Interleukin 21 and its receptor are involved in NK cell expansion and regulation of lymphocyte function

Targeting γc family cytokines with biologics: current status and future prospects

Over the recent decades the market potential of biologics has substantially expanded, and many of the top-selling drugs worldwide are now monoclonal antibodies or antibody-like molecules. The common gamma chain (γc) cytokines, Interleukin (IL-)2, IL-4, IL-7, IL-9, IL-15, and IL-21, play pivotal roles in regulating immune responses, from innate to adaptive immunity. Dysregulation of cell signaling by these cytokines is strongly associated with a range of immunological disorders, which includes cancer as well as autoimmune and inflammatory diseases. Given the essential role of γc cytokines in maintaining immune homeostasis, the development of therapeutic interventions targeting these molecules poses unique challenges. Here, we provide an overview of current biologics targeting either single or multiple γc cytokines or their respective receptor subunits across a spectrum of diseases, primarily focusing on antibodies, antibody-like constructs, and antibody-cytokine fusions. We summarize therapeutic biologics currently in clinical trials, highlighting how they may offer advantages over existing therapies and standard of care, and discuss recent advances in this field. Finally, we explore future directions and the potential of novel therapeutic intervention strategies targeting this cytokine family.

Development of a coagulation‑related gene model for prognostication, immune response and treatment prediction in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is the most prevalent form of lung cancer worldwide. Due to the lack of clinically useful molecular biomarkers, the diagnosis and prognosis of patients with LUAD remain poor. Patients with LUAD often exhibit abnormalities in the levels of coagulation factors. Therefore, the objective of the present study was to develop a model based on coagulation-related factors in LUAD. Gene expression data and clinical information from 582 patients with LUAD were obtained from The Cancer Genome Atlas (TCGA). A set of 138 coagulation-related genes (CRGs) was retrieved from The Molecular Signatures Database, and their expression levels were examined in TCGA dataset to identify differentially expressed CRGs. Predictive models were constructed using least absolute shrinkage and selection operator-Cox regression. The risk score from the model was used to establish high- and low-risk patient groups. Additionally, Kaplan-Meier analyses were performed to evaluate the differences in overall survival (OS) and progression-free survival between the two groups. The accuracy of the model was verified through receiver operating characteristic and principal component analysis. In addition, the tumor immune dysfunction and exclusion algorithm was used to assess immune escape and immunotherapy responses in relation to the CRGs. A predictive model comprising four genes, namely matrix metalloproteinase (MMP) 1, MMP10, cathepsin V and thrombin, was established to estimate the survival rate of patients with LUAD. The OS rates of patients in the high-risk group were lower compared with those in the low-risk group. Furthermore, a combination of high-risk score and low tumor mutation burden was associated with the poorest survival in patients with LUAD. Patients in different risk groups exhibited different drug sensitivities based on their risk scores. In conclusion, the four-gene based prognostic model served as an independent predictor of survival rates in patients with LUAD and may offer a novel approach for prognosis and treatment.

IL-21R-Targeted Nano-immunosuppressant Prevents Acute Rejection in Allogeneic Transplantation by Blocking Maturation of T Follicular Helper Cells

During organ transplantation, immune rejection is a primary cause of graft failure. In the underlying pathophysiology of rejection, T follicular helper (Tfh) cells and interleukin-21 (IL-21) play pivotal roles. Tfh cells exacerbate the humoral immune response by promoting B cell differentiation and antibody production, which leads to damage of the transplanted tissue. IL-21, a key pro-inflammatory cytokine, binds to its receptor (IL-21R) to enhance both the growth and function of Tfh cells, while also further driving B cell activation and differentiation into plasma cells. Building on this knowledge, we have developed a tacrolimus-based nano-inhibitor designed to target Tfh cells. This nano-inhibitor is constructed using a mPEG-PLGA-PLL (PEAL) scaffold, with IL-21R monoclonal antibodies conjugated to its surface, and tacrolimus encapsulated within the structure. In vitro experiments demonstrated that this nano-inhibitor effectively targets Tfh cells, inhibiting the differentiation of naive CD4+ T cells into Tfh cells. In co-culture systems of T and B cells, it significantly suppresses the activation of both cell types, leading to a reduction in IgG antibody production. In vivo, the nano-inhibitor selectively targets secondary lymphoid organs, reduces systemic inflammation, minimizes lymphocyte infiltration into the graft, and induces immune tolerance toward the transplanted tissue. In addition, no significant toxicity was observed in vitro or in vivo. As a therapeutic agent that simultaneously modulates both T and B cell responses, we believe it holds significant promise for broader applications in transplantation immunotherapy. STATEMENT OF SIGNIFICANCE: This study presents a groundbreaking nano-immunosuppressant designed to target both T and B cells, addressing the critical challenge of acute rejection in allogeneic transplantation. By combining tacrolimus nanoparticles with IL-21 receptor antibodies, this immunosuppressant effectively suppresses Tfh cell proliferation and B cell activation, significantly reducing IgG generation. The formulation enhances tacrolimus's bioavailability, minimizes off-target toxicity, and overcomes its narrow therapeutic window. In vitro and in vivo studies show reduced lymphocyte infiltration, lower inflammatory markers, and decreased nephrotoxicity compared to conventional tacrolimus.

Characteristics and functions of interleukin 21 in channel catfish (Ictalurus punctatus)

Interleukin-21 (IL-21) is mainly produced by CD4+ T cells and NKT cells, belonging to the gamma chain (γc) family. It promotes the proliferation, activation, and differentiation of immune cells and activates the JAK-STAT, MAPK signaling, and PI3K pathways to regulate immune responses, crucially impacting anti-infectious inflammatory responses. In this study, IL-21 was successfully identified in channel catfish (Ictalurus punctatus, Ip), with a coding sequence (CDS) length of 438 bp encoding a 145-amino acid (aa) protein. The signal peptide comprised 19 aa, while the mature peptide consists of 126 aa, featuring four α-helix structures and two pairs of disulfide bonds from four conserved cysteine residues. qPCR data revealed highest IpIL-21 expression in channel catfish gills and spleen. Bacterial and viral infections upregulated IpIL-21 expression across multiple tissues. Poly(I:C) specifically enhanced IpIL-21 expression in channel catfish kidney cells (CCK) at 48 h post-infection (hpi). In vitro, recombinant IpIL-21 (rIpIL-21) protein induced upregulation of IL-10, IL-21, IL-1β, and STAT3 expression in CCK, while inhibiting IL-22 and IL-26 expression. IL-6 and IL-20 expressions were inhibited at low doses and induced at high doses, demonstrating a dose-dependent pattern. These findings underscored IpIL-21's significance as a critical immune factor in channel catfish, pivotal for the antibacterial inflammatory response defense system.

The role of cytokines in shaping the future of Cancer immunotherapy

As essential immune system regulators, cytokines are essential for modulating both innate and adaptive immunological responses. They have become important tools in cancer immunotherapy, improving the immune system's capacity to identify and destroy tumor cells. This article examines the background, workings, and therapeutic uses of cytokines, such as interleukins, interferons, and granulocyte-macropHage colony-stimulating factors, in the management of cancer. It examines the many ways that cytokines affect immune cell activation, signaling pathways, tumor development, metastasis, and prognosis by modifying the tumor microenvironment. Despite the limited effectiveness of cytokine-based monotherapy, recent developments have concentrated on new fusion molecules such as immunocytokines, cytokine delivery improvements, and combination techniques to maximize treatment efficacy while reducing adverse effects. Current FDA-approved cytokine therapeutics and clinical trial results are also included in this study, which offers insights into how cytokines might be used with other therapies including checkpoint inhibitors, chemotherapy, and radiation therapy to address cancer treatment obstacles. This study addresses the intricacies of cytokine interactions in the tumor microenvironment, highlighting the possibility for innovative treatment methods and suggesting fresh techniques for enhancing cytokine-based immunotherapies. PEGylation, viral vector-mediated cytokine gene transfer, antibody-cytokine fusion proteins (immunocytokines), and other innovative cytokine delivery techniques are among the novelties of this work, which focuses on the most recent developments in cytokine-based immunotherapy. Additionally, the study offers a thorough examination of the little-reviewed topic of cytokine usage in conjunction with other treatment techniques. It also discusses the most recent clinical studies and FDA-approved therapies, providing a modern perspective on the developing field of cancer immunotherapy and suggesting creative ways to improve treatment effectiveness while lowering toxicity. BACKGROUND: Cytokines are crucial in cancer immunotherapy for regulating immune responses and modifying the tumor microenvironment (TME). However, challenges with efficacy and safety have driven research into advanced delivery methods and combination therapies to enhance their therapeutic potential.

