NK-Cell Exhaustion, B-Cell Exhaustion and T-Cell Exhaustion - the Differences and Similarities

Alterations in exhausted and classical memory B cells in lupus nephritis - Relationship with disease relapse

INTRODUCTION

B cell exhaustion is a functional abnormality of B lymphocytes observed in chronic infections and shows association with autoreactivity. The role of exhausted and classical memory B cells in maintaining disease stability of lupus nephritis (LN) remains unclear.

METHODS

We measured classical memory (CD19+CD21+CD27+), exhausted B cells (CD19+CD21-CD27-), and related cytokines in LN patients with multiple relapses (MR) (n = 15) and no relapse (NR) (n = 15) during disease remission. The expression of inhibitory/adhesion molecules, cell proliferation and calcium mobilization in classical memory and exhausted B cells were also assessed.

RESULTS

The MR group had higher proportion of circulating exhausted and classical memory B cells compared to the NR group and healthy controls (HC) (p all <0.05 for MR vs. NR or HC). Blood levels of IL-6, BAFF, IL-21, CD62L, CXCR3 and Siglec-6 were all higher in the MR group (p < 0.05, for all). Exhausted B cells from the MR group showed higher FcRL4, CD22, CD85j and CD183 but lower CD62L expression than NR and HC groups. Exhausted B cells from MR patients exhibited reduced proliferation compared to NR patients and HC, while classical memory B cell proliferation in MR group was higher than the other two groups. Exhausted B cells from both MR and NR patients showed impaired calcium mobilization.

CONCLUSION

Alterations in exhausted and classical memory B cells are related to disease relapse in LN. These findings may help devise new strategies for monitoring disease activity and preventing relapse in LN.

Developing and experimental validating a B cell exhaustion-related gene signature to assess prognosis and immunotherapeutic response in bladder cancer

BACKGROUND

B cell exhaustion (BEX) refers to the impairment of normal B cell functions and decreased proliferation capability. However, the prognostic value of BEX-related genes in bladder cancer (BLCA) remains unclear.

METHODS

BLCA cases from TCGA were used for training, while GSE5287, GSE13507, GSE31684, and GSE32894 cohorts from GEO were used for external validation. BEX-related genes were identified through literature retrieval, unsupervised clustering, and genomic difference detection. Gene pairing, LASSO, random forest, and Cox regression were employed to construct a predictive model. B cell samples from scRNAseqDB, GSE111636, and IMvigor210 were utilized to explore immunoprofiles and the predictive ability of the model in immunotherapeutic response. Additionally, 21 pairs of BLCA and paracarcinoma samples from Nanfang Hospital were used to re-confirm our findings through RT-qPCR, immunofluorescence, and flow cytometry.

RESULTS

39 BEX-related genes were identified. A 4-gene-pair signature was constructed and served as a reliable prognostic predictor across multiple datasets (pooled HR = 2.32; 95 % CI = 1.81-2.98). The signature reflected the BEX statuses of B cells (FDR < 0.05) and showed promise in evaluating immunotherapeutic sensitivity (P < 0.001). In the local cohort, CD52, TUBB6, and CAV1 were down-regulated in BLCA tissues, while TGFBI, UBE2L6, TINAGL1, and IL32 were up-regulated (all P < 0.05). Furthermore, the infiltration levels of CD19 + CD52 + and CD19 + TUBB6 + B cells in paracarcinoma samples were higher than those in BLCA samples (all P < 0.05).

CONCLUSION

A BEX-related gene signature was developed to predict prognosis and immunotherapeutic sensitivity in BLCA, providing valuable guidance for personalized treatment.

Enhanced abscopal anti-tumor response via a triple combination of thermal ablation, IL-21, and PD-1 inhibition therapy

Despite the success of immune checkpoint inhibitors (ICIs) in treating solid tumors, lots of patients remain unresponsive to this therapy. Microwave ablation (MWA) stimulates systemic adaptive immunity against tumor cells by releasing tumor antigens. Additionally, IL-21 has demonstrated importance in stimulating T-cell effector function. The combination of these three therapies-MWA, IL-21, and anti-PD-1 monoclonal antibodies (mAbs)-has yet to be explored in the context of cancer treatment.In this study, we explored the impact of thermal ablation on IL-21R expression in tumor-infiltrating lymphocytes (TILs). Subsequently, we assessed alterations in the tumor microenvironment (TME) and peripheral lymphoid organs. Additionally, we conducted a thorough examination of tumor-infiltrating CD45+ immune cells across various treatment groups using single-cell RNA sequencing (scRNA-seq). Moreover, we determined the potential anti-tumor effects of the triple combination involving MWA, IL-21, and anti-PD-1 mAbs.Our findings revealed that MWA upregulated the expression of IL-21R on various immune cells in the untreated tumors. The combination of MWA with IL-21 exhibited a robust abscopal anti-tumor effect, enhancing the effector function of CD8+ T cells and facilitating dendritic cells' maturation and antigen presentation in the untreated tumor. Notably, the observed abscopal anti-tumor effect resulting from the combination is contingent upon T-cell recirculation, indicating the reliance of systemic adaptive immunity for this treatment regimen. Additionally, the combination of MWA, IL-21, and PD-1 mAbs demonstrated profound abscopal anti-tumor efficacy. Our findings provide support for further clinical investigation into a triple combination therapy involving MWA, IL-21, and ICIs for the treatment of metastatic cancer.

Comparison of seven CD19 CAR designs in engineering NK cells for enhancing anti-tumour activity

Chimeric antigen receptor-natural killer (CAR-NK) cell therapy is emerging as a promising cancer treatment, with notable safety and source diversity benefits over CAR-T cells. This study focused on optimizing CAR constructs for NK cells to maximize their therapeutic potential. We designed seven CD19 CAR constructs and expressed them in NK cells using a retroviral system, assessing their tumour-killing efficacy and persistence. Results showed all constructs enhanced tumour-killing and prolonged survival in tumour-bearing mice. In particular, CAR1 (CD8 TMD-CD3ζ SD)-NK cells showed superior efficacy in treating tumour-bearing animals and exhibited enhanced persistence when combined with OX40 co-stimulatory domain. Of note, CAR1-NK cells were most effective at lower effector-to-target ratios, while CAR4 (CD8 TMD-OX40 CD- FcεRIγ SD) compromised NK cell expansion ability. Superior survival rates were noted in mice treated with CAR1-, CAR2 (CD8 TMD- FcεRIγ SD)-, CAR3 (CD8 TMD-OX40 CD- CD3ζ SD)- and CAR4-NK cells over those treated with CAR5 (CD28 TMD- FcεRIγ SD)-, CAR6 (CD8 TMD-4-1BB CD-CD3ζ 1-ITAM SD)- and CAR7 (CD8 TMD-OX40 CD-CD3ζ 1-ITAM SD)-NK cells, with CAR5-NK cells showing the weakest anti-tumour activity. Increased expression of exhaustion markers, especially in CAR7-NK cells, suggests that combining CAR-NK cells with immune checkpoint inhibitors might improve anti-tumour outcomes. These findings provide crucial insights for developing CAR-NK cell products for clinical applications.

