On the penetration mechanism of influenza viruses.

The envelopes of influenza viruses contain in addition to lipids also two glycoproteins, the hemagglutinin and the neuraminidase, that are responsible for the adsorption, receptor splitting, penetration and budding processes of these viruses. In this article, hypotheses presented in the past with regard to the virus penetration are reconsidered. Based on results obtained with the fowl plague virus (influenza A/FPV/Rostock/34, H7N1) and MDCK-cells, we conclude that a fusion between the viral envelope and the plasma membrane is the initial step of virus entry.