The effects of interleukin-21 in the biology of transplant rejection

Interleukin-21 (IL-21) is a cytokine that plays a crucial role in regulating immune responses, affecting various immune cell types, including T cells, B cells, natural killer (NK) cells, and dendritic cells. IL-21 is primarily produced by CD4+ T cells, particularly follicular helper T (Tfh) cells and Th17 cells, and has been shown to be extensively involved in regulating both innate and adaptive immunity. IL-21 is particularly significant in the differentiation, proliferation, and effector functions of T cells and B cells. In the context of organ transplantation, IL-21 contributes to the promotion of acute transplant rejection and the development of chronic rejection, which is primarily antibody-mediated. This review summarizes relevant studies on IL-21 and discusses its multifaceted roles in transplant immune rejection, providing insights into therapeutic strategies for either inhibiting graft rejection or promoting tolerance. It also explores the feasibility of blocking the IL-21 signaling pathway within current immunosuppressive regimens, aiming to provide further clinical references.

Type XVII Collagen-Specific CD4+ T Cells Induce Bullous Pemphigoid by Producing IL-5

Bullous pemphigoid is an autoimmune subepidermal blistering disease caused by anti-type XVII collagen (COL17) antibodies. Bullous pemphigoid has some immunological features such as eosinophilic infiltration and the deposition of IgE autoantibodies in the skin; however, the mechanism behind such features remains largely unclear. We focused on the autoantigen-specific CD4+ T cells, which are considered to regulate immune response. We established COL17-specific CD4+ T cell lines in vitro. Wild-type mice were immunized with synthesized peptides that include a pathogenic epitope of COL17, and lymphocytes were subjected to a limiting dilution assay. We established 5 T cell lines and examined the pathogenicity by transferring them with COL17-primed B cells into Rag-2-/-/COL17-humanized mice that express human COL17 but not mouse COL17 in the skin. Notably, 3 lines induced bullous pemphigoid-like skin changes associated with subepidermal separation and eosinophilic infiltration histologically and the production of anti-COL17 antibodies. The other 2 lines did not induce such phenotypes. RNA-sequencing analysis revealed that T helper 2 cytokines, particularly IL-5, were highly expressed in the pathogenic T-cell lines. Anti-IL-5 antibody administration significantly reduced the skin changes and attenuated the production of autoantibodies. Thus, the production of IL-5 is critical for COL17-specific CD4+ T cells to induce bullous pemphigoid phenotypes in vivo.

JAK-STAT pathway, type I/II cytokines, and new potential therapeutic strategy for autoimmune bullous diseases: update on pemphigus vulgaris and bullous pemphigoid

Autoimmune Bullous Diseases (AIBDs), characterized by the formation of blisters due to autoantibodies targeting structural proteins, pose significant therapeutic challenges. Current treatments, often involving glucocorticoids or traditional immunosuppressants, are limited by their non-specificity and side effects. Cytokines play a pivotal role in AIBDs pathogenesis by driving inflammation and immune responses. The JAK-STAT pathway is central to the biological effects of various type I and II cytokines, making it an attractive therapeutic target. Preliminary reports suggest that JAK inhibitors may be a promising approach in PV and BP, but further clinical validation is required. In AIBDs, particularly bullous pemphigoid (BP) and pemphigus vulgaris (PV), JAK inhibitors have shown promise in modulating pathogenic cytokine signaling. However, the safety and selectivity of JAK inhibitors remain critical considerations, with the potential for adverse effects and the need for tailored treatment strategies. This review explores the role of cytokines and the JAK-STAT pathway in BP and PV, evaluating the therapeutic potential and challenges associated with JAK inhibitors in managing these complex disorders.

Interleukin-21 engineering enhances CD19-specific CAR-NK cell activity against B-cell lymphoma via enriched metabolic pathways

BACKGROUND

NK cells engineered to express interleukin-15 (IL-15) and a CD19-targeted chimeric antigen receptor (CAR) have been used to treat patients with relapsed and/or refractory B cell malignances, demonstrating encouraging outcomes and favorable safety profile. However, the effect of IL-21 in CAR-NK cell therapy remains unknown.

METHODS

CD19-specific CAR with 4-1BB costimulatory domain and cytokine IL-21 or IL-15 was constructed and transduced into peripheral blood (PB)-derived NK cells to produce CD19-CAR-IL21 NK cells (CAR-21) or CD19-CAR-IL15 NK cells (CAR-15), respectively. The phenotypic profile, transcriptomic characteristics, functionality and anti-tumor activity of CAR-21 NK cells and CAR-15 NK cells were compared.

RESULTS

Compared with CAR-NK cells co-expressing IL-15, CAR-NK cells co-expressing IL-21 exhibited significantly increased IFN-γ, TNF-α and Granzyme B production, as well as degranulation, in response to CD19+ Raji lymphoma cells, resulting in enhanced cytotoxic activity upon repetitive tumor stimulation. Furthermore, IL-21 co-expression improved the in vivo persistence of CAR-NK cells and significantly suppressed tumor growth in a xenograft Raji lymphoma murine model, leading to prolonged survival of CD19+ tumor-bearing mice. RNA sequencing revealed that CAR-21 NK cells have a distinct transcriptomic signature characterized by enriched in cytokine, cytotoxicity, and metabolic related signaling, when compared with CAR-15 NK or CAR NK cells.

CONCLUSIONS

This study demonstrated that CD19-specific CAR-NK cells engineered to express IL-21 exhibit superior persistence and anti-tumor activity against CD19+ tumor compared to CAR-NK cells co-expressing IL-15, which might be a promising therapeutic strategy for treating patients with relapse or refractory B cell malignances.

Comparative transcriptomic analysis of chicken immune organs affected by Marek's disease virus infection at latency phases

Over the past decades, MDV has dramatically evolved towards more virulent strains and remains a persistent threat to the world's poultry industry. We performed genome-wide gene expression analysis in the spleen, thymus, and bursa tissues from MD-resistant line and susceptible line to explore the mechanism of MD resistance and susceptibility. We identified genes and pathways associated with the transcriptional response to MDV infection using the robust RNA sequencing approach. The transcriptome analysis revealed a tissue-specific expression pattern among immune organs when confronting MDV. At pathway and network levels, MDV infections influenced cytokine-cytokine receptor interaction and cellular development in resistant and susceptible chicken lines. Meanwhile, we also observed different genetic responses between the two chicken lines: some pathways like herpes simplex infection and influenza A were found in MD resistant line spleen tissues, whereas metabolic-related pathways and DNA replication could only be observed in MD susceptible line chickens. In summary, our research renders new perceptions of the MD progression mechanism and beckons further gene function studies into MD resistance.

Combinatorial immunotherapy with anti-ROR1 CAR NK cells and an IL-21 secreting oncolytic virus against neuroblastoma

Children with recurrent/metastatic neuroblastoma (NB) have a dismal survival (<25%). Novel therapies are desperately needed. Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is highly expressed on NB. C021 is a selective oncolytic herpes simplex virus modified to overexpress human interleukin-21 (hIL-21), a cytokine that enhances natural killer (NK) cell cytotoxicity. In the current study, we successfully engineered ex-vivo-expanded NK cells to express a chimeric antigen receptor (CAR) against ROR1 using mRNA electroporation and investigated the efficacy of anti-ROR1-CAR-NK cells combined with C021 in targeting ROR1+ NB. We found that C021-infected NB cells secreted hIL-21 in vitro and in vivo. Compared to the non-cytokine-secreting parental virus C134, C021 significantly enhanced the in vitro cytotoxicity (p < 0.05) of anti-ROR1-CAR-NK cells with increased interferon (IFN)-γ (p < 0.05), granzyme B (p < 0.05), and perforin (p < 0.05) secretion against NB cells. Furthermore, the combination of C021 and anti-ROR1-CAR-NK cells significantly extended the survival of human NB xenografted NSG mice compared to controls (mock NK, ROR1-CAR-NK, C134, C021, C134+ROR1-CAR-NK, and C021+mock NK). Our results suggest that cytokine-secreting oncolytic virus in combination with CAR-NK cells is a novel, effective immunotherapeutic approach for high-risk NB.

