Conjugating poly(ethylene) glycol (PEGylation) to a high‐affinity anti‐methamphetamine antibody fragment

Abstract

Methamphetamine (METH) is considered one of the top drug problems in the United States today, yet there are no FDA approved pharmacological treatments available for METH abuse. To this end, we have designed and produced an anti‐METH single chain antibody fragment (scFv7F9Cys) as a potential anti‐METH pharmacological treatment. However, scFv7F9Cys has a short half‐life in its native state, limiting its clinical use. Thus, the aim of this study was to examine the in vitro effects of conjugating scFv7F9Cys to poly(ethylene) glycol (PEG) as a potential method of increasing half‐life. Three different PEG moieties were tested: linear 5 kDa and 20kDa PEGs and a branched 40 kDa PEG. ScFv7F9Cys was conjugated to each PEG forming three different scFv7F9Cys‐PEG conjugates (scFv7F9Cys‐PEG5K, ‐PEG20K, or ‐PEG40K). ScFv7F9Cys‐PEG conjugates were then purified from unreacted scFv7F9Cys and PEG using affinity chromatography (IMAC). PEGylation and purification were analyzed by SDS‐PAGE and size exclusion chromatography. METH binding affinity and capacity were tested for each scFv7F9Cys‐PEG conjugate and compared to native scFv7F9Cys using saturation binding assays. Both PEGylation of scFv7F9Cys and purification of scFv7F9Cys‐PEG were successful and binding analysis suggests PEGylation did not alter METH affinity or binding capacity. NIDA R01 DA026423, NIH CSTA 1UL1RR029884, NIDA T32 DA022981