Combination Clostridium Difficile Toxin and Adhesin Vaccine

艰难梭菌毒素和粘附素联合疫苗

• 批准号: 8501352
• 负责人: DAVID D HO
• 金额: $ 34.95万
• 依托单位: AARON DIAMOND AIDS RESEARCH CENTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8501352
• 关键词: Active Immunization; Address; Adherence; Adhesions; Adjuvant; Age; Aging; Animal Model; Antibiotics; Antibodies; Antibody Formation; Antigens; Bacillus (bacterium); Bacteria; Bacterial Adhesins; Bacterial Infections; Binding; Boston; Chimeric Proteins; Clinical; Clinical Data; Clostridium difficile; Colitis; Combined Vaccines; Comorbidity; Development; Diarrhea; Disease; Disease Progression; Elderly; Enteral; Environmental Pollution; Epithelial Cells; Evaluation; Exhibits; Family; Flagella; Flagellin; Hamsters; Hand; Heating; Hospitalization; Hospitals; Human; Hygiene; Immune response; Immunity; Immunization; Immunoglobulin G; In Vitro; Incidence; Infection; Infection prevention; Injury; Intestines; Laboratories; Ligands; Measures; Mediating; Mesocricetus auratus; Modeling; Mus; New York; Organism; Outcome; Passive Immunization; Patient Isolation; Patients; Pattern recognition receptor; Play; Population; Prevention; Preventive; Production; Proteins; Receptor Signaling; Recombinant Fusion Proteins; Recombinants; Recurrence; Recurrent disease; Regimen; Reporting; Reproduction spores; Risk; Role; Route; Sampling; Serum; Surface; Symptoms; Testing; Toll-Like Receptor 5; Toll-like receptors; Toxin; United States; Vaccinated; Vaccination; Vaccines; Virulence Factors; Virus; adaptive immunity; base; design; design and construction; enterotoxin LT; experience; fliC gene product; fungus; immunogenic; immunogenicity; in vivo; mortality; neutralizing antibody; novel; pathogen; preclinical study; prevent; protective efficacy; receptor binding; rectal; response; success; therapeutic vaccine; vaccine candidate; vaccine efficacy

DESCRIPTION (provided by applicant): Clostridium difficile is a spore-forming Gram-positive anaerobic bacillus, and is the leading cause of nosocomial diarrhea and colitis in the industrialized world with more than 300,000 cases of C. difficile- associated diarrhea (CDAD) reported each year in the United States alone. Broad spectrum antibiotic usage, hospitalization, advanced age and comorbidities increase the risk for acquiring CDAD. Symptoms result from the production of two potent C. difficile toxins (toxin A and toxin B). Studies with humans have shown that protection against disease and relapse correlates predominantly with the presence of serum IgG responses directed against toxin A and less strongly with toxin B. No vaccine effective at preventing C. difficile disease is currently commercially available, and measures to prevent CDAD through patient isolation and implementation of hand-hygiene and contact precautions have had variable and often limited success. We propose to develop a recombinant C. difficile protein vaccine by fusing the non-toxic receptor binding domain (RBD) of toxin A or toxin B with C. difficile flagellar proteins, FliC and FliD. The RBD of toxin A and toxin B have been shown to induce neutralizing antibodies in immunized mice. The C. difficile FliD and FliC are involved in adherence and gut colonization, and FliC is a potent Toll-like receptor (TLR) 5 ligand. TLRs are a family of pattern recognition receptors that recognize structural components shared by bacteria, fungi and viruses. TLRs when bound to their ligands such as flagellin can trigger innate responses as well as facilitate in the development of adaptive immunity. Several promising experimental vaccines have been tested with flagellin either as an antigen or as an adjuvant. It still remains to be determined whether anti-flagellin immune responses can prevent C. difficile colonization and whether activation through TLR signaling plays a significant role in human responses against a C. difficile toxin vaccine. We hypothesize that the incorporation of flagellar proteins and toxins in a vaccine could provide protection against colonization as well as disease progression. Key milestones will be to address whether the combination vaccine using toxins and flagellar proteins can exhibit robust immunogenicity in vaccinated mice, resulting in the production of toxin neutralizing antibodies, a correlate of vaccine efficacy, and anti-flagellar antibodies that can prevent colonization. Since C difficile isa mucosal pathogen, several routes of immunization that target the mucosal surface such as intra- rectal, intranasal and transcutaneous will be compared to parenteral immunization in the presence of mucosal adjuvants such as heat labile enterotoxin, LT (r192g). The most promising vaccines will then be evaluated in challenge and protection studies. Challenge studies against multiple C. difficile strains in the mouse and the hamster model of bacterial infection will be performed to evaluate C. difficile colonization and protection against CDAD.

描述（由申请人提供）：艰难梭菌是一种形成孢子的革兰氏阳性厌氧芽孢杆菌，是工业化世界中医学上腹泻和结肠炎的主要原因，每年在美国仅报告了300,000例艰难杆菌 - 艰难核心相关的腹泻（CDAD）。广泛的抗生素使用，住院，高龄和合并症会增加获得CDAD的风险。症状是由两种有效的艰难梭菌毒素（毒素A和毒素B）产生的。对人类的研究表明，针对疾病和复发的保护主要与针对毒素A的血清IgG反应有关，而与毒素B相对较少。目前，没有有效预防艰难疾病的疫苗可预防艰难疾病，并且通过隔离和接触预先限制的患者隔离和实施而可以防止CDAD通过cdad进行可变性。 我们建议通过与艰难梭菌鞭毛蛋白（Flic and Flid）融合毒素A或毒素B的无毒受体结合结构域（RBD）来开发重组艰难梭菌蛋白疫苗。毒素A和毒素B的RBD已显示可在免疫小鼠中诱导中和抗体。艰难梭菌的氟梭菌和烟与粘附和肠道定殖有关，而FLIC是一种有效的Toll样受体（TLR）5配体。 TLR是一个识别细菌，真菌和病毒共享的结构成分的模式识别受体家族。当绑定到鞭毛等配体时，TLR可以触发先天反应，并促进自适应的发展 免疫。几种有希望的实验疫苗已用鞭毛蛋白作为抗原或辅助疫苗进行了测试。仍然有待确定的抗氟糖蛋白免疫反应是否可以预防艰难梭菌定植，以及通过TLR信号激活是否在针对艰难梭菌毒素疫苗的人类反应中起重要作用。我们假设将鞭毛蛋白和毒素掺入疫苗中可以提供防止定殖以及疾病进展的保护。关键里程碑将是解决使用毒素和鞭毛蛋白的组合疫苗是否可以在接种疫苗的小鼠中表现出强大的免疫原性，从而导致毒素中和中和抗体的产生，疫苗功效的相关性和抗氟烷抗体的相关性，可以预防结肠化。由于艰难梭菌ISA粘膜病原体，将在粘膜内，鼻内和经经皮的粘膜表面（如粘膜内和经皮）等免疫表面（如粘膜佐剂）（如热不稳定肠毒素，LT（R192G））中进行比较。然后，最有希望的疫苗将在挑战和保护研究中进行评估。将对小鼠中多个艰难梭菌菌株和细菌感染的仓鼠模型进行挑战研究，以评估艰难梭菌定植和针对CDAD的保护。