Interaction of Enteroinvasive Pathogens with Neutrophils

性状（由申请方提供）：志贺氏菌、沙门氏菌和耶尔森氏菌。这些相关病原体感染了全世界数百万人，导致不同的疾病，其中许多可能是致命的。中性粒细胞在宿主防御入侵生物体中发挥核心作用。在几个小时内，活化的中性粒细胞迁移到感染部位，在那里它们部署它们的颗粒相关的抗微生物武器库。我们最近确定了一个关键的宿主防御，颗粒蛋白;中性粒细胞弹性蛋白酶（NE），快速，特异性地破坏志贺氏菌，沙门氏菌和耶尔森氏菌的毒力因子。目前还不清楚NE如何识别病原菌并与病原菌相互作用。我们假设活化中性粒细胞的表面结合颗粒蛋白（包括NE）暴露于细菌毒力因子是其防御功能的一个关键方面，并提出以下目标： (1)鉴定活化中性粒细胞表面的生物活性NE，并确定细菌毒力因子是否靶向中性粒细胞表面。NE和其他中性蛋白酶与活化的中性粒细胞的膜结合。由于细菌毒力因子与活化的中性粒细胞的表面结合颗粒蛋白的相互作用的生物学后果是未知的，我们将研究生物活性NE和其他蛋白酶对完整的中性粒细胞在毒力因子的降解中的作用。 (2a)病原体特异性嗜中性粒细胞颗粒蛋白的鉴定。的作用。我们以前已经观察到，NE与志贺氏菌外被膜的结合在用中性粒细胞粗裂解物处理的细菌中比用同等浓度的纯化NE处理的细菌中更有效（未发表）。基于这些观察结果，我们预测，靶向的毒力因子NE增强的颗粒蛋白的完整细菌的脂多糖（LPS）的优先结合。 (2b)研究LPS特异性颗粒蛋白BPI和hCAP 18对NE募集和特异性的作用。特定的嗜中性粒细胞颗粒蛋白，如杀菌渗透性增加蛋白（BPI）和hCAP 18对革兰氏阴性菌的外被膜具有高亲和力。我们先前已经观察到（未发表）在hCAP 18的存在下，纯化的NE与志贺氏菌的结合增加，但在其不存在的情况下。我们建议，这些蛋白质可以潜在地“招募”NE的细菌包膜，从而增加NE的特异性。

DESCRIPTION (provided by applicant): Shigella, Salmonella and Yersinia spp. infect millions of people worldwide, these related pathogens cause different diseases, many of which can be lethal. Neutrophils play a central role in host defense against invading organisms. Within hours, activated neutrophils migrate to the site of infection where they deploy their granule associated anti-microbial arsenal. We recently identified a key host defense, granule protein; neutrophil elastase (NE) that rapidly and specifically destroys virulence factors of Shigella, Salmonella and Yersinia. It is unclear how NE recognizes and interacts with pathogenic bacteria. We hypothesize that the exposure of surface-bound granule proteins, including NE, of activated neutrophils to bacterial virulence factors is a critical aspect of their defense function and propose the following aims: (1) To identify bioactive NE on the surface of activated neutrophils and determine whether bacterial virulence factors are targeted at the neutrophil surface. NE and other neutral proteases associate with the membrane of activated neutrophils. Since the biological consequences of the interaction of bacterial virulence factors with surface-bound granule proteins of activated neutrophils are unknown we will examine the role of bioactive NE and other proteases on intact neutrophils in the degradation of virulence factors. (2a) Identification of pathogen specific neutrophil granule proteins by "affinity" purification with target bacteria. Role of NE. We have previously observed that the association of NE to the outer envelope of Shigella was more effective with bacteria treated with a crude lysate of neutrophils than with equivalent concentrations of purified NE (unpublished). Based on these observations we predict that targeting of virulence factors by NE is augmented by the preferential binding of granule proteins to Lipopolysaccharide (LPS) of intact bacteria. (2b) To examine the role of LPS specific granule proteins BPI and hCAP18 on NE recruitment and specificity. Specific neutrophil granule proteins such as Bactericidal Permeability Increasing protein (BPI) and hCAP18 have a high affinity for the outer envelope of Gram-negative bacteria. We have previously observed (unpublished) increased binding of purified NE to Shigella in the presence of hCAP18 but not in its absence. We propose that these proteins could potentially "recruit" NE to the bacterial envelope resulting in increased NE specificity.