Tumor hypoxia represses γδ T cell-mediated antitumor immunity against brain tumors.

The anatomic location and immunologic characteristics of brain tumors result in strong lymphocyte suppression. Consequently, conventional immunotherapies targeting CD8 T cells are ineffective against brain tumors. Tumor cells escape immunosurveillance by various mechanisms and tumor cell metabolism can affect the metabolic states and functions of tumor-infiltrating lymphocytes. Here, we discovered that brain tumor cells had a particularly high demand for oxygen, which affected γδ T cell-mediated antitumor immune responses but not those of conventional T cells. Specifically, tumor hypoxia activated the γδ T cell protein kinase A pathway at a transcriptional level, resulting in repression of the activatory receptor NKG2D. Alleviating tumor hypoxia reinvigorated NKG2D expression and the antitumor function of γδ T cells. These results reveal a hypoxia-mediated mechanism through which brain tumors and γδ T cells interact and emphasize the importance of γδ T cells for antitumor immunity against brain tumors.

STAT3 gain-of-function mutations connect leukemia with autoimmune disease by pathological NKG2Dhi CD8+ T cell dysregulation and accumulation.

The association between cancer and autoimmune disease is unexplained, exemplified by T cell large granular lymphocytic leukemia (T-LGL) where gain-of-function (GOF) somatic STAT3 mutations correlate with co-existing autoimmunity. To investigate whether these mutations are the cause or consequence of CD8+ T cell clonal expansions and autoimmunity, we analyzed patients and mice with germline STAT3 GOF mutations. STAT3 GOF mutations drove the accumulation of effector CD8+ T cell clones highly expressing NKG2D, the receptor for stress-induced MHC-class-I-related molecules. This subset also expressed genes for granzymes, perforin, interferon-γ, and Ccl5/Rantes and required NKG2D and the IL-15/IL-2 receptor IL2RB for maximal accumulation. Leukocyte-restricted STAT3 GOF was sufficient and CD8+ T cells were essential for lethal pathology in mice. These results demonstrate that STAT3 GOF mutations cause effector CD8+ T cell oligoclonal accumulation and that these rogue cells contribute to autoimmune pathology, supporting the hypothesis that somatic mutations in leukemia/lymphoma driver genes contribute to autoimmune disease.

MICa/b-dependent activation of natural killer cells by CD64+ inflammatory type 2 dendritic cells contributes to autoimmunity.

Primary Sjögren's syndrome (pSS) is an inflammatory autoimmune disorder largely mediated by type I and II interferon (IFN). The potential contribution of innate immune cells, such as natural killer (NK) cells and dendritic cells (DC), to the pSS pathology remains understudied. Here, we identified an enriched CD16+ CD56hi NK cell subset associated with higher cytotoxic function, as well as elevated proportions of inflammatory CD64+ conventional dendritic cell (cDC2) subtype that expresses increased levels of MICa/b, the ligand for the activating receptor NKG2D, in pSS individuals. Circulating cDC2 from pSS patients efficiently induced activation of cytotoxic NK cells ex vivo and were found in proximity to CD56+ NK cells in salivary glands (SG) from pSS patients. Interestingly, transcriptional activation of IFN signatures associated with the RIG-I/DDX60 pathway, IFN I receptor, and its target genes regulate the expression of NKG2D ligands on cDC2 from pSS patients. Finally, increased proportions of CD64hi RAE-1+ cDC2 and NKG2D+ CD11b+ CD27+ NK cells were present in vivo in the SG after poly I:C injection. Our study provides novel insight into the contribution and interplay of NK and cDC2 in pSS pathology and identifies new potential therapy targets.

CircARAP2 controls sMICA-induced NK cell desensitization by erasing CTCF/PRC2-induced suppression in early endosome marker RAB5A.

