title: Mycobacterial 65-kD heat shock protein induces release of proinflammatory cytokines from human monocytic cells.
abstract: Monocytes having phagocytosed mycobacteria are known to present the bacterial 65-kD heat shock protein (hsp) on their cell surface to alpha beta and gamma delta T lymphocytes. Cytotoxic CD4+ cells may then lyse monocytes expressing mycobacterial 65-kD hsp. However, it is not known whether 65-kD hsp directly stimulates monocyte functions other than antigen presentation. This study has demonstrated that following extraction of bacterial lipopolysaccharide, purified recombinant mycobacterial 65-kD hsp may directly activate THP-1 cells, a human monocytic line, to accumulate mRNA for and secrete tumour necrosis factor (TNF), a cytokine important in granuloma formation, the characteristic host immune response to mycobacterial infection. TNF gene expression and secretion following stimulation by hsp was dose-dependent and abolished by heat-induced proteolysis. Subsequently, THP-1 cells secreted IL-6 and IL-8, cytokines involved in recruitment and differentiation of T lymphocytes. The data indicate that secretion of proinflammatory cytokines from monocytes activated by mycobacterial 65-kD hsp may be important in the host immune response and in the development of antigen-specific T cell-mediated immunity.
authors.affiliation: Division of Communicable Diseases, St George's Hospital Medical School, London, UK.
authors.forename: J S
authors.initials: JS
authors.lastname: Friedland
authors.forename: R
authors.initials: R
authors.lastname: Shattock
authors.forename: D G
authors.initials: DG
authors.lastname: Remick
authors.forename: G E
authors.initials: GE
authors.lastname: Griffin
mesh_terms: D001426:Bacterial Proteins / Q000494:pharmacology*; D002460:Cell Line; D015870:Gene Expression / Q000187:drug effects; D006360:Heat-Shock Proteins / Q000494:pharmacology*; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism*; D008070:Lipopolysaccharides; D009000:Monocytes / Q000187:drug effects* / Q000276:immunology; D009161:Mycobacterium / Q000276:immunology*; D011994:Recombinant Proteins / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D006360:Heat-Shock Proteins; D015850:Interleukin-6; D016209:Interleukin-8; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha