Regulation of NK-Cell Function by HLA Class II

Development of Innate-Immune-Cell-Based Immunotherapy for Adult T-Cell Leukemia-Lymphoma

γδ T cells and natural killer (NK) cells have attracted much attention as promising effector cell subsets for adoptive transfer for use in the treatment of malignant and infectious diseases, because they exhibit potent cytotoxic activity against a variety of malignant tumors, as well as virus-infected cells, in a major histocompatibility complex (MHC)-unrestricted manner. In addition, γδ T cells and NK cells express a high level of CD16, a receptor required for antibody-dependent cellular cytotoxicity. Adult T-cell leukemia-lymphoma (ATL) is caused by human T-lymphotropic virus type I (HTLV-1) and is characterized by the proliferation of malignant peripheral CD4+ T cells. Although several treatments, such as chemotherapy, monoclonal antibodies, and allogeneic hematopoietic stem cell transplantation, are currently available, their efficacy is limited. In order to develop alternative therapeutic modalities, we considered the possibility of infusion therapy harnessing γδ T cells and NK cells expanded using a novel nitrogen-containing bisphosphonate prodrug (PTA) and interleukin (IL)-2/IL-18, and we examined the efficacy of the cell-based therapy for ATL in vitro. Peripheral blood samples were collected from 55 patients with ATL and peripheral blood mononuclear cells (PBMCs) were stimulated with PTA and IL-2/IL-18 for 11 days to expand γδ T cells and NK cells. To expand NK cells alone, CD3+ T-cell-depleted PBMCs were cultured with IL-2/IL-18 for 10 days. Subsequently, the expanded cells were examined for cytotoxicity against ATL cell lines in vitro. The proportion of γδ T cells in PBMCs was markedly low in elderly ATL patients. The median expansion rate of the γδ T cells was 1998-fold, and it was 12-fold for the NK cells, indicating that γδ T cells derived from ATL patients were efficiently expanded ex vivo, irrespective of aging and HTLV-1 infection status. Anti-CCR4 antibodies enhanced the cytotoxic activity of the γδ T cells and NK cells against HTLV-1-infected CCR4-expressing CD4+ T cells in an antibody concentration-dependent manner. Taken together, the adoptive transfer of γδ T cells and NK cells expanded with PTA/IL-2/IL-18 is a promising alternative therapy for ATL.

Human Leukocyte Antigen Alleles Compatibility and Immunophenotypic Profile Associations in Infertile Couples

Introduction: The maternal immune system has a major role in the successful embryo implantation and maintenance of the pregnancy. This study aimed to investigate the maternal immunophenotyping profile (percentage of Natural Killer [NK] cells and the CD4/CD8 [cluster designation] ratio in peripheral blood lymphocytes) and the HLA (Human Leukocyte Antigen)-DQA1 alleles sharing in infertile couples.

Methods: This cross-sectional study included 78 women who had experienced at least two spontaneous miscarriages and 110 women with a history of recurrent implantation failures after in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) and embryo transfer (ET) (IVF-ET failures). The NK cell percentage and the CD4/CD8 ratio were determined by flow cytometry. Genotyping of the HLA-DQA1 alleles was carried out for all women and their partners, and couple HLA-DQA1 compatibility was expressed as the percentage of common HLA-DQA1 alleles (totaling 35 alleles) shared between spouses to the sum of the unique alleles observed.

Results: In women with recurrent miscarriages, high values (%) of the NK population with a median (interquartile range [IQR]) of 10.3% (7.7% to 12.5%) and CD4/CD8 ratio (1.7) (1.5 to 2.1) were found. In women with IVF-ET failures, the (%) NK population (10.5%) (8.6% to 12.5%) and CD4/CD8 ratio (1.8) (1.5 to 2.1) were similarly increased (p=0.390, and p=0.490, respectively). The proportion of women with >10% NK cells was 53.8% and 58.2% in women with miscarriages and IVF-ET failures, respectively (p=0.554). The prevalence of HLA-DQA1*5 allele carriage was elevated in women with miscarriages as well as those with IVF-ET failures (52.6% and 61.8%, respectively; p=0.206). The proportion of couples with high (>50%) HLA-DQA1 sharing was 65.4% in the group with miscarriages and 73.6% in the group with IVF-ET failures, respectively (p=0.222). The CD4/CD8 ratio was statistically significantly positively correlated with the (%) NK population in women with IVF-ET failures (rho = 0.297, p=0.002) and with the (%) HLA-DQA1 sharing in the group with miscarriages (rho = 0.266, p=0.019). The couples in which both spouses were carriers of the HLA-DQA1*5 allele had an increased probability of high (>50%) HLA-DQA1 compatibility compared with the couples in which neither of the spouses carried the allele in the miscarriage group (OR = 24.3, 95% CI: 3.0 to 198.9, p<0.001), and the IVF-ET failure group (OR = 10.5, 95% CI: 2.2 to 49.8, p<0.001).