Natural killer cells (NK) are the "professional killer" of tumors and play a crucial role in anti-tumor immunotherapy. NK cell desensitization is a key mechanism of tumor immune escape. Dysregulated NKG2D-NKG2DL signaling is a primary driver of this desensitization process. However, the factors that regulate NK cell desensitization remain largely uncharacterized. Here, we present the first report that circular RNA circARAP2 (hsa_circ_0069396) is involved in the soluble MICA (sMICA)-induced NKG2D endocytosis in the NK cell desensitization model. CircARAP2 was upregulated during NK cell desensitization and the loss of circARAP2 alleviated NKG2D endocytosis and NK cell desensitization. Using Chromatin isolation by RNA purification (ChIRP) and RNA pull-down approaches, we identified that RAB5A, a molecular marker of early endosomes, was its downstream target. Notably, transcription factor CTCF was an intermediate functional partner of circARAP2. Mechanistically, we discovered that circARAP2 interacted with CTCF and inhibited the recruitment of CTCF-Polycomb Repressive Complex 2 (PRC2) to the promoter region of RAB5A, thereby erasing histone H3K27 and H3K9 methylation suppression to enhance RAB5A transcription. These data demonstrate that inhibition of circARAP2 effectively alleviates sMICA-induced NKG2D endocytosis and NK cell desensitization, providing a novel target for therapeutic intervention in tumor immune evasion.

MICB Genomic Variant Is Associated with NKG2D-mediated Acute Lung Injury and Death.

Rationale: Acute lung injury (ALI) carries a high risk of mortality but has no established pharmacologic therapy. We previously found that experimental ALI occurs through natural killer (NK) cell NKG2D receptor activation and that the cognate human ligand, MICB, was associated with ALI after transplantation. Objectives: To investigate the association of a common missense variant, MICBG406A, with ALI. Methods: We assessed MICBG406A genotypes within two multicenter observational study cohorts at risk for ALI: primary graft dysfunction (N = 619) and acute respiratory distress syndrome (N = 1,376). Variant protein functional effects were determined in cultured and ex vivo human samples. Measurements and Main Results: Recipients of MICBG406A-homozygous allografts had an 11.1% absolute risk reduction (95% confidence interval [CI], 3.2-19.4%) for severe primary graft dysfunction after lung transplantation and reduced risk for allograft failure (hazard ratio, 0.36; 95% CI, 0.13-0.98). In participants with sepsis, we observed 39% reduced odds of moderately or severely impaired oxygenation among MICBG406A-homozygous individuals (95% CI, 0.43-0.86). BAL NK cells were less frequent and less mature in participants with MICBG406A. Expression of missense variant protein MICBD136N in cultured cells resulted in reduced surface MICB and reduced NKG2D ligation relative to wild-type MICB. Coculture of variant MICBD136N cells with NK cells resulted in less NKG2D activation and less susceptibility to NK cell killing relative to the wild-type cells. Conclusions: These data support a role for MICB signaling through the NKG2D receptor in mediating ALI, suggesting a novel therapeutic approach.

Absence of ATM leads to altered NK cell function in mice.

Ataxia-telangiectasia (A-T) is a rare disorder caused by genetic defects of A-T mutated (ATM) kinase, a key regulator of stress response, and characterized by neurodegeneration, immunodeficiency, and high incidence of cancer. Here we investigated NK cells in a mouse model of A-T (Atm-/-) showing that they are strongly impaired at killing tumor cells due to a block of early signaling events. On the other hand, in Atm-/- littermates with thymic lymphoma NK cell cytotoxicity is enhanced as compared with ATM-proficient mice, possibly via tumor-produced TNF-α. Results also suggest that expansion of exhausted NKG2D+ NK cells in Atm-/- mice is driven by low-level expression of stress-inducible NKG2D ligands, whereas development of thymoma expressing the high-affinity MULT1 ligand is associated with NKG2D down-regulation on NK cells. These results expand our understanding of immunodeficiency in A-T and encourage exploring NK cell biology in A-T patients in the attempt to identify cancer predictive biomarkers and novel therapeutic targets.

A novel MICA/B-targeted chimeric antigen receptor augments the cytotoxicity of NK cells against tumor cells.

