Abstract
It may not come as a surprise that the subject of this address is concerned with viral interference, since interference phenomena have provided a sort of Leitmotif, with variations, for my laboratory during the past 20 years. It was introduced in 1942 by the repeated loss of the then new influenza B virus on serial transfers in the chick embryo which, rightly or wrongly, was ascribed by my wife and myself to interference by inactive virus particles accumulating in preceding passages under unfavorable conditions (1). To be sure, experimentally inactivated influenza virus particles were found to interfere with the propagation of various viruses in the chick embryo allantois and this and other systems of interference ever since have supplied problems for study, by design or by chance. Of late, interference entered again in the analysis of persistent viral infections of cultured cell populations, a problem which has received considerable attention in recent years because of its possible bearing, among others, on latent viral infections in intact hosts.