CD40 expression is induced by the introduction of IgM receptor on the surface of pro-B cell line NFS70.
To examine the molecular mechanism of B cell differentiation, we introduced rearranged immunoglobulin (Ig) mu- and kappa-chain genes into the NFS70 pro-B cell line and observed their maturation. The IgR(+)-transfectants had characteristics of mature surface IgM (sIgM)+ B220high CD40+ CD38+ CD25+ B cells. CD40 expression levels were regulated by stimulation via the IgR. In comparison to wild type NFS70 cells, NF-kappaB activity was up-regulated in the IgR transfectants. Anti-IgR crosslinking of IgR+ cells induced down-regulation of CD40 expression that correlated with down-regulation of NF-kappaB activity in the IgR(+)-transfectants. Immature CD19+ sIgD- B cells from bone marrow also showed an alteration of CD40 expression in response to anti-IgR crosslinking. The results suggest that expression of IgR on the surface is one of the factors responsible for further maturation of B cells.
Sumita
K
K
Department of Immunology, Kumamoto University School of Medicine, Honjo 2-2-1, 860-0811, Kumamoto, Japan.
Igarashi
H
H
Sakaguchi
N
N
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D019013:CD40 Antigens / Q000235:genetics*; D002462:Cell Membrane / Q000378:metabolism; D003432:Cross-Linking Reagents; D015536:Down-Regulation; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics; D007148:Immunoglobulin mu-Chains / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D016328:NF-kappa B / Q000378:metabolism; D011961:Receptors, Fc / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured
D019013:CD40 Antigens; D003432:Cross-Linking Reagents; D007145:Immunoglobulin kappa-Chains; D007148:Immunoglobulin mu-Chains; D016328:NF-kappa B; D011961:Receptors, Fc; C035311:immunoglobulin M receptor