A monoclonal antibody detecting an HLA-DQwl-related determinant.

A complement fixing monoclonal antibody (moab) was prepared which reacts with a polymorphic determinant on HLA class II molecules. The moab IIB3 recognises all DQwl (DC1, MB1, LB-E12) positive cells as well as some DR4, DR7, DRw8 and DRw9 positive cells. The moab reacts mainly with B-cells and not or with only a minority of the monocytes. Segregation of the determinant with HLA-DR could be shown. The determinant is strongly expressed on DR2, DR4 and DRw6 positive cell lines but only weakly on DR1 lines. In contrast to a monoclonal antibody against a monomorphic determinant on class II molecules IIB3 did not give a distinct inhibition of the MLC nor did it inhibit the generation of CTLs in MLC as has been described for the DQwl like moab BT 3/4 (Corte et al. 1982). Immunoprecipitation indicates that IIB3 reacts with DQ-like molecules.