Abstract
Multiplication of the human clonal cell line, RSa, is completely inhibited by human leukocyte interferon preparations. Synthesis of DNA and protein is markedly reduced in these cells in proportion to the concentration of interferon applied. Interferon treatment leads to accumulation of cells of an epithelial morphology which do not enter the division cycle. It is suggested that the growth inhibitory effects of interferon on RSa cells may result from these effects.