The role of complement in periodontal disease can be either protective or pathologic depending on the stage of the disease and the pathogens involved. Our hypothesis is that the humoral inflammatory factor C5a, the chemotatic cytokine IL-8 and/or formulated bacterial peptides (f-MLF) play a significant role in promoting gingival tissue injury resulting from bacterial infection. This process may be set in motion either by the anaerobic gram-negative bacteria or the proteases they elaborate. Although complement activation can be initiated directly by contact between plasma and bacterial particles, we propose that bacterial proteases are primarily responsible for prolonged generation of C5a in periodontal disease. The potent chemotactic factors C5a/f-MLF recruit neutrophils and macrophages which in turn release protases, IL-8 and other cellular cytokines that accelerate tissue degradation and promotes edema. Persistent edema due to leakage of plasma fluid from the microvasculature of the periodontium is a usual feature of periodontal diseases. Plasma protein filtrate contains C5 which may be degraded by bacterial proteases, with resultant release of the chemotaxin C5A. Prolongation of localized inflammatory cell sequestration is consistent with the hypothesis of ongoing C5a generation, which may contribute to the chronic inflammatory response that is the hallmark of periodontitis. The early events in periodontitis are likely driven by bacterial (i.e. formulated peptides) and/or humoral (i.e. C5a) chemotactic factors which initiate the cascade of cellular infiltration. The initial cellular influx may be amplified later in the process by cell-derived chemotactic factors such as PAF, IL-8 and LTB4. This proposal is designed to first demonstrate evidence for C5a/IL-8 at the injury site, examine effects of the bacterial products (i.e proteases) on the various activation factors and their receptors, and then test the hypothesis that C5a/IL-8 involvement actually occurs and contributes significantly in promoting the disease. Secondly, I propose to specifically evaluate processes such as """"""""priming"""""""" of the neutrophils/macrophages by bacterial endotoxin, which enhances responsiveness of the cells to chemotactic factors. C5a and IL-8 receptors were recently demonstrated on cultured epithelial cells (HEp-2 and KB) and on epithelial cells in human gingival tissue (see preliminary results section). Both anti-C5a/IL-8 and anti-C5a/IL-8 receptor antibodies, capable of neutralizing binding and in vivo cellular migration, have been developed. These reagents will be used to explore the actions of the proteases from P.gingivalis on the chemotaxins and their receptors. We have shown that both Arg- and Lys-gingipain degrade C3 and C5 and generate bioactive C5a (see preliminary results section). In addition, we observed that oxygen radical treatment of C5 significantly enhanced C5a generation by the gingipains (manuscript in preparation). We propose to explore possible C5a/IL-8 induced epithelial cell functions including the release of acute phase proteins and cytokines. It is proposed that early events in the inflammatory response of periodontal disease are mediated by the chemotaxins and that understanding these events may lead to therapeutically useful modes of intervention.

National Institute of Health (NIH)
National Institute of Dental & Craniofacial Research (NIDCR)
Research Project (R01)
Project #
Application #
Study Section
Oral Biology and Medicine Subcommittee 1 (OBM)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Scripps Research Institute
La Jolla
United States
Zip Code
Jagels, M A; Daffern, P J; Hugli, T E (2000) C3a and C5a enhance granulocyte adhesion to endothelial and epithelial cell monolayers: epithelial and endothelial priming is required for C3a-induced eosinophil adhesion. Immunopharmacology 46:209-22
Fischer, W H; Jagels, M A; Hugli, T E (1999) Regulation of IL-6 synthesis in human peripheral blood mononuclear cells by C3a and C3a(desArg). J Immunol 162:453-9
Fukuoka, Y; Ember, J A; Hugli, T E (1999) Ligand binding sites on guinea pig C3aR: point and deletion mutations in the large extracellular loop and vicinity. Biochem Biophys Res Commun 263:357-60
Jagels, M A; Daffern, P J; Zuraw, B L et al. (1999) Mechanisms and regulation of polymorphonuclear leukocyte and eosinophil adherence to human airway epithelial cells. Am J Respir Cell Mol Biol 21:418-27
Pfeifer, P H; Kawahara, M S; Hugli, T E (1999) Possible mechanism for in vitro complement activation in blood and plasma samples: futhan/EDTA controls in vitro complement activation. Clin Chem 45:1190-9
Daffern, P J; Jagels, M A; Saad, J J et al. (1999) Upper airway epithelial cells support eosinophil survival in vitro through production of GM-CSF and prostaglandin E2: regulation by glucocorticoids and TNF-alpha. Allergy Asthma Proc 20:243-53
Daffern, P J; Muilenburg, D; Hugli, T E et al. (1999) Association of urinary leukotriene E4 excretion during aspirin challenges with severity of respiratory responses. J Allergy Clin Immunol 104:559-64
Daffern, P J; Jagels, M A; Hugli, T E (1999) Multiple epithelial cell-derived factors enhance neutrophil survival. Regulation by glucocorticoids and tumor necrosis factor-alpha. Am J Respir Cell Mol Biol 21:259-67
Fukuoka, Y; Ember, J A; Hugli, T E (1998) Cloning and characterization of rat C3a receptor: differential expression of rat C3a and C5a receptors by LPS stimulation. Biochem Biophys Res Commun 242:663-8
Fukuoka, Y; Ember, J A; Yasui, A et al. (1998) Cloning and characterization of the guinea pig C5a anaphylatoxin receptor: interspecies diversity among the C5a receptors. Int Immunol 10:275-83

Showing the most recent 10 out of 17 publications