High-level, stable expression of blood group antigens in a heterologous system

The detection and identification of blood group antibodies in patients is crucial for successful allogeneic blood transfusions. Current methods are highly subjective and rely on red blood cells (RBCs), which simultaneously express many blood group antigens, have a short shelf-life, and carry potential biohazard risks. To overcome these problems, we have used the approach of expressing individual blood group antigen-bearing proteins in a heterologous system. We report here the high-level surface expression of type I (Knops), type II (Kell), and type III/multi-pass (Duffy) membrane proteins that carry blood group antigens in mouse erythroleukaemic (MEL) cells using a vector containing the beta-globin locus control region. Importantly, the antigens expressed were detected specifically by a panel of patients' sera containing alloantibodies at sensitivities that are comparable to antigen-positive RBCs. Furthermore, in contrast to other mammalian expression systems, antigen expression was stable following freezing and thawing of the cell lines. Thus, this system has the potential both to replace the current use of RBCs by providing a one step method to detect and identify blood group antibodies and to allow the automation of antibody identification for the clinical laboratory.