How viruses damage cells: alterations in plasma membrane function.

ABSTRACT

The effect of viruses on plasma membrane function has been studied in two types of situation (i) during the toxin-like action of paramyxoviruses when fusing with susceptible cells, and (ii) during an infectious cycle initiated by different viruses in various cell types. The nature of the permeability changes induced during the toxin-like action of viruses, and its modulation by extra-cellular Ca2+, are described membrane potential collapses, intracellular ions and metabolites leak out of, and extracellular ions leak into cells, but lysis does not take place. The biological significance of such changes, and their relation to changes induced by other pore-forming agents, are discussed. Changes in membrane permeability such as those mentioned above have not been detected during infection of cultured cells by paramyxo (Sendai, measles, mumps), orthomyxo (influenza), rhabdo (vesicular stomatitis), toga (Semliki Forest) or herpes viruses. On the contrary, sugar uptake is increased when BHK cells are infected with vesicular stomatitis virus, semliki forest virus or herpes virus. Cultured neurones infected with herpes simplex virus show changes in electrical activity. The pathophysiological significance of these alterations in membrane function, which occur in viable cells, is discussed. It is concluded that clinical symptoms may result from cell damage caused by virally induced alterations of plasma membrane function in otherwise intact cells.