T-cell identification of a private DQw5 subtype associated with DR1: contribution of endogenous peptide?

Human allospecific T-cell clones were generated against DR1 and DQw1 by limiting dilution. In proliferation experiments using a large panel of Epstein-Barr virus-transformed B-cell lines (LCL), eight T-cell clones (TLC) were found that responded only to the DR1+ LCLs* (9 of 9) and not the 94 other LCLs expressing DR specificities 2 through w9. TLCs* were analyzed further using monoclonal antibodies in blocking studies. As expected, most TLCs were blocked by anti-DR monoclonal antibodies (MoAbs)* and not by anti-DQ MoAbs. However, one clone, TLC 63.138, was not blocked by anti-DR MoAbs but was completely inhibited by anti-DQ MoAbs. This suggests that TLC 63.138 recognizes a private determinant on DQ molecules uniquely associated with DR1.