title: Enhancement of the binding of C1q to immune complexes by polyethylene glycol.
abstract: The binding of 125I-labelled human C1q to insoluble rabbit IgG:ovalbumin immune complexes was enhanced by polyethylene glycol (PEG, Mr 8 x 10(3)) in the concn range 0-2.5% (w/v). C1q with native immunoglobulin bindings sites rendered inactive by diethylpyrocarbonate treatment did not bind to immune complexes in the presence of PEG. The ionic strength dependence of the binding was independent of the presence of PEG. There was a linear relationship between the logarithm of the apparent affinity constant of the C1q:immune complex interaction and PEG concn.
authors.affiliation: Department of Biochemistry, University of Sydney, NSW, Australia.
authors.forename: B D
authors.initials: BD
authors.lastname: Wines
authors.forename: S B
authors.initials: SB
authors.lastname: Easterbrook-Smith
mesh_terms: D000818:Animals; D000936:Antigen-Antibody Complex / Q000276:immunology*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003166:Complement Activating Enzymes / Q000276:immunology*; D003172:Complement C1 / Q000276:immunology*; D015922:Complement C1q; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D010047:Ovalbumin / Q000276:immunology; D011092:Polyethylene Glycols / Q000494:pharmacology*
chemical_list: D000936:Antigen-Antibody Complex; D003172:Complement C1; D007074:Immunoglobulin G; D011092:Polyethylene Glycols; D015922:Complement C1q; D010047:Ovalbumin; D003166:Complement Activating Enzymes