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Updated: Jul 28, 2026
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Scalable Isolation and Purification of Extracellular Vesicles from Escherichia coli and Other Bacteria
Published on: October 13, 2021
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Comprehensive method for isolation and functional characterization of bacterial vesicles from human biological
Swati Thangariyal1, Sakshi Bhat1, Ashmit Mittal1
1Department of Molecular and Cellular Medicine, Institute of Liver and Biliary Sciences, Delhi, India.
Methods (San Diego, Calif.)
|March 1, 2025
Summary
Researchers developed a new method to isolate bacterial vesicles (BVs) from human samples, identifying key proteins involved in immune responses and potential diagnostic applications.
Area of Science:
- Microbiology
- Immunology
- Biochemistry
Background:
- Bacterial vesicles (BVs) are crucial for bacterial communication and pathogenesis but isolating them from human samples is challenging.
- Existing methods often struggle to differentiate BVs from host-derived extracellular vesicles (EVs).
- Knowledge of BVs is largely based on in vitro cultured bacteria, limiting understanding of their role in vivo.
Purpose of the Study:
- To develop a reliable and reproducible protocol for isolating and characterizing bacterial vesicles (BVs) from human plasma and stool samples.
- To identify and analyze the proteomic content of BVs from healthy individuals.
- To investigate the functional role of BVs in immune cell interactions.
Main Methods:
- Density gradient ultracentrifugation was used to isolate and enrich BVs from plasma and stool.
- Morphological characterization was performed using transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA).
- Western blot, ELISA, mass spectrometry, and qRT-PCR were employed for molecular and functional analyses.
Main Results:
- TEM and NTA confirmed BV presence (25-250 nm); Western blot differentiated BVs (OmpA marker) from host EVs (Alix marker).
- Proteomic analysis identified 439 proteins in plasma BVs and 327 in stool BVs, with 300 common proteins.
- Functional assays showed BVs were rapidly uptaken by PBMCs and upregulated Toll-like receptor 2 (TLR-2) expression.
Conclusions:
- A reliable method for enriching and identifying bacterial vesicles from human samples was established.
- The study revealed key proteins associated with BVs in healthy individuals and their role in immune regulation.
- These findings offer a foundation for exploring BVs in diagnostics and therapeutics for various diseases.
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