title: Recombinant human alpha-2a interferon promotes an atypical process of mast cell secretion with ultrastructural features suggestive for piecemeal degranulation.
abstract: Purified mast cells (MC), isolated from the rat peritoneum, were stimulated in vitro with recombinant human IFN-alpha 2a (rhIFN-alpha 2a) and studied ultrastructurally. Quantitative determination of histamine release was also performed. The following ultrastructural features were observed: (1) dilation of single granules, leading to the formation of cytoplasmic cavities filled with dissolved or eroded matrices; (2) induction of partially empty, nonfused granule containers close to unaltered resting granules, a process very suggestive of piecemeal degranulation; (3) focal exocytosis, characterized by opening of single granules to the cell exterior and/or fusion of a few granules into small secretory channels. Histamine release was slightly increased in rhIFN-alpha 2a-treated MC, although not to significant levels. These results indicate that rhIFN-alpha 2a induces a characteristic pattern of degranulation in rat peritoneal MC and that a small proportion of rhIFN-alpha 2a-stimulated MC shows ultrastructural features suggestive for piecemeal degranulation.
authors.affiliation: Department of Medical and Morphological Research, Anatomy Section, University of Udine Medical School, Udine, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Crivellato
authors.forename: Luigi
authors.initials: L
authors.lastname: Candussio
authors.forename: Franco
authors.initials: F
authors.lastname: Mallardi
authors.forename: Domenico
authors.initials: D
authors.lastname: Ribatti
mesh_terms: D000818:Animals; D015550:Cell Degranulation; D002478:Cells, Cultured; D006636:Histamine Release; D006801:Humans; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000494:pharmacology*; D008407:Mast Cells / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D010537:Peritoneum; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins; D013268:Stimulation, Chemical
chemical_list: D000077190:Interferon alpha-2; D016898:Interferon-alpha; D011994:Recombinant Proteins