Catalytic Antibodies To Staphylococcus Aureus: Identification and Characterizatio

金黄色葡萄球菌催化抗体：鉴定和表征

• 批准号: 7914338
• 负责人: ERIC L BROWN
• 金额: $ 22.5万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-14 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7914338
• 关键词: Abscess; Adhesions; Anatomic Sites; Anterior; Antibiotic Resistance; Antibiotics; Antibodies; Antigen-Antibody Complex; Antigens; Autoantibodies; Autoimmune Process; B-Lymphocytes; Bacteria; Bacterial Adhesion; Bacterial Infections; Binding; Biological Assay; Blood Circulation; Capsid Proteins; Catabolism; Catalysis; Catalytic Antibodies; Cleaved cell; Clinical; Communities; Community Hospitals; Development; Disease; Dissociation; Endocarditis; Enzymes; Excision; Family; HIV; HIV Envelope Protein gp120; Human; Hydrolysis; Immune; Immune system; Immunoglobulin G; Immunoglobulins; Immunologic Factors; Immunomodulators; Individual; Infection; Infectious Skin Diseases; Maps; Mediating; Microbe; Minor; Minority; Nose; Patients; Peptide Hydrolases; Peptides; Play; Pneumonia; Population; Predisposing Factor; Predisposition; Preparation; Protease Inhibitor; Proteins; Reaction; Recombinants; Reporting; Role; Serum; Site; Skin; Specificity; Staphylococcus aureus; Superantigens; Symptoms; System; Testing; Toxic effect; Toxin; Vestibule; Virulence; Virulence Factors; antigen binding; base; functional loss; human disease; human subject; in vitro Model; in vivo; methicillin resistant Staphylococcus aureus; microbial; microorganism antigen; pathogen; polypeptide; prevent; protective effect; protein function; public health relevance; resistant strain; response; single molecule; treatment strategy

DESCRIPTION (provided by applicant): We propose to test the hypothesis that catabolic antibodies play an important innate defense role in protecting against Staphylococcus aureus infections. S. aureus is an opportunistic pathogen that colonizes the skin (primarily the anterior nasal vestibule) of approximately 20-30% of the population without causing clinical symptoms. If, however, the skin is damaged, S. aureus can gain entry into the host and infections may result in a broad-range of conditions ranging from minor skin complications to lethal infections. Of growing concern are the steadily growing numbers of community-acquired methicillin-resistant S. aureus (CA-MRSA) infections in young, otherwise healthy people. Natural antibodies represent the spontaneous repertoire of circulating immunoglobulins in healthy, unimmunized individuals that form a part of the innate immune system, and they promote the clearance of pathogenic substances from the circulation and prevent pathogen dissemination. Proteolytic antibodies are immunoglobulins endowed with a capacity to catalyze the hydrolysis of polypeptide antigenic substrates, and they hold the potential of specific and efficient catabolism of polypeptides. A single molecule of a catabolic, proteolytic antibody can degrade thousands of antigen molecules. Moreover, the peptide bond cleavage reaction generally results in functional protein inactivation. In comparison, conventional antibodies act stoichiometrically (e.g., IgG binds at most 2 antigen molecules) and the binding is reversible, with the result that active antigen molecules are released upon dissociation of immune complexes. There is growing evidence that microbial antigens can also be targeted by catabolic antibodies. gp120, a coat protein of HIV, is shown to be cleaved by specific proteolytic antibodies that recognize the superantigenic site of gp120 (superantigen, i.e., an antigen recognized by antibodies present in the preimmune repertoire without the requirement for adaptive diversification of the antibody variable domains). To date, a role for catabolic antibodies in defense against bacterial infections has not been examined. In preliminary studies, we observed the cleavage of five important proteins expressed by S. aureus, Efb, protein A, LukF, Map and ClfA by antibody preparations from human subjects. In the present proposal, we will confirm this phenomenon using sera from patients defined by their S. aureus carriage state, characterize the proteolytic specificity and rates, and determine the effects of catalysis on virulence protein function. PUBLIC HEALTH RELEVANCE: S. aureus infections are a growing problem in both community and hospital settings and antibiotic resistant strains have complicated the available treatment strategies. This proposal aims to identify a family of antibodies that also serve as enzymes (catalytic) that cleave virulence factors associated with disease. Identification and characterization of these catalytic antibodies will result in the development of new preventative and treatment strategies against S. aureus infections.

描述(由申请人提供)：我们建议测试分解代谢抗体在预防金黄色葡萄球菌感染中发挥重要先天防御作用的假设。金黄色葡萄球菌是一种机会性病原体，在大约20%-30%的人群中定植于皮肤(主要是前鼻前庭)，而不会引起临床症状。然而，如果皮肤受损，金黄色葡萄球菌可能会进入宿主，感染可能导致从轻微皮肤并发症到致命感染的广泛情况。越来越令人担忧的是，在其他健康的年轻人中，社区获得的耐甲氧西林金黄色葡萄球菌(CA-MRSA)感染的数量稳步增加。天然抗体代表健康的、未免疫的个体中循环免疫球蛋白的自发谱系，形成先天免疫系统的一部分，它们促进病原体从循环中清除并防止病原体传播。蛋白水解性抗体是一种免疫球蛋白，具有催化多肽抗原底物水解的能力，具有特异性和高效分解多肽的潜力。一种分解代谢的蛋白质分解抗体的单个分子可以降解数千个抗原分子。此外，肽键断裂反应通常会导致功能蛋白失活。相比之下，传统抗体的作用是化学计量的(例如，免疫球蛋白最多结合2个抗原分子)，这种结合是可逆的，结果是免疫复合体解离时，活性抗原分子被释放。越来越多的证据表明，微生物抗原也可以成为分解代谢抗体的靶标。Gp120是HIV的一种外壳蛋白，被识别gp120(超抗原，即存在于前免疫谱系中的抗体识别的抗原，而不需要抗体可变区的适应性多样化)的特定蛋白水解性抗体切割。到目前为止，分解代谢抗体在抵御细菌感染中的作用还没有被研究过。在初步研究中，我们观察了金黄色葡萄球菌、EFB、蛋白A、LukF、Map和ClfA表达的五种重要蛋白被人体抗体制剂切割的情况。在目前的方案中，我们将使用金黄色葡萄球菌携带状态定义的患者血清来证实这一现象，表征其蛋白分解的特异性和比率，并确定催化对毒力蛋白功能的影响。公共卫生相关性：金黄色葡萄球菌感染在社区和医院环境中都是一个日益严重的问题，耐药菌株使现有的治疗策略复杂化。这项提议旨在确定一系列抗体，这些抗体也可以作为酶(催化)来裂解与疾病相关的毒力因子。这些催化抗体的鉴定和鉴定将导致开发新的预防和治疗金黄色葡萄球菌感染的策略。