Cancer microenvironments encompass both cancer-promoting and cancer-restraining factors. If these factors cancel each other, cancer dormancy may ensue. In search of microenvironmental factors that keep dormant lung-metastasizing neuroblastoma cells and brain-metastasizing melanoma cells (BMMC) in check, we identified the beta subunit of hemoglobin and a heterodimer of alpha and beta chains of hemoglobin (α/β dimer) in the lung and brain microenvironments, respectively, as anti-metastatic factors. A previous study demonstrated that the α/β dimer triggers programmed cell death of BMMC and downregulates the expression of BRD4, GAB2, and IRS2 proteins, which perform essential functions in tumorigenesis and progression. The working hypothesis of the present study is that in addition to its tumoricidal function, the α/β dimer serves as a pathfinder for the identification of therapy targets for BMMC. We, therefore, employed small-molecule inhibitors of Bromodomain-containing protein 4 (BRD4), GRB2-associated-binding protein 2 (GAB2), and Insulin receptor substrate 2 (IRS2) as potential anti-BMMC agents. A combination of sub-lethal concentrations of BRD4 and IRS2 inhibitors synergistically arrested BMMC at the subG1 phase of the cell cycle and killed more than 70% of BMMCs. The BRD4/IRS2 inhibitor cocktail (designated hereafter as BRIRi) moderated the malignancy of BMMC lines from four different human melanomas. Preliminary results suggest that the BRIRi modulated "cold" BMMC to "hot" ones. Among the top enriched functions of differentially expressed genes identified by RNAseq of BRIRi-treated versus control BMMC, TNF and apoptotic signaling pathways were observed. We propose that co-targeting BRD4 and IRS2 offers a promising approach for treating BMMC.

In chronic viral infections, sustained CD8+ T cell response relies on TCF1+ precursor-exhausted T cells (TPEX) exhibiting stem-like properties. TPEX self-renew and respond to PD-1 blockade, underscoring their paramount importance. However, strategies for effectively augmenting TPEX remain limited. Here, we demonstrate that ZC3H12A deficiency initiates a stemness program in TPEX but also increases cell death, whereas BCOR deficiency predominantly promotes TPEX proliferation. Consequently, co-targeting of both BCOR and ZC3H12A imparts exceptional stemness and functionality to TPEX, thereby enhancing viral control. Mechanistically, BCOR and ZC3H12A collaboratively suppress a core stemness program in TPEX characterized by heightened expression of ∼216 factors. While TCF1 plays a role, this core stemness program relies on novel factors, including PDZK1IP1, IFIT3, PIM2, LTB, and POU2F2. Crucially, overexpressing POU2F2 robustly boosts TPEX and enhances antiviral immunity. Thus, a core stemness program exists in exhausted T cells, jointly repressed by BCOR and ZC3H12A, robustly controlling TPEX differentiation and providing new targets for addressing T cell exhaustion.

DNA methylation is a key epigenetic modification that regulates gene expression, cell differentiation, and genome stability. Aberrant DNA methylation patterns, including the hypermethylation or global hypomethylation of tumor suppressor genes, are strongly associated with various human diseases, such as cancer, autoimmune disorders, and metabolic syndrome. DNA methylation predominantly occurs at CpG dinucleotides, influencing transcription by altering chromatin structure and accessibility. MBD2 (Methyl-CpG-binding proteins 2) play a crucial role in interpreting these epigenetic marks and regulating downstream gene expression. In disease contexts, aberrant DNA methylation disrupts cellular homeostasis by silencing key regulatory genes or activating pathological pathways. Current research primarily focuses on MBD2 in cancer, with less emphasis on its role in autoimmune diseases. This review discusses the role of MBD2 in regulating immune cell development and differentiation through epigenetic mechanisms, particularly DNA methylation and its regulatory components. Furthermore, it highlights the mechanistic contributions of MBD2 to autoimmune diseases such as systemic lupus erythematosus and evaluates its potential as a novel therapeutic target for these conditions.

