Development of a live, genetically-attenuated cholera vaccine prototype that could be delivered as hyperinfective biofilms

开发一种活的、基因减毒的霍乱疫苗原型，可以作为高度感染性生物膜提供

• 批准号: 8719928
• 负责人: Jorge Antonio Benitez
• 金额: $ 21.23万
• 依托单位: MOREHOUSE SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8719928
• 关键词: Acute; Adult; Affect; Angola; Antigens; Attenuated; Attenuated Vaccines; Biological Assay; Cells; Cessation of life; Cholera; Cholera Vaccine; Clinical Trials; Communities; Country; Development; Disease; Disease Outbreaks; Dose; Epidemic; Feces; Goals; Gram-Negative Bacteria; Haiti; Herd Immunity; Household; Human; Immune; Immune response; Immunization; Inferior; Intestines; Lead; Life; Microbial Biofilms; Modeling; Mus; Mutation; Oral; Oryctolagus cuniculus; Pattern; Peru; Phage Attachment Site; Phase; Phenotype; Physiological; Prevalence; Prevention; Preventive; Recommendation; Relative (related person); Research; Resources; Safety; Severities; Small Intestines; Staging; Testing; Vaccines; Vibrio; Vibrio cholerae; Vibrio cholerae O1; Vibrio cholerae O139; Vietnam; Water; World Health Organization; Zimbabwe; base; conventional therapy; cost; epidemiological model; immunogenic; immunogenicity; improved; in vivo; innovation; protein profiling; prototype; public health relevance; transmission process; vaccine candidate

DESCRIPTION (provided by applicant): Cholera is an acute, water-borne diarrheal disease caused by the facultative Gram-negative bacterium, Vibrio cholerae of serogroup O1 of the classical and El Tor biotypes and by V. cholerae serogroup O139. The magnitude, severity and duration of recent outbreaks in Angola, Zimbabwe, Vietnam, and Haiti, have strengthened a recommendation by the World Health Organization for the preventive use of oral cholera vaccines to avert outbreaks and control their spread. Several live genetically attenuated cholera vaccine strains such as Peru-15 and V. cholerae 638 have been demonstrated to be clinically safe, immunogenic and protective in phase I and II clinical trials. However, the efficacy of current vaccines in an outbreak scenario has not been tested and could be challenged by the fact that their infectivity and potential for transmission to households and within the community are inferior to that of epidemic strains. Recent studies have shown that V. cholerae cells present in fresh cholera stools or within biofilm aggregates display a hyperinfective phenotype. The discovery of a V. cholerae hyperinfective physiological stage has led to a new epidemiological model for cholera that incorporates human-to-human transmission. We propose to develop a live, genetically-attenuated vaccine prototype based on strain 638 that could be administered as a hyperinfective biofilm to mimic cholera transmission in outbreaks, enhance immunogenicity, and promote herd immunity. We will first modify strain 638 by deleting the cholera phage attachment site to increase its safety without affecting its colonization capacity. In Aim 1, we wil introduce additional mutations in this strain to enhance its infectivity, intestinal colonization, nd biofilm formation. Then, we will conduct competition assays in vivo to determine the capacity of planktonic and biofilm-derived cells of the modified vaccine to outcompete strain 638 for colonization of the suckling mouse small intestine. In Aim 2, we will use an oral (intragastric) adult rabbit immunization model to compare the immunogenicity and protective capacity of planktonic and biofilm-derived hyperinfective vaccine candidates to that of the classical vaccine strain 638.

描述（由申请人提供）：霍乱是由辅助革兰氏阴性细菌引起的急性，水传播的腹泻疾病，是经典和El tor Biotypes的Serogroup O1的弧菌霍乱，以及V.霍乱霍乱的Serogrop ogrogrop o139。最近在安哥拉，津巴布韦，越南和海地爆发的幅度，严重性和持续时间，加强了世界卫生组织的建议，以预防口服霍乱疫苗来避免爆发并控制其传播。在I和II期临床试验中，有几种活遗传减弱的霍乱疫苗菌株，例如秘鲁-15和V.霍乱638，在临床上是安全，免疫原性和保护性的。但是，目前疫苗在爆发情况下的疗效尚未进行测试，并且可能会受到以下事实的质疑：它们的感染力和向家庭传播的潜力和社区内部的潜力不如流行病。最近的研究表明，新鲜霍乱粪便或生物膜聚集体中存在的霍乱细胞表现出过度感染的表型。霍乱谷（V. Cholerae）过度感染生理阶段的发现导致了霍乱的新流行病学模型，该模型融合了人类对人类的传播。我们建议基于638菌株开发活的，遗传衰减的疫苗原型，该原型可以作为超感染生物膜给药，以模仿暴发中的霍乱传播，提高免疫原性并促进群疫苗的免疫力。我们将首先通过删除霍乱噬菌体附着位点来修改638菌株，以提高其安全性而不会影响其定植能力。在AIM 1中，我们将在这种菌株中引入其他突变，以增强其感染性，肠定植，ND生物膜形成。然后，我们将在体内进行竞争分析，以确定改性疫苗的浮游细胞和生物膜衍生细胞的能力，以使哺乳小鼠小肠的定殖638。在AIM 2中，我们将使用口服（胃内）成年兔免疫模型来比较浮游生物和生物膜衍生的超感染疫苗候选物与经典疫苗638的免疫原性和保护能力。