Structural and functional heterogeneity among peroxidase-negative granules in human neutrophils : identification of a distinct gelatinase-containing granule subset by combined immunocytochemistry and subcellular fractionation

摘要: The existence of separate gelatinase granules in human neutrophils has been a matter debate recent years. We have demonstrated that the 135-kD form neutrophil is complex 92-kD and novel 25-kD protein termed gelatinase-associated lipocalin (NGAL) that, addition to being complexed with part gelatinase, localized free peroxidase-negative specific granules. Because this association was not appreciated earlier studies, we decided reassess ultrastructural localization using antibodies without immunoreactivity towards NGAL. Double-labeling immunogold electron microscopy performed on frozen thin sections neutrophils. Twenty-four percent all were labeled antigelatinase antibody, but antilactoferrin antibody. These are defined as Sixteen reacted antibody rest (60%) both antibodies. All labeling for lactoferrin Gelatinase observed round oval forms considerably smaller size than granules, less dense. Isolated obtained by subcellular fractionation also examined immunoelectron microscopy. This comprise continuum from most dense contain no lightest lactoferrin. Thus, do exist subpopulation may allow exocytosis during diapedesis substantial mobilization other ie,