Abstract
Human serum butyrylcholinesterase (Hu BChE) is a promising therapeutic against the toxicity of chemical warfare nerve agents. We have showed previously 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, although 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 with 415 U of rHu BChE per milliliter 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 O-ethyl S-2-N,N-diisopropylaminoethyl methylphosphonothiolate at rates similar to those of native Hu BChE and rHu BChE expressed in vitro. Because the expression of rHu BChE rapidly decreased 6 days after 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.
Footnotes
- Received February 17, 2009.
- Accepted June 19, 2009.
This work was supported by the U.S. Department of Defense Defense Threat Reduction Agency [Grant 1.D0003_05_WR_C].
ABBREVIATIONS: OP, organophosphorus; Hu BChE, human butyrylcholinesterase; Ad, adenovirus; BTC, butyrylthiocholine iodide; DTNB, 5, 5-dithiobis-(2-nitrobenzoic acid); BSA, bovine serum albumin; VX, O-ethyl S-2-N,N-diisopropylaminoethyl methylphosphonothiolate; Ad-Hu BChE, recombinant adenovirus expressing full-length human butyrylcholinesterase; Ad-tHu BChE, recombinant adenovirus expressing truncated human butyrylcholinesterase.
- U.S. Government work not protected by U.S. copyright
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