Interferon and Its Inducers—A Never-Ending Story: 'Old' and 'New' Data in a New Perspective

The discovery of interferon (IFN), as an antiviral substance, by Isaacs and Lindenmann in 1957 [1] attracted the attention of a number of investigators, including Pieter De Somer at the Rega Institute in Leuven (Belgium) and Tom Merigan at Stanford University (California). De Somer’s original attempts were aimed at determining the mode of action of IFN [2], whereas Merigan’s work focused on trying to understand the role of IFN in human viral diseases [3], by use of the mouse as an animal model. Of pioneering importance was the demonstration by Merigan [4] in 1967 that IFN could be induced in mice by a synthetic polyanion called maleic divinyl ether copolymer (or pyran copolymer). In further experiments, pyran copolymer was also shown to induce IFN in humans [5], although the serum IFN titers obtained in humans were considerably lower than those in mice and, moreover, were accompanied by a considerable