title: Molecular mechanisms of B lymphocyte activation by the immune response modifier R-848.
abstract: The imidazoquinoline R-848, originally identified as a highly effective antiviral agent, has recently been shown to be capable of potent B lymphocyte activation. The B cell-activating properties of R-848 are strikingly similar to the effects of the CD40 ligand CD154. The present study demonstrates that this similarity extends to the intracellular signaling pathways triggered by the compound, although both overlapping and distinct mechanisms of signaling were seen. Like CD40 ligation, R-848 stimulated activation of the stress-activated protein kinases c-Jun kinase and p38 and activated the NF-kappaB family of transcription factors. Both R-848- and CD40-mediated B cell differentiation were dependent upon NF-kappaB activation, although the relative importance of individual NF-kappaB family members appeared to differ between R-848- and CD40-mediated signals. Both signals were partially dependent upon induction of TNF-alpha and IL-6, and the cytoplasmic adaptor molecule TNF receptor-associated factor 2 is involved in both R-848- and CD40-mediated differentiation.
authors.affiliation: Department of Microbiology, Graduate Program in Immunology, and Veterans Administration Medical Center, Iowa City, IA 52242, USA. gail-bishop@uiowa.edu
authors.forename: G A
authors.initials: GA
authors.lastname: Bishop
authors.forename: Y
authors.initials: Y
authors.lastname: Hsing
authors.forename: B S
authors.initials: BS
authors.lastname: Hostager
authors.forename: S V
authors.initials: SV
authors.lastname: Jalukar
authors.forename: L M
authors.initials: LM
authors.lastname: Ramirez
authors.forename: M A
authors.initials: MA
authors.lastname: Tomai
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000921:Antibody-Producing Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D001402:B-Lymphocytes / Q000187:drug effects* / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000276:immunology; D002460:Cell Line; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D015850:Interleukin-6 / Q000502:physiology; D048031:JNK Mitogen-Activated Protein Kinases; D008213:Lymphocyte Activation / Q000187:drug effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D011506:Proteins / Q000502:physiology; D018124:Receptors, Tumor Necrosis Factor / Q000502:physiology; D015398:Signal Transduction / Q000276:immunology; D047992:TNF Receptor-Associated Factor 2; D015533:Transcriptional Activation / Q000187:drug effects / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D000276:Adjuvants, Immunologic; D007093:Imidazoles; D015850:Interleukin-6; D016328:NF-kappa B; D011506:Proteins; D018124:Receptors, Tumor Necrosis Factor; D047992:TNF Receptor-Associated Factor 2; D014409:Tumor Necrosis Factor-alpha; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C402365:resiquimod