Endocytosis of alpha 1-acid glycoprotein variants by human monocytic lineage cells.
Human alpha 1-acid glycoprotein (AGP or orosomucoid) is a major glycoprotein of plasma. AGP can be separated on immobilized concanavalin A into three variants bearing none (AGP A), one (AGP B) or two (AGP C) biantennary glycans. In this paper, we show, using flow cytometry and confocal microscopy, that AGP C which is eluted from concanavalin A with mannose, binds to human monocytes, monocyte-derived macrophages as well as human promonocytic cell lines such as THP1 or U937. Conversely HL60, a promyelocytic cell line, does not express the surface AGP C binding protein. AGP C is internalized and degraded with an efficiency depending on the state of differentiation of these cells. In contrast, AGP A which is not recognized by concanavalin A, does not bind to any of these cells.
Carpentier
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V
Département de Biochimie des Glycoconjugués et Lectines Endogènes, CNRS, INSERM et Université d'Orléans, France.
Midoux
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P
Monsigny
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Roche
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AC
D002460:Cell Line; D016922:Cellular Senescence / Q000502:physiology; D004705:Endocytosis / Q000502:physiology*; D005434:Flow Cytometry; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D008264:Macrophages / Q000276:immunology; D008853:Microscopy / Q000379:methods; D009000:Monocytes / Q000276:immunology*; D009961:Orosomucoid / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding
D006023:Glycoproteins; D009961:Orosomucoid