The role of extracellular vesicles in immune cell exhaustion and resistance to immunotherapy

INTRODUCTION

Extracellular vesicles (EVs) are membrane-bound nanoparticles for intercellular communication. Subtypes of EVs, namely exosomes and microvesicles transfer diverse, bioactive cargo to their target cells and eventually interfere with immune responses. Despite being a promising approach, cancer immunotherapy currently faces several challenges including immune resistance. EVs secreted from various sources in the tumor microenvironment provoke immune cell exhaustion and lower the efficacy of immunological treatments, such as CAR T cells and immune checkpoint inhibitors.

AREAS COVERED

This article goes through the mechanisms of action of various types of EVs in inhibiting immune response and immunotherapies, and provides a comprehensive review of EV-based treatments.

EXPERT OPINION

By making use of the distinctive features of EVs, natural or modified EVs are innovatively utilized as novel cancer therapeutics. They are occasionally coupled with currently established treatments to overcome their inadequacies. Investigating the properties and interactions of EVs and EV-based treatments is crucial for determining future steps in cancer therapeutics.

A Synthetic Circuit Empowering Reprogrammed B Cells for Therapeutic Proteins Expression Regulated by Tumor Detection

Cancer remains a leading cause of death worldwide, but immunotherapies hold promises to cure it by awaking the patient's immune system to provide long-term protection. Cell therapies, involving the infusion of immune cells, either directly or genetically modified, are being developed to recognize and destroy cancer cells. Here, we explored the potential of a new synthetic circuit to reprogram B cells to cure cancers. This circuit consists in a sensor (a membrane-anchored IgG1), a transducer (a fragment of the NR4A1 promoter) and an effector molecule. Upon recognition of its target, this sensor triggers signaling pathways leading to the activation of the transducer and to effector expression (here, a reporter molecule). We showed that this circuit could discriminate tumors expressing the target antigen from those that did not, in a dose dependent manner in vitro. Going further, we replaced the original membrane-anchored sensor by an immunoglobulin expression cassette that can not only be membrane-anchored but also be secreted depending on B-cell maturation status. This allowed concomitant activation of the circuit and secretion of transgenic antibodies directed against the targeted antigen. Of note, these antibodies could correctly bind their target and were recognized by FcR expressed at the surface of immune cells, which should synergically amplify the action of the effector. The potential of reprogrammed B cells remains to be assessed in vivo by implementing a therapeutic effector. In the future, B-cell reprogramming platforms should allow personalized cancer treatment by adapting both the sensor and the therapeutic effectors to patients.

KLRG1-expressing CD8+ T cells are exhausted and polyfunctional in patients with chronic hepatitis B

Killer cell lectin-like receptor G1 (KLRG1) has traditionally been regarded as an inhibitory receptor of T cell exhaustion in chronic infection and inflammation. However, its exact role in hepatitis B virus (HBV) infection remains elusive. CD8+ T cells from 190 patients with chronic hepatitis B were analyzed ex vivo for checkpoint and apoptosis markers, transcription factors, cytokines and subtypes in 190 patients with chronic hepatitis B. KLRG1+ and KLRG1- CD8+ T cells were sorted for transcriptome analysis. The impact of the KLRG1-E-cadherin pathway on the suppression of HBV replication mediated by virus-specific T cells was validated in vitro. As expected, HBV-specific CD8+ T cells expressed higher levels of KLRG1 and showed an exhausted molecular phenotype and function. However, despite being enriched for the inhibitory molecules, thymocyte selection-associated high mobility group box protein (TOX), eomesodermin (EOMES), and Helios, CD8+ T cells expressing KLRG1 produced significant levels of tumour necrosis factor (TNF)-α, interferon (IFN)-γ, perforin, and granzyme B, demonstrating not exhausted but active function. Consistent with the in vitro phenotypic assay results, RNA sequencing (RNA-seq) data showed that signature effector T cell and exhausted T cell genes were enriched in KLRG1+ CD8+ T cells. Furthermore, in vitro testing confirmed that KLRG1-E-cadherin binding inhibits the antiviral efficacy of HBV-specific CD8+ T cells. Based on these findings, we concluded that KLRG1+ CD8+ T cells are not only a terminally exhausted subgroup but also exhibit functional diversity, despite inhibitory signs in HBV infection.

Immunoregulatory natural killer cells

This review discusses a broader scope of functional roles for NK cells. Despite the well-known cytolytic and inflammatory roles of NK cells against tumors and pathogenic diseases, extensive evidence demonstrates certain subsets of NK cells have defacto immunoregulatory effects and have a role in inducing anergy or lysis of antigen-activated T cells and regulating several autoimmune diseases. Furthermore, recent evidence suggests certain subsets of immunoregulatory NK cells can cause anergy or lysis of antigen-activated T cells to regulate hyperinflammatory diseases, including multisystem inflammatory syndrome. Several pathogens induce T cell and NK cell exhaustion and/or suppression, which impair the immune system's control of the replication speed of virulent pathogens and tumors and result in extensive antigens and antigen-antibody immune complexes, potentially inducing to some extent a Type III hypersensitivity immune reaction. The Type III hypersensitivity immune reaction induces immune cell secretion of proteinases, which can cleave specific proteins to create autoantigens which activate T cells to initiate autoimmune and/or hyperinflammatory diseases. Furthermore, pathogen induced NK cell exhaustion and/or suppression will inhibit NK cells which would have induced the anergy or lysis of activated T cells to regulate autoimmune and hyperinflammatory diseases. Autoimmune and hyperinflammatory diseases can be consequences of the dual lymphocyte exhaustion and/or suppression effects during infections, by creating autoimmune and/or hyperinflammatory diseases, while also impairing immunoregulatory lymphocytes which otherwise would have regulated these diseases.

Enhanced IL-15-mediated NK cell activation and proliferation by an ADAM17 function-blocking antibody involves CD16A, CD137, and accessory cells

Background

NK cells are being extensively studied as a cell therapy for cancer. Their effector functions are induced by the recognition of ligands on tumor cells and by various cytokines. IL-15 is broadly used to stimulate endogenous and adoptively transferred NK cells in cancer patients. These stimuli activate the membrane protease ADAM17, which then cleaves assorted receptors on the surface of NK cells as a negative feedback loop to limit their activation and function. We have shown that ADAM17 inhibition can enhance IL-15-mediated NK cell proliferation in vitro and in vivo . In this study, we investigated the underlying mechanism of this process.

Methods

PBMCs or enriched NK cells from human peripheral blood, either unlabeled or labeled with a cell proliferation dye, were cultured for up to 7 days in the presence of rhIL-15 +/- an ADAM17 function-blocking antibody. Different versions of the antibody were generated; Medi-1 (IgG1), Medi-4 (IgG4), Medi-PGLALA, Medi-F(ab') 2 , and TAB16 (anti-ADAM17 and anti-CD16 bispecific) to modulate CD16A engagement on NK cells. Flow cytometry was used to assess NK cell proliferation and phenotypic markers, immunoblotting to examine CD16A signaling, and IncuCyte-based live cell imaging to measure NK cell anti-tumor activity.

Results

The ADAM17 function-blocking mAb Medi-1 markedly increased initial NK cell activation by IL-15. Using different engineered versions of the antibody revealed that the activating Fcγ receptor CD16A, a well-described ADAM17 substrate, was critical for enhancing IL-15 stimulation. Hence, Medi-1 bound to ADAM17 on NK cells can be engaged by CD16A and block its shedding, inducing and prolonging its signaling. This process did not promote evident NK cell fratricide, phagocytosis, or dysfunction. Synergistic activity by Medi-1 and IL-15 enhanced the upregulation of CD137 on CD16A + NK cells and augmented their proliferation in the presence of PBMC accessory cells.

Conclusions

Our data reveal for the first time that CD16A and CD137 underpin Medi-1 enhancement of IL-15-driven NK cell activation and proliferation, respectively. The use of Medi-1 represents a novel strategy to enhance IL-15-driven NK cell proliferation, and it may be of therapeutic importance by increasing the anti-tumor activity of NK cells in cancer patients.

What is already known on this topic

NK cell therapies are being broadly investigated to treat cancer. NK cell stimulation by IL-15 prolongs their survival in cancer patients. Various stimuli including IL-15 activate ADAM17 in NK cells, a membrane protease that regulates the cell surface density of various receptors as a negative feedback mechanism.

What this study adds

Treating NK cells with the ADAM17 function-blocking mAb Medi-1 markedly enhanced their activation and proliferation. Our study reveals that the Fc and Fab regions of Medi-1 function synergistically with IL-15 in NK cell activation. Medi-1 treatment augments the upregulation of CD137 by NK cells, which enhances their proliferation in the presence of PBMC accessory cells.

How this study might affect research practice or policy

Our study is of translational importance as Medi-1 treatment in combination with IL-15 could potentially augment the proliferation and function of endogenous or adoptively transferred NK cells in cancer patients.

Graphical abstract

Overexpressing S100A9 ameliorates NK cell dysfunction in estrogen receptor-positive breast cancer

BACKGROUND

Estrogen receptor (ER) positive human epidermal growth factor receptor 2 (HER2) negative breast cancer (ER+/HER2-BC) and triple-negative breast cancer (TNBC) are two distinct breast cancer molecular subtypes, especially in tumor immune microenvironment (TIME). The TIME of TNBC is considered to be more inflammatory than that of ER+/HER2-BC. Natural killer (NK) cells are innate lymphocytes that play an important role of tumor eradication in TME. However, studies focusing on the different cell states of NK cells in breast cancer subtypes are still inadequate.

METHODS

In this study, single-cell mRNA sequencing (scRNA-seq) and bulk mRNA sequencing data from ER+/HER2-BC and TNBC were analyzed. Key regulator of NK cell suppression in ER+/HER2-BC, S100A9, was quantified by qPCR and ELISA in MCF-7, T47D, MDA-MB-468 and MDA-MB-231 cell lines. The prognosis predictability of S100A9 and NK activation markers was evaluated by Kaplan-Meier analyses using TCGA-BRAC data. The phenotype changes of NK cells in ER+/HER2-BC after overexpressing S100A9 in cancer cells were evaluated by the production levels of IFN-gamma, perforin and granzyme B and cytotoxicity assay.

RESULTS

By analyzing scRNA-seq data, we found that multiple genes involved in cellular stress response were upregulated in ER+/HER2-BC compared with TNBC. Moreover, TLR regulation pathway was significantly enriched using differentially expressed genes (DEGs) from comparing the transcriptome data of ER+/HER2-BC and TNBC cancer cells, and NK cell infiltration high/low groups. Among the DEGs, S100A9 was identified as a key regulator. Patients with higher expression levels of S100A9 and NK cell activation markers had better overall survival. Furthermore, we proved that overexpression of S100A9 in ER+/HER2-cells could improve cocultured NK cell function.

CONCLUSION

In conclusion, the study we presented demonstrated that NK cells in ER+/HER2-BC were hypofunctional, and S100A9 was an important regulator of NK cell function in ER+BC. Our work contributes to elucidate the regulatory networks between cancer cells and NK cells and may provide theoretical basis for novel drug development.

The role, relevance and management of immune exhaustion in bovine infectious diseases

Immune exhaustion is a state of immune cell dysfunction that occurs most commonly following chronic exposure to an antigen which persists after the immune response fails to remove it. Exhaustion has been studied most thoroughly with several cancers, but has also been observed in several chronic infectious diseases. The topic has mainly been studied with CD8+ T cells, but it can also occur with CD4+ T cells and other immune cell types too. Exhaustion is characterized by a hierarchical loss of effector cell functions, up-regulation of immuno-inhibitory receptors, disruption of metabolic activities, and altered chromatin landscapes. Exhaustion has received minimal attention so far in diseases of veterinary significance and this review's purpose is to describe examples where immune exhaustion is occurring in several bovine disease situations. We also describe methodology to evaluate immune exhaustion as well as the prospects of controlling exhaustion and achieving a more suitable outcome of therapy in some chronic disease scenarios.

Neoadjuvant chemotherapy-induced remodeling of human hormonal receptor-positive breast cancer revealed by single-cell RNA sequencing

Hormone receptor-positive breast cancer (HR+ BC) is known to be relatively insensitive to chemotherapy, and since chemotherapy has remained the major neoadjuvant therapy for HR+ BC, the undetermined mechanism of chemoresistance and how chemotherapy reshapes the immune microenvironment need to be explored by high-throughput technology. By using single-cell RNA sequencing and multiplexed immunofluorescence staining analysis of HR+ BC samples (paired pre- and post-neoadjuvant chemotherapy (NAC)), the levels of previously unrecognized immune cell subsets, including CD8+ T cells with pronounced expression of T-cell development (LMNA) and cytotoxicity (FGFBP2) markers, CD4+ T cells characterized by proliferation marker (ATP1B3) expression and macrophages characterized by CD52 expression, were found to be increased post-NAC, which were predictive of chemosensitivity and their antitumor function was also validated with in vitro experiments. In terms of immune checkpoint expression of CD8+ T cells, we found their changes were inconsistent post-NAC, that LAG3, VSIR were decreased, and PDCD1, HAVCR2, CTLA4, KLRC1 and BTLA were increased. In addition, we have identified novel genomic and transcriptional patterns of chemoresistant cancer cells, both innate and acquired, and have confirmed their prognostic value with TCGA cohorts. By shedding light on the ecosystem of HR+ BC reshaped by chemotherapy, our results uncover valuable candidates for predicting chemosensitivity and overcoming chemoresistance in HR+ BC.

Immunogenicity of tick-borne-encephalitis-virus-(TBEV)-vaccination and impact of age on humoral and cellular TBEV-specific immune responses in patients with rheumatoid arthritis

Inactivated vaccines, such as tick-borne-encephalitis-virus-(TBEV) vaccine, have been discussed as less immunogenic in elderly and in immunocompromised patients. In this controlled cross-sectional cohort study, the antibody and cellular responses after TBEV-vaccination were investigated in 36 rheumatoid arthritis (RA) patients and 112 healthy controls (HC) by evaluating IgG-anti-TBEV concentration, neutralization and relative avidity index (RAI). Cellular reactivity was assessed by IFNgamma-producing spot-forming-units (SFU) by ELISPOT assay and flow cytometry. RA patients showed lower IgG-anti-TBEV compared to HC, which were influenced by age at and time since last TBEV vaccination and disease duration. High-responders regarding cellular immunity and avidity were less frequent in RA compared to HC. RA patients who had received booster vaccinations were more likely to demonstrate higher IgG-anti-TBEV responses compared to those who had not. In conclusion, RA patients showed a negative effect of age on anti-TBEV-IgG and immunological benefits of timely booster vaccination are suggested.

The role of exhausted natural killer cells in the immunopathogenesis and treatment of leukemia

The immune responses to cancer cells involve both innate and acquired immune cells. In the meantime, the most attention has been drawn to the adaptive immune cells, especially T cells, while, it is now well known that the innate immune cells, especially natural killer (NK) cells, play a vital role in defending against malignancies. While the immune cells are trying to eliminate malignant cells, cancer cells try to prevent the function of these cells and suppress immune responses. The suppression of NK cells in various cancers can lead to the induction of an exhausted phenotype in NK cells, which will impair their function. Recent studies have shown that the occurrence of this phenotype in various types of leukemic malignancies can affect the prognosis of the disease, and targeting these cells may be considered a new immunotherapy method in the treatment of leukemia. Therefore, a detailed study of exhausted NK cells in leukemic diseases can help both to understand the mechanisms of leukemia progression and to design new treatment methods by creating a deeper understanding of these cells. Here, we will comprehensively review the immunobiology of exhausted NK cells and their role in various leukemic malignancies. Video Abstract.

Serum vitamin D deficiency is associated with increased risk of γδ T cell exhaustion in HBV-infected patients

Previous studies have demonstrated that T cell exhaustion is associated with poor clearance of Hepatitis B virus (HBV). However, whether the expression of exhaustion markers on innate-like circulating γδ T cells derived from patients with HBV infection correlates with the serum level of vitamin D is not completely understood. In this study, we found that the frequency of circulating Vδ2+ T cell and serum levels of vitamin 25(OH)D3 were significantly decreased in patients with HBV. And serum 25(OH)D3 levels in HBV-infected patients were negatively correlated with HBV DNA load and PD-1 expression on γδ T cells. Interestingly, 1α,25(OH)2 D3 alleviated the exhaustion phenotype of Vδ2 T cells in HBV-infected patients and promoted IFN-β expression in human cytotoxic Vδ2 T cells in vitro. Collectively, these findings demonstrate that vitamin D plays a pivotal role in reversing γδ T-cell exhaustion and is highly promising target for ameliorating HBV infection.

Loss of B1 and marginal zone B cells during ovarian cancer

Recent advances in immunotherapy have not addressed the challenge presented by ovarian cancer. Although the peritoneum is an "accessible" locus for this disease there has been limited characterization of the immunobiology therein. We investigated the ID8-C57BL/6J ovarian cancer model and found marked depletion of B1 cells from the ascites of the peritoneal cavity. There was also selective loss of the B1 and marginal zone B cell subsets from the spleen. Immunity to antigens that activate these subsets validated their loss rather than relocation. A marked influx of myeloid-derived suppressor cells correlated with B cell subset depletion. These observations are discussed in the context of the housekeeping burden placed on innate B cells during ovarian cancer and to foster consideration of B cell biology in therapeutic strategies to address this challenge.

Anoikis regulator GLI2 promotes NC cell immunity escape by TGF-β-mediated non-classic hedgehog signaling in colorectal cancer: based on artificial intelligence and big data analysis

BACKGROUND

Anoikis is a speed-limited procedure to inhibit tumor metastasis during epithelial-mesenchymal transition (EMT). Previous studies have explored anoikis-related genes (ARG) in predicting prognosis and distinguishing tumoral immunity in many types of cancer. However, the role of ARGs in regulating NK cell exhaustion (NKE) and in predicting chemotherapy sensitivity is not clear. Therefore, it is necessary to work on it.

METHODS

Gene expression profiles and clinical features are collected from TCGA and GEO, and data analysis is performed in R4.2.0.

RESULTS

The ARGs-based no-supervised learning algorithm identifies three ARG subgroups, amongst which the prognosis is different. WCGNA and Artificial intelligence (AI) are applied to construct an NKE-related drug sensitivity stratification and prognosis identification model in digestive system cancer. Pathways association analysis screens out GLI2 is a key gene in regulating NKE by non-classic Hedgehog signaling (GLI2/TGF-β/IL6). In vitro experiments show that down-regulation of GLI2 enhances the CAPE-mediated cell toxicity and accompanies with down-regulation of PD-L1, tumor-derive IL6, and snial1 whereas the expression of cleaved caspas3, cleaved caspase4, cleaved PARP, and E-cadherin are up-regulated in colorectal cancer. Co-culture experiments show that GLI2- decreased colorectal tumor cells lead to down-regulation of TIM-3 and PD1 in NK cells, which are restored by TGF-bate active protein powder. Besides, the Elisa assay shows that GLI2-decreased colorectal tumor cells lead to up-regulation of IFN-gamma in NK cells.

An efficient feeder-free and chemically-defined expansion strategy for highly purified natural killer cells derived from human cord blood

Introduction

Natural killer cells (NKCs) are immune cells that can attack cancer cells through the direct recognition of ligands without prior sensitization. Cord blood-derived NKCs (CBNKCs) represent a promising tool for allogenic NKC-based cancer immunotherapy. Efficient NKC expansion and decreased T cell inclusion are crucial for the success of allogeneic NKC-based immunotherapy without inducing graft-versus-host reactions. We previously established an efficient ex vivo expansion system consisting of highly purified-NKCs derived from human peripheral blood. Herein, we evaluated the performance of the NKC expansion system using CB and characterized the expanded populations.

Methods

Frozen CB mononuclear cells (CBMCs), with T cells removed, were cultured with recombinant human interleukin (rhIL)-18 and rhIL-2 under conditions where anti-NKp46 and anti-CD16 antibodies were immobilized. Following 7, 14, and 21 days of expansion, the purity, fold-expansion rates of NKCs, and the expression levels of NK activating and inhibitory receptors were assessed. The ability of these NKCs to inhibit the growth of T98G, a glioblastoma (GBM) cell line sensitive to NK activity, was also examined.

