IFNB1 and infection: These four-dsRNA producing viruses, 4C(−), Cm2′, Cm*, and D80A, produced the highest IFN-β levels in the infected cells (compare Figs. 6 and 7), and levels of dsRNA detected in the infected cells were roughly correlated with levels of IFN-β production induced by infection, implying a link between the ability of the C mutant viruses to induce IFN-β production and to produce dsRNA in the infected cells.