Octanoic acid addition: a simple, affordable modification that overcomes lipid removal limitations of traditional antivenom production processes

Abstract

Since their introduction over a century ago, antivenoms have played a central role in Public Health, especially in the world´s least developed regions. They are, in most cases, the only effective treatment for envenomation accidents by poisonous animals. A big proportion of currently available antivenoms are based on F(ab?)2 immunoglobulin fragments, produced from hyperimmune equine plasma, following slightly modified protocols developed several decades ago. These protocols show severe limitations for processing starting materials with high lipid contents. In this work, we propose minor modifications to these traditional procedures, based on the addition of octanoic acid, that significantly increase their lipid removal capacities. The method designed for use at the final stages showed reductions of 85?98 % and 64?99 % in cholesterol and phosphatidylcholines, respectively. An alternative, intended for use at the initial stages of the process, improved lipid removal capacity in three out of four independent hyperimmune equine plasmas assayed. Notably, a significant reduction in oligomeric F(ab?)2 species was also observed in all octanoic acid-treated samples. Thus, the methodologies developed and optimised in this work present simple and affordable alternatives to overcome lipid removal limitations of traditional antivenom-producing protocols.