Humanized cocaine-binding antibody characterized.

2003 JUN 18 - (NewsRx.com & NewsRx.net) -- A humanized cocaine-binding antibody has been characterized.

"The murine immunoglobulin G (IgG) cocaine-binding monoclonal antibody (mAb), GNC92H2, is notable for its exquisite specificity for cocaine, as opposed to chemically-related cocaine metabolites, and for its moderately high affinity (K[subscript]d approximately 200 nM) for cocaine," scientists in the United States report.

"Recently, we described the crystal structure of a mouse/human chimeric Fab construct at 2.3 Angstrom resolution," said El-Rashdy M. Redwan and colleagues at the Scripps Research Institute in La Jolla, California. "Herein, we report the successful framework humanization of a single-chain Fv (scFv) GNC92H2 construct without loss of affinity for cocaine. In brief, we compared the mAb GNC92H2 sequence to human antibody sequences, and used structure-based design to incorporate mutations (total=49) that would humanize the framework region without affecting the overall shape of the binding pocket or the key cocaine-contact residues. The codons of the rationally designed sequence were optimized for E. coli expression, and the gene was synthesized by a de novo PCR reaction using 14 overlapping primers."

"Expression of the scFv construct was ...