DEMONSTRATION BY THE MONOCLONAL ANTIBODY-SPECIFIC IMMOBILIZATION OF ERYTHROCYTE ANTIGENS ASSAY THAT A NEW RED-CELL ANTIGEN BELONGS TO THE KELL BLOOD-GROUP SYSTEM

Background:The Kell blood group system comprises 21 antigens residing on a red cell membrane glycoprotein of apparent M(r) 93,000. Study Design and Methods: Serologic techniques were used to identify a new red cell antigen. The monoclonal antibody-specific immobilization of erythrocyte antigens (MAIEA) assay was used to identify the red cell membrane component carrying that antigen. Results: A new high-frequency red cell antigen was identified and provisionally named RAZ. RAZ is absent from K-0 red cells and from red cells treated with 2-amino-ethylisothiouronium bromide and is; expressed weakly on McLeod phenotype cells. It differs from all other Kell system antigens, and no depression of other Kell system antigens on RAZ+ red cells was noticed. The RAZ antigen was shown by the MAIEA assay to be located on the Kell glycoprotein. Conclusion: RAZ is a new high-frequency antigen located on the Kell glycoprotein. The MAIEA assay is a very effective method of demonstrating the membrane structure carrying a red cell antigen.