Two Blood Group M Epitopes Disclosed by Monoclonal Antibodies

Abstract

Two cloned mouse hybridomas, designated G8 and E3, produced anti-M of immunoglobulin classes IgG2b and IgG1, respectively. No discrepancies were observed in testing over 5000 normal donor blood samples with appropriately diluted G8 and E3 culture supernatant fluids in parallel with rabbit anti-M and anti-N typing reagents. The specificity and titer of antibodies produced by G8 and E3 were minimally affected by changes in temperature (37.degree. C, 22.degree. C, 4.degree. C). G8 and E3 showed reduced activity with type MM red cells that were treated with either neuraminidase or papain, but differences were observed in the susceptibility of the respective epitopes to treatment with neuraminidase. G8 and E3 exhibited different specificities when used to test the red cells of nonhuman primates and erythrocytes of the rare MgMg human blood type. The existence of at least 2 M antigen epitopes was indicated.