Antiacetylcholinesterase antibodies: Enzyme antibodies interaction

Summary Erythrocyte acetylcholinesterase activity of rabbits was significantly increased over control levels by immunization with acetylcholinesterase from the electric organ of the electric eel. The increase of enzyme activity and that of anti-acetylcholinesterase antibodies had the same time course, reaching a maximum level on the 35th day. The increase in acetylcholinesterase activity could be reproduced in vitro by incubating erythrocyte ghosts of normal rabbits with sera containing antibodies against eel acetylcholinesterase. The Michaelis constant was the same before and after the activating treatment, as well as the sensitivity to the antiacetylcholinesterase agent phenylmethylsulfonylfluoride. Antiacetylcholinesterase antibodies bind to a polypeptide component of erythrocyte membrane, having an apparent molecular weight of about 90.000 in polyacrylamide gel electrophoresis. The results indicate that: 1) the existence of common antigenic determinant(s) in both rabbit erythrocyte and eel electric organ acetylcholinesterase; 2) the enzyme activation produced by interaction with the antibody is due not to a modification of the enzyme properties but probably to an unmasking effect, similar to that of some detergents.