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

项目总结(项目1) 最新报告表明，艰难梭状芽胞杆菌是40多万例胃肠道疾病的病因 每年有近30,000人死于疾病。该项目的目标是开发有效的下一代 预防艰难梭菌病的疫苗和研究艰难梭菌毒力相关活性的可能 降低疫苗效力。巴拉德实验室开发的一种领先的疫苗接种候选者是 Tcdb缺少关键信元输入序列。该突变体不能与细胞相互作用，但似乎保留了某些方面 对促进中和抗体反应至关重要。这一候选疫苗将进一步优化和 经过改装，以确保稳定性和完全无毒。我们将对这个突变体和 一种Tcdb类毒素。接下来，TcdB衍生物将与提取的多糖类抗原结合使用。 从艰难梭菌中产生一种新的组合疫苗。所有候选疫苗都将接受保护测试 在小鼠模型上对抗艰难梭菌病，其中最有希望的将在仓鼠身上进一步测试 感染模式。使用艰难梭菌的基因工程菌株来表达不活跃的TcdB，我们还将 确定艰难梭菌是否能灭活疫苗接种后提供有效记忆反应所需的关键免疫细胞 动物。这些研究将共同识别艰难梭菌新疫苗，并确定在多大程度上 这种病原体可以破坏它们的效力。

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.