Chimeric antigen receptor (CAR)-modified immune cells have emerged as a promising approach for cancer treatment, but single-target CAR therapy in solid tumors is limited by immune escape caused by tumor antigen heterogeneity and shedding. Natural killer group 2D (NKG2D) is an activating receptor expressed in human NK cells, and its ligands, such as MICA and MICB (MICA/B), are widely expressed in malignant cells and typically absent from healthy tissue. NKG2D plays an important role in anti-tumor immunity, recognizing tumor cells and initiating an anti-tumor response. Therefore, NKG2D-based CAR is a promising CAR candidate. Nevertheless, the shedding of MICA/B hinders the therapeutic efficacy of NKG2D-CARs. Here, we designed a novel CAR by engineering an anti-MICA/B shedding antibody 1D5 into the CAR construct. The engineered NK cells exhibited significantly enhanced cytotoxicity against various MICA/B-expressing tumor cells and were not inhibited by NKG2D antibody or NKG2D-Fc fusion protein, indicating no interference with NKG2D-MICA/B binding. Therefore, the developed 1D5-CAR could be combined with NKG2D-CAR to further improve the obstacles caused by MICA/B shedding.

Oncolytic adenovirus coding for shedding-resistant MICA enhances immune responses against tumors.

Cancer immunotherapies strive to overcome tumor-induced immune suppression and activate antitumor immune responses. Although cytotoxic T lymphocytes (CTLs) play a pivotal role in this process, natural killer (NK) cells have also demonstrated remarkable tumor-killing abilities, given their ability to discriminate tumor cells from normal cells and mediate specific antitumoral cytotoxicity. NK cells activation depends on a balance between activation and inhibition signals from several ligands/receptors. Among them, MICA/NKG2D axis is a master regulator of NK activation. MHC class I chain-related polypeptide A (MICA) expression is upregulated by many tumor cell lines and primary tumors and serves as a ligand for the activating NK group 2D (NKG2D) receptor on NK cells and subpopulations of T cells. However, cancer cells can cleave MICA, making it soluble and de-targeting tumor cells from NK cells, leading to tumor immune escape.In this study, we present ICOVIR15KK-MICAMut, an oncolytic adenovirus (OAdv) armed with a transgene encoding a non-cleavable MICA to promote NK-mediated cell-killing capacity and activate the immune response against cancer cells. We first demonstrated the correct MICA overexpression from infected cells. Moreover, our MICA-expressing OAdv promotes higher NK activation and killing capacity than the non-armed virus in vitro. In addition, the armed virus also demonstrated significant antitumor activity in immunodeficient mice in the presence of human PBMCs, indicating the activation of human NK cells. Finally, OAdv-MICA overexpression in immunocompetent tumor-bearing mice elicits tumor-specific immune response resulting in a greater tumor growth control.In summary, this study highlights the significance of NK cells in cancer immunotherapy and presents an innovative approach using a modified oncolytic virus to enhance NK cell activation and antitumor immune response. These findings suggest promising potential for future research and clinical applications.

Impact of donor NKG2D and MICA gene polymorphism on clinical outcomes of adult and paediatric allogeneic cord blood transplantation for malignant diseases.

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.

Association of MICA and NKG2D genetic variants with disease susceptibility and outcome of anti-TNF therapy in patients with axial spondyloarthritis.

OBJECTIVES: The disruption of the NKG2D-MICA axis can induce an enhanced immune response and promote autoimmune processes during axial spondyloarthritis (axSpA) pathogenesis. We aimed to investigate potential relationships between selected single nucleotide polymorphisms within the MICA and NKG2D genes and disease susceptibility and clinical parameters in axSpA patients treated with TNF inhibitors. METHODS: Genotyping of MICA rs1051792 and NKG2D rs1154831, rs1049174, and rs2255336 was performed in 163 axSpA patients and 234 healthy controls using a real-time PCR method. RESULTS: MICA rs1051792 A allele was more common in patients than in controls (p<0.0001). Patients with the AA genotype showed greater disease activity score (BASDAI) after three (p=4×10-4) and six (p=0.032) months of treatment compared to G carriers. After three months of therapy with anti-TNFs, the MICA AA homozygosity occurred more often in non-responsive or moderately responsive patients than good responders with the same genotype (p=1×10-4). Additionally, patients bearing the NKG2D rs1154831 CC genotype demonstrated lower BASDAI scores (p=0.035) and were significantly more common among subjects with a good outcome (p=0.004) after six months of treatment. CONCLUSIONS: These results suggest that MICA and NKG2D gene polymorphisms may be biomarkers associated with disease susceptibility and clinical outcomes after anti-TNF therapy in axSpA patients and imply a rather less favourable effect of the MICA A and NKG2D G genetic variants.

