Cross-linking of surface IgM activates NF-kappa B in B lymphocyte.
In B lymphocytes, cross-linking of surface IgM activates changes in both the cell cycle and differentiation. In normal B cells and B cell tumors, many stimuli induce the activation of NF-kappa B and its translocation from the cytoplasm to the nucleus. In this study we sought to determine if cross-linking of surface IgM led to the activation of NF-kappa B. Our results show that activation of B cells by cross-linking anti-IgM antibodies activated NF-kappa B in the murine B lymphoid cell lines 70Z/3 and M12, and in the dense fraction of splenic cells. The activation of NF-kappa B required optimal doses of anti-IgM antibodies and took 5 to 10 min to reach maximal levels. Cross-linking of IgM has also been shown to activate protein kinases including protein kinase C (PKC). To test whether PKC activation was required for NF-kappa B translocation, we treated 70Z/3 cells for 18 h with phorbol 12-myristate 13-acetate, a procedure which depletes these cells of functional PKC. This treatment did not abrogate the nuclear translocation of NF-kappa B following anti-IgM cross-linking. These results indicate that the nuclear translocation of NF-kappa B is rapidly induced by surface IgM cross-linking and that this activation appears to use a pathway which does not require PKC.
Rooney
J W
JW
Department of Genetics (SK-50), University of Washington, Seattle 98195.
Dubois
P M
PM
Sibley
C H
CH
D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology*; D002451:Cell Compartmentation / Q000187:drug effects; D002467:Cell Nucleus / Q000378:metabolism; D007075:Immunoglobulin M / Q000378:metabolism*; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000008:administration & dosage; D008213:Lymphocyte Activation; D051379:Mice; D016328:NF-kappa B / Q000502:physiology*; D011493:Protein Kinase C / Q000502:physiology; D011940:Receptor Aggregation; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction; D013154:Spleen / Q000166:cytology; D013997:Time Factors
D007075:Immunoglobulin M; D008070:Lipopolysaccharides; D016328:NF-kappa B; D011947:Receptors, Antigen, B-Cell; D007371:Interferon-gamma; D011493:Protein Kinase C