Salmonella Vaccines Against Bacterial Enteropathogens

描述（由申请人提供）：在全球每年5700万例死亡中，约180万（WHO）至220万（UNESCO）例是由于肠道病原体感染，包括沙门氏菌、大肠杆菌和志贺氏菌，以及其他肠道病原体，如耶尔森氏菌、霍乱弧菌、空肠弯曲杆菌、幽门螺杆菌、单核增生李斯特菌、产气荚膜梭菌和艰难梭菌。这些病原体可导致严重的发病率，并通过受污染的食物和水传播给人类。在发展中国家，食用动物中的细菌性肠病原体是降低牲畜生产力、造成人类粮食短缺和营养不良的主要因素。我们认为，改善健康、营养和经济福利（后者取决于前两者）是提高全球生活质量的最佳手段。因此，我们花了大量的精力来设计新的改进方法来构建重组减毒沙门氏菌疫苗载体系统，用于动物和人类，能够诱导对肠道病原体的交叉保护免疫，并提供属或种特异性的保护性抗原，以进一步增强对肠道病原体的免疫诱导。我们建议利用这些技术开发疫苗，以预防/减少农业重要动物和人类的细菌性肠病原体引起的腹泻疾病。我们的目标包括：(i)完成鼠伤寒沙门氏菌和甲型副伤寒沙门氏菌菌株的构建，这些菌株具有可调节的延迟衰减特性，可以暴露和展示交叉保护性表面抗原，最大限度地减少对血清型特异性抗原的免疫反应，具有突变以增强安全性和免疫原性，可以传递多种属和种特异性保护性抗原，并具有生物遏制作用，以防止在体内持续存在或排泄后存活。（ii）利用平衡致死、平衡衰减和调节裂解载体系统完成多重载体系统的构建，通过递送志贺氏菌、耶尔森氏菌、大肠杆菌、空肠梭菌和产气荚膜梭菌的保守保护性抗原，最大限度地诱导保护性免疫反应；（iii）开展研究，评估(a)如何最大限度地诱导交叉保护性免疫，(b)诱导针对特定肠道病原体的保护性免疫的能力；(c)疫苗接种对正常菌群的影响，(d)预防沙门氏菌和一种或两种其他菌种的混合疫苗与预防多种肠道细菌病原体的疫苗的效果，(e)通过实验验证人类疫苗预防多种病原体的方法，以及（iv）开展研究，提供临床前安全性和有效性数据，以满足兽药疫苗的APHIS和人类疫苗的FDA要求。我们将每年修订我们的主文件，准备和充分描述候选疫苗主种子的稳定性和安全性，准备和提交IRB批准的方案，并提交信息以促进临床动物和人体试验的进行。我们计划最终开发疫苗，以提供对霍乱弧菌，艰难梭菌，单核细胞增生乳杆菌和幽门螺杆菌的保护。

DESCRIPTION (provided by applicant): Of the global 57 million deaths each year, about 1.8 (WHO) to 2.2 (UNESCO) million are due to infections with enteric pathogens including Salmonella, Escherichia coli and Shigella sp., and other entero-pathogens such as Yersinia sp., Vibrio cholerae, Campylobacter jejuni, Helicobacter pylori, Listeria monocytogenes, Clostridium perfringens and C. difficile. These pathogens are responsible for significant morbidity and are transmitted to humans by contaminated food and water. In developing countries, bacterial enteropathogens in food animals are major factors that decrease productivity of livestock creating food shortages and under-nourishment in humans. We believe that improving health, nutrition and economic well-being (the latter dependent on the first two) provide the best means to enhance the quality of life globally. We therefore spent much effort to devise new improved means to construct recombinant attenuated Salmonella vaccine vector systems for animals and humans that are capable of inducing cross-protective immunity to enteric pathogens and of delivering genus- or species-specific protective antigens to further enhance induction of immunity to enteric pathogens. We propose to use these technologies to develop vaccines to prevent/reduce diarrheal diseases caused by bacterial enteropathogens in agriculturally important animals and humans. Our objectives include to: (i) complete construction of S. Typhimurium and S. Paratyphi A strains with regulated delayed attenuation attributes to expose and display cross-protective surface antigens, that minimize induction of immune responses to serotype-specific antigens, that possess mutations to enhance safety and immunogenicity, that can delivery multiple genus- and species-specific protective antigens and that display biological containment to preclude persistence in vivo or survival if excreted, (ii) complete construction of multiple vector systems using balanced-lethal, balanced-attenuation and regulated-lysis vector systems to maximize induction of protective immune responses by delivery of conserved protective antigens of Shigella, Yersinia, E. coli, C. jejuni and C. perfringens, (iii) conduct studies to evaluate (a) how best to maximize induction of cross-protective immunity, (b) ability to induce protective immunity against specific enteric pathogens, (c) consequences of vaccination on normal flora, (d) efficacy of mixtures of vaccines to protect against Salmonella and one or two other species versus a vaccine to protect against multiple enteric bacterial pathogens, and (e) means to experimentally validate a vaccine for humans to protect against multiple pathogens, and (iv) conduct studies to provide preclinical safety and efficacy data to satisfy APHIS for veterinary vaccines and FDA for human vaccines. We will annually amend our Master File, prepare and fully characterize candidate vaccine Master Seeds for stability and safety, prepare and submit protocols for IRB approvals, and submit information to facilitate conduct of clinical animal and human trials. We plan to ultimately develop vaccines to confer protection against V. cholerae, C. difficile, L. monocytogenes and H. pylori.