Production and characterization of murine monoclonal antibodies recognizing HLA-DQ polymorphisms obtained by immunizing mice with transfected L cells.

Two polymorphic anti-HLA-DQB1 mAbs, TM 902 and TM 903, have been produced by immunizing F1 mice (Balb/C x C3H) with HLA-DQ-transfected mouse L cells. Cytotoxic analysis on a panel of HLA-typed cell lines has shown that TM 902 reacts with all the DQB1* alleles except DQB1*0501, *0502, and *0503, and DQB1*0601, *0602, *0603, and *0604, whereas TM 903 reacts with the DQB1*0501, *0502, and *0503, DQB1*0601, *0602, *0603, and *0604, and DQB1*0401 and *0402 alleles. The same reactivity pattern has been confirmed by cytofluorimetric analysis. Indirect immunofluorescence with various class-II-transfected cell lines showed no binding of both mAbs to the DR or DP products, suggesting their reactivity to the DQ products. The use of transfectants expressing HLA-DR/DQ heterodimers demonstrates that TM902 and TM903 mAbs are both specific for the DQ-beta chain. Comparison of the amino acid sequences of the DQ-beta chain suggests the involvement of residues 84-90 (QLELRTT) in the formation of TM902 epitope and of residues 54-55 (GR) in the formation of TM903 epitope.