Determining Antiviral Efficacy of Experimental Drugs Through a Plaque Assay

Begin with a virus-containing sample obtained from an infected porcine cornea treated with an antiviral drug.

Perform a serial dilution of the sample to create a sequence of decreasing virus concentrations.

Optimum dilution prevents single-cell infection by multiple viruses.

Introduce the diluted samples to a host-cell monolayer and incubate.

The virus attaches to the host-cell receptor, enters the cell, and initiates its replication. The infected cell lyses, releasing virions.

Add methylcellulose, a viscous substance that confines the viruses to the nearby cells.

Subsequently, the viruses cause cell death and plaque formation in the infected region.

Add methanol to fix the cells.

Use crystal violet to stain the live cells.

Observe plaques as clear zones indicating infected cells and cell death, surrounded by crystal violet-stained uninfected cells.

Finally, count the number of plaques at the highest dilution to quantify the virus titer in the starting solution to determine the efficacy of the antiviral drug.