Results

All expanded T cell-depleted CBMCs were included in over 80%, 98%, and 99% of CD3^-CD56⁺ NKCs at 7, 14, and 21 days of expansion, respectively. The NK activating receptors LFA-1, NKG2D, DNAM-1, NKp30, NKp44, NKp46, FcγRIII and NK inhibitory receptors TIM-3, TIGIT, TACTILE, NKG2A were expressed on the expanded-CBNKCs. Two out of three of the expanded-CBNKCs weakly expressed PD-1, yet gradually expressed PD-1 according to expansion period. One of the three expanded CBNKCs almost lacked PD-1 expression during the expansion period. LAG-3 expression was variable among donors, and no consistent changes were identified during the expansion period. All of the expanded CBNKCs elicited distinct cytotoxicity-mediated growth inhibition on T98G cells. The level of cytotoxicity was gradually decreased based on the prolonged expansion period.

Conclusions

Our established feeder-free expansion system yielded large scale highly purified and cytotoxic NKCs derived from human CB. The system provides a stable supply of clinical grade off-the-shelf NKCs and may be feasible for allogeneic NKC-based immunotherapy for cancers, including GBM.

Affibody-based hBCMA x CD16 dual engagers for NK cell-mediated killing of multiple myeloma cells

We describe the development and characterization of the (to date) smallest Natural Killer (NK) cell re-directing human B Cell Maturation Antigen (hBCMA) x CD16 dual engagers for potential treatment of multiple myeloma, based on combinations of small 58 amino acid, non-immunoglobulin, affibody affinity proteins. Affibody molecules to human CD16a were selected from a combinatorial library by phage display resulting in the identification of three unique binders with affinities (KD) for CD16a in the range of 100 nM-3 µM. The affibody exhibiting the highest affinity demonstrated insensitivity towards the CD16a allotype (158F/V) and did not interfere with IgG (Fc) binding to CD16a. For the construction of hBCMA x CD16 dual engagers, different CD16a binding arms, including bi-paratopic affibody combinations, were genetically fused to a high-affinity hBCMA-specific affibody. Such 15-23 kDa dual engager constructs showed simultaneous hBCMA and CD16a binding ability and could efficiently activate resting primary NK cells and trigger specific lysis of a panel of hBCMA-positive multiple myeloma cell lines. Hence, we report a novel class of uniquely small NK cell engagers with specific binding properties and potent functional profiles.

A standardized metric to enhance clinical trial design and outcome interpretation in type 1 diabetes

The use of a standardized outcome metric enhances clinical trial interpretation and cross-trial comparison. If a disease course is predictable, comparing modeled predictions with outcome data affords the precision and confidence needed to accelerate precision medicine. We demonstrate this approach in type 1 diabetes (T1D) trials aiming to preserve endogenous insulin secretion measured by C-peptide. C-peptide is predictable given an individual's age and baseline value; quantitative response (QR) adjusts for these variables and represents the difference between the observed and predicted outcome. Validated across 13 trials, the QR metric reduces each trial's variance and increases statistical power. As smaller studies are especially subject to random sampling variability, using QR as the outcome introduces alternative interpretations of previous clinical trial results. QR can provide model-based estimates that quantify whether individuals or groups did better or worse than expected. QR also provides a purer metric to associate with biomarker measurements. Using data from more than 1300 participants, we demonstrate the value of QR in advancing disease-modifying therapy in T1D. QR applies to any disease where outcome is predictable by pre-specified baseline covariates, rendering it useful for defining responders to therapy, comparing therapeutic efficacy, and understanding causal pathways in disease.

NK cell exhaustion in the tumor microenvironment

Natural killer (NK) cells kill mutant cells through death receptors and cytotoxic granules, playing an essential role in controlling cancer progression. However, in the tumor microenvironment (TME), NK cells frequently exhibit an exhausted status, which impairs their immunosurveillance function and contributes to tumor immune evasion. Emerging studies are ongoing to reveal the properties and mechanisms of NK cell exhaustion in the TME. In this review, we will briefly introduce the maturation, localization, homeostasis, and cytotoxicity of NK cells. We will then summarize the current understanding of the main mechanisms underlying NK cell exhaustion in the TME in four aspects: dysregulation of inhibitory and activating signaling, tumor cell-derived factors, immunosuppressive cells, and metabolism and exhaustion. We will also discuss the therapeutic approaches currently being developed to reverse NK cell exhaustion and enhance NK cell cytotoxicity in the TME.

Sirtuin 2 up-regulation suppresses the anti-tumour activity of exhausted natural killer cells in mesenteric lymph nodes in murine colorectal carcinoma

Natural killer (NK) cells inhibit colorectal carcinoma (CRC) initiation and progression through their tumoricidal activity. However, cumulative evidence suggests that NK cells become functionally exhausted in patients with CRC. To deepen the understanding of the mechanisms underlying CRC-associated NK cell exhaustion, we explored the expression and effect of Sirtuin 2 (Sirt2) in mesenteric lymph node (mLN) NK cells in a murine colitis-associated CRC model. Sirt2 was remarkably up-regulated in mLN NK cells after CRC induction. Particularly, Sirt2 was increased in mLN NK cells expressing high T cell immunoglobulin and mucin domain-3 (TIM3), high lymphocyte activation protein-3 (LAG3), high programmed death-1 (PD-1), high T cell immunoreceptor with immunoglobulin and ITIM domains (TIGIT), high NK group 2 member A (NKG2A), but low tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), low interferon-gamma and low granzyme B. In addition, Sirt2 was also increased in NK cells after induction of exhaustion in vitro. Lentivirus-mediated Sirt2 silencing did not affect the acute activation and cytotoxicity of non-exhausted NK cells. However, Sirt2 silencing partially restored the expression of interferon-gamma, granzyme B and CD107a in exhausted NK cells. Meanwhile, Sirt2 silencing down-regulated TIM3, LAG3, TIGIT and NKG2A while up-regulated TRAIL on exhausted NK cells. Consequently, Sirt2 silencing restored the cytotoxicity of exhausted NK cells. Moreover, Sirt2 silencing partially ameliorates the defects in glycolysis and mitochondrial respiration of exhausted NK cells, as evidenced by increases in glycolytic capacity, glycolytic reserve, basal respiration, maximal respiration and spare respiration capacity. Accordingly, Sirt2 negatively regulates the tumoricidal activity of exhausted NK cells in CRC.

Single-cell landscape of immune cells in human livers affected by HBV-related cirrhosis

Background & Aims

HBV infection is one of the leading causes of liver cirrhosis. However, the immune microenvironment in patients with HBV cirrhosis remains elusive.

Methods

Single-cell RNA sequencing was used to analyse the transcriptomes of 76,210 immune cells in the livers of six healthy individuals and in five patients with HBV cirrhosis.

