Safety of snake antivenom immunoglobulins: Efficacy of viral inactivation in a complete downstream process

Abstract

Viral safety remains a challenge when processing a plasma-derived product. A variety of pathogens might be present in the starting material, which requires a downstream process capable of broad viral reduction. In this article, we used a wide panel of viruses to assess viral removal/inactivation of our downstream process for Snake Antivenom Immunoglobulin (SAI). First, we screened and excluded equine plasma that cross-reacted with any model virus, a procedure not published before for antivenoms. In addition, we evaluated for the first time the virucidal capacity of phenol applied to SAI products. Among the steps analyzed in the process, phenol addition was the most effective one, followed by heat, caprylic acid, and pepsin. All viruses were fully inactivated only by phenol treatment; heat, the second most effective step, did not inactivate the rotavirus and the adenovirus used. We therefore present a SAI downstream method that is cost-effective and eliminates viruses to the extent required by WHO for a safe product.