Hemolytic activity of adenylate cyclase toxin from Bordetella pertussis

Adenylate cyclase (AC) toxin from B. pertussis enters eukaryotic cells where it produces supraphysiologic levels of cAMP. Purification of AC toxin activity [(1989) J. Biol. Chem. 264, 19279] results in increasing potency of hemolytic activity and electroelution of the 216-kDa holotoxin yields a single protein with AC enzymatic, toxin and hemolytic activities. AC toxin and E. coli hemolysin, which have DNA sequence homology [(1988) EMBO J. 7, 3997] are immunologically cross-reactive. The time courses of hemolysis elicited by the two molecules are strikingly different, however, with AC toxin eliciting cAMP accumulation with rapid onset, but hemolysis with a lag of greater than or equal to 45 min. Finally, osmotic protection experiments indicate that the size of the putative pore produced by AC toxin is 3-5-fold smaller than that of E. coli hemolysin.