Ž . Journal of Immunological Methods 206 1997 87–96 Detection of blood group antigens utilising immobilised antibodies and surface plasmon resonance John G. Quinn a , Richard O’Kennedy a, ) , Malcolm Smyth b , John Moulds c , Tom Frame c a School of Biological Sciences, Dublin City UniÕersity, GlasneÕin, Dublin 9, Ireland b School of Chemical Sciences, Dublin City UniÕersity, GlasneÕin, Dublin 9, Ireland c Gamma Biologicals, Mangum Road, Houston, TX 77092-5497, USA Received 31 January 1997; revised 21 April 1997; accepted 21 May 1997 Abstract Ž . Surface plasmon resonance SPR detection using the BIAcoree biosensing system was employed for the detection of Ž . blood group-associated antigens BGAA on whole erythrocytes. The quantitative detection of erythrocytes was accom- Ž . plished by covalently immobilising blood group-specific antibodies IgM to a dextran matrix and monitoring the cell binding response. Non-specific binding of erythrocytes to the IgM coated surface was not detected. Relatively mild Ž . regeneration conditions 20 mM NaOH were employed to elute bound erythrocytes in order to preserve the activity of the immobilised antibody and allow the surface to be used repeatedly. Regeneration of the surface was particularly difficult when a high IgM immobilisation level was used and when the number of bound cells was high. Despite these considerations, a quantitative relationship between the cell binding response and erythrocyte concentration 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 allows the system to be used for blood typing. As a model study, the Ž . lectin concanavalin A ConA was covalently immobilised onto a hydrophilic dextran matrix and successfully used to support the capture of erythrocytes from suspension. q 1997 Elsevier Science B.V. Keywords: Erythrocyte; Immunoglobulin M; Concanavalin A; Surface plasmon resonance; Biospecific interaction analysis Abbreviations: SPR, surface plasmon resonance; BGAA, blood group associated antigens; IgM, immunoglobulin M; Con A, concanavalin A; BIA, biospecific interaction analysis; EDC, Ž . ethyl dimethylaminopropyl carbodiimide; NHS, N-hydroxysucci- nimide; RBC, red blood cell ) Corresponding author. Tel.: q353-1-7045319; fax: q353-1- 7045412. 1. Introduction Ž . Real-time biospecific interaction analysis BIA is a technology for the measurement of biomolecular interactions that has been applied to the study of many proteins, peptides, glycoproteins, nucleic acids, Ž viruses and other molecules Soderlind and Simons- son, 1992; Bondeson and Frostell-Karlsson, 1993; Lowman and Wells, 1993; Nice and Layton, 1993; Soderlind and Simonsson, 1993; Mani and Marchi, 0022-1759r97r$17.00 q 1997 Elsevier Science B.V. All rights reserved. Ž . PII S0022-1759 97 00092-6