title: The preparation of a lipidic endotoxin affects its biological activities.
abstract: Bacterial membrane constituents, such as Ornithine-containing lipid (OL) and the lipid A portion of lipopolysaccharide, trigger various immune responses through recognition by Toll-like receptor (TLR) 4. Usually, these lipids are dissolved in a small amount of aqueous or organic solvent before being added to the culture medium for examination of their biological activities. Macrophages stimulated with OL or lipid A sonically dissolved in saline released both interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha). In contrast, macrophages stimulated with OL or lipid A sonically dissolved in ethanol or dimethyl sulfoxide (DMSO) secreted much TNF-alpha, but very little IL-1beta. These results, taken together, indicate that how an endotoxin is prepared affects its biological activities. In addition, electromicroscopic analysis revealed that sonication of air-dried OL or lipid A in DMSO produced larger particles than those produced in saline, suggesting that the process of preparing lipidic TLR4-ligands affects their physical state including particle size, and that the physical state might be an important determinant of biological activity.
authors.affiliation: Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Okemoto
authors.forename: Kentaro
authors.initials: K
authors.lastname: Hanada
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nishijima
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Kawasaki
mesh_terms: D042441:Achromobacter denitrificans / Q000737:chemistry; D000277:Adjuvants, Pharmaceutic; D000818:Animals; D004121:Dimethyl Sulfoxide; D004731:Endotoxins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D004926:Escherichia coli / Q000737:chemistry; D053583:Interleukin-1beta / Q000096:biosynthesis; D008050:Lipid A / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D000432:Methanol / Q000737:chemistry; D051379:Mice; D008809:Mice, Inbred C3H; D008854:Microscopy, Electron; D009952:Ornithine / Q000737:chemistry / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012997:Solvents; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D000277:Adjuvants, Pharmaceutic; D004731:Endotoxins; D053583:Interleukin-1beta; D008050:Lipid A; D012333:RNA, Messenger; D012997:Solvents; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D009952:Ornithine; D000432:Methanol; D004121:Dimethyl Sulfoxide