HLA-DQ molecular heterogeneity in HLA-DR4-Dw4 consanguineous cell lines

Two-dimensional gel analysis (NEPHGE) of the molecules precipitated by the HLA-DR monomorphic antibody L243 showed a single and identical alpha chain spot from two consanguineous cell lines, BM14 and MCF. The latter was derived from a rheumatoid arthritis patient. No apparent structural polymorphism of the HLA-DR beta chains was detected. The data suggests that the HLA-DR4 haplotype expresses one alpha chain and up to four beta chains. The electrophoretic pattern of the HLA-DQ molecules precipitated with the monomorphic antibody TU22 revealed clear differences between BM14 and MCF. These differences were mainly in the beta chain profiles. Four acidic beta chains were found with the MCF cell line wheras only three beta chains at different isoelectric points were found with the BM14 cell line. The data obtained in this study argue for a considerable heterogeneity of the HLA-DQ antigens detected at the molecular level.