Abstract
A quantitative complement fixation assay which specifically measures double-stranded RNA has been used to study this RNA extracted from uninfected and arbovirus-infected cells. The double-straned RNA of the uninfected BHK-21 cells sedimented in the 12S region in sucrose gradients. The double-stranded RNA of Sinbis virus-infected cells, as measured immunochemically, included a predominant peak at 12S, a smaller 18S peak, and polydisperse material extending into the 26-30S region. All classes of this RNA detected immunochemically showed a sharp thermal denaturation curve, and increased in amount progressively during infection, with the 12S peak predominant at all times.