Antigenic similarity between the protein neurotoxin alpha-bungarotoxin and neuromuscular blocking drugs

The snake neurotoxins alpha-bungarotoxin (alpha-BGT) and beta-bungarotoxin (beta-BGT) which act at the neuromuscular junction, were found to bind to IgE antibodies directed against neuromuscular blocking (NMB) drugs in the sera of two patients who had experienced lifethreatening anaphylactic reactions to succinylcholine. alpha-BGT inhibited IgE-binding to a choline-Sepharose solid support in one patient better than the NMB drug alcuronium, choline, triethylcholine and beta-BGT. IC50s for alpha-BGT and succinylcholine were 16 and 10 nmol respectively for one patient and 34 and 6.0 nmol for the other. Recognition of the NMB drugs and alpha-BGT by the same antibody is the first demonstration of an antigenic similarity between these drugs and the protein toxin.