Abstract
Interference phenomenon which reduces the number of transformed foci in the culture of chick embryo cell (CEC) exposed to Schmidt-Ruppin strain of Rous sarcoma virus (SR-RSV) is described. The interfering substance(s) responsible for this phenomenon were detected and partially fractionated, and were also extracted from virusinfected chorioallantoic membranes (CAM). The amount of inhibitor(s) in the virus preparations was found to determine the number of cells registering as infective centers.Further, the inhibitor(s) we considered to consist mainly of inactivated virus particles and their degraded substances, suggesting that they are secreted from virus-infected cells into media during long culture.
