Production of Friend leukaemia antigens in chronically-infected cells treated with interferon

The effect of mouse interferon (ITF) on the expression of Friend leukaemia virus (FLV) an on dimethyl sulphoxide (DMSO)-stimulated haemoglobin synthesis in Friend erythroleukaemic cells (FLC) was studied. Immunofluorescent staining was used to detect intracellular antigens, and incorporation of 3H-uridine into virions to detect extracellular virus release. Interferon markedly inhibited haemoglobin synthesis and FLV production, but enhanced accumulation of virus antigens in the cytoplasm; on the cell surface, however, FLV antigens were present to the same extent whether ITF was present or not. When ITF was removed, virus production rose and intracellular virus antigens fell to the levels of untreated controls.