ABSTRACT
The events in virus infection have been arbitrarily divided into the three stages: attachment, penetration, and uncoating. A great deal of controversy has been generated by interpretations of the investigations designed to elucidate events in virus infection. A virus particle is a gene delivery system, and as such, it is required to perform a number of important functions. It is assembled from its various components into a highly organized, three-dimensional geometric structure of high stability. The surface of a virus particle is composed of a lipid-containing membrane and/or protein that present a charged and highly hydrated surface to the environment. A specific interaction between a virus particle and the cell surface presumably sets the stage for the translocation of the virus from the cell surface to its site of replication in the cell interior. In no animal virus system has it yet been possible to demonstrate that all virus particles are infectious.
