title: KIR acquisition probabilities are independent of self-HLA class I ligands and increase with cellular KIR expression.
abstract: Inhibitory killer cell immunoglobulin-like receptors (KIRs) preserve tolerance to self and shape the functional response of human natural killer (NK) cells. Here, we have evaluated the influence of selection processes in the formation of inhibitory KIR repertoires in a cohort of 44 donors homozygous for the group A KIR haplotype. Coexpression of multiple KIRs was more frequent than expected by the product rule that describes random association of independent events. In line with this observation, the probability of KIR acquisition increased with the cellular expression of KIRs. Three types of KIR repertoires were distinguished that differed in frequencies of KIR- and NKG2A-positive cells but showed no dependency on the number of self-HLA class I ligands. Furthermore, the distribution of self- and nonself-KIRs at the cell surface reflected a random combination of receptors rather than a selection process conferred by cognate HLA class I molecules. Finally, NKG2A was found to buffer overall functional responses in KIR repertoires characterized by low-KIR expression frequencies. The results provide new insights into the formation of inhibitory KIR repertoires on human NK cells and support a model in which variegated KIR repertoires are generated through sequential and random acquisition of KIRs in the absence of selection.
authors.affiliation: Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.
authors.forename: Sandra
authors.initials: S
authors.lastname: Andersson
authors.forename: Cyril
authors.initials: C
authors.lastname: Fauriat
authors.forename: Jenny-Ann
authors.initials: JA
authors.lastname: Malmberg
authors.forename: Hans-Gustaf
authors.initials: HG
authors.lastname: Ljunggren
authors.forename: Karl-Johan
authors.initials: KJ
authors.lastname: Malmberg
mesh_terms: D001324:Autoantigens / Q000378:metabolism; D015331:Cohort Studies; D015870:Gene Expression; D006680:HLA Antigens / Q000235:genetics / Q000378:metabolism*; D006239:Haplotypes; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000378:metabolism*; D006720:Homozygote; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology; D008024:Ligands; D018448:Models, Immunological; D055654:NK Cell Lectin-Like Receptor Subfamily C / Q000378:metabolism; D054340:Receptors, KIR / Q000145:classification / Q000235:genetics* / Q000378:metabolism*
chemical_list: D001324:Autoantigens; D006680:HLA Antigens; D015395:Histocompatibility Antigens Class I; C527054:KLRC1 protein, human; D008024:Ligands; D055654:NK Cell Lectin-Like Receptor Subfamily C; D054340:Receptors, KIR