Analyzing the Antigenic Relationship between Viruses using an Image-Based Microneutralization Assay

Abstract

Source: Lin, Y., et al. Optimization of a Quantitative Micro-neutralization Assay. J. Vis. Exp. (2016)

This video demonstrates the imaging-based micro-neutralization assay to analyze the antigenic relations between influenza A and B viruses. It provides a quantitative and visual way to assess the effectiveness of antibodies or other treatments in preventing viral infection.

Protocol

1. Virus Titration

NOTE: Depending on the number of viruses and the number of duplicates, a well plate can be set up with the following flexibilities: (1) The viral dilution can be arranged along either the rows or the columns (Figure 1). Each virus should occupy a separate row/column. (2) The viral dilution increment is flexible, but it should start with the highest viral concentration at the top-left corner. (3) There is no restriction on the number of duplicates.

1. Aliquot sufficient MDCK cells or MDCK-SIAT cells8 into 96-well plates (200 µl/well). Incubate the cells at 37....

Results

Figure 1: Example of a well-plate setup in a virus titration experiment. Test viruses are assigned to separate rows (A to H). Columns are designed for different viral dilutions (1 to 12). Two columns were used as duplicates for each viral dilution. Scale .......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
VGM	Sigma	D6429, P0781	500 ml DMEM+5 ml Pen/Strepb
PBS A			Nature pH Phosphate-buffered saline: NaCl 10 g, KCl 0.25 g, Na2HPO4 1.437 g, KH2PO4 0.25 g, and Dist. Water 1 L
Avicell	FMC	RC-581F	2.4 g in 100 ml distilled water dissolved by agitation on a magnetic stirrer for 1 hr. Sterilize by autoclaving
2x DMEM	Gibco	21935-028
Trypsin	Sigma	T1426
Overlay (10 ml/plate):			5 ml 2x DMEM, Trypsin 2 μg/ml final concentration, Avicell 5 ml
Triton X- 100 e	Sigma	T8787	Permeabilization buffer: 0.2% in PBS A (v/v)
Tween 80	Sigma	P5188	Wash Buffer: 0.05% Tween 80 in PBS A (v/v)
Horse serum	PAA Labs Ltd	B15-021	ELISA Buffer: 10% in PBS A (v/v) + 0.1% Tween 80
Mouse MAb against influenza type A	Biorad	MCA 400	1 st Antibody: 1:1,000 in ELISA Buffer
Goat anti-mouse IgG (H+L) HRP conjugate	Biorad	172-1011	2 nd Antibody: 1:1,000 in ELISA Buffer
True Blu peroxidase substrate	KPL	50-78-02	Substrate: True blue +0.03% H2O2 g (1:1,000 of 30% solution)
96-well flat-bottom microtitre plates	Costar	3596
8 channel multiwall-plate washer and manifold	Sigma	M2656
Perfection Plate Scanner	Epson	V750 Pro	The imaging software can be downloaded freely from http://www.epson.com/cgi-bin/ Store/support/supDetail.jsp? oid=66134&infoType=Downloads.
Software operational environment: LabVIEW	National Instruments Corporation	Window based with NI Vision builder	Version: LabVIEW2012 or above