Rapid and large scale plant-based production of catalytic nerve agent bioscavenge

U.S. Army Medical Research Inst Chem Def, Aberdeen Proving Ground MD

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Abstract

Bioscavenging of organophosphate (OP) by human proteins is emerging as a promising medical intervention[unreadable] for prophylaxis and post-exposure treatment against chemical warfare nerve agents. The best-studied[unreadable] bioscavengers (BSCs) to date, meeting considerable success in pre-clinical research, are human[unreadable] cholinesterases (ChEs). However, ChEs, which are highly efficient in binding and sequestering OPs, are also[unreadable] inactivated by the toxins and therefore administration of large amounts of protein is necessary for full[unreadable] protection, raising the question of the practicality of this approach. However the development of a new[unreadable] generation of BSCs that can catalytically degrade OPs may address this concern.[unreadable] The proposed effort offers a novel means to biomanufacture recombinant catalytic BSCs based on the[unreadable] human proteins butyrylcholinesterase and paraoxonase 1. Through efforts of other projects participating in[unreadable] the Center, the capacity of these proteins to hydrolyze OPs will be improved by subjecting their genes to[unreadable] either random in vitro evolution or rational mutagenesis. Concomitantly to the protein engineering research,[unreadable] the ASU team in this Project 5 will utilize tobacco plants to first produce research-scale quantities of BSC[unreadable] enzyme, but also provide a sustainable large-scale production platform. At present, purification of BChE from[unreadable] outdated blood-banked human plasma enables research on how bioscavenger therapy can be used. But this[unreadable] stop-gap measure cannot be practically implemented to allow for a sustained supply of that enzyme, and is[unreadable] not applicable for the new recombinant catalytic BSCs that will be developed by the Center. If it will be[unreadable] decided that such scavengers should be a component of the medical arsenal of the Departments of Defense,[unreadable] Homeland Security and Health and Human Services, it is vital that a reliable, safe, non supply-limited and[unreadable] inexpensive source of such enzymes be identified and developed. The primary significance of the proposed[unreadable] work is that it translates basic studies on the first generation ChE-based BSCs into novel biomanufacturing[unreadable] technology leading to clinical product development of the second generation catalytic BSCs.