Epstein-Barr virus (EBV) is a gamma-herpesvirus with double-stranded DNA. Primary EBV infection leads to infectious mononucleosis (IM) in 20-50% of children and young adults. EBV establishes latent infection in B lymphocytes and can infect T lymphocytes and NK cells, potentially causing lymphoproliferative disorders (LPD) and malignancies. While the PD-1/PD-L1 pathway's role in chronic viral infections is well-established, its specific functions in EBV infection remain poorly understood. Growing evidence suggests this pathway facilitates EBV immune evasion, yet the effect of PD-1 upregulation on Epstein-Barr virus-specific CD8 + T cell function during acute IM is unclear. Furthermore, the role of PD-1/PD-L1 pathway in cytotoxic T cells and immune regulation during EBV infection is still controversial. This review systematically analyzes current knowledge on PD-1/PD-L1 signaling in EBV infection, focusing on three key aspects: (1) its dual role in maintaining immune homeostasis during acute infection while potentially facilitating viral persistence, (2) its emerging potential as a diagnostic biomarker for disease progression and prognosis, particularly during acute infectious mononucleosis, and (3) the therapeutic implications of pathway modulation. We critically evaluate recent advances that position PD-1/PD-L1 at the intersection of virology and tumor immunology, while highlighting important unanswered questions that require further investigation to optimize EBV-specific immunotherapies.

Viruses that establish persistent (i.e., chronic) infections have evolved sophisticated strategies to avoid clearance by the host immune system. This is particularly true for viruses that infect immunocompetent mammals and sustain high infectious burdens in body sites under intense immune surveillance (i.e., the blood, a.k.a., "viremia"). Historically, lymphocytic choriomeningitis virus (LCMV) infection of laboratory mice has served as a powerful model to understand mechanisms of failed immunity, but other viruses may have unique and underappreciated persistence strategies. Here, we resurrect a bygone model of viral persistence-lactate dehydrogenase-elevating virus (LDV)-and use modern transgenic mouse technologies to investigate various aspects of anti-viral immunity. We find that interferons have a modest impact on LDV replication, with interferon-alpha blunting LDV viremia in the acute phase of the infection and interferon-gamma reducing LDV viral loads in the chronic phase of infection, but only when paired with an intact interferon-alpha response. Adaptive immunity, assessed in Rag-knockout mice, had only a modest impact on LDV viremia, and only during the sub-acute phase of infection. Mice lacking the critical immune checkpoint molecule PD-1 showed no signs of disease and supported LDV viral loads at levels equivalent to their wild-type counterparts. Altogether, these results point to a novel and highly effective mechanism of persistence that is minimally impacted by conventional aspects of anti-viral immunity or immune exhaustion-a rarity among persistent viruses. Given the relative paucity of chronic infection models in the laboratory mouse, LDV infection may be useful for exploring unique modes of immune system failure.

Viruses that infect a host over long periods of time have evolved unique strategies to evade the host immune system. Of particular interest are viruses that cause persistent infection in the laboratory mouse-the most well-developed tool for studying the mammalian immune system. Here, we resurrected a model of persistent RNA virus infection (lactate dehydrogenase-elevating virus, LDV) and applied modern tools of mouse immunology to further characterize its persistence. We found that host factors that typically have a dramatic effect on viral infections-e.g., the interferon system and lymphocytes-had very little impact on LDV infection. Removing "checks" on immune activation also had little effect on the virus or host health. Altogether, these findings imply that LDV uses a unique and highly effective mechanism to avoid immune clearance. Understanding this mechanism has implications for understanding ways in which the immune system fails.

BK polyomavirus (BKPyV) nephropathy is a significant complication of kidney transplantation associated with high levels of BKPyV replication in plasma and poor graft survival. It is currently treated by reducing immunosuppression to restore the immune response.

