Monoclonal antibody fragment from combinatorial phage display library neutralizes alpha-latrotoxin activity and abolishes black widow spider venom lethality, in mice

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• 作者：Francesca Bugli ; Rosalia Graffeo ; Francesco Paroni Sterbini ; Riccardo Torelli ; Luca Masucci ; Michela Sali ; Alfonso Grasso ; Stefano Rufini ; Enzo Ricci ; Giovanni Fadda ; Mario Pescatori
• 关键词：Alpha latrotoxin ; Latrodectism ; Black widow spider ; Phage display ; Recombinant antibody ; Fab
• 刊名：Toxicon
• 出版年：2008
• 出版时间：15 March 2008
• 年：2008
• 卷：51
• 期：4
• 页码：547-554
• 全文大小：307 K

文摘

Alpha-latrotoxin (-ltx), a component of the venom of black widow spiders (BWSV), binds to higher vertebrates presynaptic nerve terminals, stimulating massive neurotransmitter release. This neurotoxic protein is responsible for most of the symptoms elicited in men by the bite of black widow spider (BWS), i.e. a neurological syndrome named latrodectism. By reasoning that targeting this single component would abrogate most of the effect of BWS envenomation, we took advantage of the antibody phage display technology to generate monoclonal Fab fragments able to bind and neutralize the -ltx. To this aim, we immunized Balb/c mice with purified toxin and cloned their antibody repertoire in the pCombIII phage display vector. By combining a high-stringency affinity selection with a sensitive 45Ca²⁺ uptake assay, we isolated a Fab fragment (FM1) able to bind the -ltx in the low nM range and neutralize its ionophore activity, in vitro and in vivo. After the onset of overt symptomatology, administration of FM1 to experimentally envenomed mice induced remission of symptoms and prevented lethality.