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High-throughput Confocal Imaging of Quantum Dot-Conjugated SARS-CoV-2 Spike Trimers to Track Binding and Endocytosis in HEK293T Cells
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CD81 fusion alters SARS-CoV-2 Spike trafficking.
Allaura S Cone1,2, Yijun Zhou1,2, Ryan P McNamara3
1Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Mbio
|August 14, 2024
Summary
Researchers fused the SARS-CoV-2 Spike protein to CD81, enabling its secretion in extracellular vesicles. This novel approach maximizes viral glycoprotein display for potential vaccine development against coronaviruses.
Area of Science:
- Virology and Immunology
- Vaccine Development
- Extracellular Vesicle Biology
Background:
- The SARS-CoV-2 pandemic highlighted the need for effective vaccines against emerging coronaviruses.
- Current molecular vaccines often face challenges with viral glycoprotein degradation when expressed in isolation.
- Understanding viral glycoprotein maturation is crucial for optimizing vaccine design.
Purpose of the Study:
- To investigate a novel method for enhancing the maturation and assembly of the SARS-CoV-2 Spike (S) glycoprotein.
- To explore the potential of using extracellular vesicles (EVs) for delivering viral glycoproteins.
- To assess the immunogenicity of S glycoprotein displayed on EVs.
Main Methods:
- Engineered a fusion protein by linking the SARS-CoV-2 S glycoprotein to the tetraspanin protein CD81.
- Expressed the CD81-S fusion protein in cells to facilitate its secretion into EVs.
- Isolated and purified CD81-S containing EVs for characterization and immunogenicity studies in mice.
Main Results:
- The CD81-S fusion protein was successfully incorporated into EVs and secreted, avoiding lysosomal degradation.
- Purified EVs displayed functional S glycoprotein on their surface, confirmed by cryogenic electron microscopy.
- CD81::S-fusion EVs induced anti-S trimer and anti-RBD antibody responses in mice.
Conclusions:
- Fusing the S glycoprotein to CD81 redirects its maturation pathway, promoting assembly and release via EVs.
- This strategy offers a method to maximize viral glycoprotein display without co-expressing potentially pathogenic viral proteins.
- CD81-EVs represent a promising platform for developing next-generation viral glycoprotein vaccines.
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