Cholera toxin co-receptor interaction in the prevention of inflammatory autoimmune disorders

Funded Activity Summary

Vaccination is undoubtedly one of mankind's greatest achievements. While infections continue to be the major cause of morbidity and mortality in the developing world, heart disease, cancer, chronic allergies and autoimmune disorders are taking their toll in advanced societies. Our expanding knowledge of these 'modern diseases' shows that the immune system plays a central role and hence it is important to learn if new immunologically-based therapies can be developed for such chronic human disorders. This project takes advantage of our recent discoveries on the immunological properties of a hitherto feared molecule - cholera toxin. We have shown that one portion of the toxin, the B-subunit, responsible for binding to cell membranes, possesses remarkable immunomodulatory properties that prevent the development of inflammatory autoimmune disorders such as rheumatoid arthritis in animal models. The B-subunit, in contrast to the whole cholera toxin, is non-toxic and has no adverse effects in humans. This has sparked considerable interest in the development of such molecules as novel anti-inflammatory agents and highlighted the necessity to better understand the B-subunit's mode of action. Current theory specifies that the B-subunit mediates its immunomodulatory effects by binding and cross-linking a ubiquitous plasma membrane glycosphingolipid, GM1 ganglioside. The essential role of GM1-interaction was recently challenged by our discovery that a mutant B-subunit (H57A) was unable to modulate the immune system even though it still bound to GM1; suggesting that the B-subunits interact with another receptor (or co-receptor), and that it is this second interaction that directs the immune system to prevent development of autoimmune disease. The primary aims are to characterize the nature of B-subunit interaction with the cell membrane and to identify the co-receptor. This work has the potential to provide a new target for drug discovery and development of immunotherapeutics.

Funded Activity Details

Start Date: 01-01-2007

End Date: 01-01-2008

Funding Scheme: NHMRC Project Grants

Funding Amount: $359,577.00

Funder: National Health and Medical Research Council

Research Topics

ANZSRC Field of Research (FoR)

Medical Microbiology

ANZSRC Socio-Economic Objective (SEO)

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Other Keywords

allergies | autoimmune disorders | cholera toxin | diarrhoeal disease | innfection and immunity | membrane receptors | protein structure

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