IL-21 signaling promotes IgM+ B cell proliferation and antibody production via JAK/STAT3 and AKT pathways in early vertebrates

IL-21 is a type I cytokine that is produced by activated CD4+ T cells and has a significant impact on the growth, survival, and functional activation of B lymphocytes. While IL-21 has been identified in several teleost fish species, its function and associated mechanisms focus on teleost fish B cells remain largely unknown. In this study, we aimed to investigate the effects of IL-21 (OnIL-21) on IgM+ B cells from Nile tilapia (Oreochromis niloticus), as well as the intracellular signaling transduction pathway involved. Through intraperitoneal injection of recombinant OnIL-21 (rOnIL-21), we observed that IL-21 exerted significant effects on Nile tilapia IgM+ B cells, including the promotion of IgM+ B cell proliferation, induction of IgM secretion, and up-regulation of inflammatory cytokines. These findings suggest that OnIL-21 enhances the ability of IgM+ B cells in humoral immunity. Furthermore, when IgM + B cells were stimulated with rOnIL-21 in vitro, we observed a significant up-regulation in antibody secretion ability (sIgM), as well as increased expression of IFN-γ and IL-10. To further understand the regulatory mechanism of OnIL-21, we demonstrated that OnIL-21 binds to its heterodimer receptor complex (OnIL-21R/Onγc) to exert its function. This binding triggers the conserved JAK/STAT3 and AKT pathways, which in turn regulate the expression of genes involved in B cell proliferation, antibody secretion, and cytokine expression. Collectively, our findings establish that IL-21 plays a crucial role in the regulation of humoral immunity in lower vertebrates, and this regulation is mediated through conserved signaling pathways across vertebrates.

Contribution of interleukins in the regulation of teleost fish immunity: A review from the perspective of regulating macrophages

Interleukins (ILs) are potent secreted regulators of a wide range of cell types and cellular activities, particularly in the immune system. They are able to participate in intercellular communication in homeostasis and disease, thereby exerting immune functions. Macrophages serve as the innate immune cells of vertebrates and play a pivotal role in defending against and eliminating external pathogens. In mammals, the immune response mounted by macrophages is intricately linked to ILs. Given the fact that teleost fish have evolved an innate immune system that closely resembles those of mammals, particularly in terms of the functionality of macrophages, raises the intriguing possibility that the regulatory function of ILs in macrophage-mediated immunity might be evolutionarily conserved across both mammal and teleost fish lineages. Consequently, from the perspective of interleukin regulation of macrophages, this review outlines the relationship between ILs and macrophages in teleost fish, and elucidates the regulatory role of ILs of immune cell function in teleost fish, thereby contributing to our understanding of the key role of these cytokines in the prevention and control of aquaculture diseases.

Based on the immune system: the role of the IL-2 family in pancreatic disease

The IL-2 family, consisting of IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21, is a key regulator of the immune response. As an important endocrine and digestive organ, the function of the pancreas is regulated by the immune system. Studies have shown that each cytokine of the IL-2 family influences the occurrence and development of pancreatic diseases by participating in the regulation of the immune system. In this paper, we review the structural and functional characteristics of IL-2 family members, focus on their molecular mechanisms in pancreatic diseases including acute pancreatitis, chronic pancreatitis and pancreatic cancer, and highlight the importance of the related proteins in the regulation of immune response and disease progression, which will provide valuable insights for new biomarkers in pancreatic diseases, early diagnosis of the diseases, assessment of the disease severity, and development of new therapeutic regimens. The insights of the study are summarized in the following sections.

IL-21 shapes the B cell response in a context-dependent manner

The T-cell-derived cytokine IL-21 is crucial for germinal center (GC) responses, but its precise role in B cell function has remained elusive. Using IL-21 receptor (Il21r) conditional knockout mice and ex vivo culture systems, we demonstrate that IL-21 has dual effects on B cells. While IL-21 induced apoptosis in a STAT3-dependent manner in naive B cells, it promoted the robust proliferation of pre-activated B cells, particularly IgG1+ B cells. In vivo, B-cell-specific Il21r deletion impaired IgG1 responses post-immunization and disrupted progression from pre-GC to GC states. Although Il21r deficiency did not affect the proportion of IgG1+ cells among GC B cells, it greatly diminished the proportion of IgG1+ cells among the plasmablast/plasma cell population. Collectively, our findings suggest that IL-21 serves as a critical regulator of B cell fates, influencing B cell apoptosis and proliferation in a context-dependent manner.

Cytokines in cancer

Cytokines are proteins used by immune cells to communicate with each other and with cells in their environment. The pleiotropic effects of cytokine networks are determined by which cells express cytokines and which cells express cytokine receptors, with downstream outcomes that can differ based on cell type and environmental cues. Certain cytokines, such as interferon (IFN)-γ, have been clearly linked to anti-tumor immunity, while others, such as the innate inflammatory cytokines, promote oncogenesis. Here we provide an overview of the functional roles of cytokines in the tumor microenvironment. Although we have a sophisticated understanding of cytokine networks, therapeutically targeting cytokine pathways in cancer has been challenging. We discuss current progress in cytokine blockade, cytokine-based therapies, and engineered cytokine therapeutics as emerging cancer treatments of interest.

Potent antitumor activity of a designed interleukin-21 mimic

Long-standing goals of cancer immunotherapy are to activate cytotoxic antitumor T cells across a broad range of affinities while dampening suppressive regulatory T (Treg) cell responses, but current approaches achieve these goals with limited success. Here, we report a de novo IL-21 mimic, 21h10, designed to have augmented stability and high signaling potency in both humans and mice. In multiple animal models and in ex vivo human melanoma patient derived organotypic tumor spheroids (PDOTS), 21h10 showed robust antitumor activity. 21h10 generates significantly prolonged STAT signaling in vivo compared with native IL-21, and has considerably stronger anti-tumor activity. Toxicities associated with systemic administration of 21h10 could be mitigated by TNFα blockade without compromising antitumor efficacy. In the tumor microenvironment, 21h10 induced highly cytotoxic antitumor T cells from clonotypes with a range of affinities for endogenous tumor antigens, robustly expanding low-affinity cytotoxic T cells and driving high expression of interferon-𝛾 (IFN-𝛾) and granzyme B compared to native IL-21, while increasing the frequency of IFN-𝛾 + Th1 cells and reducing that of Foxp3 + Tregs. As 21h10 has full human/mouse cross-reactivity, high stability and potency, and potentiates low-affinity antitumor responses, it has considerable translational potential.

Implications of glycosylation for the development of selected cytokines and their derivatives for medical use

Cytokines are important regulators of immune responses, making them attractive targets for autoimmune diseases and cancer therapeutics. Yet, the significance of cytokine glycosylation remains underestimated. Many cytokines carry N- and O-glycans and some even undergo C-mannosylation. Recombinant cytokines produced in heterologous host cells may lack glycans or exhibit a different glycosylation pattern such as varying levels of galactosylation, sialylation, fucosylation or xylose addition compared to their human counterparts, potentially impacting critical immune interactions. We focused on cytokines that are currently utilized or designed in advanced therapeutic formats, including immunocytokines, fusokines, engager cytokines, and genetically engineered 'supercytokines.' Despite the innovative designs of these cytokine derivatives, their glycosylation patterns have not been extensively studied. By examining the glycosylation of the human native cytokines, G-CSF and GM-CSF, interferons β and γ, TNF-α and interleukins-2, -3 -4, -6, -7, -9, -12, -13, -15, -17A, -21, and - 22, we aim to assess its potential impact on their therapeutic derivatives. Understanding the glycosylation of the native cytokines could provide critical insights into the safety, efficacy, and functionality of these next-generation cytokine therapies, affecting factors such as stability, bioactivity, antigenicity, and half-life. This knowledge can guide the choice of optimal expression hosts for production and advance the development of effective cytokine-based therapeutics and synthetic immunology drugs.

Inflammatory response signature score model for predicting immunotherapy response and pan-cancer prognosis

Background

Inflammatory responses influence the outcome of immunotherapy and tumorigenesis by modulating host immunity. However, systematic inflammatory response assessment models for predicting cancer immunotherapy (CIT) responses and survival across human cancers remain unexplored. Here, we investigated an inflammatory response score model to predict CIT responses and patient survival in a pan-cancer analysis.

