PMNs make up sixty percent or more of whte blood cells. This is one of three types of "granulocyte" found in normal blood, and has a multi-lobed nucleus and cytoplasmic granules which take up neutral stains. Blood PMNs turn over very rapidly (with a half life of about two hours), and are mobilized rapidly in response to inflammatory stimuli.
PMNs bear receptors for the Fc portion of IgG and for complement component C3b, and these both have opsonizing activity. Complement component C5a is highly chemotactic for PMNs.