Interferon induction in marrow‐derived macrophages: Regulation by L cell conditioned medium

Publisher Website
Google Scholar
Abstract
Mouse bone marrow cells grown in medium enriched with L cell conditioned medium (LCM) as a source of colony stimulating factor (CSF) yield populations of adherent macrophages which are quite sensitive to induction of interferon (IFN) by viral and nonviral inducers. We examined the role of LCM in the sensitivity of marrow macrophage cultures to IFN induction. Removal of LCM from the cultures for as little as 3 hours markedly reduced the IFN titers induced by a double stranded ribopolynucleotide (poly I:C) or a lipopolysaccharide (LPS), while induction by Newcastle disease virus (NDV) was unaffected. Addition of anti‐CSF serum to LCM medium also reduced IFN titers in response to poly I:C but had no effect on NDV induction. The inhibitory effect of anti‐CSF indicates that the LCM requirement is at least partially related to the colony stimulating activity of the medium. We postulate that CSF regulates the initial interaction of macrophages with poly I:C or LPS rather than the synthesis and secretion of interferon by the phagocytes. Nearly complete restoration of IFN induction with poly I:C was obtained when LCM deprived cultures were reincubated with LCM medium previously conditioned by marrow cultures.