Attenuated Live and Recombinant Yersinia pestis Vaccines

描述(申请人提供)：在三次大流行中，鼠疫耶尔森氏菌导致约2亿人死亡，目前仍在世界各地流行，导致零星感染。由于鼠疫不能过腐生的生活，并且在许多啮齿动物种群中居住，鼠疫是由一种专性的动物-人类病原体引起的最可怕的人畜共患疾病之一。鼠疫杆菌至少在800年前就开始被用作生物武器，今天是最有可能的生物威胁之一。基于这些考虑，我们建议：(I)构建重组减毒鼠伤寒沙门氏菌疫苗(RASV)，在小鼠口服免疫后体内合成鼠疫K1M抗原，以确定激发保护性免疫以对抗强毒K1M的抗原。(Ii)构建和鉴定具有rpos*表型的重组减毒伤寒沙门氏菌ISP1820，以传递一个或多个保护性鼠疫杆菌Kim抗原。如果发现需要不同的抗原传递方式来诱导对鼠疫挑战的保护性免疫，我们将构建所有被认为必要的重组疫苗，作为鸡尾酒接种。(Iii)构建和评价鼠疫减毒活疫苗，该疫苗将对鼠疫杆菌用来获得铁(一个重要的毒力属性)的大部分(如果不是全部)蛋白诱导增强的免疫反应，并由于阿拉伯糖调节的延迟细胞裂解系统而在十代生长后显示出完全的生物遏制，没有存活的细菌细胞。我们将用缺乏70kb LCR质粒且完全无毒的鼠疫耶尔森菌KIM6+开始构建工作，并在引入减毒突变后重新添加LCR质粒。我们还将开发我们的主文件，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，提交获得IND所需的信息，并执行安排最佳候选疫苗在人类志愿者身上进行临床评估所需的任何其他工作。

DESCRIPTION (provided by applicant): Yersinia pestis, in three pandemics, resulted in some 200 million plague deaths and is still endemic throughout the world resulting in sporadic infections. Due to its inability to lead a saprophytic life and its residence in many rodent populations, plague is one of the most feared of zoonotic diseases caused by an obligate animal-human pathogen. The plague bacillus began to be used as a biological weapon at least 800 years ago and is today one of the more likely biological threats. Because of these considerations, we propose to: (i) Construct and evaluate recombinant attenuated Salmonella typhimurium vaccines (RASV) synthesizing Y. pestis K1M antigens in vivo after oral immunization of mice to identify antigens that stimulate protective immunity to challenge with virulent Y. pestis K1M. (ii) Construct and evaluate a recombinant attenuated S. typhi ISP1820 with an RpoS* phenotype to deliver one or more protective Y. pestis KIM antigens. If it is found that different antigen delivery modes are required to induce protective immunity to Y. pestis challenge, we will construct all deemed necessary recombinant vaccines to be administered as a cocktail. (iii) Construct and evaluate a live attenuated Y. pestis vaccine that will induce enhanced immune responses to most, if not all, proteins used by Y. pestis to acquire iron, an important virulence attribute, and exhibit complete biological containment with no surviving bacterial cells after ten generations of growth due to an arabinose-regulated delayed cell lysis system. We will initiate our construction endeavors with Y. pestis KIM6+ that lacks the 70 kb Lcr plasmid and is totally avirulent and add back the Lcr plasmid after introducing attenuating mutations. We will also develop our Master File, prepare and fully characterize candidate vaccine Master Seeds for stability and safety, prepare and submit protocols for IRB approvals, submit information necessary to obtain INDs, and perform any other work needed to arrange that the best candidate vaccines be clinically evaluated in human volunteers.