%0 Journal Article %A Krilov, Leonard R. %A Hendry, R. Michael %A Godfrey, Ellen %A McIntosh, Kenneth %T Respiratory Virus Infection of Peripheral Blood Monocytes: Correlation with Ageing of Cells and Interferon Production in vitro %D 1987 %J Journal of General Virology, %V 68 %N 6 %P 1749-1753 %@ 1465-2099 %R https://doi.org/10.1099/0022-1317-68-6-1749 %K PIV3 %K monocytes %K interferon (HuIFN-α) %K RS virus %I Microbiology Society, %X Summary The ability of respiratory syncytial virus (RSV) and parainfluenza virus type 3 (PIV3) to replicate in peripheral blood monocytes cultured in vitro for 1, 2, 4 or 7 days prior to infection was investigated. Inoculation of 1-day old monocytes produced at least tenfold less new virus than infection of the older, more macrophage-like cells for both viruses. PIV3 induced extensive syncytium formation, whereas RSV caused a cytopathic effect manifest by increased rounding of the cells with minimal syncytium formation. Supernatants of infected monocytes were assayed for human interferon-a (HuIFN-α) in an attempt to explain the restricted viral replication in the youngest monocytes. In PIV3-infected cells, HuIFN-α production was inversely correlated with new virus formation. Monocytes infected after 1 day in culture produced 800 IU/ml of HuIFN-α; the older cells produced 100 to 200 IU/ml. In contrast, monocytes infected on day 1 with RSV produced minimal amounts (1·5 IU/ml) of HuIFN-α. Increasing amounts of HuIFN-α were detected in cells infected with RSV after 2, 4 or 7 days in culture, reaching a maximum of 400 IU/ml on day 7. Further investigation of the apparent restriction of replication in young monocyte cultures may be helpful in understanding the pathogenesis of these respiratory infections. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-68-6-1749