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Neutrophil granulocytes (also known as neutrophils or occasionally neutrocytes) are the most abundant type of granulocytes and the most abundant (40% to 75%) type of white blood cells in most mammals. They form an essential part of the innate immune system. Functionality varies in different animals. They are formed from stem cells in the bone marrow. They are short-lived and highly motile. Neutrophils may be subdivided into segmented neutrophils and banded neutrophils (or bands). They form part of the polymorphonuclear cell family (PMNs) together with basophils and eosinophils. The name ''neutrophil'' derives from staining characteristics on hematoxylin and eosin (H&E) histological or cytological preparations. Whereas basophilic white blood cells stain dark blue and eosinophilic white blood cells stain bright red, neutrophils stain a neutral pink. Normally, neutrophils contain a nucleus divided into 2–5 lobes. Neutrophils are a type of phagocyte and are normally found in the bloodstream. During the beginning (acute) phase of inflammation, particularly as a result of bacterial infection, environmental exposure, and some cancers,〔 〕〔 〕 neutrophils are one of the first-responders of inflammatory cells to migrate towards the site of inflammation. They migrate through the blood vessels, then through interstitial tissue, following chemical signals such as Interleukin-8 (IL-8), C5a, fMLP and Leukotriene B4 in a process called chemotaxis. They are the predominant cells in pus, accounting for its whitish/yellowish appearance. Neutrophils are recruited to the site of injury within minutes following trauma, and are the hallmark of acute inflammation;however, due to some pathogens being indigestible, they can be unable to resolve certain infections without the assistance of other types of immune cell. ==Characteristics== Neutrophil granulocytes have an average diameter of 12-15 micrometers (µm) in peripheral blood smears. When analyzing neutrophils in suspension, neutrophils have an average diameter of 8.85 µm. With the eosinophil and the basophil, they form the class of ''polymorphonuclear cells'', named for the nucleus' multilobulated shape (as compared to lymphocytes and monocytes, the other types of white cells). The nucleus has a characteristic lobed appearance, the separate lobes connected by chromatin. The nucleolus disappears as the neutrophil matures, which is something that happens in only a few other types of nucleated cells. In the cytoplasm, the Golgi apparatus is small, mitochondria and ribosomes are sparse, and the rough endoplasmic reticulum is absent.〔 The cytoplasm also contains about 200 granules, of which a third are azurophilic.〔 Neutrophils are sexually dymorphic. Neutrophils from women exhibit a small additional X chromosome structure, known as a "neutrophil drumstick".〔 Neutrophils will show increasing segmentation (many segments of nucleus) as they mature. A normal neutrophil should have 3-5 segments. Hypersegmentation is not normal, and occurs in some disorders, most notably Vitamin B-12 deficiency. This is noted on a manual review of the blood smear, and is positive when most or all of the neutrophils have 5 or more segments. Neutrophils are the most abundant white blood cells in humans (approximately 1011 are produced daily); they account for approximately 50-70% of all white blood cells (leukocytes). The stated normal range for human blood counts varies between laboratories, but a neutrophil count of 2.5–7.5 x 109/L is a standard normal range. People of African and Middle Eastern descent may have lower counts, which are still normal. A report may divide neutrophils into segmented neutrophils and bands. When circulating in the bloodstream and unactivated, neutrophils are spherical. Once activated, they change shape and become more amorphous or amoeba-like and can extend pseudopods as they hunt for antigens. Neutrophils have a preference to engulf refined carbohydrate〔〔〔 (glucose, fructose, sucrose, honey and orange juice〔) over bacteria.〔 In 1973 Sanchez et al. found that the neutrophil phagocytic capacity to engulf bacteria is affected when simple sugars are digested,〔 and that fasting strengthens the neutrophils' phagocytic capacity to engulf bacteria.〔 However, the digestion of normal starches has no effect. It was concluded that the function, and not the number, of phagocytes in engulfing bacteria was altered by the ingestion of sugars. In 2007 researchers at the Whitehead Institute of Biomedical Research found that given a selection of sugars, neutrophils engulf some types of sugar preferentially. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Neutrophil granulocyte」の詳細全文を読む スポンサード リンク
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