PHOP/PHOQ DELETED S TYPHI VACCINE STRAINS

接种疫苗是预防疾病的一种有效和经济的方法， 多价口服疫苗将具有最广泛的 临床应用。 减毒沙门氏菌已经成功地 在小鼠模型中研究作为递送异源的活载体 免疫系统的抗原。 人体研究 有限，对人体免疫原性重要的变量 没有明确定义。 伤寒沙门氏菌菌株（Ty 800）缺失， 沙门氏菌phoP/phoQ毒力调节子非常安全， 在人类志愿者中具有免疫原性，并且该菌株已被修饰， 表达临床相关的异源抗原。这项建议 描述了一个翻译研究计划，旨在评估 利用二价沙门氏菌的人类沙门氏菌疫苗方案。伤寒 疫苗株。 这些研究强调合理修改 临床上可接受的人用疫苗株和疫苗接种方案 其可以改变异源抗原的免疫原性， 抗原，抗原在细菌细胞内的定位和 表达或分泌。 使用已确立的IRB批准的人体研究 方案，成年志愿者接种疫苗，遵循安全性和 疫苗脱落，并对粘膜， 体液和细胞免疫应答。伤寒抗原和 相关的异源抗原。 序贯口服疫苗接种方案 由S.伤寒疫苗株表达胞质 幽门螺杆菌尿素酶，然后是纯化的重组尿素酶， E.大肠杆菌不耐热毒素佐剂将在成年志愿者中进行测试 H.幽门。 色葡萄表达融合体的伤寒菌株 E.大肠杆菌溶血素A与尿素酶B连接， 将研究细菌细胞以确定分泌是否改变 免疫原性在这个系统中。 将生成其他构造 它们表达的是E. coli热不稳定毒素突变体或E.杆菌 定植因子抗原（CFA/I）。 这些新菌株将 在体外进行评估，随后在志愿者中进行测试，以确定 无论是不同结构的分子还是亚细胞的分子 定位可引起全身和/或粘膜免疫应答。 这些 研究旨在提供新的人体安全性和免疫原性 这些数据对活细菌的临床开发至关重要， 疫苗载体。

Vaccination is an effective and economical method of preventing disease, and multivalent, orally administered vaccines will have the widest clinical application. Attenuated Salmonella have been successfully studied in murine models as live vectors for delivery of heterologous antigens to the gastrointestinal immune system. Studies in humans have been limited, and variables important for immunogenicity in humans have not been clearly defined. A Salmonella typhi strain (Ty800) deleted for the phoP/phoQ virulence regulon of Salmonellae is very safe and immunogenic in human volunteers, and this strain has been modified to express clinically relevant heterologous antigens. This proposal describes a program of translational research designed to evaluate Salmonella-based vaccine regimens in humans utilizing bivalent S. typhi vaccine strains. These studies emphasize rational modification of clinically acceptable human vaccine strains and vaccination regimens which may alter immunogenicity of heterologous antigens such as type of antigen, location of antigen within the bacterial cell and mechanism of expression or secretion. Using an established IRB-approved human study protocol, adult volunteers are vaccinated, followed for safety and vaccine shedding, and intensively evaluated for evidence of mucosal, humoral and cellular immune-responses to both S. typhi antigens and the relevant heterologous antigens. A sequential oral vaccination regimen consisting of a S. typhi vaccine strain expressing cytoplasmic Helicobacter pylori urease followed by purified recombinant urease and E. coli heat labile toxin adjuvant will be tested in adult volunteers seronegative for H. pylori. An S. typhi strain expressing a fusion antigen of E. coli hemolysin A linked to urease B which is secreted from the bacterial cell will be studied to determine whether secretion alters immunogenicity in this system. Additional constructs will be generated which express either an E. coli heat labile toxin mutant or an E. coli colonization factor antigen (CFA/I). These new strains will be evaluated in vitro and subsequently tested in volunteers to determine whether these molecules with different structures or subcellular location can engender systemic and/or mucosal immune responses. These studies are designed to provide novel human safety and immunogenicity data which is vital to the clinical development of live bacterial vaccine vectors.