Functional MICA Variants Are Differentially Associated with Immune-Mediated Inflammatory Diseases.

As the principal ligand for NKG2D, MICA elicits the recruitment of subsets of T cells and NK cells in innate immunity. MICA gene variants greatly impact the functionality and expression of MICA in humans. The current study evaluated whether MICA polymorphisms distinctively influence the pathogenesis of psoriasis (PSO), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE) in Taiwanese subjects. The distributions of MICA alleles and levels of serum soluble NKG2D were compared between healthy controls and patients with PSO, RA, and SLE, respectively. The binding capacities and cell surface densities of MICA alleles were assessed by utilizing stable cell lines expressing four prominent Taiwanese MICA alleles. Our data revealed that MICA*010 was significantly associated with risks for PSO and RA (PFDR = 1.93 × 10-15 and 0.00112, respectively), while MICA*045 was significantly associated with predisposition to SLE (PFDR = 0.0002). On the other hand, MICA*002 was associated with protection against RA development (PFDR = 4.16 × 10-6), while MICA*009 was associated with a low risk for PSO (PFDR = 0.0058). MICA*002 exhibited the highest binding affinity for NKG2D compared to the other MICA alleles. Serum concentrations of soluble MICA were significantly elevated in SLE patients compared to healthy controls (p = 0.01). The lack of cell surface expression of the MICA*010 was caused by its entrapment in the endoplasmic reticulum. As a prevalent risk factor for PSO and RA, MICA*010 is deficient in cell surface expression and is unable to interact with NKG2D. Our study suggests that MICA alleles distinctively contribute to the pathogenesis of PSO, RA, and SLE in Taiwanese people.

Combination therapy of DKK1 inhibition and NKG2D chimeric antigen receptor T cells for the treatment of gastric cancer.

Despite the successful application of chimeric antigen receptor (CAR)-T cell therapy in hematological malignancies, the treatment efficacy in solid tumors remains unsatisfactory, largely due to the highly immunosuppressive tumor microenvironment and low density of specific tumor antigens. Natural killer group 2 member D (NKG2D) CAR-T cells have shown promising treatment effects on several cancers such as lymphoma and multiple myeloma. However, the application and efficacy of NKG2D-CAR-T cells in gastric cancer (GC) still needs further exploration. This study identified a novel combination immunotherapy strategy with Dickkopf-1 (DKK1) inhibition and NKG2D-CAR-T cells, exerting synergistic and superior antitumor effect in GC. We show that the baseline expression of NKG2D ligands (NKG2DLs) is at low levels in GC tissues from The Cancer Genome Atlas and multiple GC cell lines including NCI-N87, MGC803, HGC27, MKN45, SGC7901, NUGC4, and AGS. In addition, DKK1 inhibition by WAY-262611 reverses the suppressive tumor immune microenvironment (TIME) and upregulates NKG2DL expression levels in both GC cell lines and GC tissues from a xenograft NCG mouse model. DKK1 inhibition in GC cells markedly improves the immune-activating and tumor-killing ability of NKG2D-CAR-T cells as shown by cytotoxicity assays in vitro. Moreover, the combination therapy of NKG2D-CAR-T and WAY-262611 triggers superior antitumor effects in vivo in a xenograft NCG mouse model. In sum, our study reveals the role of DKK1 in remodeling GC TIME and regulating the expression levels of NKG2DLs in GC. We also provide a promising treatment strategy of combining DKK1 inhibition with NKG2D-CAR-T cell therapy, which could bring new breakthroughs for GC immunotherapy.

NKG2D receptor regulates CD4+T cell differentiation via interaction with dendritic cells in patients with juvenile idiopathic arthritis.

