Inter-individual variability in equine antibody responses to African snake venoms follows heavy-tailed distributions with implications for antivenom production

 

Inter-individual variability in equine antibody responses to African snake venoms follows heavy-tailed distributions with implications for antivenom production

Abstract

Variability in the antibody response of horses used for snake antivenom manufacture is well recognized, yet its statistical structure and implications for industrial productivity remain poorly characterized. In this study, we quantified antivenom antibody titers by ELISA in a cohort of 14 horses immunized with venoms from the clinically most important snakes in sub-Saharan Africa. To integrate antibody levels with plasma availability, we calculated the Cumulative Plasma Productivity (CPP) by converting individual plasma volumes into titer-corrected equivalents and sequentially pooling these volumes according to their corrected contribution. Distributional analysis revealed right-skewed, heavy-tailed patterns better approximated by a log-normal model than by a strict Pareto (power-law) form, with approximately 20–30% of horses accounting for nearly half of total cohort productivity. Excluding plasma from the lowest-productivity horses did not significantly improve the venom-neutralizing potency of the plasma pool in the mouse model but substantially reduced the total plasma volume. While the exact quantitative contributions may vary across cohorts, the qualitative conclusions are likely to be generalizable under similar experimental conditions.

Sánchez, A., Sánchez, P., Sánchez, A., Durán, G., Solano, G., Villalta, M., Gómez, A., Gutiérrez, J. M., & León, G. (2026). Inter-individual variability in equine antibody responses to African snake venoms follows heavy-tailed distributions with implications for antivenom production. Toxicon, 109145. https://doi.org/10.1016/j.toxicon.2026.109145