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长，使治疗进一步复杂化。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一种针对这些侵袭性NTS血清群的广谱疫苗。我们已经开发出针对B群(肠沙门氏菌肠杆菌亚种、鼠伤寒沙门氏菌)和D(肠炎沙门氏菌)血清型的口服和结合活疫苗，可以预防野生型同源病原体侵袭性NTS疾病。虽然与B和D组沙门氏菌相比不太常见，但C组细菌在NTS病例中占相当大的比例，一些C组血清型(如霍乱沙门氏菌)具有高度侵袭性。这项翻译研究建议的目的是开发沙门氏菌C组减毒活疫苗和结合疫苗。我们的中心假设是，经过适当改造的减毒沙门氏菌Cl群和C2血清型可以：1)允许安全、高产地制备用于结合疫苗的核心-0多糖(COP)和鞭毛蛋白，以及2)作为保护性减毒活疫苗。我们将选择合适的沙门氏菌Cl群和C2群，并对它们进行基因工程，使它们得到减毒，并将大量的第一相鞭毛蛋白分泌到上清液中。我们将从这些菌株中提纯COPS和鞭毛蛋白，并使用各种化学策略构建COPS-FLIC结合疫苗。这些结合物将在成年和老年小鼠身上进行评估。活的减毒沙门氏菌Cl群和C2群疫苗株也将被评估它们保护成年和老龄小鼠的能力。我们还将确定是否能通过霍乱弧菌结合疫苗和口服活疫苗保护小猪免受侵袭性疾病的侵袭。我们将通过在沙门氏菌胃肠炎猕猴模型上测试我们的减毒沙门氏菌活疫苗CVD 1931来确定NTS疫苗是否也可以预防胃肠炎。最后，我们将确定B、C和D群沙门氏菌活疫苗的多价口服或结合制剂是否可以预防由B、C和D群血清引起的侵袭性疾病。如果我们成功，这些结果将为启动未来的第一阶段临床试验铺平道路，我们将解决这项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.