title: Spontaneous membrane transfer through homotypic synapses between lymphoma cells.
abstract: Formation of an immunological synapse by T, B, or NK cells is associated with an intercellular transfer of some membrane fragments from their respective target cells. This capture is thought to require effector cell activation by surface recognition of stimulatory ligand(s). However, spontaneous synaptic transfers between homotypic lymphoid cells has never been described. In this study, we show that without adding Ag, resting healthy lymphoid cells and several tumor cell lines are inactive. Conversely, however, some leukemia cell lines including the Burkitt's lymphoma Daudi continuously uptake patches of autologous cell membranes. This intercellular transfer does not involve cytosol molecules or exosomes, but requires cell contact. In homotypic Daudi cell conjugates, this occurs through immunological synapses, involves constitutive protein kinase C and mitogen-activated protein/extracellular signal-regulated kinase kinase activity and strongly increases upon B cell receptor activation. Thus, spontaneous homosynaptic transfer may reflect the hitherto unsuspected autoreactivity of some leukemia cell lines.
authors.affiliation: Département Oncogénèse and Signalisation dans les Cellules Hématopoiétiques, Unité 563 de l'Institut National de la Santé et de la Recherche Médicale, Centre de Physiopathologie de Toulouse Purpan, BP 3028, 31024 Toulouse, France.
authors.forename: Mary
authors.initials: M
authors.lastname: Poupot
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Fournié
mesh_terms: D001693:Biological Transport, Active / Q000276:immunology; D002051:Burkitt Lymphoma / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D002450:Cell Communication / Q000276:immunology*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D003600:Cytosol / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D005456:Fluorescent Dyes / Q000378:metabolism; D006801:Humans; D007365:Intercellular Junctions / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D016393:Lymphoma, B-Cell / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D009930:Organic Chemicals / Q000378:metabolism; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism / Q000502:physiology; D012235:Rhodamines / Q000378:metabolism
chemical_list: C116572:(((4-chloromethyl)benzoyl)amino)-tetramethylrhodamine; D005456:Fluorescent Dyes; D009930:Organic Chemicals; C070080:PKH 26; C451241:PKH67; D011947:Receptors, Antigen, B-Cell; D012235:Rhodamines