title: HIV interaction with endosomes in macrophages and dendritic cells.
abstract: The human immunodeficiency virus type 1 (HIV-1) is an enveloped retrovirus that undergoes assembly at specific sites in infected cells. In macrophages, at least, this assembly occurs primarily on a subset of endocytic organelles that contain some of the markers found in late endosomes or multivesicular bodies (MVBs), in particular CD63. The budding of virus particles into endosomes has many features in common with the formation of exosomes and some limited biochemical comparison of HIV-1 particles produced from macrophages with exosomes suggests that the two have similar cellular origins. Here we show that macrophages infected with HIV contain large intracellular pools of infectious virus that can be released by homogenisation of intact cells. Immunoprecipitation experiments indicate this virus has a similar complement of cellular membrane proteins to viruses that can be recovered from the extracellular medium, further suggesting that viruses released from macrophages initially bud into endosomal organelles and are then released by fusion of these organelles with the plasma membrane.
authors.affiliation: Cell Biology Unit, MRC-Laboratory for Molecular Cell Biology, and Department of Biochemistry and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Kramer
authors.forename: Annegret
authors.initials: A
authors.lastname: Pelchen-Matthews
authors.forename: Magdalena
authors.initials: M
authors.lastname: Deneka
authors.forename: Eduardo
authors.initials: E
authors.lastname: Garcia
authors.forename: Vincent
authors.initials: V
authors.lastname: Piguet
authors.forename: Mark
authors.initials: M
authors.lastname: Marsh
mesh_terms: D002462:Cell Membrane / Q000821:virology; D003713:Dendritic Cells / Q000821:virology*; D011992:Endosomes / Q000737:chemistry / Q000821:virology*; D006678:HIV / Q000737:chemistry / Q000502:physiology*; D015658:HIV Infections / Q000209:etiology; D006801:Humans; D008264:Macrophages / Q000821:virology*; D008561:Membrane Fusion; D008565:Membrane Proteins / Q000032:analysis; D021381:Protein Transport; D013601:T-Lymphocytes / Q000821:virology; D014759:Viral Envelope Proteins / Q000032:analysis / Q000378:metabolism; D014779:Virus Replication
chemical_list: D008565:Membrane Proteins; D014759:Viral Envelope Proteins