Methods

We retrieved 12 CIT response gene expression datasets from the Gene Expression Omnibus database (GSE78220, GSE19423, GSE100797, GSE126044, GSE35640, GSE67501, GSE115821 and GSE168204), Tumor Immune Dysfunction and Exclusion database (PRJEB23709, PRJEB25780 and phs000452.v2.p1), European Genome-phenome Archive database (EGAD00001005738), and IMvigor210 cohort. The tumor samples from six cancers types: metastatic urothelial cancer, metastatic melanoma, gastric cancer, primary bladder cancer, renal cell carcinoma, and non-small cell lung cancer.We further established a binary classification model to predict CIT responses using the least absolute shrinkage and selection operator (LASSO) computational algorithm.

Findings

The model had high predictive accuracy in both the training and validation cohorts. During sub-group analysis, area under the curve (AUC) values of 0.82, 0.80, 0.71, 0.7, 0.67, and 0.64 were obtained for the non-small cell lung cancer, gastric cancer, metastatic urothelial cancer, primary bladder cancer, metastatic melanoma, and renal cell carcinoma cohorts, respectively. CIT response rates were higher in the high-scoring training cohort subjects (51%) than the low-scoring subjects (27%). The five-year survival rates in the high- and low score groups of the training cohorts were 62% and 21%, respectively, while those of the validation cohorts were 54% and 22%, respectively (P < 0·001 in all cases). Inflammatory response signature score derived from on-treatment tumor specimens are highly predictive of response to CIT in patients with metastatic melanoma. A significant correlation was observed between the inflammatory response scores and tumor purity. Regardless of the tumor purity, patients in the low score group had a significantly poorer prognosis than those in the high score group. Immune cell infiltration analysis indicated that in the high score cohort, tumor-infiltrating lymphocytes were significantly enriched, particularly effector and natural killer cells. Inflammatory response scores were positively correlated with immune checkpoint genes, suggesting that immune checkpoint inhibitors may have benefited patients with high scores. Analysis of signature scores across different cancer types from The Cancer Genome Atlas revealed that the prognostic performance of inflammatory response scores for survival in patients who have not undergone immunotherapy can be affected by tumor purity. Interleukin 21 (IL21) had the highest weight in the inflammatory response model, suggesting its vital role in the prediction mode. Since the number of metastatic melanoma patients (n = 429) was relatively large among CIT cohorts, we further performed a co-culture experiment using a melanoma cell line and CD8 + T cell populations generated from peripheral blood monocytes. The results showed that IL21 therapy combined with anti-PD1 (programmed cell death 1) antibodies (trepril monoclonal antibodies) significantly enhanced the cytotoxic activity of CD8 + T cells against the melanoma cell line.

Conclusion

In this study, we developed an inflammatory response gene signature model that predicts patient survival and immunotherapy response in multiple malignancies. We further found that the predictive performance in the non-small cell lung cancer and gastric cancer group had the highest value among the six different malignancy subgroups. When compared with existing signatures, the inflammatory response gene signature scores for on-treatment samples were more robust predictors of the response to CIT in metastatic melanoma.

Novel immunotherapeutic approaches in gastric cancer

Gastric cancer is a malignant tumor that ranks third in cancer-related deaths worldwide. Early-stage gastric cancer can often be effectively managed through surgical resection. However, the majority of cases are diagnosed in advanced stages, where outcomes with conventional radiotherapy and chemotherapy remain unsatisfactory. Immunotherapy offers a novel approach to treating molecularly heterogeneous gastric cancer by modifying the immunosuppressive tumor microenvironment. Immune checkpoint inhibitors and adoptive cell therapy are regarded as promising modalities in cancer immunotherapy. Food and Drug Administration-approved programmed death-receptor inhibitors, such as pembrolizumab, in combination with chemotherapy, have significantly extended overall survival in gastric cancer patients and is recommended as a first-line treatment. Despite challenges in solid tumor applications, adoptive cell therapy has demonstrated efficacy against various targets in gastric cancer treatment. Among these approaches, chimeric antigen receptor-T cell therapy research is the most widely explored and chimeric antigen receptor-T cell therapy targeting claudin18.2 has shown acceptable safety and robust anti-tumor capabilities. However, these advancements primarily remain in preclinical stages and further investigation should be made to promote their clinical application. This review summarizes the latest research on immune checkpoint inhibitors and adoptive cell therapy and their limitations, as well as the role of nanoparticles in enhancing immunotherapy.

Comprehensive snapshots of natural killer cells functions, signaling, molecular mechanisms and clinical utilization

Natural killer (NK) cells, initially identified for their rapid virus-infected and leukemia cell killing and tumor destruction, are pivotal in immunity. They exhibit multifaceted roles in cancer, viral infections, autoimmunity, pregnancy, wound healing, and more. Derived from a common lymphoid progenitor, they lack CD3, B-cell, or T-cell receptors but wield high cytotoxicity via perforin and granzymes. NK cells orchestrate immune responses, secreting inflammatory IFNγ or immunosuppressive TGFβ and IL-10. CD56dim and CD56bright NK cells execute cytotoxicity, while CD56bright cells also regulate immunity. However, beyond the CD56 dichotomy, detailed phenotypic diversity reveals many functional subsets that may not be optimal for cancer immunotherapy. In this review, we provide comprehensive and detailed snapshots of NK cells' functions and states of activation and inhibitions in cancer, autoimmunity, angiogenesis, wound healing, pregnancy and fertility, aging, and senescence mediated by complex signaling and ligand-receptor interactions, including the impact of the environment. As the use of engineered NK cells for cancer immunotherapy accelerates, often in the footsteps of T-cell-derived engineering, we examine the interactions of NK cells with other immune effectors and relevant signaling and the limitations in the tumor microenvironment, intending to understand how to enhance their cytolytic activities specifically for cancer immunotherapy.

Simultaneous Stimulation of Peripheral Blood Mononuclear Cells with CpG ODN2006 and α-IgM Antibodies Leads to Strong Immune Responses in Monocytes Independent of B Cell Activation

CpG ODN2006 is widely used both in vitro and in vivo to achieve B cell activation and has been previously applied in clinical trials as an adjuvant and anti-cancer agent. Recent studies have demonstrated the benefit of combining CpG ODN2006 with α-IgM antibodies to obtain optimal B cell activation in vitro. In this study, we expanded the knowledge of how both agents affect other types of peripheral blood mononuclear cells (PBMCs), thereby highlighting beneficial and potentially unfavorable properties of the combination of CpG ODN2006 and α-IgM when applied beyond isolated B cells. We elucidated the effects of both compounds on mixed PBMCs, as well as on B cell- and monocyte-depleted PBMCs, allowing us to distinguish between direct effects and indirect influences mediated by other interacting immune cells. Flow cytometry was used to measure the expression of surface markers and intracellular cytokines, while ELISA and multiplex assays were performed to determine cytokine secretion. Our results revealed that stimulation of mixed PBMCs with CpG ODN2006 and α-IgM strongly increased cytokine secretion, primarily originating from α-IgM-stimulated monocytes. Monocyte activation was confirmed by increased CD86 and HLA-DR expression and occurred independently of B cells. The high level of monocyte-derived cytokines after α-IgM exposure did not affect B cell activation. However, it represents a rather unfavorable property for clinical applications. In conclusion, α-IgM is a potent inducer of cytokine production in monocytes. Based on our findings we hypothesize that significant side effects on monocytes can occur when using α-IgM to enhance CpG ODN2006's efficacy on B cells, particularly in clinical settings.

Additional use of α-IgM antibodies potentiates CpG ODN2006-induced B cell activation by targeting mainly naïve and marginal zone-like B cells

CpG ODN2006 is widely used as a potent B cell stimulant in vitro and in vivo. However, it shows a deficit in targeting naïve B cells in vitro. In this study, we investigated whether α-IgM can support ODN2006-induced effects on B cells to obtain enhanced activation with focus on different B cell subsets. Our results delineated robust B cell activation, shown by increased activation marker expression and cytokine secretion by each agent alone, and further augmented when used in combination. Interestingly, α-IgM targeted mainly naïve and marginal zone-like B cells, thus complementing the pronounced effects of ODN2006 on memory B cells and achieving optimal activation for all B cell subsets. Taken together, combining ODN2006 and α-IgM is beneficial for in vitro activation including all B cell subsets. Furthermore, our results suggest that α-IgM could enhance efficacy of ODN2006 in vivo with further need of investigation.

