Activity of nitric oxide-generating compounds against encephalomyocarditis virus. Antimicrob. Agents Chemother

Nitric oxide (NO) generated by two NO donors (sodium nitroprusside or S-nitroso-L-glutathione) was shown to exert a dose-dependent inhibition of encephalomyocarditis virus growth in L-929 cells. This activity was not due to the cytotoxic or direct virucidal effects of NO donors. L-929 cells were shown to produce NO endog-enously, but this low level of production did not counter encephalomyocarditis virus replication. Nitric oxide (NO) is produced by a wide variety of mamma-lian cells, and throughout the last decade it has been shown to play a pathophysiological role as a first line of defense against various pathogens (13). Recently, different investigators have reported that NO has antiviral activity. Murine macrophage cell lines (2, 7, 9) or peritoneal macrophages (9) pretreated with gamma interferon have been shown to exert an NO-dependent antiviral activity, especially against several DNA viruses such as herpes simplex virus type 1 (2, 9), ectromelia virus (9), and vac-cinia virus (7, 9). Furthermore, S-nitroso-N-acetyl-penicilla-mine, as a source of NO, acts as an antiviral agent in variou