Innate receptors with high specificity for HLA class I–peptide complexes
Malcolm J. W. Sim, Paul Brennan, Katherine L. Wahl, Jinghua Lu, Sumati Rajagopalan, Peter D. Sun, Eric O. Long
Abstract
Genetic studies associate killer cell immunoglobulin-like receptors (KIRs) and their HLA class I ligands with a variety of human diseases. The basis for these associations and the relative contribution of inhibitory and activating KIR to NK cell responses are unclear. Because KIR binding to HLA-I is peptide dependent, we performed systematic screens, which totaled more than 3500 specific interactions, to determine the specificity of five KIR for peptides presented by four HLA-C ligands. Inhibitory KIR2DL1 was largely peptide sequence agnostic and could bind ~60% of hundreds of HLA-peptide complexes tested. Inhibitory KIR2DL2, KIR2DL3, and activating KIR2DS1 and KIR2DS4 bound only 10% and down to 1% of HLA-peptide complexes tested, respectively. Activating KIR2DS1, previously described as weak, had high binding affinity for HLA-C, with high peptide sequence specificity. Our data revealed MHC-restricted peptide recognition by germline-encoded NK receptors and suggest that NK cell responses can be shaped by HLA-I-bound immunopeptidomes in the context of disease or infection.