Determining Optimal Target Cell Density Using a Luciferase-Based Pseudovirus Infection Assay

Begin with a multi-well plate containing adherent mammalian cells at increasing densities.
Add an equal concentration of pseudovirus to the wells and incubate.
The pseudovirus bears influenza envelope proteins on a lentiviral core and contains a gene encoding luciferase.
The virus binds to cell surface receptors and undergoes endocytosis.
Once inside, the viral RNA is released and reverse-transcribed into DNA by reverse transcriptase. The DNA then integrates into the host genome, resulting in luciferase expression.
Remove the culture medium and wash the cells with buffer.
Add lysis buffer and incubate at a low temperature. The lytic reagent disrupts cells and releases luciferase.
Let the lysates reach room temperature and transfer them to an opaque multi-well plate.
Add luciferase substrate. Luciferase catalyzes substrate oxidation, producing luminescence.
Using a luminometer, measure luminescence to quantify viral infection.
Compare luminescence levels across cell densities. The highest luminescence indicates the optimal density with the highest infection efficiency.

For pseudovirus titration, make a single-cell suspension of five times 10 to the fourth cells per milliliter of MDCK cells in