Neurotoxin-specific immunoglobulins accelerate dissociation of the neurotoxin-acetylcholine receptor complex.

Toxin isolated from cobra venom and labeled with tritium was incubated with membranes rich in acetylcholine receptors. The amount of toxin bound to the receptors was determined and the kinetics of dissociation of the receptor-toxin complex was followed. Addition of an excess of horse antiserum to the venom resulted in a significant acceleration of the dissociation reaction. Similarly, a monoclonal antibody against the toxin accelerated dissociation of the receptor-toxin complex. The results indicate that specific antibody binding destabilizes the toxin-receptor complex.