An application of immunoblotting in the classification of the Miltenberger series of blood group antigens.

A simple scheme is described for the classification of Miltenberger cell classes I to VI, which is consistent with the serologic definition of the determinants. The scheme is based on the reaction patterns obtained by immunoblotting the normal and abnormal sialoglycoproteins (SGPs) found in these cells with several murine monoclonal antibodies that recognize different epitopes on alpha-SGP (Glycophorin A). The abnormal alpha found in MiI and MiII cells is easily identified with these antibodies, as is the abnormal alpha-delta SGP found in MiV cells. Certain alpha-SGP antibodies recognize epitopes on the abnormal SGPs found in MiIII, MiIV, and MiVI cells, although the mode of inheritance of these abnormal SGPs suggests that they are related to delta-SGP (Glycophorin B). Antibody R18 reacts with the abnormal SGP of MiIII cells but not that of MiIV or MiVI cells, whereas antibody BRIC 119 reacts with MiIII, MiIV, and MiVI cells. None of the abnormal components in these three cell classes react with antibody R10 or with an antibody (BRIC 163) that recognizes an epitope on the cytoplasmic portion of alpha-SGP. The immunostaining of membranes from persons heterozygous for the MiVII and MiVIII classes revealed patterns identical to those of normal red cell membranes. However, antibody R18 did not react with any of the SGP components of homozygous MiVII cells.