A CYTOTOXIC HUMAN HYBRIDOMA MONOCLONAL-ANTIBODY (TRJ5) SPECIFIC FOR HLA-B38(16) AND HLA-B39(16)

We have generated a cytotoxic IgMlambda human hybridoma mAb (TrJ5), th at is specific for HLA-B38(16) and -B39(16). Among a panel of 42 HLA-d efined cell lines, TrJ5 killed all five B38-positive and both B16-posi tive cell lines, as well as the single B39-positive cell line, but not any cell lines lacking these antigens. It could be ruled out that the TrJ5 epitope is located on the alpha1 domain because TrJ5 did not rea ct with cells bearing HLA-B14, the alpha1 domain of which is identical to alpha1 of B39. In the alpha2 domain of B38 and B39, a unique threo nine residue at position 158 (Thr-158) is not shared by any of 29 othe r HLA-B alleles. This suggests that Thr-158 of the alpha2-domain helix is critical for the TrJ5 epitope.