title: Characterization of complement C3, C4, and factor B molecules in human bile.
abstract: We performed molecular analysis of complement components (C3, C4, and factor B) in human bile by sodium dodecyl sulfate-polyarylamide gel electrophoresis (SDS-PAGE) and immunoblotting. Complement C3 was detected as a molecule composed of a 115-kDa alpha-chain linked to a 70-kDa beta-chain by disulfide bonds, and C3 levels ranged from 45 to 650 micrograms/ml (n = 15). C4 was detected as a triple chain (98-kDa alpha-chain, 73-kDa beta-chain, and 33-kDa gamma-chain) molecule linked by disulfide bonds, and C4 levels ranged from 2.5 to 60 micrograms/ml. Factor B, a component of the alternative pathway, was also detected, as an intact form. Factor B levels ranged from 0.3 to 8.0 micrograms/ml. The sizes and subunit structures of complement components in human bile were compatible with those reported in human serum. The results of a hemolytic assay indicated that complement molecules in human bile were functionally active. These molecules may participate in local immune and inflammatory responses in the biliary tract.
authors.affiliation: Department of Internal Medicine, Shiga University of Medical Science, Otsu, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sumiyoshi
authors.forename: A
authors.initials: A
authors.lastname: Andoh
authors.forename: Y
authors.initials: Y
authors.lastname: Fujiyama
authors.forename: H
authors.initials: H
authors.lastname: Sakumoto
authors.forename: T
authors.initials: T
authors.lastname: Bamba
mesh_terms: D001646:Bile / Q000276:immunology*; D003176:Complement C3 / Q000737:chemistry* / Q000276:immunology; D003181:Complement C4 / Q000737:chemistry* / Q000276:immunology; D011415:Complement Factor B / Q000737:chemistry* / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D015151:Immunoblotting
chemical_list: D003176:Complement C3; D003181:Complement C4; D011415:Complement Factor B