Innate and adaptive immune responses that control lymph-borne viruses in the draining lymph node

The interstitial fluids in tissues are constantly drained into the lymph nodes (LNs) as lymph through afferent lymphatic vessels and from LNs into the blood through efferent lymphatics. LNs are strategically positioned and have the appropriate cellular composition to serve as sites of adaptive immune initiation against invading pathogens. However, for lymph-borne viruses, which disseminate from the entry site to other tissues through the lymphatic system, immune cells in the draining LN (dLN) also play critical roles in curbing systemic viral dissemination during primary and secondary infections. Lymph-borne viruses in tissues can be transported to dLNs as free virions in the lymph or within infected cells. Regardless of the entry mechanism, infected myeloid antigen-presenting cells, including various subtypes of dendritic cells, inflammatory monocytes, and macrophages, play a critical role in initiating the innate immune response within the dLN. This innate immune response involves cellular crosstalk between infected and bystander innate immune cells that ultimately produce type I interferons (IFN-Is) and other cytokines and recruit inflammatory monocytes and natural killer (NK) cells. IFN-I and NK cell cytotoxicity can restrict systemic viral spread during primary infections and prevent serious disease. Additionally, the memory CD8+ T-cells that reside or rapidly migrate to the dLN can contribute to disease prevention during secondary viral infections. This review explores the intricate innate immune responses orchestrated within dLNs that contain primary viral infections and the role of memory CD8+ T-cells following secondary infection or CD8+ T-cell vaccination.

Interleukin-21 engineering enhances NK cell activity against glioblastoma via CEBPD

Glioblastoma (GBM) is an aggressive brain cancer with limited therapeutic options. Natural killer (NK) cells are innate immune cells with strong anti-tumor activity and may offer a promising treatment strategy for GBM. We compared the anti-GBM activity of NK cells engineered to express interleukin (IL)-15 or IL-21. Using multiple in vivo models, IL-21 NK cells were superior to IL-15 NK cells both in terms of safety and long-term anti-tumor activity, with locoregionally administered IL-15 NK cells proving toxic and ineffective at tumor control. IL-21 NK cells displayed a unique chromatin accessibility signature, with CCAAT/enhancer-binding proteins (C/EBP), especially CEBPD, serving as key transcription factors regulating their enhanced function. Deletion of CEBPD resulted in loss of IL-21 NK cell potency while its overexpression increased NK cell long-term cytotoxicity and metabolic fitness. These results suggest that IL-21, through C/EBP transcription factors, drives epigenetic reprogramming of NK cells, enhancing their anti-tumor efficacy against GBM.

IL-21 Shapes the B Cell Response in a Context-Dependent Manner

The cytokine interleukin-21 (IL-21) is a pivotal T cell-derived signal crucial for germinal center (GC) responses, but the precise mechanisms by which IL-21 influences B cell function remain elusive. Here, we investigated the B cell-intrinsic role of IL-21 signaling by employing a novel IL-21 receptor ( Il21r ) conditional knock-out mouse model and ex vivo culture systems and uncovered a surprising duality of IL-21 signaling in B cells. While IL-21 stimulation of naïve B cells led to Bim-dependent apoptosis, it promoted robust proliferation of pre-activated B cells, particularly class-switched IgG1 + B cells ex vivo . Consistent with this, B cell-specific deletion of Il21r led to a severe defect in IgG1 responses in vivo following immunization. Intriguingly, Il21r -deleted B cells are significantly impaired in their ability to transition from a pre-GC to a GC state following immunization. Although Il21r -deficiency did not affect the proportion of IgG1 + B cells among GC B cells, it greatly diminished the proportion of IgG1 + B cells among the plasmablast/plasma cell population. Collectively, our data suggest that IL-21 serves as a critical regulator of B cell fates, influencing B cell apoptosis and proliferation in a context-dependent manner.

A Critical Role of Culture Medium Selection in Maximizing the Purity and Expansion of Natural Killer Cells

Natural killer (NK) cells hold promise in cancer treatment due to their ability to spontaneously lyse cancer cells. For clinical use, high quantities of pure, functional NK cells are necessary. Combining adherence-based isolation with specialized media showed the unreliability of the isolation method, but demonstrated the superiority of the NK MACS® medium, particularly in suboptimal conditions. Neither human pooled serum, fetal calf serum (FCS), human platelet lysate, nor chemically defined serum replacement could substitute human AB serum. Interleukin (IL-)2, IL-15, IL-21, and combined CD2/NKp46 stimulation were assessed. IL-21 and CD2/NKp46 stimulation increased cytotoxicity, but reduced NK cell proliferation. IL-15 stimulation alone achieved the highest proliferation, but the more affordable IL-2 performed similarly. The RosetteSep™ human NK cell enrichment kit was effective for isolation, but the presence of peripheral blood mononuclear cells (PBMCs) in the culture enhanced NK cell proliferation, despite similar expression levels of CD16, NKp46, NKG2D, and ICAM-1. In line with this, purified NK cells cultured in NK MACS® medium with human AB serum and IL-2 demonstrated high cytotoxicity against primary glioblastoma stem cells.

Id1 expression in CD4 T cells promotes differentiation and function of follicular helper T cells and upregulation of related functional molecules

Although the roles of E proteins and inhibitors of DNA-binding (Id) in T follicular helper (TFH) and T follicular regulatory (TFR) cells have been previously reported, direct models demonstrating the impact of multiple E protein members have been lacking. To suppress all E proteins including E2A, HEB and E2-2, we overexpressed Id1 in CD4 cells using a CD4-Id1 mouse model, to observe any changes in TFH and TFR cell differentiation. Our objective was to gain better understanding of the roles that E proteins and Id molecules play in the differentiation of TFH and TFR cells. The CD4-Id1 transgenic (TG) mice that we constructed overexpressed Id1 in CD4 cells, inhibiting E protein function. Our results showed an increase in the proportion and absolute numbers of Treg, TFH and TFR cells in the spleen of TG mice. Additionally, the expression of surface characterisation molecules PD-1 and ICOS was significantly upregulated in TFH and TFR cells. The study also revealed a downregulation of the marginal zone B cell precursor and an increase in the activation and secretion of IgG1 in spleen B cells. Furthermore, the peripheral TFH cells of TG mice enhanced the function of assisting B cells. RNA sequencing results indicated that a variety of TFH-related functional molecules were upregulated in TFH cells of Id1 TG mice. In conclusion, E proteins play a crucial role in regulating TFH/TFR cell differentiation and function and suppressing E protein activity promotes germinal centre humoral immunity, which has important implications for immune regulation and treating related diseases.

Immune-Mediated Liver Effects Associated With Administration of a Human Anti-IL-21 Receptor Antibody (ATR-107) in Rats

The toxicity of ATR-107, a human anti-interleukin-21 receptor (IL-21R) monoclonal antibody (mAb), was evaluated in CD-1 mice and cynomolgus monkeys after single-dose intravenous (IV) administration, and in Sprague-Dawley (SD) rats and cynomolgus monkeys after weekly IV and subcutaneous (SC) administration in 13-week toxicity studies that included recovery. Adverse liver necrosis, diffuse bridging fibrosis, and higher liver enzymes occurred in rats in the low-dose IV group (10 mg/kg), but not at 50 or 250 mg/kg IV, and not following SC administration despite overlapping systemic ATR-107 exposures. Similar findings were not seen in mice or cynomolgus monkeys. A series of investigative rat toxicity studies showed liver findings only occurred after administration of at least 3 weekly doses, only occurred in rats that developed anti-drug antibodies (ADAs), and the incidence was associated with higher ADAs titers. However, the presence of ADAs did not always result in liver injury. Liver findings did not occur in nude rats, which had high ATR-107 exposures and no ADAs. These findings suggest an adaptive immune response with formation of ADAs was necessary for development of ATR-107-related liver findings, and that liver injury can occur in rats secondary to development of ADAs following repeated administration of a human therapeutic mAb.

