title: Lipopolysaccharide-binding factors are present in bovine serum.
abstract: Response of vertebrates to bacterial lipopolysaccharide (LPS) may be regulated, in part, by serum factors that influence the bioavailability and cellular binding affinity of LPS. Using 3H- or 14C-labeled LPS, or a novel fluorescence-based assay for detection in CsCl isopycnic density gradients, our studies indicate the existence of factors in adult and fetal bovine serum that bind LPS. Within serum-containing gradients, labeled LPS appeared in two peaks: least-dense fractions (< or = 1.30 g/cm3) and at 1.35 g/cm3. This profile was different from that of gradients without serum, where LPS appeared at 1.38 g/cm3. Binding of LPS to serum component(s) at 1.35 g/cm3 was rapid (< 1 min), saturable and specific. A partial shift (50%) of LPS from a density of 1.35 g/cm3 to other serum components at < or = 1.30 g/cm3 occurred over 1 h. Flow cytometric analysis indicated that bovine serum factors influence the binding of LPS to blood monocytes, because monocyte-FITC-LPS association increased in the presence of bovine serum.
authors.affiliation: Department of Pathobiology, University of Tennessee, Knoxville 37901-1071.
authors.forename: L S
authors.initials: LS
authors.lastname: Khemlani
authors.forename: P N
authors.initials: PN
authors.lastname: Bochsler
authors.forename: J M
authors.initials: JM
authors.lastname: Maddux
mesh_terms: D000818:Animals; D002417:Cattle; D002500:Centrifugation, Isopycnic; D004926:Escherichia coli; D005260:Female; D005434:Flow Cytometry; D008070:Lipopolysaccharides / Q000097:blood*
chemical_list: D008070:Lipopolysaccharides