Viral titer

Viruses infect cells in order to replicate, a task which they cannot accomplish on their own. Measuring the amount of virus in a cell-free sample does not provide information regarding their infectivity, limiting its usefulness. Instead, cell imaging is used to detect the ability of a given virus to infect cells in culture. Viral concentrations are determined from the fraction of infected cells.

• Plaque assay - University of Zurich uses the ImageXpress Widefield System to investigate host pathogen interactions
• Focus forming assay
• Endpoint dilution