Multivalent Bacillus mucosal vaccines against Clostridium difficile infection

描述(申请人提供)：艰难梭菌每年导致500,000多例感染，估计有15,000人死亡，保守估计美国每年的经济损失为10-30亿美元。目前，艰难梭菌感染(CDI)的标准治疗方法是使用几种抗生素中的一种，包括甲硝唑、万古霉素或新开发的非达克西星。虽然有效，但由于对肠道微生物群的破坏性影响，这些治疗方法的疾病复发率为15%-35%。迫切需要更有效的策略来治疗原发和复发的CDI。目前还没有针对CDI的疫苗获得许可。该项目的目标是开发针对艰难梭菌定植/生长因子和艰难梭菌毒素的新型疫苗。CDI的症状归因于艰难梭菌两种毒素TcdA和TcdB的释放。我们最近构建了一个含有TcdA和TcdB免疫优势区的重组融合蛋白mTcd138。由于孢子是疾病传播和复发的主要原因，我们建议通过增加毒力因子抗原来增强我们的原型疫苗，以减少或消除孢子的排泄。减少孢子排泄将减少或消除疾病复发和传播的风险。在目标1中，我们将首先构建含有mTcd138和艰难梭菌主要定植因子的融合免疫原，然后用融合免疫原经肌肉或舌下免疫小鼠，检测其对CDI和艰难梭菌孢子定植的免疫原性和保护性。粘膜通常对艰难梭菌等肠道病原体更有效。在目标2中，我们将通过在枯草杆菌粘膜递送系统中表达选定的Aim1候选疫苗来开发一种粘膜/口服疫苗。

DESCRIPTION (provided by applicant): Clostridium difficile causes over 500,000 cases of infections per year, with an estimated 15,000 deaths and a conservatively estimated economic cost at $1-3 billion in the US annually. Currently, standard treatment for C. difficile infection (CDI) is the administration of one of several antibiotics which include metronidazole, vancomycin or the newly developed fidaxomicin. While effective, these treatments have a disease recurrence rate of 15-35%, due to their disruptive impact on the gut microbiome. More effective strategies to treat primary and recurrent CDI are urgently needed. No vaccine is currently licensed against CDI. The objective of this project is to develop novel vaccines that target both C. difficile colonization/growth factors and C. difficile toxins. The symptoms of CDI are attributed to liberation of two C. difficile toxins, TcdA and TcdB. We recently constructed a recombinant fusion protein, mTcd138, which contains the immunodominant regions of TcdA and TcdB. Since spores are the major cause of disease transmission and recurrence, we propose to enhance our prototype vaccine by including additional virulence factor antigens to reduce or eliminate the excretion of spores. Decreasing spore excretion will reduce or eliminate the risk of disease recurrence and transmission. In Aim 1 we will first construct fusion immunogens containing mTcd138 and major C. difficile colonization factors, and then determine the immunogenicity and protection against CDI and C. difficile spore colonization in mice immunized intramuscularly or sublingually with the fusion immunogens. Mucosal is often more effective against enteric pathogens such as C. difficile. In Aim 2 we will develop a mucosal/oral vaccine by expressing the chosen vaccine candidate from Aim1 in the Bacillus subtilis mucosal delivery system.