The role of Interleukin-21 (IL-21) in allergic disorders: Biological insights and regulatory mechanisms

In recent decades, allergic diseases subsequent from an IgE-mediated response to specific allergens have become a progressively public chronic disease worldwide. They have shaped an important medical and socio-economic burden. A significant proportion of allergic disorders are branded via a form 2 immune response relating Th2 cells, type 2 natural lymphoid cells, mast cells and eosinophils. Interleukin-21 (IL-21) is a participant of the type-I cytokine family manufactured through numerous subsets of stimulated CD4+ T cells and uses controlling properties on a diversity of immune cells. Increasingly, experimental sign suggests a character for IL-21 in the pathogenesis of numerous allergic disorders. The purpose of this review is to discuss the biological properties of IL-21 and to summaries current developments in its role in the regulation of allergic disorders.

NK cells as powerful therapeutic tool in cancer immunotherapy

BACKGROUND

Natural killer (NK) cells have gained considerable attention and hold great potential for their application in tumor immunotherapy. This is mainly due to their MHC-unrestricted and pan-specific recognition capabilities, as well as their ability to rapidly respond to and eliminate target cells. To artificially generate therapeutic NK cells, various materials can be utilized, such as peripheral blood mononuclear cells (PBMCs), umbilical cord blood (UCB), induced pluripotent stem cells (iPSCs), and NK cell lines. Exploiting the therapeutic potential of NK cells to treat tumors through in vivo and in vitro therapeutic modalities has yielded positive therapeutic results.

CONCLUSION

This review provides a comprehensive description of NK cell therapeutic approaches for tumors and discusses the current problems associated with these therapeutic approaches and the prospects of NK cell therapy for tumors.

invariant Natural Killer T cell therapy as a novel therapeutic approach in hematological malignancies

Invariant Natural Killer T cell therapy is an emerging platform of immunotherapy for cancer treatment. This unique cell population is a promising candidate for cell therapy for cancer treatment because of its inherent cytotoxicity against CD1d positive cancers as well as its ability to induce host CD8 T cell cross priming. Substantial evidence supports that iNKT cells can modulate myelomonocytic populations in the tumor microenvironment to ameliorate immune dysregulation to antagonize tumor progression. iNKT cells can also protect from graft-versus-host disease (GVHD) through several mechanisms, including the expansion of regulatory T cells (Treg). Ultimately, iNKT cell-based therapy can retain antitumor activity while providing protection against GVHD simultaneously. Therefore, these biological properties render iNKT cells as a promising "off-the-shelf" therapy for diverse hematological malignancies and possible solid tumors. Further the introduction of a chimeric antigen recetor (CAR) can further target iNKT cells and enhance function. We foresee that improved vector design and other strategies such as combinatorial treatments with small molecules or immune checkpoint inhibitors could improve CAR iNKT in vivo persistence, functionality and leverage anti-tumor activity along with the abatement of iNKT cell dysfunction or exhaustion.

Spontaneous immunological activities in the target tissue of vitiligo-prone Smyth and vitiligo-susceptible Brown lines of chicken

Introduction

Vitiligo is an acquired de-pigmentation disorder characterized by the post-natal loss of epidermal melanocytes (pigment-producing cells) resulting in the appearance of white patches in the skin. The Smyth chicken is the only model for vitiligo that shares all the characteristics of the human condition including: spontaneous post-natal loss of epidermal melanocytes, interactions between genetic, environmental and immunological factors, and associations with other autoimmune diseases. In addition, an avian model for vitiligo has the added benefit of an easily accessible target tissue (a growing feather) that allows for the repeated sampling of an individual and thus the continuous monitoring of local immune responses over time.

Methods

Using a combination of flow cytometry and gene expression analyses, we sought to gain a comprehensive understanding of the initiating events leading to expression of vitiligo in growing feathers by monitoring the infiltration of leukocytes and concurrent immunological activities in the target tissue beginning prior to visual onset and continuing throughout disease development.

Results

Here, we document a sequence of immunologically significant events, including characteristic rises in infiltrating B and αβ T cells as well as evidence of active leukocyte recruitment and cell-mediated immune activities (CCL19, IFNG, GZMA) leading up to visual vitiligo onset. Examination of growing feathers from vitiligo-susceptible Brown line chickens revealed anti-inflammatory immune activities which may be responsible for preventing vitiligo (IL10, CTLA4, FOXP3). Furthermore, we detected positive correlations between infiltrating T cells and changes in their T cell receptor diversity supporting a T cell-specific immune response.

Conclusion

Collectively, these results further support the notion of cell-mediated immune destruction of epidermal melanocytes in the pulp of growing feathers and open new avenues of study in the vitiligo-prone Smyth and vitiligo-susceptible Brown line chickens.

Cooperative Armoring of CAR and TCR T Cells by T Cell-Restricted IL15 and IL21 Universally Enhances Solid Tumor Efficacy

PURPOSE

Chimeric antigen receptor (CAR) and T-cell receptor (TCR) T-cell therapies are effective in a subset of patients with solid tumors, but new approaches are needed to universally improve patient outcomes. Here, we developed a technology to leverage the cooperative effects of IL15 and IL21, two common cytokine-receptor gamma chain family members with distinct, pleiotropic effects on T cells and other lymphocytes, to enhance the efficacy of adoptive T cells.

EXPERIMENTAL DESIGN

We designed vectors that induce the constitutive expression of either membrane-tethered IL15, IL21, or IL15/IL21. We used clinically relevant preclinical models of transgenic CARs and TCRs against pediatric and adult solid tumors to determine the effect of the membrane-tethered cytokines on engineered T cells for human administration.

RESULTS

We found that self-delivery of these cytokines by CAR or TCR T cells prevents functional exhaustion by repeated stimulation and limits the emergence of dysfunctional natural killer (NK)-like T cells. Across different preclinical murine solid tumor models, we observed enhanced regression with each individual cytokine but the greatest antitumor efficacy when T cells were armored with both.

CONCLUSIONS

The coexpression of membrane-tethered IL15 and IL21 represents a technology to enhance the resilience and function of engineered T cells against solid tumors and could be applicable to multiple therapy platforms and diseases. See related commentary by Ruffin et al., p. 1431.

Therapeutic potential of interleukin-21 in cancer

Interleukin-21 (IL-21) is an immunostimulatory cytokine which belongs to the common gamma-chain family of cytokines. It plays an import role in the development, differentiation, proliferation, and activation of immune cells, in particular T and natural killer (NK) cells. Since its discovery in 2000, IL-21 has been shown to regulate both adaptive and immune responses associates with key role in antiviral and antitumor responses. Recent advances indicate IL-21 as a promising target for cancer treatment and encouraging results were obtained in preclinical studies which investigated the potency of IL-21 alone or in combination with other therapies, including monoclonal antibodies, checkpoint inhibitory molecules, oncolytic virotherapy, and adoptive cell transfer. Furthermore, IL-21 showed antitumor effects in the treatment of patients with advanced cancer, with minimal side effects in several clinical trials. In the present review, we will outline the recent progress in IL-21 research, highlighting the potential of IL-21 based therapy as single agent or in combination with other drugs to enhance cancer treatment efficiency.

The Role of Natural Killer Cells in the Tumor Immune Microenvironment of EBV-Associated Nasopharyngeal Carcinoma

Endemic nasopharyngeal carcinoma (NPC) is closely associated with the Epstein-Barr virus (EBV), which contributes to tumor development and influences the tumor immune microenvironment (TIME) in NPC. Natural killer (NK) cells, as part of the innate immune system, play a crucial role in responding to viral infections and malignant cell transformations. Notably, NK cells possess a unique ability to target tumor cells independent of major histocompatibility complex class I (MHC I) expression. This means that MHC I-deficient tumor cells, which can escape from effective T cell attack, are susceptible to NK-cell-mediated killing. The activation of NK cells is determined by the signals generated through inhibitory and activating receptors expressed on their surface. Understanding the role of NK cells in the complex TIME of EBV+ NPC is of utmost importance. In this review, we provide a comprehensive summary of the current understanding of NK cells in NPC, focusing on their subpopulations, interactions, and cytotoxicity within the TIME. Moreover, we discuss the potential translational therapeutic applications of NK cells in NPC. This review aims to enhance our knowledge of the role of NK cells in NPC and provide valuable insights for future investigations.

