Tumor necrosis factor alpha immunoreactivity of rat peritoneal mast cell granules decreases during early secretion induced by compound 48/80: an ultrastructural …

WJ Beil, GR Login, M Aoki, LO Lunardi… - International archives of …, 1996 - karger.com
WJ Beil, GR Login, M Aoki, LO Lunardi, ES Morgan, SJ Galli, AM Dvorak
International archives of allergy and immunology, 1996karger.com
We used fast (seconds) and ultrafast (milliseconds) microwave energy-assisted chemical
fixation protocols, postembedding immunogold staining, and a morphometric analysis to
investigate the early morphological changes and the TNF-α immunoreactivity in the
cytoplasmic granules of rat peritoneal mast cells that had been stimulated to secrete by
exposure to compound 48/80. Exposure to compound 48/80 induced the development of
increased numbers of cytoplasmic granules that exhibited decreased electron density; these …
Abstract
We used fast (seconds) and ultrafast (milliseconds) microwave energy-assisted chemical fixation protocols, postembedding immunogold staining, and a morphometric analysis to investigate the early morphological changes and the TNF-α immunoreactivity in the cytoplasmic granules of rat peritoneal mast cells that had been stimulated to secrete by exposure to compound 48/80. Exposure to compound 48/80 induced the development of increased numbers of cytoplasmic granules that exhibited decreased electron density; these granules often also appeared swollen. These granule alterations were accompanied by a significantly decreased proportion of granules that were positive for TNF-α immunoreactivity We also calculated the density of TNF-α labeling/μ2 in both dense (unaltered) and altered granules in specimens. TNF-α immunoreactivity was present in dense granules (regardless of whether or not the specimens had been stimulated with compound 48/80) and in cells that were fixed with either fast or ultrafast microwave energy. However, altered granules exhibited a decreased density of TNF-α label. These findings show that changes in the immunolocalization and/or density of TNF-α immunoreactivity occur very rapidly upon stimulation of rat peritoneal mast cells with compound 48/80.
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