USES OF BIOSENSORS IN THE STUDY OF VIRAL-ANTIGENS

The introduction in 1990 of a new biosensor technology based on surfac e plasmon resonance has greatly simplified the measurement of binding interactions in biology. This new technology known as biomolecular int eraction analysis makes it possible to visualize the binding process a s a function of time by following the increase in refractive index tha t occurs when one of the interacting partners binds to its ligand immo bilized on the surface of a sensor chip. None of the reactants needs t o be labelled, which avoids the artefactual changes in binding propert ies that often result when the molecules are labelled. Biosensor instr uments are well-suited for the rapid mapping of viral epitopes and for identifying which combinations of capturing and detector Mabs will gi ve the best results in sandwich assays. Biosensor binding data are als o useful for selecting peptides to be used in diagnostic solid-phase i mmunoassays. Very small changes in binding affinity can be measured wi th considerable precision which is a prerequisite for analyzing the fu nctional effect and thermodynamic implications of limited structural c hanges in interacting molecules. On-rate (k(a)) and off-rate (k(d)) ki netic constants of the interaction between virus and antibody can be r eadily measured and the equilibrium affinity constant K can be calcula ted from the ratio k(a)/k(d) = K.