title: Modulation of IgD and CD20 by ligation of CD5 on tonsillar B cells.
abstract: The CD5 molecule, pan T cell marker, has been known to be expressed on a minor population of B cells, termed B-1 cells. However, the physiological function and pathological role of CD5+B (B-1) cells remain to be fully elucidated in humans. In the present study, we aimed to clarify the significance of CD5 expression on the B lymphocytes in human tonsil. Using flow cytometric analysis by three-colour immunofluorescence staining, we observed a majority of the cell surface CD5-positive (sCD5+) B cells among the sIgD+ B-cell population, as previously described. Contrary to our expectation, approximately half of the sIgD+/sCD5+ B cells expressed CD38 on their cell surface. Furthermore, a small number of sCD5+ were observed in the sIgD- B cell population. The addition of anti-CD5 monoclonal antibody (MoAb) to the culture induced downmodulation of sCD20 and sIgD of the tonsillar B cells, resulting in an increase of sCD38-/sIgD- (memory) B cells during the 10 day culture periods in the CD40/l cell culture system. Our findings suggest that ligation of CD5 might transduce the signal to regulate B cell maturation.
authors.affiliation: Division of Clinical Nutrition, Department of Nutrition, Faculty of Liberal Arts, Sagami Women's University, 2-1-1 Bunkyo, Sagamihara, Kanagawa 228-8533, Japan. morikawa_keiko@isc.sagami-wu.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Morikawa
authors.forename: I
authors.initials: I
authors.lastname: Torii
authors.forename: S
authors.initials: S
authors.lastname: Morikawa
mesh_terms: D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015703:Antigens, CD; D018951:Antigens, CD20 / Q000378:metabolism*; D000943:Antigens, Differentiation / Q000378:metabolism; D017209:Apoptosis / Q000276:immunology; D016175:B-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D018956:CD5 Antigens / Q000378:metabolism*; D002454:Cell Differentiation; D002648:Child; D006801:Humans; D007072:Immunoglobulin D / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins; D009244:NAD+ Nucleosidase / Q000378:metabolism; D014066:Palatine Tonsil / Q000166:cytology / Q000276:immunology; D010641:Phenotype; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D018951:Antigens, CD20; D000943:Antigens, Differentiation; D018956:CD5 Antigens; D007072:Immunoglobulin D; D008562:Membrane Glycoproteins; D011947:Receptors, Antigen, B-Cell; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D009244:NAD+ Nucleosidase; D051997:ADP-ribosyl Cyclase 1