DNA typing for natural killer cell inhibiting HLA-Cw groups NK1 and NK2 by PCR-SSP

Over the last few years, natural killer (NK) cells have been shown to express MHC molecule recognizing receptors which are thought to function primarily as negative signaling receptors. HLA-Cw seems to play a key role as the corresponding ligand. Two distinct HLA-Cw groups which differ in amino acid residues 77 and 80 inhibit separate subsets of NK cells. In order to classify target cells with respect to their expression of HLA-Cw groups we established a group specific PCR-SSP which directly amplifies the relevant epitope coding sequences. The PCR protocol was validated by retyping cell lines obtained from the International Histocompatibility Workshop and by comparing those results with those acquired from allele-specific genotyping and serotyping on 80 donor-recipient pairs from our kidney transplantation unit. In the context of inhibitory HLA-Cw receptors, our protocol which definitively discriminates the two alternative epitopes is the more direct and thus more reliable approach, and is less labor intensive compared to an allele specific PCR or serotyping. In addition serotyping does not detect at all certain alleles. Basic NK cell research and clinical transplantation immunology may benefit from this newly established PCR SSP technique.