Salmonella Group C as part of a multivalent Salmonella vaccine

在美国，非伤寒沙门氏菌（NTS）越来越多地被认为是年轻人和老年人侵袭性疾病（例如败血症，脑膜炎）的重要原因。NTS菌株对多种抗生素的耐药性不断增加，使治疗进一步复杂化。在美国，NTS疾病主要由属于三个血清群（B、C和D）的血清型引起。我们的总体目标是开发一种针对这些侵入性NTS血清群的广谱疫苗。我们已经开发出了针对B群（沙门氏菌肠道亚种鼠伤寒血清型）和D群（沙门氏菌肠道亚种鼠伤寒血清型）的口服活疫苗和结合疫苗。肠杆菌）血清型，其可以保护免受具有野生型同源病原体的侵袭性NTS疾病。虽然C组微生物比沙门氏菌B和D组菌株不常见，但C组微生物在NTS病例中占很大比例，并且一些C组血清型（例如沙门氏菌）猪霍乱是高度侵袭性的。本转化研究提案的目的是开发C组沙门氏菌减毒活疫苗和结合疫苗。我们的中心假设是肠道沙门氏菌Cl组和C2血清型的适当工程化的减毒菌株可以：1）允许安全、高产率地制备用于制备缀合物疫苗的核心-0多糖（COPS）和鞭毛蛋白，和2）用作保护性活减毒疫苗。我们将选择合适的沙门氏菌C1和C2群菌株，并对其进行遗传工程改造，使其减毒并分泌大量的1期鞭毛蛋白到上清液中。我们将从这些菌株中纯化COPS和鞭毛蛋白，并使用各种化学策略构建COPS-FliC缀合物疫苗。将在成年和老年小鼠中评价这些偶联物。还将评价活减毒沙门氏菌Cl组和C2疫苗株保护成年和老年小鼠的能力。我们还将确定是否能保护特定生菌仔猪免受S.猪霍乱结合疫苗和口服活疫苗。我们会测试减毒沙门氏菌活疫苗，以确定新界西疫苗是否也能预防肠胃炎。鼠伤寒疫苗CVD 1931在沙门氏菌胃肠炎恒河猴模型中的应用。最后，我们将确定多价口服活疫苗或结合物B、C和D群沙门氏菌疫苗是否可以预防由B、C和D群血清型引起的侵袭性疾病。如果我们成功，这些结果将为启动未来的1期临床试验铺平道路，我们将解决这个多中心研究提案的四个广泛目标中的三个。

Non-typhoidal Salmonella (NTS) are increasingly being recognized as important causes of invasive disease (e.g. sepsis, meningitis) in the very young and the elderly in the USA. The growing resistance of NTS strains to multiple antibiotics further complicates treatment. NTS disease in the USA is accounted for primarily by serovars belonging to three serogroups (B, C and D). Our overall goal is to develop a broad-spectrum vaccine against these invasive NTS serogroups. We have already developed live oral and conjugate vaccines against Group B {Salmonella enterica subspecies enterica serovar Typhimurium) and D (S. Enteritidis) serovars that can protect against invasive NTS disease with the wild-type homologous pathogen. Although less common than strains of Salmonella Groups B and D, Group C organisms represent a significant proportion of NTS cases, and some Group C serovars (e.g. S. Choleraesuis) are highly invasive. The purpose of this translational research proposal is to develop Salmonella Group C live attenuated and conjugate vaccines. Our central hypothesis is that appropriately engineered attenuated strains of Salmonella enterica Group Cl and C2 serovars can: 1) allow safe, high yield preparation of core-0 polysaccharide (COPS) and flagella protein for making conjugate vaccines, and 2) serve as protective live attenuated vaccines. We will select suitable Salmonella Group Cl and C2 strains and genetically engineer them so that they are attenuated and secrete large amounts of Phase 1 flagellin protein into the supernatant. We will purify COPS and flagellin from these strains and construct COPS-FliC conjugate vaccines using various chemical strategies. These conjugates will be evaluated in adult and aged mice. Live attenuated Salmonella Group Cl and C2 vaccine strains will also be evaluated for their ability to protect adult and aged mice. We will also determine whether gnotobiotic piglets can be protected from invasive disease by S. Choleraesuis conjugate and live oral vaccines. We will ascertain whether NTS vaccines can also protect against gastroenteritis by testing our live attenuated S. Typhimurium vaccine CVD 1931 in the rhesus macaque model of Salmonella gastroenteritis. Finally, we will determine whether a multivalent formulation of live oral or conjugate Group B, C and D Salmonella vaccines can prevent invasive disease caused by Group B, C and D serovars. If we are successful, these results will pave the way for initiating future Phase 1 clinical trials and we will have addressed three ofthe four broad objectives of this multi-center research proposal.