title: Expression and functional characteristics of the complement receptor type 2 on adult and neonatal B lymphocytes.
abstract: In vivo antibody synthesis against thymus-independent type 2 (TI-2) antigens such as type-specific polysaccharides of pneumococci is low or absent during the first 2 years of life. Recently, we described a role for CR2 in the in vitro antibody response of B cells of adults to the TI-2 antigen type 4 pneumococcal polysaccharide. In the present study a decreased expression of CR2 is described on cord blood B cells using HB5 and OKB7 anti-CR2 MAb. Crosslinking of HB5 anti-CR2 antibodies on the B cell membrane leads to increases in intracellular calcium ([Ca2+]i) in both adult and neonatal B cells. In adult B cells, a synergism between CR2 and sIgM could be demonstrated on the level of calcium mobilization by occupying CR2 and crosslinking of sIgM with substimulatory concentrations of anti-IgM antibodies. This synergistic action between CR2 and sIgM could not be demonstrated in neonatal B cells. In addition, it is demonstrated that HB5 MAb cannot induce B cell differentiation in neonatal B cells, while adult B cells can be induced to differentiate into Ig-producing cells by this MAb.
authors.affiliation: Department of Immunology, University Hospital for Children and Youth Het Wilhelmina Kinderziekenhuis, Utrecht, The Netherlands.
authors.forename: A W
authors.initials: AW
authors.lastname: Griffioen
authors.forename: S W
authors.initials: SW
authors.lastname: Franklin
authors.forename: B J
authors.initials: BJ
authors.lastname: Zegers
authors.forename: G T
authors.initials: GT
authors.lastname: Rijkers
mesh_terms: D000328:Adult; D000375:Aging / Q000097:blood* / Q000276:immunology*; D000911:Antibodies, Monoclonal; D000917:Antibody Formation / Q000276:immunology; D000955:Antigens, T-Independent / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology* / Q000648:ultrastructure*; D002118:Calcium / Q000097:blood; D002454:Cell Differentiation; D002462:Cell Membrane / Q000502:physiology; D005312:Fetal Blood / Q000166:cytology / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D007211:Indoles; D007231:Infant, Newborn; D008213:Lymphocyte Activation / Q000276:immunology; D017464:Receptors, Complement 3d / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology
chemical_list: D000911:Antibodies, Monoclonal; D000955:Antigens, T-Independent; D007075:Immunoglobulin M; D007211:Indoles; D017464:Receptors, Complement 3d; C048960:indo-1; D002118:Calcium