Immunobiology of the DsrA protein of H. ducreyi

杜克雷嗜血杆菌（Haemophilus ducreyi）是生殖器溃疡性疾病软下疳的病原体， 全世界几个区域都有健康问题。我们建议继续对外层的结构/功能进行研究， 膜蛋白DsrA。ducreyi并确定其疫苗潜力。长期目标是 研究是开发一种预防软下疳的疫苗。 DsrA是一种多功能的三聚体自转运蛋白，赋予高水平的血清抗H。 ducreyi。此外，DsrA结合细胞外基质组分纤连蛋白和玻连蛋白，并赋予 在H。ducreyi附着于角质形成细胞的能力。DsrA的这4个功能中的每一个都被认为是 其他细菌系统中的毒力因子。 具体目标1建议继续研究DsrA的结构组成， 功能协调发展的将使用一组dsrA突变体鉴定角质形成细胞结合所需的结构域。 DsrA的4种功能中的每一种所需的特定残基也将使用肽精确定位。 文库和定点诱变。定义的dsrA突变体将在实验人类中进行测试。 软下疳模型，以确定感染所需的DsrA功能。结果从这些 实验将侧重于目标2所述的疫苗研究，并为之提供信息。 具体目标2提出确定DsrA在实验性猪模型中是否是有效的疫苗。 软下疳rDsrA主动免疫或抗DsrA单克隆抗体被动免疫 将进行DsrA作为预防软下疳疫苗的有效性研究。无毒佐剂将 作为弗氏佐剂的替代品进行检查。

Haemophilus ducreyi, the etiological agent of the genital ulcer disease chancroid, is a significant public health problem in several regions woridwide. We propose to continue structure/function studies of the outer membrane protein DsrA of H. ducreyi and determine its vaccine potential. The long-term goal of this research is to develop a vaccine against chancroid. DsrA is a multifunctional trimeric autotransporter protein conferring high levels of serum resistance to H. ducreyi. Additionally, DsrA binds the extracellular matrix components fibronectin and vitronectin and confers upon H. ducreyi the ability to attach to keratinocytes. Each of these 4 functions of DsrA is considered a virulence factor in other bacterial systems. Specific aim 1 proposes to continue investigating the structural components of DsrA involved in its multiple functions. The domain(s) required for keratinocyte binding will be identified using a panel of dsrA mutants. The specific residues required for each of the 4 functions of DsrA will also be pinpointed using peptide libraries and site-directed mutagenesis. Defined dsrA mutants will be tested in the experimental human model of chancroid to determine which function of DsrA is required for infection. The results from these experiments will focus and inform efforts for the vaccine studies described in aim 2. Specific aim 2 proposes to determine if DsrA is an effective vaccine in the experimental swine model of chancroid. Active immunization with rDsrA or passive immunization with an anti-DsrA monoclonal antibody will be done to examine the efficacy of DsrA as a vaccine against chancroid. Non-toxic adjuvants will be examined as substitutes for Freund's adjuvant.