NKG2D provides a costimulatory signal for activation of CD4+ T cells. We explored its role in interactions of CD4+ T cells and dendritic cells (DCs) in juvenile idiopathic arthritis (JIA) patients by using NKG2D genetically modified CD4+ T cells. We found active JIA patients had significantly higher content of CD4 + NKG2D+ T cells than healthy controls. Expression of NKG2D on CD4+ T cells, and MICA and MICB on DCs were significantly greater in articular JIA than systemic JIA. NKG2D induced IL- 12 and suppressed IL-10 and TGF-ß from CD4+ T cells, increased IFN-γ + CD4+ T and IL-17+ CD4+ T cells, RORc and T-bet, but reduced CD25+ Foxp3+ CD4+ T cells, IL-4+ CD4+ T cells, Foxp3, and GATA3 in JIA patients. NKG2D decreased IL-10 and increased CD83, MICA, and MICB of DCs in JIA and controls. So NKG2D regulates differentiation of CD4+ T cells directly and the maturation of DCs indirectly.

The murine cytomegalovirus immunoevasin gp40/m152 inhibits NKG2D receptor RAE-1γ by intracellular retention and cell surface masking.

NKG2D (also known as KLRK1) is a crucial natural killer (NK) cell-activating receptor, and the murine cytomegalovirus (MCMV) employs multiple immunoevasins to avoid NKG2D-mediated activation. One of the MCMV immunoevasins, gp40 (m152), downregulates the cell surface NKG2D ligand RAE-1γ (also known as Raet1c) thus limiting NK cell activation. This study establishes the molecular mechanism by which gp40 retains RAE-1γ in the secretory pathway. Using flow cytometry and pulse-chase analysis, we demonstrate that gp40 retains RAE-1γ in the early secretory pathway, and that this effect depends on the binding of gp40 to a host protein, TMED10, a member of the p24 protein family. We also show that the TMED10-based retention mechanism can be saturated, and that gp40 has a backup mechanism as it masks RAE-1γ on the cell surface, blocking the interaction with the NKG2D receptor and thus NK cell activation.

Dual CAR-T cells to treat cancers co-expressing NKG2D and PD1 ligands in xenograft models of peritoneal metastasis.

While the expression of either NKG2D ligands or PD-1 ligands has been reported in various types of cancers, the co-expression of the two sets of ligands in the same tumour tissues is still un-investigated. After examining 68 primary ovarian cancer samples, we observed around 80% of the co-expression in low grade serous and endometrioid ovarian cancer samples. We then constructed a dual CAR system that splits the conventional single-input of a 2nd generation CAR into two independent chimeric receptors, one composed of the NKG2D extracellular domain linked with DAP12 for T cell activation and another using the PD-1 extracellular domain linked with 4-1BB for costimulatory signal 2 input. Given the limitation of the low-affinity PD-1 receptor in recognizing cancer cells with low levels of PD-1 ligands, we also used a high-affinity scFv specific to PD-L1 in our combinatorial approach to expand the range of target cancer cells with different expression levels of PD-L1. The two types of dual CAR-T cells were generated through electroporation of non-viral piggyBac transposon plasmids and were effective in eliminating the target cancer cells. Especially, the dual CAR-T cells with anti-PD-L1 scFv were capable of eradicating established tumors in mouse models of peritoneal metastasis of colorectal cancer and ovarian cancer. Since both NKG2D ligands and PD-1 ligands have been marked as favourable cancer therapeutic targets, the new dual CAR-T cells developed in this study hold attractive application potential in treating metastatic peritoneal carcinoma.

IL-21 collaborates with anti-TIGIT to restore NK cell function in chronic HBV infection.

