A LOW-MOLECULAR WEIGHT INHIBITOR OF THE ALTERNATIVE COMPLEMENT PATHWAY .1. ITS ISOLATION FROM HUMAN-URINE AND THE REACTION-MECHANISM

  • 1 January 1980
    • journal article
    • research article
    • Vol. 41  (4) , 789-798
Abstract
A low MW inhibitor (LMW-INH) of the alternative pathway activation was isolated from healthy human urine. Its MW was slightly higher than 1000. LMW-INH inhibited C3 [complement component 3] convertase formation in fluid phase, on sheep erythrocytes and on zymosan particles. In contrast with .beta.1H globulin, LMW-INH showed no effect on the C3b binding site for [complement factor] B, and it inhibited the CVF [cobra venom factor] B complex activation by D only when LMW-INH was simultaneously present with D. Apparently the LMW-INH reaction mechanism is different from that of .beta.1H globulin.