In a previous study, we used transfectants expressing hybrid HLA-DR(β1*0403)/DR(β1*0701) chains to map sequences involved in polymorphic antibody binding epitopes on DR(α,β1*0403) or DR(α,β1*0701) molecules. Amino acids 1-40 of the β1 domain were found to make the major contributions to most of the antibody binding epitopes studied. To begin to localize sequences that contribute to polymorphic antibody epitopes on DR(α,β1*0101), DR(α,β1*1101) and DR(α,β3*0202) molecules, we used indirect immunofluorescence and flow cytometry to assess the binding of mAb to transfectants expressing hybrid DR(β1*0101)/DR(β1*1101) or DR(β1*1101)/DR(β3*0202) chains that divide the DRβ chain into three segments: amino acids 1-40, 41-97, and the β2 domain. The results indicate that amino acids 41-97 of the β1 domain on DR(β1*0101), DR(β1*1101), or DR(β3*0202) are critical in most of the epitopes, including those recognized by human antibodies MP4 and MP12, and mouse mAb GS88.2, I-LR1, 21r5, and 126.96.36.199, whereas amino acids 1-40 of DR(β1*1101) are critical in the epitope recognized by the MCS-7 mAb, and both segments 1-40 and 41-97 of DR(β1*1101) are important in the epitopes recognized by the I-LR2 and UL-52 mAbs. Based on these data and comparison of DRβ allelic protein sequences, the residues that may play critical roles in these antibody binding epitopes are predicted.
ASJC Scopus subject areas
- Immunology and Allergy