Clinical utility of plasma membrane vesicles expressing recombinant glycophorin A-encoded blood group antigens

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 feasibility of using plasma membrane vesicles expressing recombinant glycophorin A blood group antigens as soluble immunoadsorbants.

Chinese hamster ovary cells were transfected with plasmids containing the cDNA encoding the M- or N-allele of glycophorin A. Plasma membrane vesicles were chemically induced from stable, high-expressing cell lines. Antibodies were assessed for reactivity in hemagglutination-inhibition assays.

Eight anti-M antibodies were evaluated. Vesicles expressing the M-allele of glycophorin A neutralized four antibodies (two murine monoclonals; two human sera), while the activity of four human sera was unaffected. Three anti-N reagents were also evaluated (murine monoclonal antibody; rabbit polyclonal antibody; Vicia graminea lectin). All were neutralized by vesicles expressing the N-allele of glycophorin A. There was no detectable neutralization of other clinically significant blood group antibodies.

Plasma membrane vesicles expressing recombinant glycophorin blood group determinants may prove to be useful reagents in the clinical laboratory. However, the partial failure of M antibody recognition requires further study. This general approach could be utilized for any similarly expressed recombinant blood group antigen.