Identification of potent nanobodies to neutralize the most poisonous polypeptide from scorpion venom.

TitleIdentification of potent nanobodies to neutralize the most poisonous polypeptide from scorpion venom.
Publication TypeJournal Article
Year of Publication2009
AuthorsBen Abderrazek, R., I. Hmila, C. Vincke, Z. Benlasfar, M. Pellis, H. Dabbek, D. Saerens, M. El Ayeb, S. Muyldermans, and B. Bouhaouala-Zahar
JournalBiochem J
Date Published2009 Dec 1
KeywordsAmino Acid Sequence, Animals, Antibodies, Antibody Formation, Antibody Specificity, Camels, Epitopes, Female, Mice, Molecular Sequence Data, Neurotoxicity Syndromes, Neurotoxins, Peptides, Scorpion Venoms, Scorpions, Sequence Alignment, Sequence Homology, Amino Acid

Scorpion venom, containing highly toxic, small polypeptides that diffuse rapidly within the patient, causes serious medical problems. Nanobodies, single-domain antigen-binding fragments derived from dromedary heavy-chain antibodies, have a size that closely matches that of scorpion toxins. Therefore these nanobodies might be developed into potent immunotherapeutics to treat scorpion envenoming. Multiple nanobodies of sub-nanomolar affinity to AahII, the most toxic polypeptide within the Androctonus australis hector venom, were isolated from a dromedary immunized with AahII. These nanobodies neutralize the lethal effect of AahII to various extents without clear correlation with the kinetic rate constants kon or koff, or the equilibrium dissociation constant, KD. One particular nanobody, referred to as NbAahII10, which targets a unique epitope on AahII, neutralizes 7 LD50 of this toxin in mice, corresponding to a neutralizing capacity of approx. 37000 LD50 of AahII/mg of nanobody. Such high neutralizing potency has never been reached before by any other monoclonal antibody fragment.

Alternate JournalBiochem. J.
PubMed ID19732033