Effect of coumermycin on influenza A virus replicative cycle.

Coumermycin A1, a Novobiocin related antibiotic, has been tested in vivo and in vitro for its activity on Influenza A viruses. In a range of concentrations between 3 and 5 micrograms/ml virus production was drastically reduced. The drug was able to inhibit virus release into culture medium also if added up to the sixth hour following infection and its action was reversible within this time. The synthesis of virus induced polypeptides was generally depressed but production of the HA was more deeply inhibited. Viral transcriptase activity in vitro was also affected by the presence of Coumermycin A1 but at doses which seem to high to consider this event as a phenomenon likely to play a role in vivo. It is suggested that the antiviral activity of the drug is mediated by the inhibition of the host cell metabolism.