Attachment of viruses to cell receptors and penetration of viruses into cells

This chapter describes the process of attachment of viruses to cell receptors and penetration of viruses into cells. Enveloped viruses contain a number of glycoprotein-type projections that are anchored in the membrane. Orthomyxoviruses, paramyxoviruses, rhabdoviruses, togaviruses, in addition to coronaviruses and arenaviruses, have such projections. The large poxviruses also have an envelope but peplomers have so far not been identified. Virus infection in cell cultures and in animals is to a large extent dependent upon the capacity of a virus to adsorb to the target cells, that is, upon the presence of receptors. When a virus is adsorbed irreversibly to the plasma membrane, parts of the virus or the whole virus is taken into the cytoplasm to initiate virus-specific protein and mRNA synthesis. The intake of adenovirus particles into cells requires a long sequence of events before mRNA synthesis can be initiated in the nucleus of the infected cell.