Conclusion: The peripheral NK (%) population and CD4/CD8 ratio, as well as the prevalence of the HLA-DQA1*5 allele, were elevated in women with recurrent miscarriages and IVF-ET failures. Furthermore, these couples with negative reproductive outcomes had a high percentage of HLA-DQA1 allele similarity. The presence of the HLA-DQA1*5 allele in spouses was strongly associated with overall couple HLA-DQA1 compatibility, implying that it could be used as a surrogate marker for assessing overall immunological compatibility in infertile couples.

Current state of NK cell-mediated immunotherapy in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) has become one of the most common hematological diseases in western countries, with an annual incidence of 42/100,000. Conventional chemotherapy and targeted therapeutic drugs showed limitations in prognosis or in efficiency in high-risk patients. Immunotherapy represented is one of the most effective therapeutic approaches with the potential of better effect and prognosis. Natural killer (NK) cells are good options for immunotherapy as they can effectively mediate anti-tumor activity of immune system by expressing activating and inhibiting receptors and recognizing specific ligands on various tumor cells. NK cells are critical in the immunotherapy of CLL by enhancing self-mediated antibody-dependent cytotoxicity (ADCC), allogeneic NK cell therapy and chimeric antigen receptor-natural killer (CAR-NK) cell therapy. In this article, we reviewed the features, working mechanisms, and receptors of NK cells, and the available evidence of the advantages and disadvantages of NK cell-based immunotherapies, and put forward future study directions in this field.

HLA-SPREAD: a natural language processing based resource for curating HLA association from PubMed abstracts

Extreme complexity in the Human Leukocyte Antigens (HLA) system and its nomenclature makes it difficult to interpret and integrate relevant information for HLA associations with diseases, Adverse Drug Reactions (ADR) and Transplantation. PubMed search displays ~ 146,000 studies on HLA reported from diverse locations. Currently, IPD-IMGT/HLA (Robinson et al., Nucleic Acids Research 48:D948-D955, 2019) database houses data on 28,320 HLA alleles. We developed an automated pipeline with a unified graphical user interface HLA-SPREAD that provides a structured information on SNPs, Populations, REsources, ADRs and Diseases information. Information on HLA was extracted from ~ 28 million PubMed abstracts extracted using Natural Language Processing (NLP). Python scripts were used to mine and curate information on diseases, filter false positives and categorize to 24 tree hierarchical groups and named Entity Recognition (NER) algorithms followed by semantic analysis to infer HLA association(s). This resource from 109 countries and 40 ethnic groups provides interesting insights on: markers associated with allelic/haplotypic association in autoimmune, cancer, viral and skin diseases, transplantation outcome and ADRs for hypersensitivity. Summary information on clinically relevant biomarkers related to HLA disease associations with mapped susceptible/risk alleles are readily retrievable from HLASPREAD. The resource is available at URL http://hla-spread.igib.res.in/ . This resource is first of its kind that can help uncover novel patterns in HLA gene-disease associations.

Expanded natural killer cells augment the antimyeloma effect of daratumumab, bortezomib, and dexamethasone in a mouse model

The use of natural killer (NK) cells is a promising and safe immunotherapeutic approach in the field of cancer immunotherapy. However, combination treatments are required to enhance the effector functions and therapeutic efficacy of NK cells. In this study, we investigated the potential of daratumumab (Dara), bortezomib, and dexamethasone (Dvd) to augment the antitumor effects of NK cells in a multiple myeloma (MM) xenograft mouse model. NK cells were expanded and activated using the K562-OX40 ligand and membrane-bound IL-18 and IL-21 in the presence of IL-2 and IL-15 from peripheral blood mononuclear cells from MM patients. A human MM xenograft model was established using human RPMI8226-RFP-FLuc cells in NOD/SCID IL-2Rγ^null (NSG) mice. Tumor-bearing mice were divided into six treatment groups: no treatment, expanded NK cells (eNKs), Dara, Dara + eNKs, Dvd, and Dvd + eNKs. Dvd treatment strongly enhanced the cytotoxicity of eNKs by upregulating expression of NK cell activation ligands, downregulating expression of NK cell inhibitory ligands, and promoting antibody-dependent cellular cytotoxicity. The combination of eNKs with Dvd significantly prolonged mouse survival and reduced the tumor burden and serum M-protein level. Furthermore, Dvd pretreatment significantly increased eNK persistence and homing to MM sites. Our findings suggest that Dvd treatment potentiates the antimyeloma effects of NK cells expanded and activated ex vivo by modulating immune responses in MM-bearing mice.

