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Biochim Biophys Acta. 2002 Aug 19;1591(1-3):29-35.

Defensin-rich granules of human neutrophils: characterization of secretory properties.

Author information

1
The Granulocyte Research Laboratory, Department of Hematology, The National University Hospital, Rigshospitalet, Juliane Maries Vej 20, DK-2100 OE Copenhagen, Denmark. mfaurschou@rh.dk

Abstract

The various granule subtypes of the human neutrophil differ in propensity for exocytosis. As a rule, granules formed at late stages of myelopoiesis have a higher secretory potential than granules formed in more immature myeloid cells. Neutrophils contain four closely related alpha-defensins, which are stored in a subset of azurophil granules. These defensin-rich azurophil granules (DRG) are formed later than defensin-poor azurophil granules, near the promyelocyte/myelocyte transition. In order to characterize the secretory properties of DRG, we developed a sensitive and accurate ELISA for detection of the neutrophil alpha-defensins HNP 1-3. This allowed us to quantify the exocytosis of alpha-defensins and markers of azurophil (myeloperoxidase), specific (lactoferrin) and gelatinase (gelatinase) granules from neutrophils stimulated with different secretagogues. The release pattern of alpha-defensins correlated perfectly with the release of myeloperoxidase and showed no resemblance to the exocytosis of lactoferrin or gelatinase. This finding was substantiated through subcellular fractionation experiments. In conclusion, despite a distinct profile of biosynthesis, DRG are indistinguishable from defensin-poor azurophil granules with respect to exocytosis. Thus, in contrast to peroxidase-negative granules, azurophil granules display homogeneity in their availability for extracellular release.

PMID:
12183052
DOI:
10.1016/s0167-4889(02)00243-4
[Indexed for MEDLINE]
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