Abstract:

Abstract:Objective To explore the mechanism of modified amantadine（NAM）against influenza A(H5N1) virus and to provide experimental basis for development of NAM.  Methods DCK cells were cult ivated in vitro. Normal control group, virus control group and test group were included in this study. ① Cytopathic effect(CPE) with MTT was used to detect the inhibitory effect of NAM against influenza A(H5N1) virus. The 50% inhibitory concentration(IC50) and therapeutic index(TI) of NAM on influenza A(H5N1) virus were studied in three ways: adding NAM before contracting virus, contracting virus before adding NAM and contracting virus with adding NAM at the same time. ② The neuramidinase(NA) inhibitory effect was observed to obtain the effect of NAM on neuramidinase activity. Results ①Positive correlation was observed between logarithm of dose and protect rate of NAM in MDCK cells in the three different ways(0.95，0.95 and 0.99 ; all P<0.05). IC50 of NAM was 15.32 mg·L^-1 and TI was 103.31 when adding NAM before contracting virus, IC50 of NAM was 30.78 mg·L^-1 and TI was 28.10 when contracting virus before adding NAM, and IC50 of NAM was 203.92 mg·L^-1 and TI was 4.24 when contracting virus with adding NAM at the same time. ② NAM can inhibit neuramidinase activity, and IC50 was 87.36 mg·L^-1. Conclusion NAM can better inhibit influenza A(H5N1) virus in cells, and has some effects on interfering viral adsorption and invading the process of cell uncoating. NAM can also inhibit neuramidinase activity to some extent.

Key words: influenza virus, amantadine, influenza A virus,H5N1 subtype