Abstract
Double-stranded RNA has been widely regarded as the inducer of interferon formation, both in virus-infected cells and in cells treated with synthetic polynucleotides (Colby, 1971). It is not difficult to see how infection with RNA viruses may lead to the formation of double-stranded RNA, but how do DNA viruses induce interferon formation? Colby & Duesberg (1969) have isolated a double-stranded RNA from chick cells infected with vaccinia virus, and shown that this double-stranded RNA induced interference against a virus challenge. However, they did not measure interferon production, either by virus infected cells or by the cells treated with double-stranded RNA, and since were found that chick cells infected by vaccinia virus did not produce interferon, there was some doubt about their explanation.
* On leave from the Institute of Microbiology, University Medical School, Szeged, Hungary.