Neutrophil Granulocyte - Life Span

Life Span

The average lifespan of (non-activated human) neutrophils in the circulation is about 5.4 days. Upon activation, they marginate (position themselves adjacent to the blood vessel endothelium), and undergo selectin-dependent capture followed by integrin-dependent adhesion in most cases, after which they migrate into tissues, where they survive for 1–2 days.

Neutrophils are much more numerous than the longer-lived monocyte/macrophage phagocytes. A pathogen (disease-causing microorganism or virus) is likely to first encounter a neutrophil. Some experts hypothesize that the short lifetime of neutrophils is an evolutionary adaptation. The short lifetime of neutrophils minimizes propagation of those pathogens that parasitize phagocytes because the more time such parasites spend outside a host cell, the more likely they will be destroyed by some component of the body's defenses. Also, because neutrophil antimicrobial products can also damage host tissues, their short life limits damage to the host during inflammation.

Neutrophils will often be phagocytosed themselves by macrophages after digestion of pathogens. PECAM-1 and phosphatidylserine on the cell surface are involved in this process.

Read more about this topic:  Neutrophil Granulocyte

Famous quotes containing the words life and/or span:

    The authoritarian child-rearing style so often found in working-class families stems in part from the fact that parents see around them so many young people whose lives are touched by the pain and delinquency that so often accompanies a life of poverty. Therefore, these parents live in fear for their children’s future—fear that they’ll lose control, that the children will wind up on the streets or, worse yet, in jail.
    Lillian Breslow Rubin (20th century)

    The last bear, shot drinking in the Dakotas
    Loped under wires that span the mountain stream.
    Hart Crane (1899–1932)