title: Clearance of CD43-capped cells by macrophages: capping alone leads to phagocytosis.
abstract: Apoptotic cells must be recognized early for phagocytosis to ensure that their toxic contents do not damage neighboring cells. In some cases this is achieved via CD43-capped membrane glycoproteins, the sialylpolylactosaminyl chains of which serve as ligands for phagocytosis by macrophages. However, because many additional changes occur during apoptosis, determining exactly which events are responsible for signaling macrophages to initiate phagocytosis remains a challenge. Here, we examined one clearance mechanism in detail and determined that capping of CD43 alone is sufficient to initiate phagocytosis. We induced macrophage-mediated phagocytosis by using cytochalasin B to artificially cap CD43 on healthy (non-apoptotic) Jurkat cells. Additional experiments confirmed that sialylpolylactosaminyl chains formed through this capping method are a prerequisite for removal, and that nucleolin is the macrophage receptor responsible for their detection. These findings strongly suggest that capping of CD43 presents a sufficient signal for phagocytosis without any additional membrane changes.
authors.affiliation: School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Japan.
authors.forename: Emiri
authors.initials: E
authors.lastname: Oguri
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Miki
authors.forename: Kazuya
authors.initials: K
authors.lastname: Hirano
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamanaka
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Beppu
mesh_terms: D017209:Apoptosis; D003571:Cytochalasin B / Q000494:pharmacology*; D057809:HEK293 Cells; D006801:Humans; D019169:Jurkat Cells; D051917:Leukosialin / Q000276:immunology*; D008264:Macrophages / Q000276:immunology*; D010587:Phagocytosis / Q000276:immunology*; D010750:Phosphoproteins / Q000276:immunology; D016601:RNA-Binding Proteins / Q000276:immunology; D000097796:Nucleolin
chemical_list: D003571:Cytochalasin B; D051917:Leukosialin; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D000097796:Nucleolin