Results

Patients with HBV cirrhosis have a unique immune ecosystem characterised by an accumulation of macrophage-CD9/IL18, macrophage-C1QA, NK Cell-JUNB, CD4+ T cell-IL7R, and a loss of B cell-IGLC1 clusters. Furthermore, our analysis predicted enhanced cell communication between myeloid cells and all immune cells in patients with HBV-related cirrhosis. Pseudo-time analysis of myeloid cells, natural killer (NK) cells, and B cells demonstrated a significant accumulation of mature cells and a depletion of naive cells in HBV cirrhosis. In addition, we observed an increase in antigen processing and presentation capacities in myeloid cells in patients with HBV cirrhosis, whereas NK cell-mediated cytotoxicity was substantially reduced.

Conclusions

Our results provide valuable insight into the immune landscape of HBV cirrhosis, suggesting that HBV cirrhosis is associated with the accumulation of activated myeloid cells and impaired cytotoxicity in NK cells.

Impact and implications

The absence of single-cell transcriptome profiling of immune cells in HBV cirrhosis hinders our understanding of the underlying mechanisms driving disease progression. To address this knowledge gap, our study unveils a distinctive immune ecosystem in HBV cirrhosis and represents a crucial advancement in elucidating the impact of the immune milieu on the development of this condition. These findings constitute significant strides towards the identification of more effective therapeutic approaches for HBV cirrhosis and are relevant for healthcare professionals, researchers, and pharmaceutical developers dedicated to combating this disease.

Exploring the dual role of B cells in solid tumors: implications for head and neck squamous cell carcinoma

In the tumor milieu of head and neck squamous cell carcinoma (HNSCC), distinct B cell subpopulations are present, which exert either pro- or anti-tumor activities. Multiple factors, including hypoxia, cytokines, interactions with tumor cells, and other immune infiltrating lymphocytes (TILs), alter the equilibrium between the dual roles of B cells leading to cancerogenesis. Certain B cell subsets in the tumor microenvironment (TME) exhibit immunosuppressive function. These cells are known as regulatory B (Breg) cells. Breg cells suppress immune responses by secreting a series of immunosuppressive cytokines, including IL-10, IL-35, TGF-β, granzyme B, and adenosine or dampen effector TILs by intercellular contacts. Multiple Breg phenotypes have been discovered in human and mouse cancer models. However, when compartmentalized within a tertiary lymphoid structure (TLS), B cells predominantly play anti-tumor effects. A mature TLS contains a CD20+ B cell zone with several important types of B cells, including germinal-center like B cells, antibody-secreting plasma cells, and memory B cells. They kill tumor cells via antibody-dependent cytotoxicity and phagocytosis, and local complement activation effects. TLSs are also privileged sites for local T and B cell coordination and activation. Nonetheless, in some cases, TLSs may serve as a niche for hidden tumor cells and indicate a bad prognosis. Thus, TIL-B cells exhibit bidirectional immune-modulatory activity and are responsive to a variety of immunotherapies. In this review, we discuss the functional distinctions between immunosuppressive Breg cells and immunogenic effector B cells that mature within TLSs with the focus on tumors of HNSCC patients. Additionally, we review contemporary immunotherapies that aim to target TIL-B cells. For the development of innovative therapeutic approaches to complement T-cell-based immunotherapy, a full understanding of either effector B cells or Breg cells is necessary.

Natural killer cells in the lung: potential role in asthma and virus-induced exacerbation?

Asthma is a chronic inflammatory airway disorder whose pathophysiological and immunological mechanisms are not completely understood. Asthma exacerbations are mostly driven by respiratory viral infections and characterised by worsening of symptoms. Despite current therapies, asthma exacerbations can still be life-threatening. Natural killer (NK) cells are innate lymphoid cells well known for their antiviral activity and are present in the lung as circulating and resident cells. However, their functions in asthma and its exacerbations are still unclear. In this review, we will address NK cell activation and functions, which are particularly relevant for asthma and virus-induced asthma exacerbations. Then, the role of NK cells in the lungs at homeostasis in healthy individuals will be described, as well as their functions during pulmonary viral infections, with an emphasis on those associated with asthma exacerbations. Finally, we will discuss the involvement of NK cells in asthma and virus-induced exacerbations and examine the effect of asthma treatments on NK cells.

Early expansion of activated adaptive but also exhausted NK cells during acute severe SARS-CoV-2 infection

The analysis of immunological parameters during the course of a SARS-CoV-2 infection is of great importance, both to identify diagnostic markers for the risk of a severe course of COVID-19, and to better understand the role of the immune system during the infection. By using multicolor flow cytometry we compared the phenotype of Natural Killer (NK) cells from hospitalized COVID-19 patients during early SARS-CoV-2 infection with samples from recovered and SARS-CoV-2 naïve subjects. Unsupervised high-dimensional analysis of 28-color flow cytometric data revealed a strong enrichment of NKG2C expressing NK cells in response to the acute viral infection. In addition, we found an overrepresentation of highly activated NK cell subsets with an exhausted phenotype. Moreover, our data show long-lasting phenotypic changes within the NK cell compartment that did not completely reverse up to 2 months after recovery. This demonstrates that NK cells are involved in the early innate immune response against SARS-CoV-2.

Beyond αβ T cells: NK, iNKT, and γδT cell biology in leukemic patients and potential for off-the-shelf adoptive cell therapies for AML

Acute myeloid leukemia (AML) remains an elusive disease to treat, let alone cure, even after highly intensive therapies such as stem cell transplants. Adoptive cell therapeutic strategies based on conventional alpha beta (αβ)T cells are an active area of research in myeloid neoplasms given their remarkable success in other hematologic malignancies, particularly B-cell-derived acute lymphoid leukemia, myeloma, and lymphomas. Several limitations have hindered clinical application of adoptive cell therapies in AML including lack of leukemia-specific antigens, on-target-off-leukemic toxicity, immunosuppressive microenvironments, and leukemic stem cell populations elusive to immune recognition and destruction. While there are promising T cell-based therapies including chimeric antigen receptor (CAR)-T designs under development, other cytotoxic lymphocyte cell subsets have unique phenotypes and capabilities that might be of additional benefit in AML treatment. Of particular interest are the natural killer (NK) and unconventional T cells known as invariant natural killer T (iNKT) and gamma delta (γδ) T cells. NK, iNKT, and γδT cells exhibit intrinsic anti-malignant properties, potential for alloreactivity, and human leukocyte-antigen (HLA)-independent function. Here we review the biology of each of these unconventional cytotoxic lymphocyte cell types and compare and contrast their strengths and limitations as the basis for adoptive cell therapies for AML.

