CLINICAL UTILITY OF PLASMA-MEMBRANE VESICLES EXPRESSING RECOMBINANT GLYCOPHORIN A-ENCODED BLOOD-GROUP ANTIGENS

BACKGROUND: Although the genes encoding most of the major blood group determinants are now cloned, recombinant blood group antigens are not commonly used in the clinical laboratory. This study assessed the feas ibility of using plasma membrane vesicles expressing recombinant glyco phorin A blood group antigens as soluble immunoadsorbants. STUDY DESIG N AND METHODS: Chinese hamster ovary cells were transfected with plasm ids containing the cDNA encoding the M- or N-allele of glycophorin A. Plasma membrane vesicles were chemically induced from stable, high-exp ressing cell lines. Antibodies were assessed for reactivity in hemaggl utination-inhibition assays. RESULTS: Eight anti-M antibodies were eva luated. Vesicles expressing the M-allele of glycophorin A neutralized four antibodies (two murine monoclonals; two human sera), while the ac tivity of four human sera was unaffected. Three anti-N reagents were a lso evaluated (murine monoclonal antibody; rabbit polyclonal antibody; Vicia graminea lectin). All were neutralized by vesicles expressing t he N-allele of glycophorin A.There was no detectable neutralization of other clinically significant blood group antibodies. CONCLUSIONS: Pla sma membrane vesicles expressing recombinant glycophorin blood group d eterminants may prove to be useful reagents in the clinical laboratory . However, the partial failure of M antibody recognition requires furt her study. This general approach could be utilized for any similarly e xpressed recombinant blood group antigen.