title: A null mutation in the gene encoding a type I interferon receptor component eliminates antiproliferative and antiviral responses to interferons alpha and beta and alters macrophage responses.
abstract: To examine the in vivo role(s) of type I interferons (IFNs) and to determine the role of a component of the type I IFN receptor (IFNAR1) in mediating responses to these IFNs, we generated mice with a null mutation (-/-) in the IFNAR1 gene. Despite compelling evidence for modulation of cell proliferation and differentiation by type I IFNs, there were no gross signs of abnormal fetal development or morphological changes in adult IFNAR1-/- mice. However, abnormalities of hemopoietic cells were detected in IFNAR1 -/- mice. Elevated levels of myeloid lineage cells were detected in peripheral blood and bone marrow by staining with Mac-1 and Gr-1 antibodies. Furthermore, bone marrow macrophages from IFNAR1 -/- mice showed abnormal responses to colony-stimulating factor 1 and lipopolysaccharide. IFNAR1 -/- mice were highly susceptible to viral infection: viral titers were undetected 24 hr after infection of IFNAR1 +/+ mice but were extremely high in organs of IFNAR1 -/- mice, demonstrating that the type I IFN system is a major acute antiviral defence. In cell lines derived from IFNAR1 -/- mice, there was no signaling in response to IFN-alpha or -beta as measured by induction of 2'-5' oligoadenylate synthetase, antiviral, or antiproliferative responses. Importantly, these studies demonstrate that type I IFNs function in the development and responses of myeloid lineage cells, particularly macrophages, and that the IFNAR1 receptor component is essential for antiproliferative and antiviral responses to IFN-alpha and -beta.
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells; D002455:Cell Division; D005796:Genes; D006412:Hematopoietic Stem Cells / Q000166:cytology; D007370:Interferon Type I / Q000502:physiology*; D008262:Macrophage Activation; D008264:Macrophages / Q000502:physiology*; D008565:Membrane Proteins; D051379:Mice; D018345:Mice, Knockout; D053633:Receptor, Interferon alpha-beta; D017471:Receptors, Interferon / Q000502:physiology*; D015398:Signal Transduction; D014762:Viral Interference; D014777:Virus Diseases / Q000276:immunology*
chemical_list: C508032:Ifnar1 protein, mouse; D007370:Interferon Type I; D008565:Membrane Proteins; D017471:Receptors, Interferon; D053633:Receptor, Interferon alpha-beta