Anti-CD40 monoclonal antibody induces the proliferation of murine B cells as a B-cell mitogen through a distinct pathway from receptors for antigens or lipopolysaccharide.
To study the activation and differentiation of murine B cells, we prepared a hybridoma secreting monoclonal antibody, LB429, which can directly induce the proliferation of murine B cells in vitro. LB429 recognizes a B cell specific surface molecule of 45 kDa. It recognizes an epitope of murine CD40 produced as a soluble fusion protein with glutathione S-transferase. LB429 stains COS-7 transfectant with murine CD40 cDNA and mature B-cell lines but does not stain pre-B cell lines. Two color staining demonstrated that the epitope recognized with LB429 appears on the surface of B220+ cells of spleen and bone marrow. LB429 can induce a strong proliferation of murine B cells from spleen in the absence of initial triggering with anti-IgM antibody or with anti-IgM antibody + IL-4. LB429 induced the cell size enlargement and the cell cycle transition of resting B cells as well as lipopolysaccharide (LPS). LB429 and LPS stimulate B cells synergistically in vitro by accumulating 44.7% of cells in S/G2/M phases of cell cycle. However, stimulation of spleen B cells with LB429 resulted in the increase of sIgM high+ sIgD(high)+ B cells, in contrast LPS showed the proliferation of both sIgM(high)+ sIgD(high)+ B cells and sIgM(low)+ sIgD(high)+ B cells. These results suggested that LB429 and LPS cause the proliferation of B cells through different stimulatory pathways. This anti-mouse CD40 antibody (LB429) is a very useful reagent to study the activation and differentiation of B cells in vitro.
Nomura
J
J
Department of Immunology, School of Life Science, Faculty of Medicine, Tottori University, Yonago, Japan.
Inui
S
S
Yamasaki
T
T
Kataoka
S
S
Maeda
K
K
Nakanishi
K
K
Sakaguchi
N
N
D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000494:pharmacology*; D000937:Antigen-Antibody Reactions; D001402:B-Lymphocytes / Q000737:chemistry / Q000276:immunology*; D019013:CD40 Antigens / Q000276:immunology*; D002460:Cell Line; D005260:Female; D006825:Hybridomas / Q000378:metabolism; D008070:Lipopolysaccharides / Q000276:immunology* / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects* / Q000502:physiology; D008565:Membrane Proteins / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008934:Mitogens / Q000276:immunology*; D051381:Rats; D011917:Rats, Inbred Lew; D011947:Receptors, Antigen, B-Cell / Q000276:immunology*; D013194:Staining and Labeling
D000911:Antibodies, Monoclonal; D019013:CD40 Antigens; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D008934:Mitogens; D011947:Receptors, Antigen, B-Cell