Croonian Lecture - The interaction of virus and cell surface

Abstract

It is not so many years ago since the statement in a text-book of medicine that a given disease was probably due to a filterable virus, meant merely that up to that time no visible or cultivable micro-organism had been shown responsible. The filterable viruses were mysterious entities with no very evident relation to any biological field more general than clinical medicine. During the last 25 years it has been of the greatest interest to watch how virus research has gradually swollen, as it were, from an insignificant trickle in no-man’s-land into one of the major streams of biological thought. The first requirement was the development of techniques that would allow the handling and the characterization of viruses-techniques appropriately modified according to whether animals, green plants or bacteria were the susceptible hosts. With viruses pathogenic for man and higher animals, the first application of such techniques was naturally to the immediately practical problems of diagnosis, prevention and treatment of the disease concerned. Such matters will always remain of the first importance, but at the present time they are not, in my opinion, the most interesting aspects of virus research to a biologist. There is always a fascination in the possibility of bringing a small corner of biology, with very specialized techniques and interpretations, into its most effective relationship with the main body of biological science. To-day it seems to me that virus research is in a particularly favourable position to make effective contribu­tions to some of the most fundamental of biological problems. On one hand we have the questions of the physical and chemical properties of virus particles, of their modes of reproduction and variation, and, at a more speculative level, of their evolutionary history. From another angle we may consider the implication of the fundamental part of the definition of a virus as a transmissible agent 'capable of multiplication only within the living cells of a susceptible host species’. Most of us believe that viruses have lost virtually all the complement of enzymic mechanisms by which organisms from bacteria upwards provide energy and material for maintenance and replication of structure. For their replication viruses must make use of the host cell’s mechanisms for the provision of energy and material. It may be that by the study of virus multiplication we shall eventually gain an insight into intracellular processes that cannot be obtained by any other means. Before a virus can multiply intracellularly it must have a means of entering the cell. Again the characteristic reactions of the cell surface with viruses may provide important new approaches to the problems of surface structure.