We analyzed circulating T cells from 28 kidney transplant recipients with detectable levels of BKPyV DNA in the blood (BKPyV DNAemia). Immunosuppression was significantly reduced in all these patients. We evaluated BKPyV-specific T-cell functionality and phenotype and assessed graft outcomes prospectively.

BKPyV DNAemia was rapidly controlled in 13 patients (controllers [C] group), whereas viral replication was sustained in the other 15, who were considered not to have responded to reduced immunosuppression (noncontroller [NC] group). The induction and maintenance therapies used were similar in the C and NC groups. The slope of renal function decline tended to be worse in the NC group than in the C group (P < 0.055). BKPyV-specific T-cell functions (T-cell proliferation and cytokine secretion) were weaker in the NC group than in the C group. This functional impairment was associated with an overexpression of several inhibitory receptors (programmed cell death protein 1 [PD1], T-cell immunoreceptor with Ig and immunoreceptor tyrosine-based inhibitory motif domains, or T-cell immunoglobulin and mucin-containing protein 3 [TIM3]), highlighting an exhausted-like phenotype of BKPyV-specific CD4 and CD8 T cells in the NC group. T-cell inhibition was not overcome by a single blocking antibody against inhibitory receptors, whereas a combination of anti-PD1 and anti-TIM3 antibodies significantly restored BKPyV-specific CD8 T-cell functions (P < 0.05).

Sustained BKPyV DNAemia was associated with an exhausted phenotype of BKPyV-specific T cells despite immunosuppression reduction in kidney transplant recipients. We show that anti-BKPyV-specific CD8 functions can be restored ex vivo by blocking the PD1 and TIM3 pathways, paving the way for new treatment strategies.

Recent studies have promoted new insights into the biology of non-small cell lung cancer (NSCLC) and made considerable progress in the field of treatment, including targeted therapy for driver gene mutations. Immunotherapy (IO) is another breakthrough, which has achieved amazing clinical efficacy. However, the survival status of advanced NSCLC patients is still unsatisfactory. Drug resistance is an urgent problem to be solved in almost all anti-cancer treatment schemes. Nowadays, platinum based chemotherapy remains the standard treatment for patients with driver gene negative advanced NSCLC. Previous studies have shown that the reduction of intracellular accumulation of platinum drugs, DNA damage repair and the enhancement of detoxification effect all lead to platinum resistance. The mechanisms of tyrosine kinase inhibitors (TKIs) resistance include the emergence of secondary mutation, the activation of bypass signal pathways, the abnormality of downstream signal pathways and the transformation of phenotype. The mechanisms of immune checkpoint inhibitors (ICIs) resistance are more complex. A variety of cells, cytokines and metabolites participate in it to form an immunosuppressive microenvironment, resulting in the impairment of effector T cell function. Exosomes are small molecules secreted by a variety of cells. They can carry information such as miRNA, lncRNA, and protein, and play a pivotal role in signal transduction between cells. More and more studies show that exosomes are important transmitters in lung cancer cells, which can transfer drug resistance information from drug-resistant cells to sensitive cells. However, the underling specific mechanisms need to be further explored to find a new breakthrough for overcoming drug resistance of NSCLC.

: Liver cirrhosis involves chronic inflammation and progressive fibrosis. Among various immune cells, CD8+ T cells are considered a major contributor to hepatic inflammation and fibrosis. However, the exact molecular pathways governing CD8+ T-cell-mediated effects in cirrhosis remain unclear.

: This study analyzed transcriptomic and single-cell sequencing data to elucidate CD8+ T-cell heterogeneity and implications in cirrhosis.

