DETECTION OF BLOOD-GROUP ANTIGENS UTILIZING IMMOBILIZED ANTIBODIES AND SURFACE-PLASMON RESONANCE

Surface plasmon resonance (SPR) detection using the BLAcore(TM) biosen sing system was employed for the detection of blood group-associated a ntigens (BGAA) on whole erythrocytes. The quantitative detection of er ythrocytes was accomplished by covalently immobilising blood group-spe cific antibodies (IgM) to a dextran matrix and monitoring the cell bin ding response. Non-specific binding of erythrocytes to the IgM coated surface was not detected. Relatively mild regeneration conditions (20 mM NaOH) were employed to elute bound erythrocytes in order to preserv e the activity of the immobilised antibody and allow the surface to be used repeatedly. Regeneration of the surface was particularly difficu lt when a high IgM immobilisation level was used and when the number o f bound cells was high. Despite these considerations, a quantitative r elationship between the cell binding response and erythrocyte concentr ation was confirmed. Erythrocyte preparations, diluted by a factor of ten as compared to physiological concentrations, were detectable. The occurrence of non-specific false positives appears to be minimal and a llows the system to be used for blood typing. As a model study, the le ctin concanavalin A (ConA) was covalently immobilised onto a hydrophil ic dextran matrix and successfully used to support the capture of eryt hrocytes from suspension. (C) 1997 Elsevier Science B.V.