Toxicovenomics and antivenom profiling of the Eastern green mamba

32 A toxicovenomic study was performed on the venom of the green mamba, 33 Dendroaspis angusticeps. Forty-two different proteins were identified in the venom of 34 D. angusticeps, in addition to the nucleoside adenosine. The most abundant proteins 35 belong to the three-finger toxin (3FTx) (69.2%) and the Kunitz-type proteinase inhibitor 36 (16.3%) families. Several sub-subfamilies of the 3FTxs were identified, such as Orphan 37 Group XI (Toxin F-VIII), acetylcholinesterase inhibitors (fasciculins), and aminergic 38 toxins (muscarinic toxins, synergistic-like toxins, and adrenergic toxins). Remarkably, 39 no -neurotoxins were identified. Proteins of the Kunitz-type proteinase inhibitor 40 family include dendrotoxins. Toxicological screening revealed a lack of lethal activity 41 in all RP-HPLC fractions, except one, at the doses tested. Thus, the overall toxicity 42 depends on the synergistic action of various types of proteins, such as dendrotoxins, 43 fasciculins, and probably other synergistically-acting toxins. Polyspecific antivenoms 44 manufactured in South Africa and India were effective in the neutralization of venom45 induced lethality. These antivenoms also showed a pattern of broad immunorecognition 46 of the different HPLC fractions by ELISA and immunoprecipitated the crude venom by 47 gel immunodiffusion. The synergistic mechanism of toxicity constitutes a challenge for 48 the development of effective recombinant antibodies, as it requires the identification of 49 the most relevant synergistic toxins. 50