Inhibitory axes impacting on the activity and fate of Innate Lymphoid Cells

In neoplastic patients, an effective immune response ideally should be achieved by the coordinated action of different immune cells with tumor-suppressive functions. These include the more cytolytic members of the Innate Lymphoid Cells (ILCs) family represented by the Natural Killer (NK) cells, whose activities in cancer patients, however, can be hampered by several inhibitory signals. These are generated by membrane-bound and soluble molecules that, interacting with specific inhibitory receptors, create inhibitory axes impacting the NK cell differentiation and effector functions. These breaks, which now represent major immunotherapeutic targets, may be sensitive to interferon (IFN)-γ, whose source, in vivo, is represented by different cell types including the NK and ILC1. Since also ILCs can express receptors of the inhibitory axes like PD-1 and TIGIT, their therapeutic blockade might further amplify the IFN-γ release that, as an unwanted side effect, would promote the onset of NK cell-resistant tumor variants (NKRTV) expressing ligands involved in inhibitory axes. These variants might also arise from the activity of other cytokines such as IL-27, which can increase the expression of HLA class I and PD-Ls in different cell types, including tumor cells. Besides the amplification of membrane-bound inhibitory axes, tumors can reduce the number of infiltrating cytolytic ILCs, promote the recruitment of poorly cytolytic NK cell subsets, and manipulate to their advantage the infiltrating immune cells, which acquire tumor-promoting activities. This occurs thanks to the production of soluble factors including TGF-β1 and IL-18 that, alone or in combination, modify the activating and chemokine receptor repertoire of NK cells, and induce the ILCs differentiation towards cells ineffective in fighting cancer or, even worse, with tumor-promoting functions. The present review aims to present and discuss major inhibitory axes impacting on ILCs functions, migration, and differentiation with a major focus on tumor context.

An Immunoinformatics Approach for SARS-CoV-2 in Latam Populations and Multi-Epitope Vaccine Candidate Directed towards the World's Population

The coronavirus pandemic is a major public health crisis affecting global health systems with dire socioeconomic consequences, especially in vulnerable regions such as Latin America (LATAM). There is an urgent need for a vaccine to help control contagion, reduce mortality and alleviate social costs. In this study, we propose a rational multi-epitope candidate vaccine against SARS-CoV-2. Using bioinformatics, we constructed a library of potential vaccine peptides, based on the affinity of the most common major human histocompatibility complex (HLA) I and II molecules in the LATAM population to predict immunological complexes among antigenic, non-toxic and non-allergenic peptides extracted from the conserved regions of 92 proteomes. Although HLA-C, had the greatest antigenic peptide capacity from SARS-CoV-2, HLA-B and HLA-A, could be more relevant based on COVID-19 risk of infection in LATAM countries. We also used three-dimensional structures of SARS-CoV-2 proteins to identify potential regions for antibody production. The best HLA-I and II predictions (with increased coverage in common alleles and regions evoking B lymphocyte responses) were grouped into an optimized final multi-epitope construct containing the adjuvants Beta defensin-3, TpD, and PADRE, which are recognized for invoking a safe and specific immune response. Finally, we used Molecular Dynamics to identify the multi-epitope construct which may be a stable target for TLR-4/MD-2. This would prove to be safe and provide the physicochemical requirements for conducting experimental tests around the world.

Variation and expression of HLA-DPB1 gene in HBV infection

Hepatitis B virus (HBV) affects approximately 68 million people in China, and 10-15% of adults infected with HBV develop chronic hepatitis B, liver cirrhosis, liver failure or hepatocellular carcinoma (HCC). HLA-DPB1 gene polymorphism and expression have been shown to be associated with HBV infection susceptibility and spontaneous clearance. The aim of this study is to evaluate the role of HLA-DPB1 gene polymorphism in HBV infection. HLA-DPB1 and rs9277535 polymorphisms were investigated in 259 patients with HBV infection and 442 healthy controls (HCs) using sequence-based typing. The mRNA of HLA-DPB1 was measured by real-time polymerase chain reaction. HLA-DPB1 genes and rs9277535 polymorphisms were all associated with HBV infection in the Sichuan Han population. rs9277535A and HLA-DPB1*04:02 played a protective role against HBV infection. rs9277535G and DPB1*05:01 were associated with susceptibility to HBV infection. rs9277535GG had significantly higher HLA-DPB1 mRNA expression in the HBV infection group compared with the HC group. HLA-DPB1*05:01 and HLA-DPB1*21:01 had significantly lower mRNA expression in the HBV infection group compared with the HC group. The meta-analysis revealed that HLA-DPB1*02:01, HLA-DPB1*02:02, HAL-DPB1*04:01 and HLA-DPB1*04:02 protected against HBV infection, while HLA-DPB1*05:01, HLA-DPB1*09:01, and HLA-DPB1*13:01 were risk factors for susceptibility to HBV infection. HLA-DPB1*02:01, HLA-DPB1*02:02, and HLA-DPB1*04:01 were associated with HBV spontaneous clearance, while HLA-DPB1*05:01 was associated with chronic HBV infection. HLA-DPB1 alleles and rs9277535 have a major effect on the risk of HBV infection, and HBV infection is associated with lower HLA-DPB1 expression. HLA-DPB1 alleles have an important role in HBV susceptibility and spontaneous clearance.

