Structural and functional differences between decay-accelerating factor and
red cell acetylcholinesterase [published erratum appears in Blood 1987
Jul;70(1):339]
J Sugarman, DV Devine and WF Rosse
The abnormal erythrocytes in paroxysmal nocturnal hemoglobinuria, both PNH
II (the moderately abnormal cells) and PNH III (the markedly abnormal
cells), lack both acetylcholinesterase (AChE) activity and
decay-accelerating factor (DAF) activity. Both of these activities are
found on glycoprotein molecules with a molecular weight of about 70 Kd. To
demonstrate that these two activities are in fact on different proteins, we
have shown that binding to normal red cells of antibody to DAF does not
inhibit the subsequent binding of monoclonal antibody to AChE nor AChE
activity. Inhibition of DAF activity by polyclonal antibody increases the
susceptibility of normal erythrocytes to lysis by complement but inhibition
of AChE activity by antibody does not. The rate of decay of the C3
convertase complex of the classical pathway of complement activation was
inhibited by DAF added in the fluid phase but not by AChE. When DAF was
exhaustively immunoprecipitated from a solution of the erythrocyte membrane
proteins, AChE remained and vice versa. These studies indicate that
acetylcholinesterase and decay- accelerating factor are two different
proteins, both of which are lacking on PNH II and PNH III erythrocytes.
Volume 68,
Issue 3,
pp. 680-684,
09/01/1986
Copyright © 1986 by The American Society of Hematology
