title: Involvement of CD14 and complement receptors CR3 and CR4 in nuclear factor-kappaB activation and TNF production induced by lipopolysaccharide and group B streptococcal cell walls.
abstract: This study was undertaken to evaluate the role of CD14 and complement receptors type 3 (CR3) and 4 (CR4) in mediating TNF release and NF-kappaB activation induced by LPS and cell wall preparations from group B streptococci type III (GBS). LPS and GBS caused TNF secretion from human monocytes in a CD14-dependent manner, and soluble CD14, LPS binding protein, or their combination potentiated both LPS- and GBS-induced activities. Blocking of either CD14 or CD18, the common beta-subunit of CR3 and CR4, decreased GBS-induced TNF release, while LPS-mediated TNF production was inhibited by anti-CD14 mAb only. Chinese hamster ovary cell transfectants (CHO) that express human CD14 (CHO/CD14) responded to both LPS and GBS with NF-kappaB translocation, which was inhibited by anti-CD14 mAb and enhanced by LPS binding protein. While LPS showed fast kinetics of NF-kappaB activation in CHO/CD14 cells, a slower NF-kappaB response was induced by GBS. LPS also activated NF-kappaB in CHO cells transfected with either human CR3 or CR4 cDNA, although responses were delayed and weaker than those of CHO/CD14 cells. In contrast to LPS, GBS failed to induce NF-kappaB in CHO/CR3 or CHO/CR4 cells. Both C3H/OuJ (Lps[n]) and C3H/HeJ (Lps[d]) mouse peritoneal macrophages responded to GBS with TNF production and NF-kappaB translocation, whereas LPS was active only in C3H/OuJ macrophages. Thus, LPS and GBS differentially involve CD14 and CR3 or CR4 for signaling NF-kappaB activation in CHO cells and TNF release in human monocytes, and engage a different set of receptors and/or intracellular signaling pathways in mouse macrophages.
authors.affiliation: Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA. amedved@mx3.usuhs.mil
authors.forename: A E
authors.initials: AE
authors.lastname: Medvedev
authors.forename: T
authors.initials: T
authors.lastname: Flo
authors.forename: R R
authors.initials: RR
authors.lastname: Ingalls
authors.forename: D T
authors.initials: DT
authors.lastname: Golenbock
authors.forename: G
authors.initials: G
authors.lastname: Teti
authors.forename: S N
authors.initials: SN
authors.lastname: Vogel
authors.forename: T
authors.initials: T
authors.lastname: Espevik
mesh_terms: D000818:Animals; D016466:CHO Cells; D002473:Cell Wall / Q000276:immunology; D006224:Cricetinae; D006801:Humans; D018950:Lipopolysaccharide Receptors / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology* / Q000494:pharmacology; D016177:Macrophage-1 Antigen / Q000276:immunology*; D051379:Mice; D016328:NF-kappa B / Q000276:immunology*; D015398:Signal Transduction / Q000276:immunology; D013292:Streptococcus agalactiae / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology*
chemical_list: D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D016177:Macrophage-1 Antigen; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha