[Recombinant antibodies: a new application in scorpion envenomation?]

Serotherapy is the only specific treatment for envenomation. The antibodies are obtained after the purification of serum from hyperimmunised horses and are used after fragmentation in the form of polyclonal Fab or F(ab)'2. The anti-venom sera are heterogeneous, and their protective effect is often weak. The administration of these preparations induces risks of immediate or delayed side effects: hypersensitivity reactions, anaphylactic shock and serum sickness. This observation led us to develop new forms of antibodies produced by molecular engineering, capable of specifically neutralizing the neurotoxins responsible for the toxicity of the venom of Androctonus australis Hector. The recombinant antibody fragments are more homogeneous than conventional antivenoms and perfectly characterized in terms of specific activity. The method used to obtain them eliminates the risk of transmission by non-conventional transmissible agents. The earliest results confirm the importance of these new molecules (scFv recombinant Fab, diabody, triabody) and their ability to neutralize the action of scorpion neurotoxins. They could open the path to a new generation of more homogeneous antivenoms that are better tolerated and have well-characterized intrinsic properties.