Cholera toxin, LT-I, LT-IIa and LT-IIb: the critical role of ganglioside binding in immunomodulation by Type I and Type II heat-labile enterotoxins

Abstract

The heat-labile enterotoxins expressed by Vibrio cholerae (cholera toxin) and Escherichia coli (LT-I, LT-IIa and LT-IIb) are potent systemic and mucosal adjuvants. Coadministration of the enterotoxins with a foreign antigen produces an augmented immune response to that antigen. Although each enterotoxin has potent adjuvant properties, the means by which the enterotoxins induce various immune responses are distinctive for each adjuvant. Various mutants have been engineered to dissect the functions of the enterotoxins required for their adjuvanticity. The capacity to strongly bind to one or more specific ganglioside receptors appears to drive the distinctive immunomodulatory properties associated with each enterotoxin. Mutant enterotoxins with ablated or altered ganglioside-binding affinities have been employed to investigate the role of gangliosides in enterotoxin-dependent immunomodulation.

Keywords::

• adjuvant
• enterotoxin
• ganglioside
• immunomodulation
• signal transduction

Acknowledgements

I would like to thank Natalie King-Lyons for reading the manuscript and providing useful critical comments.

Financial & competing interests disclosure

The author was supported by The National Institutes of Health research grants DE013833 and DE014357. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.