Available therapies for chronic hepatitis B virus (HBV) infection are not satisfying, and interleukin-21 (IL-21) and checkpoint inhibitors are potential therapeutic options. However, the mechanism underlying IL-21 and checkpoint inhibitors in treating chronic HBV infection is unclear. To explore whether IL-21 and checkpoint inhibitors promote HBV clearance by modulating the function of natural killer (NK) cells, we measured the phenotypes and functions of NK cells in chronic HBV-infected patients and healthy controls on mRNA and protein levels. We found that chronic HBV infection disturbed the transcriptome of NK cells, including decreased expression of KLRK1, TIGIT, GZMA, PRF1, and increased expression of CD69. We also observed altered phenotypes and functions of NK cells in chronic HBV-infected patients, characterized by decreased NKG2D expression, increased TIGIT expression and impaired interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α) production. Furthermore, these alterations cannot be restored by telbivudine treatment but can be partially restored by IL-21 and anti-TIGIT stimulation. IL-21 upregulated the expression of activating receptor CD16, CD69, and NKG2D on NK cells, enhanced IFN-γ production, cytolysis, and proliferation of NK cells, while anti-TIGIT promoted IFN-γ production in CD56dim subset exclusively in chronic HBV infected patients. Additionally, IL-21 was indispensable for anti-TIGIT in HBsAg clearance in mice bearing HBV. It enhanced IFN-γ production in splenic NK cells rather than intrahepatic NK cells, indicating a brand-new mechanism of IL-21 in HBV clearance when combined with anti-TIGIT. Overall, our findings contribute to the design of immunotherapy through enhancing the antiviral efficacy of NK cells in chronic HBV infection.

KLF4-mediated upregulation of the NKG2D ligand MICA in acute myeloid leukemia: a novel therapeutic target identified by enChIP.

The immunoreceptor NKG2D, which is expressed on NK cells and T cell subsets is critically involved in tumor immune surveillance. This applies in particular to acute myeloid leukemia (AML), which evades immune detection by downregulation of NKG2D ligands (NKG2D-L), including MICA. The absence of NKG2D-L on AML cells is moreover associated with leukemia stem cell characteristics. The NKG2D/NKG2D-L system thus qualifies as an interesting and promising therapeutic target.Here we aimed to identify transcription factors susceptible to pharmacological stimulation resulting in the expression of the NKG2D-L MICA in AML cells to restore anti-tumor activity. Using a CRISPR-based engineered ChIP (enChIP) assay for the MICA promoter region and readout by mass spectrometry-based proteomics, we identified the transcription factor krüppel-like factor 4 (KLF4) as associated with the promoter. We demonstrated that the MICA promoter comprises functional binding sites for KLF4 and genetic as well as pharmacological gain- and loss-of-function experiments revealed inducible MICA expression to be mediated by KLF4.Furthermore, induction in AML cells was achieved with the small compound APTO253, a KLF4 activator, which also inhibits MYC expression and causes DNA damage. This induction in turn yielded increased expression and cell surface presentation of MICA, thus rendering AML cells more susceptible to NK cell-mediated killing. These data unravel a novel link between APTO253 and the innate anti-tumor immune response providing a rationale for targeting AML cells via APTO253-dependent KFL4/MICA induction to allow elimination by endogenous or transplanted NK and T cells in vivo. Video Abstract.

Association of inhibitory NKG2A and activating NKG2D natural killer cell receptor genes with resistance to SARS-CoV-2 infection in a western Indian population.

We have evaluated the association of polymorphisms in the intronic variable-number tandem repeat (VNTR) regions of the human NKG2D, NKG2A, and IL-1RN genes with resistance and/or susceptibility to SARS-CoV-2 infection in a total of 209 patients with SARS-CoV-2 infection (125 asymptomatic patients and 84 symptomatic patients with mild symptoms) and 355 healthy controls, using the PCR-RFLP method. The genotypic and allelic frequency distributions for an IL-1RN (VNTR) single-nucleotide polymorphism (SNP) were found to be comparable among the patient groups. Overall, in SARS-CoV-2 patients, NKG2A (rs2734440) showed a protective association in the codominant [(A/A vs. A/G): (OR = 0.53, 95% CI = 0.34-0.83, p = 0.006)], recessive [(A/A vs. A/G+G/G): (OR = 0.6, 95% CI = 0.39-0.92, p = 0.02)] and over-dominant [(A/A+G/G vs. A/G): (OR = 0.57, 95% CI = 0.38-0.84, p = 0.005)] models. Similarly, NKG2D (rs7980470) showed a protective association in the codominant [(A/A vs. A/G): (OR = 0.46, 95% CI = 0.3-0.7, p = 0.0003), codominant (A/A vs. G/G): (OR = 0.54, 95% CI = 0.31-0.71, p = 0.027)], recessive [(A/A vs. A/G+G/G): (OR = 0.47, 95% CI = 0.32-0.7, p = 0.0001) and over-dominant [(A/A+G/G vs. A/G): (OR = 0.56, 95% CI = 0.38-0.82, p = 0.003)] models. At the allelic level, there was a higher frequency of the "G" allele of NKG2D (rs7980470) in healthy controls than in patients with SARS-CoV-2 infection, suggesting that individuals with the "G" allele in the intronic region of NKG2D are likely to be protected against SARS-CoV-2 infection. Overall, our data suggest that polymorphisms in the host NKG2D and NKG2A genes have a protective role in SARS-CoV-2 infection, although the functional impact of these polymorphisms on control of SARS-CoV-2 infection remains unknown.

