Influenza A Virus

Figure 1. Virions of influenza A virus (arrows) are seen budding from the surface of kidney cells (K) from rhesus monkeys. In the inset, the dense nucleoprotein core of the virus (arrows) can be distinguished from the lighter fringe of individual hemagglutinin and neuraminidase spikes (arrowheads). The surface hemagglutinin is responsible for two important biologic phenomena. Hemadsorption of guinea-pig erythrocytes (E) onto the surface of the cellular monolayer (K) is an important tool for documenting the presence of virus in cell cultures. Hemagglutination is the aggregation by viral hemagglutinin of adjacent erythrocytes. The aggregates enlarge to form a lattice that . . .