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Updated: Aug 8, 2026
Imaging of HIV-1 Envelope-induced Virological Synapse and Signaling on Synthetic Lipid Bilayers
Published on: March 8, 2012
Microscopic analysis of interactions between HIV particles and living leukocytes
1Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202.
Insights
Non-infectious HIV particles interact with CD4+ cells via fusion and endocytosis. Cell type and origin significantly influence these viral entry pathways, offering insights for antiviral drug screening.
Area of Science:
- Cell biology
- Virology
- Microscopy
Background:
- Non-infectious HIV8E5 particles retain gp120 antigenic sites.
- Fluorescent lipids were incorporated into viral envelopes for visualization.
Purpose of the Study:
- To investigate the interaction mechanisms between HIV8E5 particles and living cells.
- To determine the role of fusion and endocytosis in virion-cell interactions.
- To assess the influence of cell type on viral entry pathways.
Main Methods:
- Video-enhanced/intensified optical microscopy was employed.
- Studies involved incubation of HIV8E5 particles with CD4+ and CD4- cell lines.
- Control experiments used concanavalin A to assess non-specific binding.
Main Results:
- Approximately 90% of CD4+ cells bound HIV8E5 particles, with varying degrees of fusion and endocytosis.
- CD4- cells showed minimal binding, fusion, or internalization.
- Adherent human peripheral blood mononuclear cells were less efficient at binding HIV8E5 compared to non-adherent cells.
- Both endocytosis and fusion were observed in lymphocytes.
Conclusions:
- Fusion and endocytosis are key mechanisms in HIV-cell interactions.
- Cellular interactions with HIV8E5 are multifactorial, influenced by cell type (lymphocyte/monocyte) and origin.
- The described microscopy methods can aid in characterizing viral entry and antiviral drug screening.
Abstract:
Video-enhanced/-intensified optical microscopy has been used to study the interaction of non-infectious HIV8E5 particles with living cells. The purified particles retained gp120 antigenic sites. Fluorescent lipids were intercalated into the particles' envelopes. When incubated with CD4+ cell lines, roughly 90% of the cells bound HIV8E5 particles. The extent of fusion and endocytosis varied among the cell lines tested. CD4- control cells did not significantly bind, fuse, or internalize particles. To control for non-specific exchange of the fluorescent label, HIV8E5 were bound to CD4- murine WEHI cells using concanavalin A; no apparent fusion or internalization took place. We suggest that both fusion and internalization are important mechanisms of virion-cell interaction. Adherent human peripheral blood mononuclear cells were much less efficient in binding HIV8E5 than non-adherent mononuclear cells. Both endocytosis and apparent fusion were observed for lymphocytes. Our results indicate that cells interact with HIV8E5 by multiple pathways and that these pathways are strongly affected by cell type (lymphocyte or monocyte) and origin (normal or transformed). These methods may be useful in characterizing viral entry and in anti-viral drug screening.
