title: Visualization of HIV T Cell Virological Synapses and Virus-Containing Compartments by Three-Dimensional Correlative Light and Electron Microscopy.
abstract: Virological synapses (VS) are adhesive structures that form between infected and uninfected cells to enhance the spread of HIV-1. During T cell VS formation, viral proteins are actively recruited to the site of cell-cell contact where the viral material is efficiently translocated to target cells into heterogeneous, protease-resistant, antibody-inaccessible compartments. Using correlative light and electron microscopy (CLEM), we define the membrane topography of the virus-containing compartments (VCC) where HIV is found following VS-mediated transfer. Focused ion beam scanning electron microscopy (FIB-SEM) and serial sectioning transmission electron microscopy (SS-TEM) were used to better resolve the fluorescent Gag-containing structures within the VCC. We found that small punctate fluorescent signals correlated with single viral particles in enclosed vesicular compartments or surface-localized virus particles and that large fluorescent signals correlated with membranous Gag-containing structures with unknown pathological function. CLEM imaging revealed distinct pools of newly deposited viral proteins within endocytic and nonendocytic compartments in VS target T cells.
  
  
  OBJECTIVE
  This study directly correlates individual virus-associated objects observed in light microscopy with ultrastructural features seen by electron microscopy in the HIV-1 virological synapse. This approach elucidates which infection-associated ultrastructural features represent bona fide HIV protein complexes. We define the morphology of some HIV cell-to-cell transfer intermediates as true endocytic compartments and resolve unique synapse-associated viral structures created by transfer across virological synapses.
authors.affiliation: Division of Infectious Disease, Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Lili
authors.initials: L
authors.lastname: Wang
authors.affiliation: Simons Electron Microscopy Center, New York Structural Biology Center, New York, New York, USA.
authors.forename: Edward T
authors.initials: ET
authors.lastname: Eng
authors.affiliation: Division of Infectious Disease, Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Law
authors.affiliation: Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Gordon
authors.affiliation: Simons Electron Microscopy Center, New York Structural Biology Center, New York, New York, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Rice
authors.affiliation: Division of Infectious Disease, Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA ben.chen@mssm.edu.
authors.forename: Benjamin K
authors.initials: BK
authors.lastname: Chen
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000648:ultrastructure* / Q000821:virology*; D015658:HIV Infections / Q000821:virology*; D015497:HIV-1 / Q000502:physiology* / Q000648:ultrastructure*; D054884:Host-Pathogen Interactions; D006801:Humans; D014771:Virion / Q000502:physiology; D053586:Virus Internalization; D014779:Virus Replication; D057646:Virus Uncoating
keywords: Gag; HIV-1; T cells; correlative light and electron microscopy; endosome; focused ion beam electron microscopy; transmission electron microscopy; virological synapses; virus dissemination