A simplified plaque assay for influenza viruses in Madin-Darby kidney (MDCK) cells

Area of Science:

• Virology
• Cell Biology
• Biotechnology

Background:

• Influenza virus plaque assays are crucial for quantifying viral infectivity.
• Traditional methods often require proteolytic enzymes like trypsin for plaque formation in cell cultures.
• Enzyme addition can complicate assay procedures and increase costs.

Purpose of the Study:

• To develop a simplified and economical plaque assay for influenza A and B viruses.
• To evaluate the efficacy of a soft-agar overlay method without exogenous proteolytic enzymes.

Main Methods:

• Utilized Madin-Darby Canine Kidney (MDCK) cells for influenza virus culture.
• Employed a soft-agar overlay technique for plaque visualization.
• Added trypsin solely during the viral adsorption phase, not in the overlay.

Main Results:

• Influenza A and B viruses successfully formed plaques in MDCK cells using the modified soft-agar overlay.
• Plaquing efficiency was comparable to that achieved with conventional methods using embryonated eggs.
• The assay demonstrated simplicity and cost-effectiveness.

Conclusions:

• A conventional soft-agar overlay can be effectively used for influenza virus plaque assays without continuous addition of proteolytic enzymes.
• This method provides a viable, simple, and economical alternative for determining influenza virus infectivity.
• The findings support the use of this simplified assay in virological research and diagnostics.