: Weighted gene co-expression analysis of bulk RNA-seq data revealed an association between cirrhosis severity and activated T-cell markers like HLA and chemokine genes. Furthermore, single-cell profiling uncovered eight CD8+ T-cell subtypes, notably, effector memory (Tem) and exhausted (Tex) T cells. Tex cells, defined by PDCD1, LAG3, and CXCL13 expression, were increased in cirrhosis, while Tem cells were decreased. Lineage tracing and differential analysis highlighted CXCL13+ Tex cells as a terminal, exhausted subtype of cells with roles in PD-1 signaling, glycolysis, and T-cell regulation. CXCL13+ Tex cells displayed T-cell exhaustion markers like PDCD1, HAVCR2, TIGIT, and TNFRSF9. Functional analysis implicated potential roles of these cells in immunosuppression. Finally, a CXCL13+ Tex-cell gene signature was found that correlated with cirrhosis severity and poorer prognosis of liver cancer.

: In summary, this comprehensive study defines specialized CD8+ T-cell subpopulations in cirrhosis, with CXCL13+ Tex cells displaying an exhausted phenotype associated with immune dysregulation and advanced disease. Key genes and pathways regulating these cells present potential therapeutic targets.

Esophageal squamous cell carcinoma (ESCC) presents significant health challenges due to its aggressive nature and poor prognosis from late-stage diagnosis. Despite these challenges, emerging therapies like immune checkpoint inhibitors offer hope. β1-adrenergic signaling has been implicated in T cell exhaustion, which weakens the immune response in ESCC. Blocking this pathway could restore T cell function. Recent advances in single-cell RNA sequencing (scRNA-seq) have enabled deeper insights into tumor heterogeneity and the immune landscape, opening the door for personalized treatment strategies that may improve survival and reduce resistance to therapy.

We combined scRNA-seq with bulk RNA analysis to explore adrenergic receptor signaling in ESCC, focusing on changes before and after neoadjuvant therapy. We identified ADRB1+ T cells through data analysis and experimental validation. Copy number variation (CNV) analysis detected malignant cells within scRNA-seq data, while intercellular interaction analysis examined communication between cell populations. Deconvolution of TCGA data revealed key immune populations, which were integrated into a prognostic model based on the adrenergic receptor signaling pathway and differentially expressed genes.

The adrenergic receptor signaling pathway was found in various immune cells, including T cells. scRNA-seq analysis revealed increased ADRB1 expression in T cells after neoadjuvant therapy. Immunofluorescence confirmed colocalization of ADRB1 with T cells, and fluorescence-activated cell sorting (FACS) showed that ADRB1 expression was elevated alongside exhaustion markers, while immune function markers were reduced. CNV analysis highlighted malignant cells in the tumor microenvironment, and intercellular interaction analysis explored ADRB1+ T cells' role in immune support. Deconvolution of TCGA data identified ADRB1+ T cells, SPP1+ macrophages, and CD44+ malignant cells, all of which were prognostically significant. A prognostic model constructed from the intersection of the adrenergic receptor signaling pathway and differentially expressed genes following neoadjuvant therapy showed a significant prognostic effect.

ADRB1 expression increases after neoadjuvant therapy in ESCC and correlates with poor prognosis. Our findings suggest ADRB1 as a potential prognostic biomarker and therapeutic target for post-neoadjuvant immunotherapy.

Vaccines have been proven to be one of the safest and most effective ways to prevent and combat diseases. However, the main focus has been on the evaluation of the potency of effector mechanisms and the lack of adverse effects of vaccine candidates. Recently, the importance of induced regulatory mechanisms of the immune system after vaccination has come to light. With the increase in our knowledge about these regulatory mechanisms including the regulatory T cells (Tregs), we have come to understand the significance of this arm of the immune system in controlling immunopathology and/or diminishing the effectiveness of vaccines, especially viral vaccines. Tregs play a dual role during infectious diseases by limiting immune-mediated pathology and also contributing to chronic pathogen persistence by decreasing effector immunity and clearance of infection. Tregs may also affect immune responses after vaccination primarily by inhibiting antigen presenting cell function such as cytokine secretion and co-stimulatory molecule expression as well as effector T (Teff) and B cell function. In this article, we review the current knowledge on the induction of Tregs after several life-threatening virus infections and their available vaccines to bring them to the spotlight and emphasise that studying viral-induced antigen-specific Tregs will help us improve the effectiveness and decrease the immunopathology or side effects of viral vaccines. Trial Registration: ClinicalTrials.gov identifier: NCT04357444.