Spatial Analysis and Clinical Significance of HLA Class-I and Class-II Subunit Expression in Non-Small Cell Lung Cancer

PURPOSE

To analyze the distribution, associated immune contexture, and clinical significance of human leukocyte antigen (HLA) class-I and HLA class-II subunits in non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

Using spatially resolved and quantitative multiplexed immunofluorescence we studied the tumor/stromal tissue distribution, cancer cell-specific defects, and clinicopathologic/survival associations of β2 microglobulin (β2M), HLA-A, and HLA-B,-C heavy chains, as well as HLA class-II β chain in >700 immunotherapy-naïve NSCLCs from four independent cohorts. Genomic analysis of HLA genes in NSCLC was performed using two publicly available cohorts.

RESULTS

Cancer cell-specific downregulation of HLA markers was identified in 30.4% of cases. β2M was downregulated in 9.8% (70/714), HLA-A in 9% (65/722), HLA-B,-C in 12.1% (87/719), and HLA class-II in 17.7% (127/717) of evaluable samples. Concurrent downregulation of β2M, HLA-B,-C, and HLA class-II was commonly identified. Deleterious mutations in HLA genes were detected in <5% of lung malignancies. Tumors with cancer cell-specific β2M downregulation displayed reduced T cells and increased natural killer (NK)-cell infiltration. Samples with cancer cell HLA-A downregulation displayed modest increase in CD8⁺ T cells and NK-cell infiltration. Samples with cancer cell-selective HLA-B,-C or HLA class-II downregulation displayed reduced T cells and NK-cell infiltration. There was limited association of the markers with clinicopathologic variables and KRAS/EGFR mutations. Cancer cell-selective downregulation of the HLA subunits was associated with shorter overall survival.

CONCLUSIONS

Our results reveal frequent and differential defects in HLA class-I and HLA class-II protein subunit expression in immunotherapy-naïve NSCLCs associated with distinct tumor microenvironment composition and patient survival.

Roles for the FCRL6 Immunoreceptor in Tumor Immunology

Members of the Fc receptor-like (FCRL1-6) gene family encode transmembrane glycoproteins that are preferentially expressed by B cells and generally repress responses via cytoplasmic tyrosine-based regulation. Given their distribution and function, there is a growing appreciation for their roles in lymphoproliferative disorders and as immunotherapeutic targets. In contrast to FCRL1-5, FCRL6 is distinctly expressed outside the B lineage by cytotoxic T and NK lymphocytes. Its restricted expression by these orchestrators of cell-mediated immunity, along with its inhibitory properties and extracellular interactions with MHCII/HLA-DR, represent a newly appreciated axis with relevance in tolerance and cancer defense. The significance of FCRL6 in this arena has been recently demonstrated by its upregulation in HLA-DR⁺ tumor samples from melanoma, breast, and lung cancer patients who relapsed following PD-1 blockade. These findings imply a potential mechanistic role for FCRL6 in adaptive evasion to immune checkpoint therapy. Here we review these new developments in the FCRL field and identify new evidence for the prognostic significance of FCRL6 in malignancies that collectively indicate its potential as a biomarker and therapeutic target.

Harnessing NK Cell Checkpoint-Modulating Immunotherapies

During the host immune response, the precise balance of the immune system, regulated by immune checkpoint, is required to avoid infection and cancer. These immune checkpoints are the mainstream regulator of the immune response and are crucial for self-tolerance. During the last decade, various new immune checkpoint molecules have been studied, providing an attractive path to evaluate their potential role as targets for effective therapeutic interventions. Checkpoint inhibitors have mainly been explored in T cells until now, but natural killer (NK) cells are a newly emerging target for the determination of checkpoint molecules. Simultaneously, an increasing number of therapeutic dimensions have been explored, including modulatory and inhibitory checkpoint molecules, either causing dysfunction or promoting effector functions. Furthermore, the combination of the immune checkpoint with other NK cell-based therapeutic strategies could also strengthen its efficacy as an antitumor therapy. In this review, we have undertaken a comprehensive review of the literature to date regarding underlying mechanisms of modulatory and inhibitory checkpoint molecules.