Two forms of Bordetella pertussis adenylate cyclase of 200 and 47 kDa have been purified from dialyzed urea extract of the bacteria to specific activities of 466 and 1685 mumol.min-1.mg-1, respectively. Both forms are activated 50-200-fold by calmodulin. The half-maximum concentration required for the activation of the 200-kDa catalyst is 5.4.10(-9) M, whereas the one required for activation of the 47-kDa catalyst is 1.8.10(-10) M. Polyclonal antibodies raised against the 47-kDa catalyst specifically recognize both forms of the enzyme in purified state as well as in bacterial extracts on immunoblots. The antibody inhibits at similar titer adenylate cyclase activity of the purified forms as well as the activity present in dialyzed urea extract of the bacteria. It also prevents the penetration of the invasive B. pertussis adenylate cyclase into human lymphocytes. The inhibition induced by the antisera is specific to B. pertussis enzyme, since both calmodulin-dependent brain and sperm adenylate cyclase are not affected by the antibody.