title: Respiratory syncytial virus persistence in macrophages downregulates intercellular adhesion molecule-1 expression and reduces adhesion of non-typeable Haemophilus influenzae.
abstract: BACKGROUND
  Persistence of respiratory syncytial virus (RSV) has been associated with episodes of chronic obstructive pulmonary disease (COPD); furthermore, co-infection of RSV with non-typeable Haemophilus influenzae (NTHi) is increasingly recognized as a cause of exacerbations of COPD.
  
  
  OBJECTIVE
  To study whether RSV persistence in a macrophage (Mφ)-like cell line alters NTHi uptake (adhesion and ingestion).
  
  
  METHODS
  A murine Mφ-like cell line persistently infected with RSV (MφP) was used. The effects of RSV persistence on NTHi uptake by MφP and mock-infected Mφ (MφN) were determined by flow-cytometric assays with NTHi labelled with either ethidium bromide or FITC. Expression of intercellular adhesion molecule-1 (ICAM-1), a ligand for NTHi, was determined by measuring mRNA through real-time PCR and protein by Western blot assays.
  
  
  RESULTS
  RSV persistence reduced both the capacity of Mφ to take up bacteria and the expression of ICAM-1 mRNA and protein. Furthermore, when ICAM-1 was blocked with anti-ICAM-1 antibody, the adhesion capacity of NTHi was significantly reduced for MφN, whereas for MφP the effect was less evident, implying that ICAM-1 participates in NTHi adhesion to Mφ.
  
  
  CONCLUSIONS
  RSV persistence in murine Mφ diminishes their capacity to adhere and ingest NTHi through downregulation of ICAM-1 expression at the transcriptional level.
authors.affiliation: Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, México D.F., México.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Arrevillaga
authors.forename: Jorge
authors.initials: J
authors.lastname: Gaona
authors.forename: Carla
authors.initials: C
authors.lastname: Sánchez
authors.forename: Víctor
authors.initials: V
authors.lastname: Rosales
authors.forename: Beatríz
authors.initials: B
authors.lastname: Gómez
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D001422:Bacterial Adhesion; D002460:Cell Line; D060085:Coinfection; D015536:Down-Regulation; D006192:Haemophilus Infections / Q000150:complications / Q000382:microbiology; D006193:Haemophilus influenzae / Q000145:classification / Q000502:physiology*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D008264:Macrophages / Q000502:physiology* / Q000821:virology*; D051379:Mice; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000382:microbiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012136:Respiratory Syncytial Viruses / Q000502:physiology*
chemical_list: D000906:Antibodies; C090509:Icam1 protein, mouse; D012333:RNA, Messenger; D018799:Intercellular Adhesion Molecule-1