Quantifying Kaposi’s Sarcoma-Associated Herpesvirus Infectivity Using an Infectious Units Assay

Take a multi-well plate containing mammalian cancer cells.

Remove the medium. Add a serially diluted inoculum of Kaposi's sarcoma-associated herpesvirus from a virus stock.

The viral genome carries a green fluorescent protein, or GFP, gene.

Centrifuge the plate to allow viral adsorption. Incubate briefly to stabilize virus-cell interactions.

Remove the inoculum, add fresh growth medium, and incubate the plate.

The adsorbed virus enters the cell through endocytosis and releases its genome into the cytoplasm.

The viral genome enters the nucleus, where early genes are expressed to produce proteins that promote viral genome replication.

The viral genome replicates, and viral proteins are produced, along with GFP.

Using flow cytometry, measure the number of GFP-positive cells for each dilution, which represent virus-infected cells.

Using the GFP-positive cell count at each dilution, the dilution factor, and the inoculum volume, calculate the infectious units in the virus stock.

Seed one times 10 to the power of four SLK cells per well in a 96-well plate 24 hours before infection. Label nine 1.5 milliliter microcentrifuge tubes for a serial two-fold dilution series. Add 200 microliters of virus su