Plaque Forming Unit

∞ generated and posted on 2016.02.25 ∞

Entity capable of initiating the localized, observable clearance of immobilized cells, such as bacteria suspended within agar.

A Plaque-Forming Unit is something other than necessarily an individual, e.g., virus particle (virion), but instead takes into account that viruses or other plaque-forming infectious entities can clump prior to plating or, instead, may be plated as virus-infected cells.

Ideally each PFU produces one plaque though this correspondence can fail if plaques are too crowded upon such that plaques substantially overlap.

An additional consideration is that not only can plaque-forming units be virions but so too can plaque-forming units be virus-. Key is that an effectively point-source exists for the formation of a single plaque.

Compare and contrast with colony-forming unit. See also plaque-forming unit in Phage Terms.