Enhancing C. difficile vaccination in the context of TcdB-mediated immunosuppression.

项目概要（项目1） 最近的报告表明，艰难梭菌是40多万例胃肠道疾病的原因。 每年有近30，000人死亡。该项目的目标是培养一个有效的下一代 疫苗预防C.艰难梭菌病，并探讨其毒力相关活动。困难，可能 降低疫苗效力。巴拉德实验室开发的疫苗接种的主要候选者是 TcdB缺乏关键细胞进入序列。这种突变体不能与细胞相互作用，但似乎保留了 对促进中和抗体反应至关重要。该候选疫苗将进一步优化， 经修饰以确保稳定性和完全无毒性。将在这种突变体和 TcdB类毒素。接下来，TcdB衍生物将与多糖抗原衍生物组合使用。 梭很难产生新的组合疫苗。所有候选疫苗都将接受保护性测试 针对C.艰难梭菌病的小鼠模型和最有希望的将进一步测试在仓鼠 感染的模式。利用C.艰难基因工程表达失活TcdB，我们也将 确定C. difficile灭活关键免疫细胞，这些细胞是在接种疫苗后提供有效记忆反应所必需的。 动物总之，这些研究都将确定新的C。艰难的疫苗，并确定在何种程度上， 这种病原体会破坏它们的效力

PROJECT SUMMARY (Project 1) The most recent reports indicate Clostridioides difficile is the cause of over 400,000 cases of gastrointestinal illness and nearly 30,000 deaths annually. The goals of this project are to develop an effective next generation vaccine to prevent C. difficile disease and investigate the virulence-related activities of C. difficile that might reduce vaccine effectiveness. A leading candidate developed for vaccination in the Ballard lab is a mutant of TcdB lacking a key cell entry sequence. This mutant is unable to interact with cells but appears to retain aspects critical to promoting a neutralizing antibody response. This vaccine candidate will be further optimized and modified to ensure stability and a total absence of toxicity. Comparisons will be made between this mutant and a toxoid of TcdB. Next, the TcdB derivative will be used in combination with a polysaccharide antigen derived from C. difficile to generate a novel combination vaccine. All vaccine candidates will be tested for protection against C. difficile disease in a mouse model and the most promising of those will be further tested in a hamster model of infection. Using strains of C. difficile genetically engineered to express inactive TcdB, we will also determine if C. difficile inactivates key immune cells needed to provide effective memory responses in vaccinated animals. Together, these studies will both identify new C. difficile vaccines and determine the extent to which this pathogen can subvert their effectiveness.