KIR3DL05 and KIR3DS02 Recognition of a Nonclassical MHC Class I Molecule in the Rhesus Macaque Implicated in Pregnancy Success

Abstract

Knowledge of the MHC class I ligands of rhesus macaque killer-cell Ig-like receptors (KIRs) is fundamental to understanding the role of natural killer (NK) cells in this species as a nonhuman primate model for infectious diseases, transplantation and reproductive biology. We previously identified Mamu-AG as a ligand for KIR3DL05. Mamu-AG is a nonclassical MHC class I molecule that is expressed at the maternal-fetal interface of the placenta in rhesus macaques similar to HLA-G in humans. Although Mamu-AG and HLA-G share similar molecular features, including limited polymorphism and a short cytoplasmic tail, Mamu-AG is considerably more polymorphic. To determine which allotypes of Mamu-AG serve as ligands for KIR3DL05, we tested reporter cell lines expressing five different alleles of KIR3DL05 (KIR3DL05*001, KIR3DL05*004, KIR3DL05*005, KIR3DL05*008 and KIR3DL05*X) for responses to target cells expressing eight different alleles of Mamu-AG. All five allotypes of KIR3DL05 responded to Mamu-AG2*01:01, two exhibited dominant responses to Mamu-AG1*05:01, and three had low but detectable responses to Mamu-AG3*03:01, -AG3*03:02, -AG3*03:03 and -AG3*03:04. Since KIR3DL05*X is the product of recombination between KIR3DL05 and KIR3DS02, we also tested an allotype of KIR3DS02 (KIR3DS02*004) and found that this activating KIR also recognizes Mamu-AG2*01:01. Additional analysis of Mamu-AG variants with single amino acid substitutions identified residues in the α1-domain essential for recognition by KIR3DL05. These results reveal variation in KIR3DL05 and KIR3DS02 responses to Mamu-AG and define Mamu-AG polymorphisms that differentially affect KIR recognition.

MHC class I Ligands of Rhesus Macaque Killer-Cell Immunoglobulin-Like Receptors

“…In this case, the detection of weak binding interactions with Mamu-AG*01*05:01 that were not detectable with KIR-CD3ζ JNL cells may reflect somewhat greater sensitivity of KIR-Fc staining. Together with the previous identification of Mamu-AG ligands for KIR3DL05 and KIR3DS02*004 (75, 79), these findings bring the number of rhesus macaque KIRs known to interact with Mamu-AG to seven (Table I).…”

“…Six of the KIRs in this study (KIR3DL07*004, KIR3DS01*003, KIR3DS02*004, KIR3DS06*002, KIR3DSw07*001 and KIR3DSw09*003) were found to interact with Mamu-AG2*01:01 alone or in combination with Mamu-B*45:03, a hybrid molecule that contains MHC-A α1-domain sequences. Together with earlier studies defining similar ligands for KIR3DL05 (72, 74, 82), at least seven rhesus macaque KIRs are known to encode receptors for Mamu-A or -A-related ligands (Table I).…”

“…Extensive sequencing and segregation analyses of KIR transcripts support the existence of at least 22 KIR genes in Indian-origin rhesus macaques (53–56). Although our group and others have identified ligands for a few rhesus macaque KIRs (72–76), ligands for most of the KIR in this species remain undefined. To provide a more complete foundation for studying NK cell biology in this species, we investigated the MHC class I interactions of 16 KIRs representing common alleles of distinct lineage II genes in animals of Indian descent (Fig.…”

“…The rhesus macaque has become an increasingly valuable animal model for infectious diseases (57–68), reproductive biology (44, 69), and transplantation (70, 71). Although MHC class I ligands have been identified for a few macaque KIRs (72–76), ligands for most of these receptors remain undefined. We therefore performed a systematic survey of MHC class I interactions for common lineage II KIR allotypes representing 16 predicted genes of Indian-origin rhesus macaques.…”

Complete sequencing of a cynomolgus macaque major histocompatibility complex haplotype

“…Both genes are primarily expressed on the surface of invasive extravillous trophoblasts of the placenta and are thought to regulate the maternal immune response to pregnancy through the engagement of NK receptors. Indeed, rhesus macaque Mamu-AG2*01:01 has been shown to have broad recognition by KIR genes KIR3DL05, KIR3DL07, KIR3DS01, KIR3DS02, KIR3DSw07 , and KIR3DSw09 (Nicholas et al 2022; Anderson et al 2022). Given the dramatic expansion of lineage II KIRs in macaques, iit is not surprising that the MHC-AG gene has also undergone tandem duplication events relative to the single copy HLA-G gene (de Groot et al 2015).…”