Interleukin-21 as an adjuvant in cancer immunotherapy: Current advances and future directions

Immunotherapy has revolutionized cancer treatment. However, it's well-recognized that a considerable proportion of patients fail to benefit from immunotherapy, and to improve immunotherapy response is clinically urgent. Insufficient immune infiltration and immunosuppressive tumor microenvironments (TME) are main contributors to immunotherapy resistance. Thus sustaining functional self-renewal capacity for immune cells and subverting immune-suppressive signals are potential strategies for boosting the efficacy of immunotherapy. Interleukin-21 (IL-21), a crucial cytokine, which could enhance cytotoxic function of immune cells and reduces immunosuppressive cells enrichment in TME, shows promising orientations as an immunoadjuvant in tumor immunotherapy. This review focuses on IL-21 in cancer treatment, including function and mechanisms of IL-21, preclinical and clinical studies, and future directions for IL-21-assisted therapies.

Circular RNA-mediated miRNA sponge & RNA binding protein in biological modulation of breast cancer

Circular RNAs (circRNAs) and small non-coding RNAs of the head-to-junction circle in the construct play critical roles in gene regulation and are significantly associated with breast cancer (BC). Numerous circRNAs are potential cancer biomarkers that may be used for diagnosis and prognosis. Widespread expression of circRNAs is regarded as a feature of gene expression in highly diverged eukaryotes. Recent studies show that circRNAs have two main biological modulation models: sponging and RNA-binding. This review explained the biogenesis of circRNAs and assessed emerging findings on their sponge function and role as RNA-binding proteins (RBPs) to better understand how their interaction alters cellular function in BC. We focused on how sponges significantly affect the phenotype and progression of BC. We described how circRNAs exercise the translation functions in ribosomes. Furthermore, we reviewed recent studies on RBPs, and post-protein modifications influencing BC and provided a perspective on future research directions for treating BC.

The trajectory of human B-cell function, immune deficiency, and allergy revealed by inborn errors of immunity

The essential role of B cells is to produce protective immunoglobulins (Ig) that recognize, neutralize, and clear invading pathogens. This results from the integration of signals provided by pathogens or vaccines and the stimulatory microenvironment within sites of immune activation, such as secondary lymphoid tissues, that drive mature B cells to differentiate into memory B cells and antibody (Ab)-secreting plasma cells. In this context, B cells undergo several molecular events including Ig class switching and somatic hypermutation that results in the production of high-affinity Ag-specific Abs of different classes, enabling effective pathogen neutralization and long-lived humoral immunity. However, perturbations to these key signaling pathways underpin immune dyscrasias including immune deficiency and autoimmunity or allergy. Inborn errors of immunity that disrupt critical immune pathways have identified non-redundant requirements for eliciting and maintaining humoral immune memory but concomitantly prevent immune dysregulation. Here, we will discuss our studies on human B cells, and how our investigation of cytokine signaling in B cells have identified fundamental requirements for memory B-cell formation, Ab production as well as regulating Ig class switching in the context of protective versus allergic immune responses.

Targeting natural killer cells: from basic biology to clinical application in hematologic malignancies

Natural killer (NK) cell belongs to innate lymphoid cell family that contributes to host immunosurveillance and defense without pre-immunization. Emerging studies have sought to understand the underlying mechanism behind NK cell dysfunction in tumor environments, and provide numerous novel therapeutic targets for tumor treatment. Strategies to enhance functional activities of NK cell have exhibited promising efficacy and favorable tolerance in clinical treatment of tumor patients, such as immune checkpoint blockade (ICB), chimeric antigen receptor NK (CAR-NK) cell, and bi/trispecific killer cell engager (BiKE/TriKE). Immunotherapy targeting NK cell provides remarkable advantages compared to T cell therapy, including a decreased rate of graft versus-host disease (GvHD) and neurotoxicity. Nevertheless, advanced details on how to support the maintenance and function of NK cell to obtain better response rate and longer duration still remain to be elucidated. This review systematically summarizes the profound role of NK cells in tumor development, highlights up-to-date advances and current challenges of therapy targeting NK cell in the clinical treatment of hematologic malignancies.

A Large-Scale Meta-Analysis Reveals Positive Feedback between Macrophages and T Cells That Sensitizes Tumors to Immunotherapy

Although considerable efforts have been dedicated to identifying predictive signatures for immune checkpoint inhibitor (ICI) treatment response, current biomarkers suffer from poor generalizability and reproducibility across different studies and cancer types. The integration of large-scale multiomics studies holds great promise for discovering robust biomarkers and shedding light on the mechanisms of immune resistance. In this study, we conducted the most extensive meta-analysis involving 3,037 ICI-treated patients with genetic and/or transcriptomics profiles across 14 types of solid tumor. The comprehensive analysis uncovered both known and novel reliable signatures associated with ICI treatment outcomes. The signatures included tumor mutational burden (TMB), IFNG and PDCD1 expression, and notably, interactions between macrophages and T cells driving their activation and recruitment. Independent data from single-cell RNA sequencing and dynamic transcriptomic profiles during the ICI treatment provided further evidence that enhanced cross-talk between macrophages and T cells contributes to ICI response. A multivariable model based on eight nonredundant signatures significantly outperformed existing models in five independent validation datasets representing various cancer types. Collectively, this study discovered biomarkers predicting ICI response that highlight the contribution of immune cell networks to immunotherapy efficacy and could help guide patient treatment.

SIGNIFICANCE

Identification of robust immunogenomic connections, particularly macrophage T-cell interactions, in a large-scale pan-cancer meta-analysis and development of a predictive model for immunotherapy response that outperformed existing models could facilitate clinical decision-making.

Cytokine gene polymorphisms implicated in the pathogenesis of Plasmodium falciparum infection outcome

Cytokines play a critical role in the immune mechanisms involved in fighting infections including malaria. Polymorphisms in cytokine genes may affect immune responses during an infection with Plasmodium parasites and immunization outcomes during routine administration of malaria vaccines. These polymorphisms can increase or reduce susceptibility to this deadly infection, and this may affect the physiologically needed balance between anti-inflammatory and pro-inflammatory cytokines. The purpose of this review is to present an overview of the effect of selected cytokine gene polymorphisms on immune responses against malaria.

Translatability of findings from cynomolgus monkey to human suggests a mechanistic role for IL-21 in promoting immunogenicity to an anti-PD-1/IL-21 mutein fusion protein

AMG 256 is a bi-specific, heteroimmunoglobulin molecule with an anti-PD-1 antibody domain and a single IL-21 mutein domain on the C-terminus. Nonclinical studies in cynomolgus monkeys revealed that AMG 256 administration led to the development of immunogenicity-mediated responses and indicated that the IL-21 mutein domain of AMG 256 could enhance the anti-drug antibody response directed toward the monoclonal antibody domain. Anti-AMG 256 IgE were also observed in cynomolgus monkeys. A first-in-human (FIH) study in patients with advanced solid tumors was designed with these risks in mind. AMG 256 elicited ADA in 28 of 33 subjects (84.8%). However, ADA responses were only robust and exposure-impacting at the 2 lowest doses. At mid to high doses, ADA responses remained low magnitude and all subjects maintained exposure, despite most subjects developing ADA. Limited drug-specific IgE were also observed during the FIH study. ADA responses were not associated with any type of adverse event. The AMG 256 program represents a unique case where nonclinical studies informed on the risk of immunogenicity in humans, due to the IL-21-driven nature of the response.

Co-expression of IL-21-Enhanced NKG2D CAR-NK cell therapy for lung cancer

BACKGROUND

Adoptive cell therapy has achieved great success in treating hematological malignancies. However, the production of chimeric antigen receptor T (CAR-T) cell therapy still faces various difficulties. Natural killer (NK)-92 is a continuously expandable cell line and provides a promising alternative for patient's own immune cells.

METHODS

We established CAR-NK cells by co-expressing natural killer group 2 member D (NKG2D) and IL-21, and evaluated the efficacy of NKG2D-IL-21 CAR-NK cells in treating lung cancer in vitro and in vivo.

RESULTS

Our data suggested that the expression of IL-21 effectively increased the cytotoxicity of NKG2D CAR-NK cells against lung cancer cells in a dose-dependent manner and suppressed tumor growth in vitro and in vivo. In addition, the proliferation of NKG2D-IL-21 CAR-NK cells were enhanced while the apoptosis and exhaustion of these cells were suppressed. Mechanistically, IL-21-mediated NKG2D CAR-NK cells function by activating AKT signaling pathway.

