Development of Vaccines against Clostridium difficile Infection

艰难梭菌感染疫苗的研制

• 批准号: 7903007
• 负责人: Hanping Feng
• 金额: $ 66.39万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-15 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7903007
• 关键词: Accounting; Acute; Address; Adjuvant; Affinity; Age; Amino Acids; Anorexia; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Antibodies; Antibody Formation; Antigens; Bacillus megaterium; Biological Assay; Body Weight decreased; Cell Culture Techniques; Characteristics; Chemicals; Chimera organism; Chimeric Proteins; Chronic; Chronic Disease; Clostridium difficile; Data; Development; Diarrhea; Disease; Dose; Encapsulated; Endotoxins; Enteral; Epithelial; Epithelium; Epitopes; Europe; Exotoxins; Family; Feces; Fluids and Secretions; Formalin; Gnotobiotic; Goals; Health; Hospitalization; Human; Immunity; Immunization; Immunoglobulin Fragments; Immunoglobulin G; Incidence; Infection; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Inflammatory disease of the intestine; Intervention; Intoxication; Laboratories; Laboratory mice; Length; Measures; Mediating; Methods; Modeling; Monitor; Morbidity - disease rate; Mucosal Immunity; Mucous Membrane; Mus; Nature; Necrosis; North America; Oral; Outcome; Patients; Placebos; Point Mutation; Polymers; Positioning Attribute; Prevention; Probiotics; Proteins; Pseudomembranous Colitis; Recombinant Proteins; Recombinants; Recurrence; Regimen; Relapse; Request for Applications; Research; Route; Safety; Secondary Immunization; Secretory Immunoglobulin A; Serum; Severities; Staging; Symptoms; System; Testing; Time; Toxic effect; Toxin; Toxoids; Transmembrane Domain; Vaccination; Vaccines; Virulence; abstracting; aluminum sulfate; base; comparative efficacy; cytotoxicity; design; holotoxins; molecular mass; mortality; neutralizing antibody; pathogen; preclinical evaluation; prevent; protective efficacy; receptor binding; research clinical testing; research study; response; rho GTP-Binding Proteins; treatment strategy; vaccine candidate; vaccine development

DESCRIPTION (provided by applicant): This proposal is in response to RFA-AI-09-016 requesting applications to develop vaccines for selected pathogens including Clostridium difficile, the cause of pseudomembranous colitis, which accounts for a quarter of all cases of antibiotic-associated diarrhea. With the recent emergence of hypervirulent strains, the incidence of C. difficile infection (CDI) has increased significantly in both North America and Europe, causing lengthy hospitalization, substantial morbidity and mortality. CDI is thought to be mainly mediated by exotoxins TcdA and TcdB, which glucosylate low molecular mass GTPases of the Rho family, leading to massive fluid secretion, acute inflammation, and necrosis of the colonic mucosa. Protection against CDI was shown to be mediated through systemic and mucosal antibodies against the 2 key toxins, although other virulence attributes are known to exist which may also contribute to the manifestation of CDI. The goal of this proposal is to design a vaccine that targets both TcdA and TcdB, with a view to elicit strong systemic and mucosal immunity to prevent CDI, reduce the severity, or eliminate an ongoing chronic disease. We propose to exploit the recently expressed atoxic C. difficile holotoxin proteins in an endotoxin-free Bacillus megaterium system. Two immunogens will be evaluated: a mixture of atoxic full-length C. difficile toxin A and B generated by point mutations (designated as aTxAB), and a chimera protein containing full-length TcdB but with its receptor binding domain replaced with that of TcdA (designated as cTxAB). cTxAB has a small deletion (97 amino acids) in transmembrane domain rendering it non-toxic. Preliminary studies showed that atoxic TcdB vaccination induced antibody responses against a wide-spectrum of epitopes and potent protective immunity superior to toxoid; cTxAB immunization induced antibody and protective responses against both TcdA and TcdB. In this project, we will first evaluate the ability of these atoxic recombinant proteins to induce protective antibody responses following parenteral immunization followed by challenge with wild type toxins (Aim 1). This will be followed by evaluating several regimens of mucosal immunizations (oral, intranasal and sublingual) designed to induce protection against systemic and mucosal challenges with wild type toxins (Aim 2). We will test the protective efficacy of the various immunization regimens developed in Aims 1 and 2 in the recently described mouse acute infection model (Aim 3a), and the most efficient immunization method resulting from the mouse infection studies will undergo preclinical evaluation in the chronic piglet model of CDI developed in this laboratory (Aim 3b). Because at this early stage the nature of the candidate vaccine is unknown, nor is the adjuvant required, we are not in a position to form a suitable partnership. Abstract Narrative: Clostridium difficile-associated diarrhea and enteric inflammatory diseases are caused primarily by two secretory toxins. This project will use recombinant atoxic holotoxins produced in this lab as a basis for a vaccine to elicit strong systemic and mucosal immunity to prevent C. difficile infection, reduce the severity, or eliminate an ongoing chronic disease.

