EFFECT OF MERCAPTANS AND OTHER AGENTS ON HUMAN COMPLEMENT COMPONENT BETA 1C-GLOBULIN

Abstract

Immunoelectrophoretic analyses and complement titrations of whole human serum show that a number of physical, chemical and immunological agents affect the [beta]1c[beta]1A-globulin system which is considered to represent the third component of complement (C''3). The transformation from [beta]1C-globulin to [beta]1A-globulin is the normal result of ageing, while antigen-antibody complexes, polylysine, hydrazine and cobra venom accelerate this change. In addition, [alpha]-globulin fragments of [beta]1A-globulin appear after interaction of normal sera with antigen-antibody complexes, treatment with cobra venom, and by storage under nitrogen in glass tubes or in polyethylene containers. Similar [alpha]-fragments are seen in the aged sera of some patients with glomerulonephritis or renal allografts. With prolonged storage these [alpha]-fragments can reform [beta]1A-globulin. On the other hand, 2-mercaptoethanol and penicil-lamine produce complete dissolution of [beta]1C-globulin into rapidly migrating, poorly defined fragments in the a-globulin and albumin regions, and transform [beta]1A-globulin into a stable [beta]2-globulin. The reduced fragments of B1C-globulin, if not alkylated, can subsequently form the [beta]2-globulin, but not the [beta]1A-globulin These results indicate that [beta]1C-globulin is composed of several subunits, some of which are joined by disulphide bonds, but that the [alpha]-globulin fragments seen in some pathological sera are not a result of disulphide bond reduction.