Specific subsets of urothelial bladder carcinoma infiltrating T cells associated with poor prognosis

Comprehensive investigation of tumor-infiltrating lymphocytes in cancer is crucial to explore the effective immunotherapies, but the composition of infiltrating T cells in urothelial bladder carcinoma (UBC) remains elusive. Here, single-cell RNA sequencing (scRNA-seq) were performed on total 30,905 T cells derived from peripheral blood, adjacent normal and tumor tissues from two UBC patients. We identified 18 distinct T cell subsets based on molecular profiles and functional properties. Specifically, exhausted T (TEx) cells, exhausted NKT (NKTEx) cells, Ki67+ T cells and B cell-like T (B-T) cells were exclusively enriched in UBC. Additionally, the gene signatures of TEx, NKTEx, Ki67+ T and B-T cells were significantly associated with poor survival in patients with BC and various tumor types. Finally, IKZF3 and TRGC2 are the potential biomarkers of TEx cells. Overall, our study demonstrated an exhausted context of T cells in UBC, which layed a theoretical foundation for the development of effective tumor immunotherapies.

The current state and future of T-cell exhaustion research

'Exhaustion' is a term used to describe a state of native and redirected T-cell hypo-responsiveness resulting from persistent antigen exposure during chronic viral infections or cancer. Although a well-established phenotype across mice and humans, exhaustion at the molecular level remains poorly defined and inconsistent across the literature. This is, in part, due to an overreliance on surface receptors to define these cells and explain exhaustive behaviours, an incomplete understanding of how exhaustion arises, and a lack of clarity over whether exhaustion is the same across contexts, e.g. chronic viral infections versus cancer. With the development of systems-based genetic approaches such as single-cell RNA-seq and CRISPR screens applied to in vivo data, we are moving closer to a consensus view of exhaustion, although understanding how it arises remains challenging given the difficulty in manipulating the in vivo setting. Accordingly, producing and studying exhausted T-cells ex vivo are burgeoning, allowing experiments to be conducted at scale up and with high throughput. Here, we first review what is currently known about T-cell exhaustion and how it's being studied. We then discuss how improvements in their method of isolation/production and examining the impact of different microenvironmental signals and cell interactions have now become an active area of research. Finally, we discuss what the future holds for the analysis of this physiological condition and, given the diversity of ways in which exhausted cells are now being generated, propose the adoption of a unified approach to clearly defining exhaustion using a set of metabolic-, epigenetic-, transcriptional-, and activation-based phenotypic markers, that we call 'M.E.T.A'.

Fibroblast Growth Factor 11 Enables Tumor Cell Immune Escape by Promoting T Cell Exhaustion and Predicts Poor Prognosis in Patients with Lung Adenocarcinoma

Fibroblast growth factor 11 (FGF11) accelerates tumor proliferation in a variety of cancer types. This study aimed to examine the link between FGF11 and the prognosis of lung adenocarcinoma. FGF11 was searched in the Tumor Cancer Genome Atlas (TCGA) and ImmProt databases. The link between FGF11 and lung cancer clinical data was investigated using TCGA and Kaplan-Meier (KM)-plotter databases, and we developed a prediction model. Putative mechanisms of action were investigated using Gene Ontology (GO) and KEGG enrichment analyses. The GeneMANIA and STRING databases were used to search for genes that interact with FGF11, and the Tumor Immune Estimation Resource (TIMER) database was used to discover connections between FGF11 and immune cells, as well as any correlations with immune-related genes. We found that FGF11 expression was higher in the lung adenocarcinoma tissue than in the paracancerous tissue, and patients with high FGF11 expression had a lower overall survival, progression-free survival, and disease specific survival rate than those with low FGF11 expression. The expression of FGF11 was inversely linked to six types of infiltrating immune cells in the TIMER database and was associated with EGFR, VEGFA, BRAF, and MET expressions. The FGF11 gene is negatively correlated with the expression of most immune cells, mainly with various functional T cells including Th1, Th1-like, Treg, and Resting Treg characterization genes. These results indicate that FGF11 has the potential to be a new lung adenocarcinoma biomarker. It increases tumor cell immune escape by boosting T cell exhaustion in the tumor microenvironment, contributing to the poor prognosis of the patients with lung adenocarcinoma. These results provide incentive to further research FGF11 as a possible biomarker and drug target for patients with lung adenocarcinoma.

Pediatric Brain Tumours: Lessons from the Immune Microenvironment

In spite of recent advances in tumour molecular subtyping, pediatric brain tumours (PBTs) remain the leading cause of cancer-related deaths in children. While some PBTs are treatable with favourable outcomes, recurrent and metastatic disease for certain types of PBTs remains challenging and is often fatal. Tumour immunotherapy has emerged as a hopeful avenue for the treatment of childhood tumours, and recent immunotherapy efforts have been directed towards PBTs. This strategy has the potential to combat otherwise incurable PBTs, while minimizing off-target effects and long-term sequelae. As the infiltration and activation states of immune cells, including tumour-infiltrating lymphocytes and tumour-associated macrophages, are key to shaping responses towards immunotherapy, this review explores the immune landscape of the developing brain and discusses the tumour immune microenvironments of common PBTs, with hopes of conferring insights that may inform future treatment design.

Navigating the immunometabolic heterogeneity of B cells in murine hepatocellular carcinoma at single cell resolution

Induction of antitumor immunity is critical for the therapeutic efficacy of hepatocellular carcinoma (HCC) immunotherapy. The cellular metabolic state underpins the effector function of immune cells, yet our understanding of the phenotypic and metabolic heterogeneity of B cells within HCC microenvironment is poorly developed. Herein, we investigated the composition, distribution, phenotype, function and metabolic profiles of B-cell subsets in HCC and adjacent liver tissues from an orthotopic HCC mouse model using single-cell RNA sequencing (scRNA-seq). Our results identified six B-cell clusters, which can be classified into plasma cells and activated and exhausted B cells according to marker expression, functional and temporal distribution. Exhausted B cells exhibited low metabolic activities and impaired effector functions. Activated B and plasma cells showed higher metabolic activity than exhausted B cells, but there were clear differences in their metabolic profiles. In addition, we found that the effector function of exhausted B cells was further diminished in HCC tissues compared with adjacent liver tissues, but their metabolic activity was significantly enhanced. Collectively, we comprehensively characterized the metabolic profile and alterations in B-cell subsets in HCC, which contributes to the understanding of B-cell immunology in HCC and lays the foundation for exploring novel targets in HCC immunotherapy.

Nanoparticle-based immunotherapeutics: from the properties of nanocores to the differential effects of administration routes

The engagement with the immune system is one of the main cornerstones in the development of nanotechnologies for therapy and diagnostics. Recent advances have made possible the tuning of features like size, shape and biomolecular modifications that influence such interactions, however, the capabilities for immune modulation of nanoparticles are still not well defined and exploited. This review focuses on recent advances made in preclinical research for the application of nanoparticles to modulate immune responses, and the main features making them relevant for such applications. We review and discuss newest evidence in the field, which include in vivo experiments with an extensive physicochemical characterization as well as detailed study of the induced immune response. We emphasize the need of incorporating knowledge about immune response development and regulation in the design and application of nanoparticles, including the effect by parameters such as the administration route and the differential interactions with immune subsets.

