USE OF THE MAIEA TECHNIQUE TO CONFIRM THE RELATIONSHIP BETWEEN THE CROMER ANTIGENS AND DECAY-ACCELERATING FACTOR AND TO ASSIGN PROVISIONALLY ANTIGENS TO THE SHORT-CONSENSUS REPEATS

The MAIEA (monoclonal-antibody-specific immobilisation of erythrocyte antigens) assay has recently been developed for the assignment of red cell antigens, recognised by human alloantisera, to particular membrane components of the red cell membrane [17]. This technique detects trimolecular complexes formed by the reaction of a human antibody and a mouse antibody with a particular red cell protein. A positive reaction, in an ELISA-type detection procedure, occurs if the epitopes to the human and mouse antibodies are present on the same membrane component but at different regions. In this report, we show how the MAIEA assay can be used to confirm the relationship between Cromer system antigens and the complement-regulatory protein, decay-accelerating factor (DAF, CD 55). In addition, the location of the antigens along the protein is postulated by using three anti-DAF monoclonal antibodies with specificities to different regions of DAF. Tc(a) and Es(a) are assigned provisionally to the first short-consensus repeat (SCR), UMC to the second SCR, Dr(a) to the third SCR and Cr(a), WES(a) and WES(b) to the fourth SCR or to the serine/threonine rich region of the DAF protein.