-02 至 2027-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10576491
• 关键词: Abbreviations; Accounting; Active immunity; Adult; Age; Animal Model; Animals; Antibodies; Antibody-mediated protection; Antigen Targeting; Antigens; Autoimmune Diseases; Bacteria; Binding; Biological; Carbohydrates; Cessation of life; Child; Childhood; Clinical Trials; Collection; Colony-forming units; Complex; Data; Development; Disease; Disease model; Dose; Elements; Epidemiological trend; Epithelium; Equation; Exhibits; Failure; Fibronectins; Future; General Practitioners; Goals; Habitats; Human; Immune response; Immunity; Immunize; Immunodeficient Mouse; Immunoglobulins; Immunologic Deficiency Syndromes; Impetigo; Incidence; Infection; Lead; Life; Lymphoid Tissue; Measures; Modeling; Morbidity - disease rate; Mus; Nose; Organ; Passive Immunity; Passive Immunization; Pharyngeal structure; Physiological; Plasminogen; Predisposition; Resources; Rest; Route; Secretory Immunoglobulin A; Serology; Serum; Severe Combined Immunodeficiency; Skin; Skin Tissue; Soft Tissue Infections; Source; Specialist; Specificity; Specimen; Standardization; Streptococcal Infections; Streptococcal Vaccines; Streptococcus; Streptococcus pyogenes; Streptolysins; Surface; Swab; Testing; Upper Respiratory Infections; Upper respiratory tract; Vaccines; Virulence; Virulence Factors; Work; comparison group; flexibility; human disease; human subject; human tissue; humanized mouse; immunodeficient mouse model; immunoreactivity; improved; longitudinal, prospective study; mortality; mouse model; multiple myeloma M Protein; novel; pathogen; preclinical development; protective efficacy; relative effectiveness; screening; transmission process; vaccine candidate; vaccine development; wound

ABSTRACT The initial contact between newly transmitted group A streptococci (GAS) and its human host can be readily thwarted by antibody (Ab) directed to the appropriate GAS antigens (Ags). To best simulate this microenvironment, physiological (i.e., low) inoculum doses of GAS are essential. The goal of this proposal is to identify Ags, alone and in combinations representing multicomponent vaccines, that are the most effective targets of Ab-mediated immunity and collectively can provide worldwide coverage against all GAS strains. The underlying rationale for the proposed approach rests on two principles: That serum obtained from children just prior to a new GAS infection lacks protective Ab, and that serum obtained from most adults has at least low levels of persisting protective Ab. The latter is based on the very low incidence of GAS infection in adults, likely the result of protective immunity that developed following repeated infections earlier in life. Hypotheses on protective Ag-specific Ab generated from analysis of pediatric serum (aim 1) are experimentally tested in mice (aim 2). Pre-infection pediatric serum is analyzed for lack of protective Ab to leading vaccine candidates. Adult serum is used as a source for purified immunoglobulin (Ig) specific to the vaccine target Ags missing in susceptible children. Immunodeficient mice are passively immunized with the Ag-specific Ig purified from adults and challenged with low infective doses of GAS. The Ag-specific Ig that confers protection in mice equates to a human serum-based correlate of protection (CoP). Four major forms of GAS disease are modeled in mice and evaluated for protective immunity: upper respiratory tract infection, impetigo, skin and soft tissue infection and invasive disease. GAS from all three major subpopulations of strains are tested: throat specialists, skin specialists and generalists. The Ag targets evaluated are leading vaccine candidates and include broadly and semi-conserved Ags as well as surface and secreted Ags. If successful, this work will identify a collection of Ag targets that can serve as the basis for global protection. It will also deliver two new standardized platforms – screening of pre-infection human serum Ab to GAS Ags and improved mouse models - for future identification and straightforward comparison of additional GAS vaccine candidates.

抽象的 新传播的 A 族链球菌 (GAS) 与其人类宿主之间的初次接触很容易 受到针对适当 GAS 抗原 (Ags) 的抗体 (Ab) 的阻碍，以最好地模拟这一点。 微环境中，GAS 的生理（即低）接种剂量至关重要。 确定代表多组分疫苗的单独或组合的最有效的抗原 Ab 介导的免疫目标，共同可以提供针对所有 GAS 菌株的全球覆盖。 该方法的基本原理基于两个原则： 从儿童身上获得的血清 在新的 GAS 感染之前缺乏保护性抗体，并且从大多数成年人获得的血清至少含有 低水平的持久保护性抗体是基于成人 GAS 感染的发生率非常低， 可能是生命早期反复感染后产生的保护性免疫力的结果。 对儿科血清分析产生的保护性 Ag 特异性抗体（目标 1）进行了实验测试 分析小鼠（目标 2）感染前的儿科血清是否缺乏针对主要候选疫苗的保护性抗体。 成人血清用作纯化免疫球蛋白 (Ig) 的来源，该免疫球蛋白特异性针对疫苗中缺失的目标 Ag。 使用从成年小鼠中纯化的 Ag 特异性 Ig 对免疫缺陷小鼠进行被动免疫 并用低感染剂量的 GAS 进行攻击，为小鼠提供保护的 Ag 特异性 Ig 相当于 基于人血清的保护相关性（CoP）。 在小鼠中建立了四种主要形式的 GAS 疾病模型并评估其保护性免疫： 呼吸道感染、脓疱病、皮肤软组织感染和侵袭性疾病均来自GAS。 测试主要菌株亚群：喉咙专家、皮肤专家和Ag目标。 评估是领先的候选疫苗，包括广泛和半保守的抗原以及表面和 如果成功，这项工作将确定一系列可作为基础的 Ag 目标。 它还将提供两个新的标准化平台——感染前人血清筛查。 GAS Ags 抗体和改进的小鼠模型 - 用于未来识别和直接比较 其他候选 GAS 疫苗。