Regulatory Mechanisms and Reversal of CD8+T Cell Exhaustion: A Literature Review

CD8+T cell exhaustion is a state of T cell dysfunction during chronic infection and tumor progression. Exhausted CD8+T cells are characterized by low effector function, high expression of inhibitory receptors, unique metabolic patterns, and altered transcriptional profiles. Recently, advances in understanding and interfering with the regulatory mechanisms associated with T cell exhaustion in tumor immunotherapy have brought greater attention to the field. Therefore, we emphasize the typical features and related mechanisms of CD8+T cell exhaustion and particularly the potential for its reversal, which has clinical implications for immunotherapy.

Suppression of CEBPδ recovers exhaustion in anti-metastatic immune cells

The pre-metastatic microenvironment consists of pro-metastatic and anti-metastatic immune cells in the early stages of cancer, when the primary tumor begins to proliferate. Redundantly, pro-inflammatory immune cells predominated during tumor growth. Although it is well known that pre-metastatic innate immune cells and immune cells fighting primary tumor cells become exhausted, the mechanism by which this occurs is unknown. We discovered that anti-metastatic NK cells were mobilized from the liver to the lung during primary tumor progression and that the transcription factor CEBPδ, which was upregulated in a tumor-stimulated liver environment, inhibited NK cell attachment to the fibrinogen-rich bed in pulmonary vessels and sensitization to the environmental mRNA activator. CEBPδ-siRNA treated anti-metastatic NK cells regenerated the binding proteins that support sitting in fibrinogen-rich soil, such as vitronectin and thrombospondin, increasing fibrinogen attachment. Furthermore, CEBPδ knockdown restored an RNA-binding protein, ZC3H12D, which captured extracellular mRNA to increase tumoricidal activity. Refreshed NK cells using CEBPδ-siRNA with anti-metastatic abilities would work at metastatic risk areas in the pre-metastatic phase, resulting in a reduction in lung metastasis. Furthermore, tissue-specific siRNA-based therapy in lymphocyte exhaustion may be beneficial in the treatment of early metastases.

Bibliometric and visual analyses of trends in the field of T cell exhaustion research: Findings from 2000 to 2022

BACKGROUND

T cell exhaustion refers to a state wherein T cells become less functional as a result of their prolonged exposure to cognate antigens. A wealth of T cell exhaustion-focused research has been conducted in recent decades, transforming the current understanding of this biologically relevant process. However, there have not been any comprehensive bibliometric analyses to date focused on clarifying the T cell exhaustion-related research landscape. Here, a bibliometric analysis was thus conducted with the goal of better elucidating the current state of knowledge and emerging research hotspots in this field.

METHODS

The Web of Science Core Collection was searched for articles and reviews related to T cell exhaustion, with the CiteSpace and VOSviewer programs then being employed to analyze the countries, institutions, authors, references, and keywords associated with studies in this research space.

RESULTS

In total, 2676 studies were incorporated in this analysis, highlighting progressive annual increases in the number of T cell exhaustion-focused publications over the study period. These publications were affiliated with 3117 institutions in 85 countries, with the USA and China being the largest contributors to the field. Of the 18,032 authors associated with these publications, E. John Wherry exhibited the highest publication count and the greatest citation frequency. Keyword analyses indicated that immunotherapy, T cell exhaustion, and PD-1 are the dominant foci for T cell exhaustion-related research.

CONCLUSION

These findings highlight the importance of collaborations among institutions and nations in order to further propel novel studies of T cell exhaustion. Efforts to unravel the signal transduction and transcriptional mechanisms underlying the onset of T cell exhaustion were also identified as an emerging hotspot in this field. Ultimately, these results support the pivotal status of T cell exhaustion research as a key direction for immunotherapeutic research and development efforts in the coming years.

Concurrent infections of cells by two pathogens can enable a reactivation of the first pathogen and the second pathogen's accelerated T-cell exhaustion

When multiple intracellular pathogens, such as viruses, bacteria, fungi and protozoan parasites, infect the same host cell, they can help each other. A pathogen can substantially help another pathogen by disabling cellular immune defenses, using non-coding ribonucleic acids and/or pathogen proteins that target interferon-stimulated genes and other genes that express immune defense proteins. This can enable reactivation of a latent first pathogen and accelerate T-cell exhaustion and/or T-cell suppression regarding a second pathogen. In a worst-case scenario, accelerated T-cell exhaustion and/or T-cell suppression regarding the second pathogen can impair T-cell functionality and allow a first-time, immunologically novel second pathogen infection to escape all adaptive immune system defenses, including antibodies. The interactions of herpesviruses with concurrent intracellular pathogens in epithelial cells and B-cells, the interactions of the human immunodeficiency virus with Mycobacterium tuberculosis in macrophages and the interactions of Toxoplasma gondii with other pathogens in almost any type of animal cell are considered. The reactivation of latent pathogens and the acceleration of T-cell exhaustion for the second pathogen can explain several puzzling aspects of viral epidemics, such as COVID-19 and their unusual comorbidity mortality rates and post-infection symptoms.

ZL-1211 Exhibits Robust Antitumor Activity by Enhancing ADCC and Activating NK Cell-mediated Inflammation in CLDN18.2-High and -Low Expressing Gastric Cancer Models

CLDN18.2 (Claudin18.2)-targeting therapeutic antibodies have shown promising clinical efficacy in approximately 30% of gastric cancers expressing high levels of CLDN18.2 and less pronounced activity in low expressing malignancies. Here, we report that ZL-1211 is a mAb targeting CLDN18.2 engineered to promote enhanced antibody-dependent cellular cytotoxicity (ADCC) with the goal of achieving more potent activity in a wider spectrum of high- and low-CLDN18.2 expressing tumors. ZL-1211 demonstrated more robust in vitro ADCC activity than clinical benchmark not only in CLDN18.2-high but also CLDN18.2-low expressing gastric tumor cell lines. Greater antitumor efficacy was also observed in mouse xenograft models. Natural killer (NK) cell played critical roles in ZL-1211 efficacy and NK-cell depletion abrogated ZL-1211-mediated ADCC activity in vitro. ZL-1211 efficacy in vivo was also dependent on the presence of an NK compartment. Strikingly, NK cells strongly induced an inflammatory response in response to ZL-1211 treatment, including increased IFNγ, TNFα, and IL6 production, and were recruited into tumor microenvironment in patient-derived gastric tumors expressing CLDN18.2 upon ZL-1211 treatment to lyse the tumor cells. Taken together, our data suggest that ZL-1211 more effectively targets CLDN18.2-high gastric cancers as well as -low expressing malignancies that may not be eligible for treatment with the leading clinical benchmark by inducing enhanced ADCC response and activating NK cells with robust inflammation to enhance antitumor efficacy. Clinical activity of ZL-1211 is currently under evaluation in a phase I clinical trial (NCT05065710).

Significance

ZL-1211, anti-CLDN18.2 therapeutic antibody can target CLDN18.2-high as well as -low gastric cancers that may not be eligible for treatment with clinical benchmark. ZL-1211 treatment induces NK-cell activation with robust inflammation to further activate antitumor immunity in tumor microenvironment.