Treatment of dimethyl sulfoxide-stimulated Friend erythroleukemic cells (clone 745) with mouse interferon (50 U/ml) led to the following changes: (i) a net decrease (40 to 60%) in both the total number of apparently newly synthesized virion particles per cell section and in the average number of cell sections containing one or more virion particles; (ii) a large decrease (80 to 90%) in the number of particles released into the supernatant fluid, as assayed by reverse transcriptase activity; (iii) an initial increase in the number of "immature" or "enveloped A-type" virions followed by an increase in the accumulation of empty, core shell-like particles; and (iv) a decrease in the number of cytoplasmic vacuolar structures, which have been implicated as a major site of virus production and which we show here by serial sectioning to be, in several instances, invaginations of the plasma membrane. The effects on virus production were noticeable 2 h after interferon addition and reached their full extent by 13 h. We conclude from these observations that interferon acts upon the late stage(s) of virion maturation, leading both to a decrease in virion production as well as to the formation of defective particles. In contrast, a small but significant increase in the rate at which globin mRNA and hemoglobin accumulate is observed after interferon treatment.

Luftig, R. B., Conscience, J. F., Skoultchi, A., McMillan, P., Revel, M., & Ruddle, F. H. (1977). Effect of interferon on dimethyl sulfoxide-stimulated Friend erythroleukemic cells: ultrastructural and biochemical study. Journal of Virology, 23(3), 799–810.