Amino acid substitutions can influence the natural killer (NK)-mediated recognition of HLA-C molecules. Role of serine-77 and lysine-80 in the target cell protection from lysis mediated by "group 2" or "group 1" NK clones.

Abstract

SummaryNatural killer (NK) cells have been shown to express a clonally distributed ability to recognize HLA class I alleles. The previously defined NK clones belonging to "group 1" recognize HLACw*0401 (Cw4) and other HLA-C alleles sharing Asn at position 77 and Lys at position 80. Conversely, the "group 2" NK clones recognize HLA-Cw*0302 (Cw3) and other HLA-C alleles characterized by Ser at position 77 and Asn at position 80. We assessed directly the involvement of these two residues in the capacity of NK cell clones to discriminate between the two groups of HLA-C alleles. To this end, Cw3 and Cw4 alleles were subjected to site-directed mutagenesis. Substitution of the amino acids typical of the Cw3 allele (Ser-77 and Asn-80) with those present in Cw4 (Ash-77 and Lys-80) resulted in a Cw3 mutant that was no longer recognized by group 2 NK cell clones, but that was recognized by group I clones. Analysis of Cw3 or Cw4 molecules containing single amino acid substitutions indicates roles for Lys-80 in recognition mediated by group I clones and for Ser-77 in recognition mediated by group 2 clones. These results demonstrate that NK-mediated specific recognition of HLA-C allotypes is affected by single natural amino acid substitutions at positions 77 and 80 of the heavy chain.

Combined Genotypic and Phenotypic Killer Cell Ig-Like Receptor Analyses Reveal KIR2DL3 Alleles Displaying Unexpected Monoclonal Antibody Reactivity: Identification of the Amino Acid Residues Critical for Staining

“…In this study, we used as target cells 721.221 cells transfected with HLA-Cw3 or -Cw4 alleles (11). For masking experiments, NK cells were preincubated with mAb specific to the various NKRs, whereas the anti-HLA class I mAb (a mixture of A6-136 and F[ab9] 2 6A4 mAb) was added as last reagent in the cytolytic assay; mAb concentration was 10 mg/ml.…”

Novel SLA class I alleles of Chinese pig strains and their significance in xenotransplantation

“…It is thus of importance to determine the relevant structures in class I molecules of Chinese pig strains. Two residues at position 77 and 80 in KIR's ligand have been recognized crucial for recognition by three kinds of human KIRs, NKTA-1, NKTA-2 and NKTA-3 [15][16][17]. As indicated in Tab 2, for the NKTA-1-related ligand, the two residues are neally all changed in three Chinese pig strains as N 77G and K 80T.…”

Células natural killer e vigilância imunológica

“…Groups 1 and 2 are distinguished by a dimorphism at position 80 of helix of the HLA-C molecule. 15 Both forms are characterized by the presence of Ser77/Asn80 and Asn77/Lys80, and there is a certain hierarchy to the interaction of KIR with HLA-C molecules, been the interaction KIR2DL1-C2 stronger than KIR2DL3-C1.…”