Received for publication February 24, 2009.
Revised June 19, 2009.
Accepted for publication June 19, 2009.

Adenovirus transduced human butyrylcholinesterase in mouse blood functions as a bioscavenger of chemical warfare nerve agents

Abstract

Human serum butyrylcholinesterase (Hu BChE) is a promising therapeutic against the toxicity of chemical warfare nerve agents. Recently, we showed that recombinant (r) Hu BChE can be expressed at very high-levels, 400 to 600 U/mL in mouse blood by delivering the Hu BChE gene using adenovirus (Ad). Here, we report the biochemical properties of the Ad-expressed full-length and truncated rHu BChE in mouse blood. The molecular sizes of the full-length rHu BChE subunit and its oligomers were similar to those of native Hu BChE, though only a small portion of the full-length rHu BChE subunit underwent assembly into dimers and tetramers. As expected, Ad-containing the truncated Hu BChE gene transduced the expression of monomeric rHu BChE only. Compared to 415U of rHu BChE per mL in blood, tissues including liver, lung, heart, brain, kidney, muscle, intestine, diaphragm, salivary gland and fat expressed <10 U/g of rHu BChE activity. Ad-expressed rHu BChE in mouse blood neutralized soman and VX at rates similar to those of native Hu BChE and rHu BChE expressed in vitro. Since the expression of rHu BChE rapidly declined 6 days post-virus administration, sera were assayed for the presence of anti-Hu BChE antibodies. Anti-Hu BChE antibodies were detected on day 7 and in increased amounts thereafter which coincided with the loss of Hu BChE expression in sera. In conclusion, the delivery of Hu BChE gene using Ad can be a promising strategy that can provide protection against multiple lethal doses of chemical warfare nerve agents in vivo.

Key words: Enzymology, Overexpression, Pharmacokinetics, metabolism and activation, Cocaine