Retargeting IL-2 Signaling to NKG2D-Expressing Tumor-Infiltrating Leukocytes Improves Adoptive Transfer Immunotherapy.

Ex vivo expansion followed by reinfusion of tumor-infiltrating leukocytes (TILs) has been used successfully for the treatment of multiple malignancies. Most protocols rely on the use of the cytokine IL-2 to expand TILs prior to reinfusion. In addition, TIL administration relies on systemic administration of IL-2 after reinfusion to support transferred cell survival. The use of IL-2, however, can be problematic because of its preferential expansion of regulatory T and myeloid cells as well as its systemic side effects. In this study, we describe the use of a novel IL-2 mutant retargeted to NKG2D rather than the high-affinity IL-2R for TIL-mediated immunotherapy in a murine model of malignant melanoma. We demonstrate that the NKG2D-retargeted IL-2 (called OMCPmutIL-2) preferentially expands TIL-resident CTLs, such as CD8+ T cells, NK cells, and γδT cells, whereas wild-type IL-2 provides a growth advantage for CD4+Foxp3+ T cells as well as myeloid cells. OMCPmutIL-2-expanded CTLs express higher levels of tumor-homing receptors, such as LFA-1, CD49a, and CXCR3, which correlate with TIL localization to the tumor bed after i.v. injection. Consistent with this, OMCPmutIL-2-expanded TILs provided superior tumor control compared with those expanded in wild-type IL-2. Our data demonstrate that adoptive transfer immunotherapy can be improved by rational retargeting of cytokine signaling to NKG2D-expressing CTLs rather than indiscriminate expansion of all TILs.

p53 missense mutant G242A subverts natural killer cells in sheltering mouse breast cancer cells against immune rejection.

Cancer cells acquire immunoediting ability to evade immune surveillance and thus escape eradication. It is widely known that mutant proteins encoded from tumor suppressor TP53 exhibit gain-of-function in cancer cells, thereby promoting progression; however, how mutant p53 contributes to the sheltering of cancer cells from host anticancer immunity remains unclear. Herein, we report that murine p53 missense mutation G242A (corresponding to human G245A) suppresses the activation of host natural killer (NK) cells, thereby enabling breast cancer cells to avoid immune assault. We found that serial injection of EMT6 breast cancer cells that carry wild-type (wt) Trp53, like normal fibroblasts, promoted NK activity in mice, while SVTneg2 cells carrying Trp53 G242A+/+ mutation decreased NK cell numbers and increased CD8+ T lymphocyte numbers in spleen. Innate immunity based on NK cells and CD8 T cells was reduced in p53 mutant-carrying transgenic mice (Trp53 R172H/+, corresponding to human R175H/+). Further, upon co-culture with isolated NK cells, EMT6 cells substantively activated NK cells and proliferation thereof, increasing interferon-gamma (IFN-γ) production; however, SVTneg2 cells suppressed NK cell activation. Further mechanistic study elucidated that p53 can modulate expression by cancer cells of Mult-1 and H60a, which are activating and inhibitory ligands for NKG2D receptors of NK cells, respectively, to enhance immune surveillance against cancer. Our findings demonstrate that wt p53 is requisite for NK cell-based immune recognition and elimination of cancerous cells, and perhaps more importantly, that p53 missense mutant presence in cancer cells impairs NK cell-attributable responses, thus veiling cancerous cells from host immunity and enabling cancer progression.