Autoantibody catalysis: no longer hostage to Occam's razor.

Autoantibody catalysis is now a well-established phenomenon, but the initial finding of autoantibody-catalyzed VIP cleavage was suspected to be an artefact by certain practitioners of designer antibody catalysis, mainly because of conceptual complexities not foreseen in our training about the immune system and about the mechanisms of biological catalysis. Confirmation that antibodies can acquire proteolytic activity by entirely natural means has emerged, ironically, in part from the field of designer catalytic antibodies. Recent studies have provided insight into the molecular strategies whereby antibodies can combine antigen binding with chemical catalysis, and the contributions of innate and adaptive immune mechanisms in the proteolytic activity. The history of this field illustrates the dangers of assuming that novel observations must fit into the simple confines of established theories. Scientific theories are changeable entities, dependent on empirical data and interpretations of the data, and their growth is better served by keeping an open mind.