An Assay to Quantify the Binding of Human Norovirus VLPs to Intestinal Bacteria
Published: April 30, 2024
Abstract
Source: Madrigal, J. L., et al. Quantifying Human Norovirus Virus-like Particles Binding to Commensal Bacteria Using Flow Cytometry. J. Vis. Exp. (2020).
This video demonstrates an assay for quantifying human norovirus virus-like particles (VLPs) binding to human intestinal bacteria. The bacterial suspensions are mixed with the VLPs and incubated to allow the formation of VLP-bacteria complexes. The complexes are then labeled with fluorophore-tagged VLP-specific antibodies, followed by flow cytometry-based visualization and quantification to identify the percentage of VLP-bound bacteria.
Protocol
1. VLP-bacteria Attachment Assay CAUTION: Human norovirus VLPs are a biosafety level (BSL)-2 hazard, and all work involving VLPs should be performed in a biosafety cabinet. Preparation of the bacterial cultures before the attachment assay should be performed using safety conditions appropriate for the organism. Reagent preparation 1x phosphate-buffered saline (PBS) Prepare 1 L of 10x PBS by dissolvi…
Disclosures
The authors have nothing to disclose.
Materials
| 5ml Polystrene Round-Bottom Tubes with Cell-Strainer Cap | Corning | 352235 | After antibody staining, sample are transferred into tubes for flow cytometry analysis. |
| AnaeroPack | Thermo Scientific | R681001 | Anaerobic gas pack used for culture of Lactobacillus gasseri |
| BD FacsDiva software | |||
| BD LSR Fortessa flow cytometer | |||
| Bovine Serum Albumin | Fisher Bioreagents | BP1605 | Used for flow cytometry |
| Flow Cytometry Stain Buffer (FCSB) | BD Biosciences | 554657 | Used for flow cytometry |
| Mouse IgG2b kappa Isotype Control (eBMG2b), PE, eBioscience | Thermo Fisher Scientific | 12473281 | Isotype control. This antibody is purchased in the conjugated form from the manufacturer. |
| MRS Powder | BD Biosciences | 288130 | Used for media preparation and to culture Lactobacillus gasseri. |
| Norovirus capsid G2 Monoclonal Antibody (L34D) | Thermo Fisher Scientific | MA5-18241 | Norovirus GII antibody. This antibody is only available in the unconjugated form and thus must be fluorescently conjugated prior to use in the outlined flow cytometry assays. In this protocol, PE was the chosen fluor, however, other fluorescent molecules can be chosen as best suits the flow cytometer being used by the researcher. |
| Norovirus GII.4 VLP | Creative Biostructure | CBS-V700 | Human norovirus virus like particle, VLPs were generated using the baculovirus system and resuspended in phosphate buffered saline with 10% glycerol. The authors performed independent nanosight tracking analysis to determine the particle concentration of the VLPs. The concentration is approximately 1011 VLPs per milliliter. Based on the protein concentration of the VLPs, approximately 200 particles are added per bacterium in VLP attachment assays. |
| PBS 10X | Fisher Bioreagents | BP665 | Dilute to 1X prior to use. |
| SiteClick R-PE Antibody Labeling Kit | Thermo Fisher Scientific | S10467 | Conjugation kit used for labling of unconjugated antibody. |
| Sodium Chloride | Fisher Scientific | S271 | Used for media preparation |
| Tryptone | Oxoid | LP0042 | Used for media preparation |
| Tube Revolver | ThermoFisher Scientific | 88881001 | Used in virus:bacterium attachment assay. Set to max speed (40 rpm). |
| Yeast Extract | BD Biosciences | 212750 | Used for media preparation |
| Agar | Sigma | A7002 | Used for media preparation |
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Cite This Article
An Assay to Quantify the Binding of Human Norovirus VLPs to Intestinal Bacteria. J. Vis. Exp. (Pending Publication), e22132, doi: (2024).