Porphyromonas gingivalis cysteine proteinases in modulation of cell-mediated immune response in periodontitis

Funded Activity Summary

Chronic inflammatory diseases of the tissues supporting the teeth comprise some of the most widespread and common diseases to affect mankind. Recent research has indicated the major contributor to the most common form of destructive periodontal disease is the bacterium Porphyromonas gingivalis. This organism produces powerful enzymes which overcome the body's attempts to neutralise them. It is also known that the destructive phase of the disease is characterised by a change in the behaviour of the immune system cells which accumulate in the diseased tissues. This is manifest as a loss of protective immunity and replacement by ineffective or even tissue damaging responses. Critical in directing the pattern of behaviour of the immune system cells are the potent messenger molecules or cytokines which pass between cells. We have demonstrated that the bacterial proteinases can destroy a critical messenger molecule that instructs the defensive phagocytic cells to attack bacteria. These cells in return normally send a powerful signal back to the controlling T lymphocyte to amplify the protective signals. Associated bacterial molecules stimulate more secretion of messenger molecules which are paradoxically destroyed by the bacterial enzymes. This could cause chaos in the local tissue environment. Further, the bacterial proteinases can also eliminate some important surface molecules of T lymphocyte that are important in the activation process. The effect of this could produce impairment of T lymphocyte at periodontal sites. The planned research will define how the proteinases modulate T lymphocyte immune response. Further, the relation between the capacity of the bacterial enzymes to disrupt the vascular cells and the progression of periodontitis will also be determined.

Funded Activity Details

Start Date: 01-01-2005

End Date: 01-01-2007

Funding Scheme: NHMRC Project Grants

Funding Amount: $228,000.00

Funder: National Health and Medical Research Council

Research Topics

ANZSRC Field of Research (FoR)

Dentistry

ANZSRC Socio-Economic Objective (SEO)

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Other Keywords

T lymphocyte responses | adhesion molecules | cell mediated immunity | chronic periodontitis | endothelial apoptosis | endothelial damage | immune responses to porphyromonas gingivalis | oral biology | protease | regulation of p53 tumour supressor activity

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