P. gingivalis Capsule in Cell Inflammation

牙龈卟啉单胞菌是一种革兰氏阴性、厌氧、口腔病原体，是成人牙周病的主要病原体。最近的报道表明，包膜的牙龈假单胞菌比未包膜的菌株毒力更强。然而，牙龈假单胞菌荚膜多糖在疾病发病机制中的确切作用，以及这种毒力因子的作用机制，在很大程度上还不清楚。我们推测牙龈卟啉单胞菌的荚膜多糖促进了牙龈卟啉单胞菌感染所特有的细胞炎症反应，并参与了牙龈卟啉单胞菌介导的成人牙周病的病理。我们的初步体外研究表明，这种抗原与宿主细胞结合，并刺激先天免疫反应，这是允许中性粒细胞趋化的。体内观察证实了我们的体外数据，并证明纯化的牙龈假单胞菌荚膜多糖刺激宿主炎症细胞反应，这模拟活的，牙龈假单胞菌全细胞挑战。提出了三个具体的目标：1)确定纯化的牙龈卟啉单胞菌荚膜多糖与上皮细胞的结合动力学，并确定相关的免疫细胞群。我们将表征1个剂量和时间相关的结合动力学、2个结合的特异性，并使用阻断研究来确定纯化的牙龈假单胞菌胶囊多糖与宿主细胞的附着。2)：研究牙周炎上皮细胞及相关白细胞群对牙周膜多糖的天然免疫反应。将检测细胞因子的分泌、细胞黏附分子的产生和中性粒细胞的募集。我们将描述细胞受到刺激时产生的细胞因子、趋化因子和细胞黏附分子与中性粒细胞迁移的刺激和特征。3)：在小鼠气囊模型中，确定牙龈卟啉单胞菌包膜多糖引起的细胞炎症事件。我们将描述宿主细胞对纯化的牙龈假单胞菌荚膜多糖的炎症反应，并开始定义控制白细胞募集的先天免疫反应。

DESCRIPTION: Porphyromonas gingivalis, a Gram-negative, anaerobic, oral pathogen is the primary etiologic agent of adult periodontal disease. Recent reports indicate that encapsulated P. gingivalis are more virulent then unencapsulated strains. Nevertheless, the precise role of P. gingivalis capsular polysaccharide in disease pathogenesis, and the mechanism by which this virulence factor acts, are largely unknown. We posit that the capsular polysaccharide of Porphyromonas gingivalis promotes a cellular inflammatory response characteristic of P. gingivaIis infection, and contributes to the pathology observed in P. gingivalis-mediated adult periodontal disease. Our preliminary, in vitro studies demonstrate that this antigen binds to host cells and stimulates an innate immune response, which is permissive for PMN chemotaxis. In vivo observations confirmed our in vitro data, and demonstrate that purified P. gingivalis capsular polysaccharide stimulates a host inflammatory cell response, that mimics live, P. gingivalis whole cell challenge. Three Specific Aims are proposed: 1): To define the binding kinetics of purified Porphyromonas gingivalis capsular polysaccharide to epithelial cells and defined populations of relevant immune cells. We will characterize 1- dose-and time-dependent binding kinetics, 2- binding specificity, and employ blocking studies to define the attachment of purified P. gingivalis capsular polysaccharide to host cells. 2): To characterize the innate immune response of epithelial cells and relevant leukocyte populations to P. gingivalis capsular polysaccharide. Cytokine secretion, cell adhesion molecule production and neutrophil recruitment will be examined. We will delineate the cytokine, chemokine and cell adhesion molecule repertoire produced by cells challenged as related to stimulation and characterization of PMN transmigration. 3): To define the cellular inflammatory event that occurs in response to Porphyromonas gingivalis capsular polysaccharide in a murine air pouch model. We will characterize the host cellular inflammatory response to purified P. gingivalis capsular polysaccharide and begin to define the innate immune responses that govern leukocyte recruitment.