Open AccessMonoclonal antibodies to Torpedo acetylcholine receptor
Author(s) -
WHITING Paul,
VINCENT Angela,
NEWSOMDAVIS John
Publication year - 1985
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1985.tb09054.x
Subject(s) - torpedo , acetylcholine receptor , binding site , monoclonal antibody , decamethonium , chemistry , receptor , avidity , antibody , cholinergic , biochemistry , microbiology and biotechnology , biology , endocrinology , immunology
Thirteen monoclonal antibodies (mAb) to the acetylcholine receptor (AChR) from Torpedo marmorata showed high avidity for the receptor but none exhibited binding to muscle AChR solubilised from seven other animal species. Five mAb and Fab monomer fragments prepared from two of them, inhibited α‐bungarotoxin (αBuTx) binding to receptor by a maximum of 50%. In the presence of excess mAb the 125 I‐αBuTx bound could be precipitated by anti‐IgG indicating that the mAb bound to only one of the two αBuTx binding sites on each AChR monomer. This site appeared to have a lower affinity for d ‐tubocurarine and decamethonium than the non‐mAb site. Binding of five anti‐site mAb was mutually competitive and four of them (AS2 – AS5) were inhibited by other cholinergic ligands and influenced by four non‐toxin binding site antibodies. One (AS1) bound within the toxin binding site yet outside the main neurotransmitter binding region. It is concluded that these five mAb distinguish between the two αBuTx binding sites on the Torpedo AChR, and bind only to the site which displays lower affinity for d ‐tubocurarine and other competitive ligands.