Immune checkpoint inhibitors (ICI) upregulate host antitumor immunity, proving efficacy across diverse tumor types. Currently approved ICI treatment primarily targets the programmed cell death receptor 1 (PD-1) and its ligand PD-L1, and cytotoxic T lymphocyte-antigen 4 (CTLA-4). Nivolumab is a monoclonal antibody that targets the human PD-1 receptor and is an entirely human immunoglobulin G4 (IgG4), approved by the FDA for various cancers like advanced melanoma, metastatic renal cell carcinoma, Hodgkin lymphoma, and advanced lung carcinoma. This review will summarise and discuss the recent literature on cardiotoxicity associated with nivolumab therapy.

We searched online databases like PubMed, Scopus, Google Scholar, and Embase for articles related to Nivolumab.

Cardiotoxicity with ICI use is most commonly represented as myocarditis. Patients present with complaints of shortness of breath, palpitations, edema, and fatigue. Takotsubo cardiomyopathy, or broken heart syndrome, is characterized by systolic dysfunction of the left ventricle, mimicking a myocardial infarction but without associated coronary ischemia and with minimal elevation of cardiac enzymes. In the CHECKMATE-037 trial, ventricular arrhythmias occurred in <10% of those who received nivolumab. In a retrospective analysis of patients treated with ICI (predominantly nivolumab monotherapy) for lung cancer, 11% of the patients developed major adverse cardiac events, including myocarditis, non-ST-segment elevated myocardial infarction, supraventricular tachycardia, and pericardial disorders.

Close collaboration between cardiology and oncology specialists is crucial for early detection and effective management of cardiac complications, enhancing the safety of nivolumab anticancer therapy.

Anti-viral immunity can vary tremendously from individual to individual but mechanistic understanding is still scarce. Here, we show that a defined, low complex bacterial community (OMM12) but not the general absence of microbes in germ-free mice leads to a more potent immune response compared to the microbiome of specific-pathogen-free (SPF) mice after a systemic viral infection with LCMV Clone-13. Consequently, gnotobiotic mice colonized with OMM12 have more severe LCMV-induced disease pathology but also enhance viral clearance in the intestinal tract. Mechanistically, single-cell RNA sequencing analysis of adoptively transferred virus-specific T helper cells and endogenous T helper cells in the intestinal tract reveal a stronger pro-inflammatory Th1 profile and a more vigorous expansion in OMM12 than SPF mice. Altogether, our work highlights the causative function of the intestinal microbiome for shaping adaptive anti-viral immunity with implications for vaccination strategies and anti-cancer treatment regimens.

To investigate the efficacy of PD-L1 blockade in restoring humoral immune response against HBV.

HBV-persistent C57BL/6J mice were established through hydrodynamic tail vein injection of 10 µg pAAV-HBV1.2 plasmid. Subsequently, mice treated i.p. with anti-PD-L1 and/or anti-CTLA-4 at specified time points, with dosages of 500 µg, 250 µg, and 250 µg, respectively. Additionally, 5 × 105 magnetic bead-purified plasmacytoid dendritic cells (pDCs) were adoptively transferred i.v. into the acute mouse model followed by anti-PD-L1 treatment. Quantitative real-time PCR was employed to assess the expression levels of costimulatory and tolerogenic molecules in two dendritic cell subsets. Serum HBsAg and HBsAb were measured using ELISA. Flow cytometry was utilized to quantify T follicular helper (Tfh) cells, regulatory T cells (Treg), and germinal center (GC) B cells.

PD-L1 blockade markedly enhanced the differentiation of Tfh cells and GC B cells in HBV-persistent C57BL/6J mice, thereby promoting HBV clearance. Additionally, pDCs exhibited an increased capacity to induce immune tolerance, with pDCs isolated from HBV carriers inducing viral persistence. This persistence was effectively counteracted by treatment with anti-PD-L1.

pDCs mediate the dysregulation of the humoral immune response to HBV through PD-L1 in chronic hepatitis B infection, highlighting a promising target for the management of chronic HBV.

