A recombinant single-chain antibody fragment that neutralizes toxin II from the venom of the scorpion Androctonus australis hector

Monoclonal antibody 4C1 specifically binds to and neutralizes the most pote nt neurotoxin (AahII) of the scorpion Androctonus nustralis. The cDNAs enco ding the variable regions of this antibody were isolated by PCR-mediated cl oning. A single-chain Fv gene was engineered and expressed in Escherichia c oli, The recombinant protein had neutralizing activity similar to that of t he intact antibody in vitro and in vivo. We have thus neutralized the pharm acological and biological properties of a scorpion neurotoxin with a single -chain Fv, which opens nem perspectives for the treatment of envenomization s, (C) 1999 Federation of European Biochemical Societies.