Abstracts of Papers Presented at the Third International Complement Workshop, Harvard Medical School, Boston, Massachusetts, June 3–5, 1968

Abstract

Abstract Plasma from persons with hereditary angioneurotic edema develops permeability factor and kinin activity, both of which seem to be due to the action of a relatively small polypeptide molecule. Histamine plays no role in these activities, clearly distinguishing the permeability factor and kinin properties in this plasma from the anaphylatoxins which may be formed from purified components of complement. Partially purified preparations of this kinin-permeability factor activity contracted rat uterus but not guinea pig ileum; and when injected intravenously into anesthetized rats, their arterial blood pressure was raised slightly. The kinin and permeability factor activity of this preparation could be destroyed during incubation with trypsin, chymotrypsin and carboxypeptidase. The effect on rat arterial blood pressure and susceptibility to trypsin suggest that the polypeptide differs from bradykinin and lysyl bradykinin, both of which have vasodepressor effects in the rat, and neither of which loses its kinin or permeability factor activity during incubation with trypsin.