Immunochemical characterization of cobrotoxin modified with glutaraldehyde.

Abstract

Modification of cobrotoxin with glutaraldehyde, a bifunctional reagent, resulted in the formation of cross-inked derivatives.The intra-molecular cross-linked monomeric derlvatives as well as dimers, trilllers, and higher molecular weigllt derivatives arising from intermolecular reactions were separated by gel filtration. Polymeric dsrivatives were completely detoxified and the others lost almost completely their lethality. However, all the modified derlvatives retained relatively high antigenic activities towards the antibody against native toxin . Rabbits immunized with these modified derivatives (except for trimeric derivatives) produced considsrable amounts of non-precipitating antibody but much less precipitating antibody to cobrotoxin. The neutralizing capacity of anti-onomeric derivatives sera had 1.4 times more potent than that of anti-cobrotoxin sera. Antisera prepared by immunization with the unfractionated reaction products of cobrotoxin or with dimeric derivatives had the same or almost the same capacity as that of anti-cobrotoxin sera for neutralizing the lethality of cobrotoxin. These antisera were obtained in only one-half period required for anti-cobrotoxin sera. However, polymeric cobrotoxin derivatives were poor linmunogens for the production of neutralizing antibody against native toxin.