Scientists Say: Neutrophil

This is a cell in the immune system that traps and destroys invaders


A neutrophil (right, in yellow) engulfs a bacterium (left, orange).

Volker Brinkmann/Wikipedia (CC-2.5)

Neutrophil (noun, “NEW-troh-fill”)

This is a type of cell in your immune system — the collection of cells in your body that fight off infections. Neutrophils are the most abundant immune cells in the body. They form in the bone marrow and circulate in the blood. Each neutrophil lives only a few days, but while they are alive they are on constant patrol.

Neutrophils are one of the first cell types to arrive when an infection takes hold. When a cell in the body is infected with a harmful microbe, the cell sends out a chemical distress signal. When neutrophils detect this signal, they crawl toward the infected cell. Once they arrive, they release cytokines — chemicals that serve as an additional alarm call. These chemicals summon more immune cells to the scene.

But neutrophils don’t stop there. They can engulf microbes and digest them. Neutrophils can also spew out antimicrobial chemicals to kill bigger invaders. They can even release a web of fibers that trap and kill invading microbes.

In a sentence

Scientists are using computer models to figure out how to make neutrophils into more efficient killers.

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Bethany Brookshire was a longtime staff writer at Science News Explores and is the author of the book Pests: How Humans Create Animal Villains. She has a Ph.D. in physiology and pharmacology and likes to write about neuroscience, biology, climate and more. She thinks Porgs are an invasive species.

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