title: Monoclonal antibodies to the 140,000 mol wt glycoprotein of B lymphocyte membranes (CR2 receptor) initiates proliferation of B cells in vitro.
abstract: Several mouse monoclonal IgG antibodies (AB1, AB2, AB3, and AB5) were developed that reacted with a 140,000 mol wt glycoprotein on the surface of cultured RAJI B lymphoid cells. The antibodies reacted with purified normal human peripheral blood B cells and CLL Ig+ B cells and showed specific germinal center and mantle zone staining in tissue sections of secondary lymphoid organs. Immunodepletion studies using 125I surface-labeled Raji cell membrane antigens demonstrated that the antigen identified by AB5 is the same 140,000 mol wt glycoprotein detected by anti-B2 that has recently been shown to react with the C3d fragment or CR2 receptor. (Iida et al: J Exp Med 158:1021, 1983). Addition of the AB series and anti-B2 monoclonal antibodies to cultures of purified human peripheral blood B cells resulted in the uptake of 3H-thymidine at two to six times background control levels provided that irradiated autologous T cells were added to the culture. Stimulation was not evoked by other monoclonal antibodies to B cell surface molecules (ie, B1, BA-1, BA-2, and HLA-DR). Pepsin-generated F(ab')2 fragments of anti-CR2 antibodies were essentially as effective as the intact IgG molecule in stimulating B cells. Induction of B cell proliferation by antibody binding to CR2 suggests that the C3d receptor may have an integral role in regulation of humoral immune response.
authors.forename: B S
authors.initials: BS
authors.lastname: Wilson
authors.forename: J L
authors.initials: JL
authors.lastname: Platt
authors.forename: N E
authors.initials: NE
authors.lastname: Kay
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000954:Antigens, Surface / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D002462:Cell Membrane / Q000276:immunology; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice / Q000276:immunology; D008970:Molecular Weight; D011951:Receptors, Complement / Q000276:immunology*; D017464:Receptors, Complement 3d
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D006023:Glycoproteins; D011951:Receptors, Complement; D017464:Receptors, Complement 3d