Receptor-binding and Translocation

These effects are responsible for most of the systemic features of whooping cough, the disease caused by Bordetella pertussis, the micro-organism that produces PT (Pittman, 1984). Accordingly, the existence of PT was first predicted by the expression of its numerous biological activities detected after infection with 6. pertussis or administration of whole cell pertussis vaccines. These activities include histamine sensitization, islet activation, induction of leukocytosis, immuno-potentiation and many others (Munoz, 1985). 

Aktories (Ed.), Bacterial Toxins. Chapman Hall, Weinheim, 1997. ISBN 3-8261-0080-8 

The expression of the ptx genes requires a transactivating factor, named BvgA. This transactivator is part of a two-component system composed of the sensor BvgS and the activator BvgA (for review, see Uhl and /Vliller, 1995). PTX is coordinately produced together with other 6. pertussis virulence factors. All known virulence factors are under the control of the same BvgA/S two-component system. 

BvgA is a cytoplasmic protein with an N-terminal receiver domain and a C-terminal DNA-binding domain. In the active form, this pro- 

PT secretion through the outer membrane depends on the expression of accessory genes located directly downstream from the five structural genes (Weiss et al., 1993). These genes, named pfi genes 

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