Innovative production of highly potent equine neutralizing antibody against Hemiscorpius lepturus scorpion venom using recombinant mPLD1 protein

Scorpion envenomation, especially from Hemiscorpius lepturus, poses a significant health risk, leading to considerable morbidity and mortality. The venom's major toxin, which includes phospholipase D (PLD), is responsible for various systemic complications. In prior studies, we identified a native phospholipase D (PLD) toxin as a key lethal factor in the venom of H. lepturus. A recombinant PLD that retained its toxicity was developed and designated as PLD1. Additionally, a non-toxic and devoid of lethal effects mutant form of the recombinant PLD1 protein, was produced and named as mPLD1. Building on this knowledge, we aimed to produce a novel antivenom using recombinant mPLD1-based immunogen and commercial antisera were included for comparison. Two horses were immunized separately with either recombinant or mutant PLD1, resulting in high titer antisera with no significant difference between the two immunogens. Purified F(ab')2 fragments derived from horse antisera demonstrated a markedly enhanced specificity in the detection of PLD1 and crude venom when compared to commercial alternatives. Furthermore, in vivo neutralization assays revealed that the antisera generated from mPLD1 protein was 89 and 36 times more potent than those of commercial ones. Horses produced highly neutralizing antibodies against PLD1 than the two local commercial antisera. These findings underscore the promise of the developed anti-mPLD1 as a highly effective therapeutic molecule for H. lepturus envenomation. Given that the production process for the recombinant immunogen is straightforward and utilizes cost-effective technologies, focusing on the manufacture of this highly efficient antisera could lead to significant advancements in horse antisera production platforms.