title: T-cell control of IL-12p75 production.
abstract: It is currently thought that IL-12, produced by dendritic cells (DC) early after stimulation by bacterial pathogens or lipopolysaccharide (LPS), acts as a pro-inflammatory cytokine bridging the innate and adaptive immune responses. We found, however, that it is only the p40 subunit and not the IL-12p75 heterodimer that is secreted early in copious amounts in response to LPS. Neither naïve T cells, nor a variety of microbial products, were able to induce IL-12p75 production unless the DC were conditioned by the presence of interferon-gamma (IFN-gamma) or by encounter with previously activated T cells. The inability of naïve T cells or of bacterial products to induce IL-12 argues against its early role as the initiator of innate and adaptive immune responses.
authors.affiliation: Ghost Lab, Laboratory of Cellular and Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. kabdi@niaid.nih.gov
authors.forename: K
authors.initials: K
authors.lastname: Abdi
authors.forename: N
authors.initials: N
authors.lastname: Singh
authors.forename: P
authors.initials: P
authors.lastname: Matzinger
mesh_terms: D000818:Animals; D016207:Cytokines / Q000276:immunology; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D016654:Genes, RAG-1 / Q000276:immunology; D007113:Immunity, Innate / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology; D018664:Interleukin-12 / Q000096:biosynthesis* / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D021122:Protein Subunits; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; D021122:Protein Subunits; D018664:Interleukin-12; D007371:Interferon-gamma