MONOCLONAL-ANTIBODIES RECOGNIZING EPITOPES ON THE EXTRACELLULAR FACE AND INTRACELLULAR N-TERMINUS OF THE HUMAN ERYTHROCYTE ANION TRANSPORTER (BAND-3) AND THEIR APPLICATION TO THE ANALYSIS OF SOUTH EAST-ASIAN OVALOCYTES

This report describes the production and characterization of 13 rodent monoclonal antibodies to the human erythrocyte anion transport protei n AE1 (syn. band 3). Eleven antibodies (4 murine and 7 rat) recognize epitopes dependent on the integrity of the third extracellular loop of the protein. Two antibodies (1 murine and 1 rat) recognize epitopes o n the N-terminal cytoplasmic domain. Quantitative binding studies usin g radioiodinated IgG and Fab fragments of antibodies to extracellular epitopes on AE1 ranged from 77,000 to 313,000 (IgG) and from 241,000 t o 772,000 (Fab) molecules bound at saturation. The results indicate th at the epitopes recognized by different antibodies vary in their acces sibility and suggest that there is heterogeneity in the organization o f individual AE1 molecules in the red blood cell membrane. Quantitativ e binding studies on South East Asian ovalocytes using several antibod ies to AE1 and an anti-Wr(b) show a marked reduction in the number of antibody molecules bound at saturation. These results are consistent w ith the existence of highly cooperative interactions between transmemb rane domains of AE1 in normal erythrocytes and the disruption of these interactions in the variant AE1 found in South East Asian ovalocytes. (C) 1995 by The American Society of Hematology.