CONCLUSION

Our findings provide a novel option for treating lung cancer using NKG2D-IL-21 CAR-NK cell therapy.

Obtaining Gene-Modified HLA-E-Expressing Feeder Cells for Stimulation of Natural Killer Cells

Human cytomegalovirus (HCMV)-specific adaptive NK cells are capable of recognizing viral peptides presented by HLA-E on infected cells via the NKG2C receptor. Using retroviral transduction, we have generated a K562-cell-based line expressing HLA-E in the presence of the HLA-E-stabilizing peptide, which has previously shown the capacity to enhance adaptive NK cell response. The obtained K562-21E cell line was employed to investigate proliferative responses of the CD57- NK cell subset of HCMV-seropositive and seronegative donors. Stimulation of CD57- NK cells with K562-21E/peptide resulted in an increased cell expansion during the 12-day culturing period, regardless of the serological HCMV status of the donor. The enhanced proliferation in response to the peptide was associated with a greater proportion of CD56brightHLA-DR+ NK cells. In later stages of cultivation, the greatest proliferative response to K562-21E/peptide was shown for a highly HCMV-seropositive donor. These expanded NK cells were characterized by the accumulation of CD57-KIR2DL2/3+NKG2C+NKG2A- cells, which are hypothesized to represent adaptive NK cell progenitors. The K562-21E feeder cells can be applied both for the accumulation of NK cells as therapeutic effectors, and for the study of NK cell maturation into the adaptive state after the HLA-E peptide presentation.

Combined Role of Interleukin-15 Stimulated Natural Killer Cell-Derived Extracellular Vesicles and Carboplatin in Osimertinib-Resistant H1975 Lung Cancer Cells with EGFR Mutations

In this study, we evaluated IL-15 stimulated natural killer cell-derived EVs (NK-EVs) as therapeutic agents in vitro and in vivo in Osimertinib-resistant lung cancer (H1975R) with EGFR mutations (L858R) in combination with carboplatin (CBP). NK-EVs were isolated by ultracentrifugation and characterized by nanoparticle tracking analysis, and atomic force microscopy imaging revealed vesicles with a spherical form and sizes meeting the criteria of exosomal EVs. Further, Western blot studies demonstrated the presence of regular EV markers along with specific NK markers (perforin and granzyme). EVs were also characterized by proteomic analysis, which demonstrated that EVs had proteins for natural killer cell-mediated cytotoxicity (Granzyme B) and T cell activation (perforin and plastin-2). Gene oncology analysis showed that these differentially expressed proteins are involved in programmed cell death and positive regulation of cell death. Further, isolated NK-EVs were cytotoxic to H1975R cells in vitro in 2D and 3D cell cultures. CBP's IC50 was reduced by approximately in 2D and 3D cell cultures when combined with NK-EVs. The EVs were then combined with CBP and administered by i.p. route to H1975R tumor xenografts, and a significant reduction in tumor volume in vivo was observed. Our findings show for the first time that NK-EVs target the PD-L1/PD-1 immunological checkpoint to induce apoptosis and anti-inflammatory response by downregulation of SOD2, PARP, BCL2, SET, NF-κB, and TGF-ß. The ability to isolate functional NK-EVs on a large scale and use them with platinum-based drugs may lead to new clinical applications. The results of the present study suggest the possibility of the combination of NK-cell-derived EVs and CBP as a viable immunochemotherapeutic strategy for resistant cancers.

Biological effects of IL-21 on immune cells and its potential for cancer treatment

Interleukin-21 (IL-21), a member of the IL-2 cytokine family, is one of the most important effector and messenger molecules in the immune system. Produced by various immune cells, IL-21 has pleiotropic effects on innate and adaptive immune responses via regulation of natural killer, T, and B cells. An anti-tumor role of IL-21 has also been reported in the literature, as it may support cell proliferation or on the contrary induce growth arrest or apoptosis of the tumor cell. Anti-tumor effect of IL-21 enhances when combined with other agents that target tumor cells, immune regulatory circuits, or other immune-enhancing molecules. Therefore, understanding the biology of IL-21 in the tumor microenvironment (TME) and reducing its systemic toxic and side effects is crucial to ensure the maximum benefits of anti-tumor treatment strategies. In this review, we provide a comprehensive overview on the biological functions, roles in tumors, and the recent advances in preclinical and clinical research of IL-21 in tumor immunotherapy.

The role of Interleukin-21 in autoimmune Diseases: Mechanisms, therapeutic Implications, and future directions

IL-21 is a multifunctional cytokine that regulates the functional activity of various immune cells. Initial studies have shown that IL-21 can influence the differentiation, proliferation and function of T and B cells, as well as promote the maturation and increase the cytotoxicity of CD8 + T cells and NK cells. During humoral immune responses, IL-21 has significant effects on B cell activation, differentiation and apoptosis. In addition, IL-21 promotes the differentiation of both naive and memory B cells, ultimately leading to the activation of plasma cells. The function of IL-21 in the immune system is complex, as it has the ability to either stimulate or inhibit immune responses. in addition, IL-21 facilitates the differentiation of naive and memory B cells into plasma cells. The functionality of IL-21 in the immune system is diverse, as it has the ability to stimulate or inhibit immune responses. This cytokine has been implicated in several diseases including cancer, allergies and autoimmune diseases. Research has suggested that this cytokine is involved in the development of autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. Several studies have suggested that inhibition of IL-21 has a therapeutic effect on autoimmune diseases. Therefore, targeting both the cytokine's receptor and IL-21 in autoimmune diseases may be an effective approach to reduce the severity of the disease or to treat it. This review will examine the biological effects of IL-21 on various immune cells and the role of the cytokine in autoimmune diseases.

Suppression of NK Cell Activation by JAK3 Inhibition: Implication in the Treatment of Autoimmune Diseases

Natural killer (NK) cell is an essential cytotoxic lymphocyte in our innate immunity. Activation of NK cells is of paramount importance in defending against pathogens, suppressing autoantibody production and regulating other immune cells. Common gamma chain (γc) cytokines, including IL-2, IL-15, and IL-21, are defined as essential regulators for NK cell homeostasis and development. However, it is inconclusive whether γc cytokine-driven NK cell activation plays a protective or pathogenic role in the development of autoimmunity. In this study, we investigate and correlate the differential effects of γc cytokines in NK cell expansion and activation. IL-2 and IL-15 are mainly responsible for NK cell activation, while IL-21 preferentially stimulates NK cell proliferation. Blockade of Janus tyrosine kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway by either JAK inhibitors or antibodies targeting γc receptor subunits reverses the γc cytokine-induced NK cell activation, leading to suppression of its autoimmunity-like phenotype in vitro. These results underline the mechanisms of how γc cytokines trigger autoimmune phenotype in NK cells as a potential target to autoimmune diseases.

New insights into the stemness of adoptively transferred T cells by γc family cytokines

T cell-based adoptive cell therapy (ACT) has exhibited excellent antitumoral efficacy exemplified by the clinical breakthrough of chimeric antigen receptor therapy (CAR-T) in hematologic malignancies. It relies on the pool of functional T cells to retain the developmental potential to serially kill targeted cells. However, failure in the continuous supply and persistence of functional T cells has been recognized as a critical barrier to sustainable responses. Conferring stemness on infused T cells, yielding stem cell-like memory T cells (TSCM) characterized by constant self-renewal and multilineage differentiation similar to pluripotent stem cells, is indeed necessary and promising for enhancing T cell function and sustaining antitumor immunity. Therefore, it is crucial to identify TSCM cell induction regulators and acquire more TSCM cells as resource cells during production and after infusion to improve antitumoral efficacy. Recently, four common cytokine receptor γ chain (γc) family cytokines, encompassing interleukin-2 (IL-2), IL-7, IL-15, and IL-21, have been widely used in the development of long-lived adoptively transferred TSCM in vitro. However, challenges, including their non-specific toxicities and off-target effects, have led to substantial efforts for the development of engineered versions to unleash their full potential in the induction and maintenance of T cell stemness in ACT. In this review, we summarize the roles of the four γc family cytokines in the orchestration of adoptively transferred T cell stemness, introduce their engineered versions that modulate TSCM cell formation and demonstrate the potential of their various combinations. Video Abstract.