It is thus plausible that the capacity of CyaA to block monocyte-to-macrophage transition plays a role in immune evasion of the whooping cough agent, as gradients of the cAMP-elevating adenylate cyclase would form in the B. pertussis-infected mucosal tissue at levels that would vary as a function of the distance from the site at which the adhering bacteria are growing. The gene discussed is ADCY1; the disease is pertussis.