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Phagosome Migration and Velocity Measured in Live Primary Human Macrophages Infected with HIV-1
07:32

Phagosome Migration and Velocity Measured in Live Primary Human Macrophages Infected with HIV-1

Published on: September 5, 2016

HIV-1 buds predominantly at the plasma membrane of primary human macrophages

Sonja Welsch1, Oliver T Keppler, Anja Habermann

  • 1Department of Virology, University of Heidelberg, Heidelberg, Germany.

Plos Pathogens
|March 27, 2007
PubMed

Insights

Contrary to popular belief, Human Immunodeficiency Virus type 1 (HIV-1) primarily buds from the plasma membrane, not late endosomes, in macrophages. This study used a novel ultrastructural method to reveal this key finding about HIV-1 assembly and release.

Area of Science:

  • Virology
  • Cell Biology
  • Immunology

Background:

  • HIV-1 assembly and release typically occur at the plasma membrane.
  • Previous studies suggested exclusive HIV-1 budding at late endosomes in primary macrophages.
  • This discrepancy highlights a gap in understanding HIV-1 egress mechanisms in different cell types.

Purpose of the Study:

  • To investigate the precise site of HIV-1 assembly and release in primary macrophages.
  • To challenge the existing paradigm of HIV-1 budding occurring exclusively at late endosomes in macrophages.
  • To utilize a novel ultrastructural approach for immunomarker-independent analysis of HIV-1 budding.

Main Methods:

  • Employed a novel ultrastructural technique in primary macrophages infected with HIV-1.
  • Utilized BSA-gold to label endosomes and ruthenium red to stain the plasma membrane.
  • Analyzed virus-filled vacuolar structures for the presence of BSA-gold and ruthenium red staining.
  • Examined the composition of cellular marker proteins within the HIV-1 envelope.

Main Results:

  • Virus-containing vacuoles showed ruthenium red staining (indicating plasma membrane) but lacked BSA-gold (indicating not endosomes).
  • HIV-1 budding profiles were rarely found on gold-labeled endosomes.
  • HIV-1 budding was frequently observed on ruthenium red-positive membranes.
  • Analysis of incorporated cellular proteins supported a plasma membrane origin for the viral envelope.

Conclusions:

  • The plasma membrane is the primary site of HIV-1 budding in primary macrophages.
  • This finding contradicts the prevailing view of exclusive late endosomal budding in these cells.
  • The study provides crucial insights into the cell biology of HIV-1 replication and release.

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