ABSTRACT
Bordetella pertussis produces an adenylyl cyclase toxin (AC toxin) that is primarily extracytoplasmic in location. This novel toxin is an adenylyl cyclase, some or all of which enters target cells, is activated by endogenous target cell calmodulin, and increases intracellular cAMP to supraphysiologic levels. The activities of this AC toxin can be separated into its catalytic or enzyme activity (ability to convert A TP to cAMP), its
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invasive or toxin activity (the ability to enter target cells and raise intracellular cAMP concentration), its hemolytic activity (ability to hemolyze red blood cells), and its pore-forming activity (ability to produce ion conductance in a lipid bilayer). In this chapter, the discovery of the various activities of this toxin is reviewed along with its operon organization, the present understanding of its structure and function, and its homology with other bacterial toxins. Finally, the role of AC toxin in the pathogenesis of whooping cough and its potential usefulness in an acellular vaccine are discussed.
