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In macrophages, HIV-1 assembles into an intracellular plasma membrane domain containing the tetraspanins CD81, CD9,

Magdalena Deneka1, Annegret Pelchen-Matthews, Rahel Byland

  • 1Cell Biology Unit, Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, England, UK.

The Journal of Cell Biology
|April 18, 2007
PubMed

Insights

Human immunodeficiency virus type 1 (HIV-1) assembles in macrophages within a unique intracellular plasma membrane domain, not endosomes. This compartment sequesters cell surface proteins and is exploited by HIV-1 for viral replication.

Area of Science:

  • Cell Biology
  • Virology
  • Immunology

Background:

  • Previous studies indicated Human immunodeficiency virus type 1 (HIV-1) buds into intracellular structures containing the late endosome marker CD63 in macrophages.
  • The precise nature and origin of these intracellular compartments remained unclear.

Purpose of the Study:

  • To elucidate the identity of the intracellular compartments where HIV-1 assembles in macrophages.
  • To investigate the relationship between these compartments, cell surface proteins, and HIV-1 replication.

Main Methods:

  • Immunofluorescence microscopy and immunoelectron microscopy were employed.
  • Analysis of tetraspanin expression (CD81, CD9, CD53) on uninfected and infected macrophages.
  • Tracer uptake experiments (horseradish peroxidase, ruthenium red) at 4°C to assess compartment accessibility.

Main Results:

  • The studied organelles are internally sequestered plasma membrane domains, not endosomes, containing tetraspanins CD81, CD9, and CD53.
  • These structures are connected to the cell surface, as evidenced by tracer accessibility.
  • HIV-1 assembles and accumulates within these intracellular plasma membrane domains, recruiting CD63, which is then incorporated into virions.

Conclusions:

  • Macrophages utilize a previously undescribed intracellular plasma membrane domain for HIV-1 assembly.
  • HIV-1 hijacks this unique compartment, sequestering cell surface proteins for its replication cycle.
  • This finding redefines the intracellular site of HIV-1 assembly in macrophages.

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