IMMUNOBIOLOGY OF A 30 KDA PROTEIN OF HAEMOPHILUS DUCREYI

该项目旨在了解在感染的初始阶段，衰老嗜血杆菌与人中性粒细胞(PMN)和宿主上皮细胞的分子相互作用。宿主细胞对病原体的附着和内化通常是感染过程的第一步。在体外，杜氏嗜血杆菌在没有血清调理素的情况下被中性粒细胞结合和内化，并被上皮细胞结合和内化，这可能是一种配体(粘附素)/受体相互作用(S)。在感染过程的早期进行免疫干预可以改变或预防细胞附着和可能的疾病。中性粒细胞是软骨肉软骨样病变开始时招募的第一批细胞，因此可能是抵抗感染的重要防御措施。这些研究将增强我们对附着上皮细胞和PMN在感染过程中的作用以及PMN杀死杜氏杆菌的能力的全面了解，并可能导致新的疫苗策略。有五个具体目标。在第一个特定目标中，将构建30 kDa外膜蛋白的等基因突变体。如以下各节详细描述的那样，30 kDa的蛋白质与细胞粘附素和其他细菌中介导血清抵抗的蛋白质有关。第二个具体目标是确定这种蛋白质的功能。我们将使用突变/亲本比较来确定其在粘附中性粒细胞、上皮细胞和细胞基质蛋白方面的可能作用。我们还将进行30 kDa突变体/亲本对血清和吞噬细胞杀伤的抵抗力比较。在第三个特定目标中，我们将在温度依赖的兔感染模型和人类实验模型中测试杜氏疟原虫30 kDa蛋白的等基因突变体。第四个具体目标涉及某些与疫苗相关的问题。我们将确定30 kDa蛋白的抗体是否在软下盘感染期间被激发，以记录体内的表达。我们将测试纯化的重组表达30 kDa的能力，以保护动物免受攻击感染。在特定的目标5中，我们将识别PMN和细胞粘附素，而不是30 kDa的蛋白。

This project seeks to understand the molecular interactions of Haemophilus decreyi with human neutrophils (PMN) and host epithelial cells during the initial stages of infection. Attachment to, and internalization of, pathogens by host cells is often the first step in the infectious process. In vitro, H. ducreyi is bound and internalized by PMN in the absence of serum opsonins and by epithelial cells suggesting a ligand (adhesin)/receptor interaction(s). Immunological intervention early in the infectious process could modify or prevent cellular attachment and possibly disease. PMNs are the first cells recruited at the onset of chancroidal lesion and therefore might be an important defense against infection. These studies will enhance our overall understanding of the role of attachment to epithelial cells and PMN in the infectious process, the ability of PMN to kill H. ducreyi, and perhaps, lead to new vaccine strategies. There are five Specific Aims. In the first Specific Aim, an isogenic mutant of the 30 kDa outer membrane protein will be constructed. As described in detail in the following sections, the 30 kDa protein is related to cellular adhesins and proteins which mediate serum resistance in other bacteria. The second Specific aim is to determine the function of this protein. We will use mutant/parent comparisons to determine its possible role in adherence to PMN, epithelial cells, and cellular matrix proteins,. We will also perform 30 kDa mutant/parent comparisons for resistance to serum and phagocytic killing. In the third Specific aim, we will test an isogenic mutant of the H. ducreyi 30 kDa protein in the temperature dependent rabbit model of infection and in the human experimental model of H. ducreyi infection. The fourth Specific aim addresses certain vaccine related issues. We will determine if antibodies to the 30 kDa protein are elicited during chancroid infection to document in vivo expression. We will test the ability of purified recombinantly expressed 30 kDa to protect animals from a challenge infection. In Specific Aim 5 we will identify PMN and cellular adhesins other than the 30 kDa protein.