Engineering of a recombinant Fab from a neutralizing IgG directed against scorpion neurotoxin AahI, and functional evaluation versus other antibody fragments.
Antibody-based therapy is the only specific treatment for scorpion envenomation. However, there are still major drawbacks associated with its use; mainly because antivenoms are still prepared from immune equine serum raised against crude venoms, whereas only a limited number of neurotoxins are responsible for the lethality of the venom. Using a murine hybridoma that secretes a well-characterized neutralizing IgG directed to neurotoxins AahI and AahIII from the venom of the scorpion Androctonus australis, we constructed a recombinant Fab (rFab) fragment, which was produced and purified from transformed bacteria. It recognized toxin AahI with a high affinity (KD = 8.2 x 10(-11)) equivalent to the homologous pFab prepared by papain digestion of whole IgG. Although the AahI-neutralizing capacity of protein L-purified rFab was low compared to other recombinant antibody formats (scFv and diabody) investigated in parallel, the antibody engineering approach presented here provides an innovative way to synthesize novel toxin-neutralizing molecules. It may serve as a strategy for designing a new generation of antivenoms.
Aubrey
Nicolas
N
Muséum National d'Histoire Naturelle, USM 0505-Lerai, 57 rue Cuvier, F75231 Paris cedex 05, France.
Muzard
Julien
J
Christophe Peter
Jean
J
Rochat
Hervé
H
Goyffon
Max
M
Devaux
Christiane
C
Billiald
Philippe
P
D000595:Amino Acid Sequence; D000818:Animals; D000915:Antibody Affinity; D017931:DNA Primers; D004926:Escherichia coli / Q000378:metabolism; D005260:Female; D007128:Immunoglobulin Fragments / Q000737:chemistry*; D007074:Immunoglobulin G / Q000737:chemistry*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000276:immunology; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012604:Scorpion Venoms / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000276:immunology
D017931:DNA Primers; D007128:Immunoglobulin Fragments; D007074:Immunoglobulin G; D009498:Neurotoxins; D011994:Recombinant Proteins; D012604:Scorpion Venoms; C065314:scorpion toxin I, Androctonus