Membrane-bound glycoconjugates of fetal mouse erythropoietic cells with special reference to phagocytosis by hepatic macrophages.
Using lectin and colloidal iron (CI) stainings in combination with neuraminidase digestion, glycoconjugates on the surface of erythropoietic cells of the yolk sac and liver in fetal mice were examined. Fetal hepatic macrophages were capable of distinguishing between phagocytozed and non-phagocytozed erythroid elements as described in our previous study. Marked differences between these two elements could be ultrahistochemically detected on their cell surface. The phagocytozed elements, such as nuclei expelled from erythroblasts and degenerating primitive erythroblasts, faintly bound neuraminidase-sensitive CI, and neuraminidase digestion imparted a weak peanut agglutinin (PNA) binding. In contrast, erythroblasts at various maturation stages, erythrocytes and normal primitive erythroblasts heavily bound neuraminidase-sensitive CI, and neuraminidase digestion imparted a moderate PNA binding. No differences in binding of either concanavalin agglutinin, Ricinus communis agglutinin-I or PNA were noted between phagocytozed and non-phagocytozed erythroid elements. Desialylation appears to be one of the most important signs for the recognition mechanism of fetal macrophage phagocytosis. During maturation of hepatic erythroblasts, sialic acid changes its affinity for Limax flavus agglutinin from strong to weak, and soybean agglutinin binding sites disappear at the basophilic erythroblast stage. Glycoconjugates on polychromatophilic erythroblasts acquire similar compositions to those of erythrocytes.
Department of Anatomy, Kawasaki Medical School, Kurashiki, Japan.
H
H
Iwatsuki
K
K
Sasaki
M
M
Suda
C
C
Itano
D000818:Animals; D000954:Antigens, Surface / Q000276:immunology; D002462:Cell Membrane / Q000201:enzymology; D002467:Cell Nucleus; D004900:Erythroblasts / Q000502:physiology; D004905:Erythrocyte Aging / Q000502:physiology; D015672:Erythroid Precursor Cells / Q000276:immunology / Q000378:metabolism* / Q000648:ultrastructure; D005333:Fetus; D006001:Glycoconjugates / Q000276:immunology / Q000378:metabolism*; D006651:Histocytochemistry; D007501:Iron; D037102:Lectins; D008099:Liver / Q000196:embryology / Q000201:enzymology*; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008813:Mice, Inbred ICR; D009005:Monosaccharides / Q000032:analysis / Q000378:metabolism; D019158:N-Acetylneuraminic Acid; D009439:Neuraminidase / Q000378:metabolism; D010587:Phagocytosis / Q000502:physiology*; D012794:Sialic Acids / Q000378:metabolism; D013194:Staining and Labeling
D000954:Antigens, Surface; D006001:Glycoconjugates; D037102:Lectins; D009005:Monosaccharides; D012794:Sialic Acids; D007501:Iron; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid