Vanderbilt Antibody and Antigen Discovery for Clostridioides difficile Vaccines

总体项目摘要 艰难梭菌疫苗VANDy-CdV的范德比尔特抗体和抗原发现 艰难梭菌是一种形成孢子的厌氧菌，是导致医院感染的主要原因。 在美国获得性胃肠道感染。社区发病率的上升- 获得C.在其他方面健康的成年人中，艰难梭菌感染（CDI）与抗生素使用增加有关 以及新菌株的出现。CDI症状和病理由两个大的 同源毒素，TcdA和TcdB，因此毒素代表有吸引力的目标， 预防和治疗策略。虽然努力集中在使用类毒素， 免疫接种在减轻症状严重程度方面显示出希望，类毒素方法 在临床试验中未导致CDI发生率降低。有几个机会， 改进现有的疫苗策略。首先，大规模的基因组研究表明，TcdB是 经历快速进化变化;保守毒素表位的鉴定可用于 引导免疫反应产生广泛的中和反应。第二、 鉴定营养细菌或孢子表面的保守抗原， 可以作为免疫原，使宿主引发粘膜免疫应答， 细菌定植粘膜免疫途径的纳入有望进一步 提高疫苗的效力和持久性。VANDy-CdV计划的总体目标是 鉴定毒素亚单位和新细胞表面抗原，当它们结合时， 保护C。艰难的感染和症状在众多创新优势中， 方法包括使用人类CDI患者样本作为了解 抗原在自然感染中促进IgG、伊加和sIgA应答。该方法还包括 使用强大的单B细胞分选和测序方法。识别配对的能力 来自结合毒素和/或细菌的单个记忆B细胞的重链和轻链序列 允许产生独特的抗体，然后可以用作表位作图的工具 和新抗原的发现。该方法的第三个亮点涉及使用新创建的 C.艰难梭菌转座子文库，其将用于在体内鉴定新的抗原。 疫苗接种/攻击实验。其他创新包括结构导向的方法， 确定有效的中和表位，并系统评价肠道淋巴细胞如何 反应因免疫途径而异。疫苗效力和粘膜相关性 将在定殖、感染和复发的临床前模型中评价保护作用。在 五年后，我们希望获得开发新抗原所需的临床前数据 鸡尾酒和免疫策略进入人体安全性和有效性试验。

OVERALL PROJECT SUMMARY Vanderbilt Antibody and Antigen Discovery for Clostridioides difficile Vaccines VANDy-CdV Clostridioides difficile is a spore-forming anaerobic bacterium that is the leading cause of hospital- acquired gastrointestinal infection in the United States. The rising incidence of community- acquired C. difficile infection (CDI) in otherwise healthy adults is linked to increased antibiotic use and the emergence of new strains. CDI symptoms and pathology are mediated by two large homologous toxins, TcdA and TcdB, and therefore the toxins represent attractive targets for prevention and therapeutic strategies. While efforts centered around the use of toxoids for immunization have shown promise in reducing the severity of symptoms, the toxoid approach has not resulted in a decreased incidence of CDI in clinical trials. There are several opportunities to improve upon existing vaccine strategies. First, large scale genomic studies show that TcdB is undergoing rapid evolutionary change; the identification of conserved toxin epitopes can be used to direct the immune response toward the production of broadly neutralizing responses. Second, the identification of conserved antigens on the surface of the vegetative bacteria or spores that can serve as immunogens will allow the host to elicit mucosal immune responses that prevent bacterial colonization. The inclusion of mucosal immunization routes is expected to further enhance vaccine efficacy and durability. The overarching goal of the VANDy-CdV program is to identify toxin subunits and novel cell surface antigens that, when combined, promote durable protection against C. difficile infection and symptoms. Among many innovative strengths, the approach includes the use of human CDI patient samples as a resource for understanding what antigens promote IgG, IgA, and sIgA responses in natural infection. The approach also includes the use of powerful single B cell sorting and sequencing methods. The ability to identify paired heavy and light chain sequences from individual memory B cells binding toxins and/or bacteria allows for the production of unique antibodies that can then be used as tools for epitope mapping and novel antigen discovery. A third highlight of the approach involves the use of a newly created C. difficile transposon library which will be used to identify novel antigens in an in vivo vaccination/challenge experiment. Other innovations include a structure-guided approach to identifying potent, neutralizing epitopes and a systematic evaluation of how intestinal lymphocyte responses vary with routes of immunization. Vaccine efficacy and the mucosal correlates of protection will be evaluated in pre-clinical models of colonization, infection, and recurrence. At the end of five years, we expect to have the pre-clinical data needed to advance a novel antigen cocktail and immunization strategy forward into human safety and efficacy trials.