Salmonella Group C as part of a multivalent Salmonella vaccine

非伤寒沙门氏菌（NTS）越来越被认为是美国年轻人和老年人侵袭性疾病（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日益增强，进一步使治疗复杂化。在美国，NTS疾病主要由属于三个血清组（B、C和D）的血清型引起。我们的总体目标是开发针对这些侵袭性NTS血清群的广谱疫苗。我们已经开发出了针对B组（肠道沙门氏菌亚种、肠炎沙门氏菌血清型、鼠伤寒沙门氏菌）和D组（肠炎沙门氏菌）血清型的口服活疫苗和结合疫苗，可以预防具有野生型同源病原体的侵袭性NTS疾病。虽然不像沙门氏菌B组和D组那样常见，但C组生物在NTS病例中占很大比例，一些C组血清型（如霍乱沙门氏菌）具有高度侵袭性。本转化研究计划的目的是开发C组沙门氏菌减毒活疫苗和结合疫苗。我们的中心假设是，适当改造的肠沙门氏菌Cl组和C2血清型减毒菌株可以：1)允许安全、高产地制备核心-0多糖（cop）和鞭毛蛋白用于制备结合疫苗，2)作为保护性减毒活疫苗。我们将选择合适的沙门氏菌群Cl和C2菌株，并对其进行基因工程改造，使其减毒并分泌大量的一期鞭毛蛋白到上清液中。我们将从这些菌株中纯化cop和鞭毛蛋白，并采用不同的化学策略构建cop - flc结合疫苗。这些结合物将在成年和老年小鼠中进行评估。还将评估减毒沙门氏菌Cl组和C2组疫苗株对成年和老年小鼠的保护能力。我们还将确定霍乱弧菌结合疫苗和口服活疫苗是否能保护猪免受侵袭性疾病的侵袭。我们将通过在恒河猴沙门氏菌胃肠炎模型中测试我们的鼠伤寒沙门氏菌减毒活疫苗CVD 1931，来确定NTS疫苗是否也能预防胃肠炎。最后，我们将确定口服活疫苗或结合B、C和D组沙门氏菌疫苗的多价制剂是否可以预防B、C和D组血清型引起的侵袭性疾病。如果我们成功了，这些结果将为开始未来的1期临床试验铺平道路，我们将解决这个多中心研究计划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.