Signal transmission through the B cell-specific MB-1 molecule at the pre-B cell stage.
Specific binding of antigens to the surface immunoglobulin M (sIgM) triggers B cells with several biochemical events involved in receptor-mediated signal transmission for proliferation and differentiation into antibody-producing cells. Recent studies with the Digitonin lysis method identified the sIgM-associated component, IgM-alpha (B34)/Ig-beta, as the possible candidate for the transducer molecule(s) in the immunoglobulin receptor-mediated signal transmission. The 34 kd protein (B34 or IgM-alpha) of this component is suggested to be encoded by the B cell-specific mb-1 gene. We prepared monoclonal antibodies which recognize the mb-1 gene product (MB-1) and studied the functional role of MB-1 in the signal transmission in B lineage cells. Using murine pre-B lymphoma cells (18-81 and 70Z/3), we demonstrated the early phase increase of the intracellular [Ca2+]i concentration and the subsequent inhibition of the proliferation by the monoclonal anti-MB-1 antibody (11-18-5). These results clearly demonstrate signal transmission through the surface MB-1 molecule on B lineage lymphomas. This MB-1-mediated signal transmission in pre-B cell lines would suggest an alternative function of MB-1 acting at the pre-B cell stage.
Nomura
J
J
Department of Immunology, Saga Medical School, Japan.
Matsuo
T
T
Kubota
E
E
Kimoto
M
M
Sakaguchi
N
N
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD; D001402:B-Lymphocytes / Q000276:immunology*; D051925:CD79 Antigens; D002118:Calcium / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000276:immunology; D005434:Flow Cytometry; D007075:Immunoglobulin M / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D008221:Lymphoid Tissue / Q000276:immunology; D008562:Membrane Glycoproteins / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D011817:Rabbits; D051381:Rats; D011917:Rats, Inbred Lew; D011947:Receptors, Antigen, B-Cell; D015398:Signal Transduction / Q000502:physiology*; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D051925:CD79 Antigens; C497882:Cd79a protein, mouse; D000939:Epitopes; D007075:Immunoglobulin M; D008562:Membrane Glycoproteins; D011947:Receptors, Antigen, B-Cell; D002118:Calcium