RESUMEN
Neutrophils were examined for their ability to recognize and ingest beads coated with amino-derivatives of glucose, mannose, and galactose. Radioactive or fluorescent beads coated with any of the three sugars were ingested to an extent three times that observed with albumin-coated beads. Enhancement of ingestion of sugar-coated beads was much more evident when examined by electron micrographic studies. Inclusion of glucose or mannose in the medium with glucose- or mannose-coated beads caused a dose-dependent reduction of ingestion to control levels, but ingestion of galactose-coated beads was poorly inhibited. Similarly, galactose or fucose (6-deoxy-galactose) markedly inhibited ingestion of galactose-coated beads, but caused only a slight decrease in ingestion of glucose- or mannose-coated beads. Thus, neutrophils possess carbohydrate-binding membrane structures that can mediate recognition and ingestion of sugar-coated beads. Such carbohydrate recognition systems may underlie certain interactions of neutrophils and other surfaces.
Asunto(s)
Amino Azúcares/farmacología , Neutrófilos/inmunología , Fagocitosis/efectos de los fármacos , Fucosa/farmacología , Galactosa/farmacología , Glucosa/farmacología , Glutaral/análogos & derivados , Glutaral/inmunología , Humanos , Manosa/farmacología , Microscopía Electrónica , Neutrófilos/ultraestructuraAsunto(s)
Hierro/metabolismo , Macrófagos del Hígado/citología , Hígado/citología , Adenilil Ciclasas/metabolismo , Animales , Células Cultivadas , Endotelio/citología , Endotelio/ultraestructura , Femenino , Ferritinas/metabolismo , Hemosiderina/metabolismo , Macrófagos del Hígado/enzimología , Macrófagos del Hígado/ultraestructura , Hígado/enzimología , Hígado/ultraestructura , Ratas , Ratas EndogámicasRESUMEN
Cultures of Kupffer cells and of hepatocytes, prepared from single rat livers, synthesized ferritin protein equally efficiently. In culture but not in suspension, both sorts of cells responded significantly to stimulation with iron by increased ferritin synthesis. As determined by isoelectric focusing, the isoferritin profiles of newly synthesized 14C-labeled Kupffer cell and hepatocyte ferritin were identical, each having three bands. However, unlabeled ferritin, extracted from nonparenchymal liver cells (mainly Kupffer and endothelial cells) of iron-loaded rats, contained an acidic isoferritin that was not present in hepatocyte ferritin. Investigation of ferritin synthesis in cultured peritoneal and alveolar macrophages yielded similar results. The isofocusing profile of newly synthesized peritoneal macrophage ferritin was indistinguishable from the profile of fresh Kupffer cell or hepatocyte ferritin. Thus, the three isoferritins common to Kupffer cells, hepatocytes, and extrahepatic macrophages are neither cell- nor tissue-specific. However, modifications on intracellular storage may affect the isofocusing properties. The findings, although consistent with the LnH24-n subunit model of ferritin protein, indicate identical restrictive genomic control of the H:L ratios in these sorts of cells. Further, they make it probable that Kupffer cell ferritin iron, originating by endogenous synthesis, is the principal source of Kupffer cell hemosiderin iron.