Activation of dense human tonsilar B cells. Induction of c-myc gene expression via two distinct signal transduction pathways

J Immunol. 1991 Feb 1;146(3):846-53.

Abstract

Antibodies to surface Ig or to the B cell marker CD20 trigger resting human B cells in similar yet distinct ways. Either antibody induces five-fold increases in the expression of the protooncogene, c-myc, as detected with semi-quantitative Northern blot assays. The induction of c-myc mRNA by anti-IgM or anti-CD20 is blocked by inhibitors of protein kinase C (PKC) such as staurosporine and by pretreatment of B cells with phorbol esters to reduce cellular PKC levels. This suggests that PKC is involved in the pathways stimulated by both anti-IgM and anti-CD20. However, anti-CD20, unlike anti-IgM, does not activate significant increases in inositol triphosphate or intracellular-free calcium. Further, anti-CD20-triggered elevation of c-myc mRNA is inhibited by pertussis and cholera toxins, whereas the pathway initiated by anti-IgM if anything is stimulated by pertussis toxin and unchanged by cholera toxin. Further differences in the nature of these two signals were seen when the expression of adhesion/recognition molecules were examined. Anti-IgM consistently induces increased expression of the adhesion molecules CD54 (I-CAM-1) and B7/BB-1 on B cells, but anti-CD20 does not. Yet both anti-CD20 and anti-IgM increase class II MHC, CD18 (LFA-1 beta-chain) and LFA-3 levels. These data suggest that the way in which B cells are activated may influence their surface phenotype and possibly subsequent migration or cell-cell interactions.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies, Anti-Idiotypic / immunology
  • Antibodies, Monoclonal / immunology
  • Antigens, CD20
  • Antigens, Differentiation, B-Lymphocyte / immunology
  • Antigens, Differentiation, B-Lymphocyte / physiology
  • B-Lymphocytes / immunology*
  • Cell Adhesion Molecules / analysis
  • Cholera Toxin / pharmacology
  • Gene Expression*
  • Genes, myc*
  • Humans
  • Immunoglobulin M / immunology
  • Inositol Phosphates / metabolism
  • Lymphocyte Activation*
  • Palatine Tonsil / immunology
  • Pertussis Toxin
  • Protein Kinase C / physiology
  • Signal Transduction*
  • Virulence Factors, Bordetella / pharmacology

Substances

  • Antibodies, Anti-Idiotypic
  • Antibodies, Monoclonal
  • Antigens, CD20
  • Antigens, Differentiation, B-Lymphocyte
  • Cell Adhesion Molecules
  • Immunoglobulin M
  • Inositol Phosphates
  • Virulence Factors, Bordetella
  • Cholera Toxin
  • Pertussis Toxin
  • Protein Kinase C