RT Journal Article SR Electronic(1) A1 Pitha, P. M. A1 Wivel, N. A. A1 Fernie, B. F. A1 Harper, H. P.YR 1979 T1 Effect of Interferon on Murine Leukaemia Virus Infection. IV. Formation of Non-infectious Virus in Chronically Infected Cells JF Journal of General Virology, VO 42 IS 3 SP 467 OP 480 DO https://doi.org/10.1099/0022-1317-42-3-467 PB Microbiology Society, SN 1465-2099, AB SUMMARY Interferon (150 units/ml) was used to treat SC-1 and AKR-2B cells which were chronically infected with murine leukaemia virus (MuLV). This led to a 100-fold decrease in the amount of infectious virus released into the medium and a 10-fold decrease in the number of virus particles measured by the virion-associated reverse transcriptase assay. However, there was little change in the amount of cell-associated infectious virus, though nearly twice as many cell-associated virions were counted in electron micrographs. With both types of cells, interferon blocked MuLV replication at the post-budding stage, but it did not change the morphology of the particles produced or their content of virion 70S RNA. Infectious virus assembled on the cell membranes of interferon-treated cells was less stable at 37°C than that grown in the absence of interferon. Release of infectious virus from interferon-treated cells was not inhibited by actinomycin D or cycloheximide, though both agents inhibited virus production in controls. These results show that interferon inhibits MuLV replication through effects on virion assembly; these lead both to the formation of non-infectious particles and of fewer virions. Kinetic analysis further shows that interferon affects MuLV assembly rapidly and induction of an antiviral protein may not be required., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-42-3-467