A strategy for inducing an immune response against Androctonus australis scorpion venom toxin I in mice. Production of high-affinity monoclonal antibodies and their use in a sensitive two-site immunometric assay

Abstract Scorpion neurotoxins acting on ion channels share some structural features but differ in antigenic and immunogenic properties. They are highly structured peptides, 60–70 amino acids long. Monoclonal antibodies have been obtained for Androctonus australis hector scorpion venom neurotoxin II (AahII) and a nontoxic synthetic analog ((Abu) 8 AahII). In this study, no antibody response was elicited in mice of various strains injected with AahI, the other important toxin of the venom, in a native or an inactive ((Abu) 8 AahI) form. We found that AahI was only immunogenic in BALB/c or C57BL/6 mice if it was coupled to a carrier protein. The helper protein molecule could be BSA, KLH, or the nontoxic analog of AahII. We obtained a panel of high-affinity mAbs with these immunogens. Two of these mAbs, including the very high-affinity antibody 9C2 ( K D =0.11×10 −11 M), were used to set up a two-site ELISA, sensitive enough for the quantification of AahI in the biological fluids of envenomed animals. The detection limit of the assay was 75 pg/ml.