The pas de deux of viruses and CD8 T cells.

The vertebrate immune system has evolved to deal with parasitic life forms, so it is hardly surprising that experiments with pathogens have proved illuminating for immunology. Those of us who have worked for years with infectious processes are acutely conscious that we do little more than probe the vast 'experiment of nature.' There is no place for doctrinaire rigidity in this extraordinarily complex area of biology. Though we have obviously tried to do rational experiments, much of the novelty that has been brought in to immunology from the analysis of the virus-specific host response has, in a very real sense, been the product of what we now call 'discovery science'. The following relates some of the research that I was involved in personally and attempts to put it in the context of both the history of the field and the events of the time. Virus infections, particularly HIV, pose enormous challenges for the future. It is generally helpful to know a little of what went before.