title: Loss of ELISA specificity due to biotinylation of monoclonal antibodies.
abstract: A significant degree of nonspecificity was found in ELISA determinations of soluble urokinase receptor (suPAR) in human blood plasma when biotinylated monoclonal antibodies (Mabs) were used for the detection layer. Surface plasmon resonance studies using both nonbiotinylated and biotinylated antibodies demonstrated that biotinylation reduced specific binding of the antibodies to their target antigen, suPAR. Furthermore, biotinylation produced a new interaction with unknown human plasma protein(s), unrelated to suPAR. Nonspecific interaction with plasma protein(s) was also observed after biotinylation of a Mab having no specific target antigen in human plasma and, in both cases, the level of nonspecific interaction was directly related to the degree of antibody biotinylation. These results reinforce earlier observations that biotinylation of antibodies can reduce the affinity of antibodies, but also indicate that, in addition, biotinylation can reduce the specificity of immunoassays for plasma proteins.
authors.affiliation: The Finsen Laboratory, Copenhagen University Hospital, Strandboulevarden 49, DK-2100, Copenhagen, Denmark. gunilla@finsenlab.dk
authors.forename: G
authors.initials: G
authors.lastname: Høyer-Hansen
authors.forename: M J
authors.initials: MJ
authors.lastname: Hamers
authors.forename: A N
authors.initials: AN
authors.lastname: Pedersen
authors.forename: H J
authors.initials: HJ
authors.lastname: Nielsen
authors.forename: N
authors.initials: N
authors.lastname: Brünner
authors.forename: K
authors.initials: K
authors.lastname: Danø
authors.forename: R W
authors.initials: RW
authors.lastname: Stephens
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D019921:Biotinylation; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D011956:Receptors, Cell Surface / Q000097:blood*; D055293:Receptors, Urokinase Plasminogen Activator; D020349:Surface Plasmon Resonance
chemical_list: D000911:Antibodies, Monoclonal; C524898:PLAUR protein, human; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator