title: Pushing antibody-based labeling systems to higher sensitivity by linker-assisted affinity enhancement.
abstract: The sensitivity of antibody/hapten-based labeling systems is limited by the natural affinity ceiling of immunoglobulins. Breaking this limit by antibody engineering is difficult. We thus attempted a different approach and investigated if the so-called bridge effect, a corecognition of the linker present between hapten and carrier protein during antibody generation, can be utilized to improve the affinity of such labeling systems. The well-known haptens 2,4-dinitrophenol (2,4-DNP) and 2,4-dichlorophenoxyacetic acid (2,4-D) were equipped with various linkers, and the resulting affinity change of their cognate antibodies was analyzed by ELISA. Anti-2,4-DNP antibodies exhibited the best affinity to their hapten when it was combined with aminobutanoic acid or aminohexanoic acid. The affinity of anti-2,4-D antibodies could be enhanced even further with longer aliphatic spacers connected to the hapten. The affinity toward aminoundecanoic acid-2,4-D derivatives, for instance, was improved about 100-fold compared to 2,4-D alone and yielded detection limits as low as 100 amoles of analyte. As the effect occurred for all antibodies and haptens tested, it may be sensible to implement the bridge effect in future antibody/hapten-labeling systems in order to achieve the highest sensitivity possible.
authors: Division of Mucosal Immunology and Diagnostics, Research Center Borstel, Parkallee 22, 23845 Borstel, Germany.
authors: Hans H
authors: HH
authors: Gorris
authors: Steffen
authors: S
authors: Bade
authors: Niels
authors: N
authors: Röckendorf
authors: Milan
authors: M
authors: Fránek
authors: Andreas
authors: A
authors: Frey
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000276:immunology; D019297:2,4-Dinitrophenol / Q000276:immunology; D000906:Antibodies / Q000737:chemistry*; D000915:Antibody Affinity; D003432:Cross-Linking Reagents / Q000737:chemistry*; D006241:Haptens; D057230:Limit of Detection; D015336:Molecular Probe Techniques
chemical_list: D000906:Antibodies; D003432:Cross-Linking Reagents; D006241:Haptens; D015084:2,4-Dichlorophenoxyacetic Acid; D019297:2,4-Dinitrophenol