The antrax toxin is made up of three fractions. Protective antigen factor,edema factor and lethal factor. Protective antigen factor binds to the receptors of the host cell surface and facilitates the entry of edema factor and lethal factor. Edema factor is an adenyl cyclase which causes intracellular accumulation of cyclic AMP. And this cyclic AMP is believed to cause edema. What is the mechanism of this?