title: Towards a biosensor immunoassay of protein-bound isopeptides in human plasma.
abstract: This study demonstrates that synthetic isopeptides formed on BSA can be quantitatively analyzed by a surface plasmon resonance-based biosensor method. A monoclonal IgM antibody 81D4, that reacts with the synthetic isopeptide and also with the natural isopeptide cross-link in D-dimer (but not with its non-cross-linked fibrin monomer), was covalently immobilized to a carboxymethylated dextran surface, a CM5 surface. Its immunocapturing efficiency was found to be good. The affinity of the interaction between the monoclonal 81D4 and the synthetic isopeptide was estimated to approximately 4x10(-7)M. Good reactivity was also observed when human plasma spiked with this isopeptide was used as test solution. Cross-linked D-dimer in the plasma of patients is a marker of disseminated intravascular coagulation (DIC) which occurs late in sepsis. This biosensor method has the potential to be developed into a rapid sensitive assay for measuring the level of natural isopeptide cross-links in proteins in the plasma of patients with a suspected diagnosis of sepsis.
authors.affiliation: Department of Chemical and Biological Engineering, Applied Surface Chemistry, Chalmers University of Technology, Kemivägen 10, SE-412 96 Göteborg, Sweden. anna.bergstrand@chalmers.se
authors.forename: Anna
authors.initials: A
authors.lastname: Bergstrand
authors.forename: Ismail
authors.initials: I
authors.lastname: Ceylan
authors.forename: Gerard
authors.initials: G
authors.lastname: Quash
authors.forename: Magnus
authors.initials: M
authors.lastname: Nydén
authors.forename: Krister
authors.initials: K
authors.lastname: Holmberg
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism; D015374:Biosensing Techniques; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry / Q000378:metabolism; D007118:Immunoassay; D007075:Immunoglobulin M / Q000276:immunology / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D010949:Plasma / Q000276:immunology / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000378:metabolism*; D020349:Surface Plasmon Resonance
chemical_list: D000911:Antibodies, Monoclonal; D007075:Immunoglobulin M; D010455:Peptides; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D012710:Serum Albumin, Bovine