描述（由申请人提供）： 该提案是对RFA-AI-09-016的响应，要求应用于开发选定病原体的疫苗，包括艰难梭菌（艰难梭菌），这是假膜性结肠炎的原因，该病原体是所有抗生素相关腹泻病例的四分之一。随着近期高呼吸菌株的出现，北美和欧洲的艰难梭菌感染（CDI）的发生率显着增加，导致长期住院，大量发病率和死亡率。 CDI被认为主要是由Exotoxins TCDA和TCDB介导的，TCDA和TCDB是​​Rho家族的低分子质量GTPase，导致结肠粘膜的大规模液体分泌，急性炎症和坏死。对CDI的保护被证明是通过针对2种关键毒素的全身性和粘膜抗体介导的，尽管已知存在其他毒力属性，这也可能有助于CDI的表现。该提案的目的是设计一种针对TCDA和TCDB的疫苗，以期引起强烈的系统性和粘膜免疫，以防止CDI，减少严重程度或消除持续的慢性疾病。我们建议利用无内毒素巨型巨型芽孢杆菌系统中最近表达的氧化艰难梭状芽胞杆菌蛋白质蛋白。将评估两种免疫原分：由点突变（指定为ATXAB）产生的毒性全长艰难梭菌毒素A和B的混合物，以及含有全长TCDB的嵌合体蛋白，但其受体结合结构域替换为TCDA（指定为CTXAB）。 CTXAB在跨膜结构域中具有少量缺失（97个氨基酸），使其无毒。初步研究表明，毒性TCDB疫苗接种引起了针对广泛表位和有效的保护性免疫的抗体反应，优于毒素。 CTXAB免疫诱导了针对TCDA和TCDB的抗体和保护反应。在该项目中，我们将首先评估这些毒性重组蛋白在肠胃外免疫后诱导保护性抗体反应的能力，然后对野生型毒素进行挑战（AIM 1）。随后将评估旨在诱导野生型毒素的系统性和粘膜挑战的粘膜免疫（口服，鼻内和舌下）方案（AIM 2）。我们将测试在最近描述的小鼠急性感染模型中在AIMS 1和2中开发的各种免疫方案的保护性功效（AIM 3A），而小鼠感染研究引起的最有效的免疫方法将在该实验室中开发的CDI慢性小猪模型中进行临床前评估（AIM 3B）。因为在这个早期阶段，候选疫苗的性质尚不清楚，也不需要辅助疫苗，所以我们无法建立合适的伙伴关系。 摘要叙述：艰难梭菌相关的腹泻和肠炎疾病主要由两种分泌毒素引起。该项目将使用本实验室中产生的重组毒性全毒素作为疫苗引起强烈的全身性和粘膜免疫的基础，以防止艰难梭菌感染，减少严重程度或消除持续的慢性疾病。