Early Steps of Individual Multireceptor Viral Interactions Dissected by High-Density, Multicolor Quantum Dot Mapping...

Area of Science:

• Virology
• Cell Biology
• Biophysics

Background:

• Viral entry into host cells is a critical step in infection, necessitating understanding of virus-receptor interactions.
• Studying these early viral capture events is key for developing effective antiviral therapies and vaccines.
• Single virus tracking offers real-time insights, but visualizing multireceptor dynamics at nanoscale and millisecond resolution remains challenging.

Purpose of the Study:

• To develop and validate a novel imaging methodology for visualizing real-time, single-molecule interactions between virus-like particles (VLPs) and multiple viral receptors on living immune cells.
• To investigate the spatiotemporal dynamics of viral (co-)receptors and their role in the initial stages of viral capture.
• To assess the impact of coordinated receptor diffusion on the binding and infectivity of HIV-1 and SARS-CoV-2 VLPs.

Main Methods:

• Developed a four-color, high-density quantum dot spatiotemporal mapping technique.
• Applied the methodology to primary living immune cells from healthy donors to track VLPs and their interactions with three distinct viral (co-)receptors.
• Utilized quantitative analysis tools and varied temporal-windows of single-molecule localization to analyze diffusion dynamics and residence times.

Main Results:

• Revealed coordinated spatiotemporal diffusion of three different viral (co-)receptors on the cell membrane preceding viral engagement.
• Demonstrated that this concerted receptor diffusion influences the residence time of HIV-1 and SARS-CoV-2 VLPs on the host cell membrane.
• Showed a correlation between receptor dynamics, VLP residence time, and potential viral infectivity.

Conclusions:

• The developed quantum dot methodology enables detailed, real-time analysis of early viral-host interactions at the single-molecule level.
• Coordinated diffusion of viral (co-)receptors plays a significant role in modulating VLP binding and subsequent infectivity.
• This approach offers a powerful platform for investigating viral entry mechanisms and can be adapted for other multimolecular systems.