ABSTRACT
NKG2D is a natural killer cell activating receptor recognising ligands on infected or tumorigenic cells, leading to their cytolysis. There are eight known genes encoding NKG2D ligands: MICA, MICB and ULBP1-6. MICA and MICB are highly polymorphic and well characterised, whilst ULBP ligands are less polymorphic and the functional implication of their diversity is not well understood. Using International HLA and Immunogenetics Workshop (IHIW) cell line DNA, we previously characterised alleles of the RAET1E gene (encoding ULBP4 proteins), including the 5' UTR promoter region and exons 1-3. We found 11 promoter haplotypes associating with alleles based on exons 1-3, revealing 19 alleles overall. The current study extends this analysis using 87 individual DNA samples from IHIW cell lines or cord blood to include RAET1E exon 4 and the 3' UTR, as polymorphism in these regions have not been previously investigated. We found two novel exon 4 polymorphisms encoding amino acid substitutions altering the transmembrane domain. An amino acid substitution at residue 233 was unique to the RAET1E*008 allele whereas the substitution at residue 237 was shared between groups of alleles. Additionally, four haplotypes were found based on 3' UTR sequences, which were unique to certain alleles or shared with allele groups based on exons 1-4 polymorphisms. Furthermore, putative microRNAs were identified that may interact with these polymorphic sites, repressing transcription and potentially affecting expression levels.
Subject(s)
DNA , NK Cell Lectin-Like Receptor Subfamily K , Humans , 3' Untranslated Regions , Alleles , NK Cell Lectin-Like Receptor Subfamily K/genetics , Exons/genetics , Histocompatibility Antigens Class I/genetics , Carrier Proteins/genetics , Membrane Proteins/metabolismABSTRACT
OBJECTIVES: NKG2D is an activating receptor expressed by natural killer (NK) and CD8+ T cells and activation intensity varies by NKG2D expression level or nature of its ligand. An NKG2D gene polymorphism determines high (HNK1) or low (LNK1) expression. MICA is the most polymorphic NKG2D ligand and stronger effector cell activation associates with methionine rather than valine at residue 129. We investigated correlation between cord blood (CB) NKG2D and MICA genotypes and haematopoietic stem cell (HSC) transplant outcome. METHODS: We retrospectively studied 267 CB HSC recipients (178 adult and 87 paediatric) who underwent transplant for malignant disease between 2007 and 2018, analysing CB graft DNA for NKG2D and MICA polymorphisms using Sanger sequencing. Multivariate analysis was used to correlate these results with transplant outcomes. RESULTS: In adult patients, LNK1 homozygous CB significantly improved 60-day neutrophil engraftment (hazard ratio (HR) 0.6; 95% confidence interval (CI) 0.4-0.9; p = .003). In paediatrics, HNK1 homozygous CB improved 60-day engraftment (HR 0.4; 95% CI 0.2-0.7; p = .003), as did MICA-129 methionine+ CB grafts (HR 1.7 95% CI 1.1-2.6; p = .02). CONCLUSION: CB NKG2D and MICA genotypes potentially improve CB HSC engraftment. However, results contrast between adult and paediatric recipients and may reflect transplant procedure disparities between cohorts.
Subject(s)
Cord Blood Stem Cell Transplantation , Histocompatibility Antigens Class I , NK Cell Lectin-Like Receptor Subfamily K , Humans , NK Cell Lectin-Like Receptor Subfamily K/genetics , Child , Male , Histocompatibility Antigens Class I/genetics , Adult , Female , Adolescent , Child, Preschool , Middle Aged , Retrospective Studies , Infant , Genotype , Transplantation, Homologous , Polymorphism, Genetic , Young Adult , Treatment Outcome , Aged , Alleles , Tissue Donors , Neoplasms/genetics , Neoplasms/therapy , Graft Survival , Graft vs Host Disease/etiology , Graft vs Host Disease/genetics , Hematopoietic Stem Cell Transplantation/methodsABSTRACT
Innate lymphoid cells (ILCs) play a key role in tissue-mediated immunity and can be controlled by coreceptor signaling. Here, we define a subset of ILCs that are Tbet+NK1.1- and are present within the tumor microenvironment (TME). We show programmed death-1 receptor (PD-1) expression on ILCs within TME is found in Tbet+NK1.1- ILCs. PD-1 significantly controlled the proliferation and function of Tbet+NK1.1- ILCs in multiple murine and human tumors. We found tumor-derived lactate enhanced PD-1 expression on Tbet+NK1.1- ILCs within the TME, which resulted in dampened the mammalian target of rapamycin (mTOR) signaling along with increased fatty acid uptake. In line with these metabolic changes, PD-1-deficient Tbet+NK1.1- ILCs expressed significantly increased IFNγ and granzyme B and K. Furthermore, PD-1-deficient Tbet+NK1.1- ILCs contributed toward diminished tumor growth in an experimental murine model of melanoma. These data demonstrate that PD-1 can regulate antitumor responses of Tbet+NK1.1- ILCs within the TME.
Subject(s)
Lymphocytes , Neoplasms , Mice , Animals , Humans , Immunity, Innate , Programmed Cell Death 1 Receptor/genetics , Programmed Cell Death 1 Receptor/metabolism , Tumor Microenvironment , Neoplasms/metabolism , Apoptosis , Mammals/metabolismABSTRACT
Innate lymphoid cells (ILCs) are important for both tissue immunity and tissue homeostasis. They are classified into three groups: Group 1 ILCs include NK cells, which are important in eliciting immunity against intracellular pathogens; group 2 ILCs protect against parasitic helminths; and group 3 ILCs protect against extracellular pathogens. The role of ILCs in cancer immunity remains unclear. In this chapter, we discuss methods for isolating and characterizing tumor-infiltrating ILC subsets within the tumor microenvironment in an experimental murine model of B16 melanoma. The chapter also highlights the expression of PD-1 on the various ILC subsets within the tumor microenvironment.
