Development of a Conjugate Vaccine for the Prevention of Tularemia

图拉氏方济氏菌是一种高度传染性的细菌，作为生物恐怖主义的媒介构成了严重的威胁。 目前有一种活的全细胞疫苗可用于高危人群，但它与不完全 免疫力和副作用。对人类和小鼠接种这种制剂的研究表明， 体液和细胞介导的免疫反应是受感染宿主的完全保护所必需的。 目前，与图拉氏丝虫有关的毒力因子对其致病作用知之甚少。 导致致命疾病的能力。然而，以前的研究已经确定胶囊和脂多糖为原理 其致病潜力的决定因素。我们对最近公布的基因组的分析。图拉尔牛 $4已经证明它具有一个单一的多糖生物合成位点，负责One的表达 表面多糖。根据这些数据，我们假设之前描述的胶囊和 这种生物体的O-抗原实际上代表一个O-抗原/胶囊，它具有相同的重复 单元结构，但表现为明显的大分子量聚合物和小分子量聚合物 脂类A连接的多糖。我们预测，这种结构在 这种微生物的致病机制，并可用作新型糖结合疫苗的基础 获得对实验性图拉热症的完全保护。为了解决这一结构性问题， 毒力因子及其在图拉氏丝虫致病和免疫中的作用，我们建议：1)表征 O-抗原/胶囊的结构和遗传性质；2)决定O-抗原/胶囊在 毒力；3)确定对O抗原/衣壳的体液和细胞免疫反应，以及 蛋白质去除了。以及4)开发一种针对图拉氏丝虫感染的结合疫苗。这些研究将 使用基于蛋白质组学的方法从图拉氏丝虫中鉴定新的免疫原性蛋白，这些蛋白可以是 在新型无细胞糖结合疫苗的开发中用作载体。预计这些 疫苗将激活体液和细胞介导的免疫反应，并产生完全保护作用。 治疗图拉热症。糖结合疫苗是有史以来最有效的生物制品之一。 用于预防细菌感染。预计这种方法可以成功地应用于 开发一种疫苗，最终可以在预防图拉热症的临床试验中进行测试。

Francisella tularensis is a highly infectious bacterium that poses a serious threat as an agent ofbioterrorism. A live whole cell vaccine is currently available for at-risk populations, but it is associated with incomplete immunity and side-effects. Studies of humans and mice vaccinated with this preparation indicate that humoral and cell-mediated immune responses are required for complete protection in the infected host. Currently, little is known concerning the virulence factors associated with F. tularensis that contribute to its ability to cause lethal disease. However, previous studies have identified the capsule and LPS as principle determinants of its pathogenic potential. Our analysis of the recently released genome ofF. tularensis Schu $4 has shown that it possesses a single polysaccharide biosynthetic locus responsible for expression of one surface polysaccharide. Based on these data, we hypothesize that the previously described capsule and O-antigen of this organism actually represents a single O-antigen/capsule that has the same repeating unit structure, but is expressed as a distinct large molecular-weight polymer and smaller molecularweight Lipid A-linked polysaccharide. We predict that this structure has a central role in the pathogenesis of this organism and can be used as the basis for novel glycoconjugate vaccines that will elicit complete protection against experimental tularemia. To address the structural nature of this virulence factor and its role in the pathogenesis and immunity to F. tularensis, we propose to: 1) Characterize the structural and genetic nature of the O-antigen/capsule; 2) Determine the role of the O-antigen/capsule in virulence; 3) Determine the humoral and cell-mediated immune responses to the O-antigen/capsule and proteins ofF. tularensis; and 4) Develop a conjugate vaccine for F. tularensis infections. These studies will employ a proteomics-based approach to identify new immunogenic proteins from F. tularensis that can be used as carriers in the development of novel acellular glycoconjugate vaccines. It is anticipated that these vaccines will activate both humoral and cell-mediated immune responses and elicit complete protection against tularemia. Glycoconjugate vaccines have been among the most effective biologics ever developed for the prevention of bacterial infections. It is expected that this approach can be applied successfully to the development of a vaccine that can ultimately be tested in clinical trials for the prevention of tularemia.