Characterization of monoclonal antibodies against beta-bungarotoxin and their use as structural probes for related phospholipase A2 enzymes and presynaptic phospholipase neurotoxins.

Hybridoma lines secreting monoclonal antibodies against a phospholipase-inactive derivative of the presynaptic neurotoxin, beta-bungarotoxin, have been established. These antibodies, either of the IgG1 or IgG2b isotype with affinities in the range 1-2 X 10(8) 1/mol, recognized a single immunodominant region of native beta-bungarotoxin, most probably located on the A (phospholipase homologue) chain of the toxin. Using plate-adsorbed radioimmunoassay procedures, antibodies reacted with native beta-bungarotoxin and other beta-bungarotoxin isotoxins as well as with the non-toxic phospholipase A also present in Bungarus multicinctus venom. Other phospholipase A enzymes and presynaptic phospholipase neurotoxins did not show any competition with beta-bungarotoxin in the radioimmunoassay. Globulin fractions of monoclonal antibodies partially inhibited the phospholipase activity of beta-bungarotoxin.