关键词：腺病毒；基因表达；肝；含量测定
摘 要：Human liver prolidase, a metal-dependent dipeptidase, is being tested as a potential catalytic bioscavenger against organophosphorus (OP) chemical warfare nerve agents. The purpose of this study was to determine whether persistent and high-levels of biologically active and intact recombinant human (rHu) prolidase could be introduced in vivo in mice using adenovirus (Ad). Here, we report that a single intravenous injection of Ad containing the prolidase gene with a 6x histidine-tag (Ad-prolidase) introduced high-levels of rHu prolidase in the circulation of mice which peaked on days 5 7 at 159 129 U/ mL. This level of prolidase is approximately 120 times greater than that of the enzyme level in mice injected with Ad-null virus. To determine if all of Ad- prolidase-produced rHu prolidase was exported into the circulation, enzyme activity was measured in a variety of tissues. Liver contained the highest levels of rHu prolidase on day 7 (5647 454 U/g) compared to blood or any other tissue. Recombinant Hu prolidase hydrolyzed DFP, a simulant of OP nerve agents, in vitro. In vivo, prolidase overexpression extended the survival of 4 out of 6 mice by 4 8 h against exposure to two 1 x LD50 doses of DFP. In contrast, overexpression of mouse butyrylcholinesterase (BChE), a proven stoichiometric bioscavenger of OP compounds, protected 5 out of 6 mice from DFP lethality and surviving mice showed no symptoms of DFP toxicity. In conclusion, the results suggest that gene delivery using Ad is capable of introducing persistent and high levels of human liver prolidase in vivo. The gene-delivered prolidase hydrolyzed DFP in vitro but provided only modest protection in vivo in mice, delaying the death of the animals by only 4 8 h.