Cutting edge: Requirement of class I signal sequence-derived peptides for HLA-E recognition by a mouse cytotoxic T cell clone

The human nonclassical MHC class I molecule HLA-E has recently been shown t o act as a major ligand for NK cell inhibitory receptors, Using HLA-E-expre ssing transgenic mice, we produced a cytotoxic T cell clone that specifical ly recognizes the HLA-E molecule. We report here that this T cell clone lys es HLA-E-transfected RMA-S target cells sensitized,vith synthetic class I s ignal sequence nonamers, Moreover, this T cell clone lyses human EBV-infect ed B lymphocytes, PHA blasts, and PBL, formally demonstrating the surface e xpression of HLA-E/class I signal-derived peptide complex on human cells. F urthermore, these data show that HLA-E complexed with class I signal sequen ce-derived peptides is not only a ligand for NK cell inhibitory receptors, but can also trigger cytotoxic T cells (CTL).