The plaque assay is a well established method for measuring virus concentration as it relates to infectious dose. The assay relies on determining the number of plaque forming units (pfu) created in a monolayer of virus-infected cells. Plaques form when a virus-infected cell Iyses, leading to a subsequent cycle of infection and lysis of neighboring cells. Plaques are visualized by staining the fixed cell monolayer with crystal violet. Automated high contrast brightfield or color brightfield imaging with the Lionheart™ FX Automated Microscope or Cytation™ Cell Imaging Multi-Mode Reader and optimized Gen5™ image analysis protocols capture and quantify pfu number in 6- to 96-well microplates. The plaque reduction neutralization (PRNT) assay is a powerful variation on the plaque assay for measuring antibody neutralization using the same methods described here.
Plaque Assay Procedure
Color brightfield images are acquired and stitched together to generate a single image per well that is then processed to reduce background.
Plaques are automatically identified (yellow masks) by Gen5 cellular analysis tools using the green color brightfield channel.
Plaque count, average plaque area, and total plaque area are automatically calculated and reported for each sample.
Increase assay throughput and performance
Liquid handling automation
BioStack™ Compatible Assay:
Process up to 50 microplates
Incorporating the BioStack Microplate Stacker enables processing and analysis of up to 50 plates.