Gp.Mur is a clinically relevant antigen of the MNS blood group system that is highly

prevalent in several Asian populations. Its corresponding antibody, anti-Gp.Mur, has been implicated

in hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. Currently,

identifying and confirming anti-Gp.Mur antibody presence in sera via agglutination of a panel of red

blood cells (RBCs) is inefficient and difficult to quantify. Using a baculovirus expression system to

express Gp.Mur antigen on insect cell surfaces, we have developed a quantitative cell-based system

to confirm the presence of anti-Gp.Mur antibody in human serum. We obtained 10 serum samples

preidentified as having anti-Gp.Mur antibody and another 4 samples containing noncorresponding

antibodies from hospital patients. Insect cells displaying Gp.Mur antigen successfully adsorbed

anti-Gp.Mur antibody in the sera and inhibited the RBC agglutination mediated by this antibody. By

varying the concentration of Gp.Mur-displaying cells, we could grade levels of RBC agglutination by

anti-Gp.Mur antibody. Densitometric analysis further enabled quantitative determinations of hemagglutination

inhibition by Gp.Mur-displaying cells. We believe that this cell-based hemagglutination

inhibition system greatly improves or supplements existing technology and is a convenient means

for accurately identifying and quantifying anti-Gp.Mur antibody.