title: Alveolar Macrophages Can Control Respiratory Syncytial Virus Infection in the Absence of Type I Interferons.
abstract: Respiratory syncytial virus (RSV) is a common cause of lower respiratory tract infections. Immunity to RSV is initiated upon detection of the virus by pattern recognition receptors, such as RIG-I-like receptors. RIG-I-like receptors signal via MAVS to induce the synthesis of proinflammatory mediators, including type I interferons (IFNs), which trigger and shape antiviral responses and protect cells from infection. Alveolar macrophages (AMs) are amongst the first cells to encounter invading viruses and the ones producing type I IFNs. However, it is unclear whether IFNs act to prevent AMs from serving as vehicles for viral replication. In this study, primary AMs from MAVS (Mavs-/-)- or type I IFN receptor (Ifnar1-/-)-deficient mice were exposed to RSV ex vivo. Wild-type (wt) AMs but not Mavs-/- and Ifnar1-/- AMs produced inflammatory mediators in response to RSV. Furthermore, Mavs-/- and Ifnar1-/- AMs accumulated more RSV proteins than wt AMs, but the infection was abortive. Thus, RIG-I-like receptor-MAVS and IFNAR signalling are important for the induction of proinflammatory mediators from AMs upon RSV infection, but this signalling is not central for controlling viral replication. The ability to restrict viral replication makes AMs ideal sensors of RSV infection and important initiators of immune responses in the lung.
authors.affiliation: Respiratory Infections Section, St. Mary's Campus, National Heart and Lung Institute, Imperial College London, London, UK.
authors.forename: Spyridon
authors.initials: S
authors.lastname: Makris
authors.forename: Monika
authors.initials: M
authors.lastname: Bajorek
authors.forename: Fiona J
authors.initials: FJ
authors.lastname: Culley
authors.forename: Michelle
authors.initials: M
authors.lastname: Goritzka
authors.forename: Cecilia
authors.initials: C
authors.lastname: Johansson
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D018836:Inflammation Mediators / Q000378:metabolism; D007370:Interferon Type I / Q000378:metabolism; D016676:Macrophages, Alveolar / Q000276:immunology* / Q000821:virology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D053633:Receptor, Interferon alpha-beta / Q000235:genetics / Q000378:metabolism*; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology*; D012136:Respiratory Syncytial Viruses / Q000502:physiology*; D015398:Signal Transduction; D014779:Virus Replication
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D016207:Cytokines; D018836:Inflammation Mediators; D007370:Interferon Type I; D053633:Receptor, Interferon alpha-beta; C512612:MAVS protein, mouse; C508032:Ifnar1 protein, mouse