Granules of the human neutrophilic polymorphonuclear leukocyte

N Borregaard, JB Cowland - … Journal of the American Society of …, 1997 - ashpublications.org
N Borregaard, JB Cowland
Blood, The Journal of the American Society of Hematology, 1997ashpublications.org
Fig 2. Classification of granules in neutrophils. Peroxidase-positive (azurophilic or primary)
granules are characterized by the content of MPO and may be further divided based on their
content of defensins into large, defensin-rich granules and the smaller defensin-poor
granules. The peroxidase-negative granules may be divided into specific (secondary)
granules and gelatinase (tertiary) granules on the basis of their relative content of lactoferrin
and gelatinase. All granules contain lysozyme. Secretory vesicles share some of their …
Fig 2. Classification of granules in neutrophils. Peroxidase-positive (azurophilic or primary) granules are characterized by the content of MPO and may be further divided based on their content of defensins into large, defensin-rich granules and the smaller defensin-poor granules. The peroxidase-negative granules may be divided into specific (secondary) granules and gelatinase (tertiary) granules on the basis of their relative content of lactoferrin and gelatinase. All granules contain lysozyme. Secretory vesicles share some of their membrane proteins with peroxidase-negative granules, whereas others are unique to secretory vesicles. Def., defensins; Gela., gelatinase; Tert., tertiary.
Aggregation of smaller unit vesicles to form mature gran- ogy, eg, for classification of myeloproliferative or myelodysplastic disorders. ules creates a surface to volume problem because the surface area of the final granule is the sum of the surface area of It is well established that major differences exist between the different granule subsets regarding the extent to which these the transport vesicles that fused to create the mature granule, and the volume of the mature granule is the sum of the are mobilized both in vitro and in vivo. 46-50 Gelatinase granules (identifiedbygelatinase) aremobilizedmorereadilythanspecific volume of cargo carried by the transport vesicles (Fig 1). Azurophil granules are generally described as spherical or granules (identified by lactoferrin), 16, 51, 52 which again are exocytosed more readily than azurophil granules (identified by MPO). football shaped, whereas specific granules are known to adopt more irregular and elongated forms. 5 This might be a This hierarchy applies both when neutrophils isolated from peripheral blood are stimulated with various secretagogues and reflection of volume adjustment in azurophil granules, which are known to proteolytically process a significant part of when exudate neutrophils collected in a skin window chamber are analyzed and further stimulated. 48, 50 It therefore makes sense the proteins that are targeted to these. 32, 37, 38 In this respect, azurophil granules resemble lysosomes. 39 In contrast, no pro- from a functional point of view to classify the neutrophil granules into peroxidase-positive (or azurophilic or primary) granules, cessing and therefore no increase in osmotic activity due to proteolysis has been observed in specific granules, with one defined by their content of MPO, and to further subdivide the peroxidase-negative granules into specific (or secondary) granpossible exception. 40
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