title: Mechanism and function of a newly identified CpG DNA motif in human primary B cells.
abstract: The vertebrate immune system recognizes bacterial DNA based on the presence of unmethylated CpG-dinucleotides in particular base contexts ("CpG motifs"). In contrast to mice, knowledge about CpG-mediated effects on human B cells is poor. In the present study we identify and determine an optimal human CpG motif. A phosphodiester oligonucleotide containing this motif strongly stimulated CD86, CD40, CD54, and MHC class II expression, IL-6 synthesis, and proliferation of primary human B cells. These effects required internalization of the oligonucleotide and endosomal maturation. The molecular mechanism of action of this CpG motif was associated with the sustained induction of the NF-kappaB p50/p65 heterodimer and of the transcription-factor complex AP-1. Transcription-factor activation by CpG DNA was preceded by increased phosphorylation of the stress kinases c-Jun N-terminal kinase and p38, and of activating transcription factor-2. In contrast to CpG, signaling through the B cell receptor led to activation of extracellular receptor kinase and to phosphorylation of a different isoform of c-Jun N-terminal kinase. These studies define the structure of a highly active human CpG motif and characterize its molecular mechanism of action in primary human B cells.
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA.
authors.forename: G
authors.initials: G
authors.lastname: Hartmann
authors.forename: A M
authors.initials: AM
authors.lastname: Krieg
mesh_terms: D051698:Activating Transcription Factor 2; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites / Q000276:immunology; D019013:CD40 Antigens / Q000096:biosynthesis; D018899:CpG Islands / Q000276:immunology*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D004247:DNA / Q000276:immunology* / Q000302:isolation & purification* / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D006681:HLA-D Antigens / Q000096:biosynthesis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D015850:Interleukin-6 / Q000096:biosynthesis; D048031:JNK Mitogen-Activated Protein Kinases; D008213:Lymphocyte Activation; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009838:Oligodeoxyribonucleotides / Q000276:immunology; D010766:Phosphorylation; D013873:Thionucleotides / Q000276:immunology; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: C497105:ATF2 protein, human; D051698:Activating Transcription Factor 2; D019013:CD40 Antigens; D017362:Cyclic AMP Response Element-Binding Protein; D006681:HLA-D Antigens; D015850:Interleukin-6; D016328:NF-kappa B; D009838:Oligodeoxyribonucleotides; D013873:Thionucleotides; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D018799:Intercellular Adhesion Molecule-1; D004247:DNA; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases