Human anti-Di^a monoclonal antibodies for mass screening

The use of monoclonal antibodies (mabs) to blood group antigens is constantly increasing for routine typing. Two heterohybridoma cell lines, HMR15 and HMR22, were established by Epstein-Barr virus transformation of peripheral blood lymphocytes from a blood donor with anti-Di^a. HMR15 mab directly agglutinated Di(a+) red cells, and HMR22 mab agglutinated Di(a+) red cells exclusively by the indirect antiglobulin test. Reactivities of both HMR15 and HMR22 mabs were specific for Di^a and had good correlation with the reactivity of a commercial, polyclonal antiserum. The binding of monoclonal antibodies to antigen-positive red cells was mutually blocked by each other as well as by polyclonal anti-Di^a. Immunoprecipitates by HMR22 mab with a Di(a+) preparation showed a 120kDa band that was stained by anti-band 3. Di^a typing of 2427 blood donors with the mabs and polyclonal typing serum detected 244 Di(a+) individuals (10.1%). No discrepancy was observed between the mabs and the polyclonal antiserum. HMR15 and HMR22 mabs are useful Di^a typing reagents and can substitute for commercial antiserum. Immunohematology 2000;16:78–81.