Modular Subunit Vaccine for Salmonella

描述(申请人提供)：沙门氏菌种类每年导致数百万摄入受污染食物或水的人患病或死亡。在沙门氏菌感染中幸存下来的人产生了强大的免疫力，这种免疫力依赖于促进巨噬细胞吞噬细菌的抗体，以及刺激巨噬细胞杀死吞噬细菌的CD4+T细胞的淋巴因子。出于实际原因，需要一种能够诱导免疫水平的亚单位疫苗，这种水平可以由活的生物体诱导。不幸的是，单独的沙门氏菌蛋白免疫通常只能诱导部分免疫。该项目的长期目标是克服这种低效，并生产出一种有效的沙门氏菌亚单位疫苗。我们的假设是，个别沙门氏菌蛋白的免疫原性低于减毒生物，因为缺乏固有的佐剂活性，难以进入粘膜淋巴器官，以及这些器官中的树突状抗原提呈细胞摄取不足。我们的具体目标是生产一种单一的疫苗蛋白来解决这些弱点。我们建议从保护性抗原中鉴定出一种针对CD4+T细胞的免疫优势多肽；使用一种多肽：MHCⅡ特异性单抗来鉴定最初从沙门氏菌中产生多肽的树突状细胞：MHC II复合体，构建针对该树突状细胞的单链抗体。该多肽和单链抗体将与鼠伤寒沙门氏菌的Toll样受体5结合部分(起佐剂作用)和假结核耶尔森菌的Beta1整合素结合域(促进M细胞将颗粒转移到佩耶S贴片)结合。这种多组分疫苗将测试其对沙门氏菌产生保护性免疫的能力，并将使用跟踪多肽的新方法：MHC II复合体和特定的CD4+T细胞来评估导致免疫的细胞机制。这些目标的完成将为沙门氏菌、其他感染源和癌症的有效亚单位疫苗的合理设计提供一个框架。

DESCRIPTION (provided by applicant): Salmonella species causes disease or death in millions of individuals every year who ingest contaminated food or water. Individuals who survive Salmonella infection develop robust immunity that is dependent on antibodies that facilitate bacterial phagocytosis by macrophages, and lymphokines from CD4+ T cells that stimulate macrophages to kill engulfed bacteria. For practical reasons, a subunit vaccine capable of inducing the level of immunity that can be induced by live organisms, is desirable. Unfortunately, immunization with individual Salmonella proteins usually induces only partial immunity. The long-term goal of this project is to overcome this inefficiency and produce an effective subunit vaccine for Salmonella. Our hypothesis is that individual Salmonella proteins are less immunogenic than attenuated organisms because of a lack of inherent adjuvant activity, poor entry into the mucosal lymphoid organs, and poor uptake by the dendritic antigen-presenting cells in these organs. Our specific aim is to produce a single vaccine protein that addresses each of these weaknesses. We propose to identify an immunodominant peptide for CD4+ T cells from a protective antigen; use a peptide:MHC ll-specific monoclonal antibody to identify the dendritic cells that initially generate peptide:MHC II complexes from Salmonella organisms, construct a single chain Fv specific for this dendritic cell. The peptide and single chain Fv will be combined with the Toll-like receptor 5-binding portion of S. typhimurium FliC, which functions an adjuvant, and the beta1 integrin-binding domain of Yersinia pseudotuberculosis, which facilitates M cell translocation of particles into the Peyer s patches. This multi-component vaccine will be tested for its ability to generate protective immunity to Salmonella, and novel methods to track peptide:MHC II complexes and specific CD4+ T cells will be employed to assess the cellular mechanisms responsible for immunity. Completion of these aims will provide a framework for the rational design of effective subunit vaccines for Salmonella, other infectious agents, and cancer.