Heat Inactivation of Coronavirus and Assessment of Infectivity in Host Cells

Take a frozen stock of the coronavirus.

Thaw it rapidly, then heat-inactivate it at high temperature to denature viral proteins and disrupt the lipid envelope.

Use the untreated virus as the control.

Take human lung cells engineered to express the coronavirus entry receptor.

Add the untreated and heat-inactivated virus dilutions to the wells and incubate.

In the control, the untreated virus binds to the receptor, enters the cell, and replicates into mature virions.

Infected cells undergo structural changes, a phenomenon known as the cytopathic effect or CPE, and eventually die.

In the test, the heat-inactivated virus fails to infect, and the cells remain healthy.

Add a fixative to preserve the cells. Apply a dye to stain the cells and wash to remove the excess dye.

A uniformly stained cell monolayer in the test indicates the absence of CPE, validating successful heat inactivation of the virus.