CD8+ T cells are crucial for both spontaneous and therapy-induced restriction of tumor progression. Although many patients with cancer undergo radiotherapy, the precise effect of this genotoxic treatment on tumor-associated CD8+ T cells is insufficiently understood. Here, we investigated the influence of radiotherapy on intratumoral CD8+ T cells. We found that, although these CD8+ T cells initially decline following radiotherapy, they subsequently expand and are both essential and sufficient for early tumor control. In response to radiotherapy, stem-like CD8+ T cells proliferate and differentiate into effector CD8+ T cells, making them key drivers of tumor immunity. Our findings underscore the pivotal role of intratumoral stem-like CD8+ T cells in mediating radiotherapy-induced anti-tumor immunity and provide deeper insights into the dynamic behavior of CD8+ T cells during tumor control after radiotherapy.

Immune checkpoint inhibitors (ICIs) have transformed melanoma treatment; however, predicting patient responses remains a significant challenge. This study reviews the potential of artificial intelligence (AI) to optimize ICI therapy in melanoma by integrating various diagnostic tools. Through a comprehensive literature review, we analyzed studies on AI applications in melanoma immunotherapy, focusing on predictive modeling, biomarker identification, and treatment response prediction. Key findings highlight the efficacy of AI in improving ICI outcomes. Machine learning models successfully identified prognostic cytokine signatures linked to nivolumab clearance. The combination of AI with RNAseq analysis had the potential for the development of personalized treatment with ICIs. A machine learning-based approach was able to assess the risk-benefit ratio for the prediction of immune-related adverse events (irAEs) using the electronic health record (EHR) data. Deep learning algorithms demonstrated high accuracy in tumor microenvironment analysis, including tumor region identification and lymphocyte detection. AI-assisted quantification of tumor-infiltrating lymphocytes (TILs) proved prognostically valuable in primary melanoma and predictive of anti-PD-1 therapy response in metastatic cases. Integrating multiple diagnostic modalities, such as CT imaging and laboratory data, modestly enhanced predictive performance for 1-year survival in advanced cancers treated with immunotherapy. These findings underscore the potential of AI-driven approaches to refine biomarker identification, treatment prediction, and patient stratification in melanoma immunotherapy. While promising, clinical validation and implementation challenges remain.

Background: The incidence of malignant melanoma (MM) continues to increase annually, and tumour invasiveness is a main prognostic factor. Single-nucleotide polymorphisms (SNPs) have become key tools in the study of cancer genetics, influencing susceptibility and prognosis. Methods: In the present study, we analysed the relationship between five SNPs on the PDCDL1 gene (rs822336, rs822337, rs822338, rs229736, rs4143815) with prognosis as well as primary tumour invasiveness characteristics in 377 whole blood samples from MM individuals. Results: Patients who presented the rs822336 CG or GG genotypes (OR = 3.01, 95% CI = 1.53-5.92; p = 0.0017), TA or TT in rs822337 (OR = 2.45, 95% CI = 1.22-4.93; p = 0.0098), and CT or CC of rs822338 (OR = 2.23, 95% CI = 1.05-4.73; p = 0.028) were at an increased risk of developing invasive melanomas. Cases with the AG or GG genotype in rs2297136 presented a lower risk (OR = 0.29, 95% CI = 0.11-0.75; p = 0.0038) of invasive MM. The genetic analysis at the haplotype level resulted in similar findings (OR: 2.95, 95% CI: 1.08-8.10), p = 0.036). Furthermore, patients carrying the homozygous AA genotype in rs2297136 had thicker tumours than those harbouring the AG or GG (1.4 mm vs. 1.0 and 0.8 mm; p = 0.030). No significant association was found between the studied SNPs and melanoma-specific survival (MSS) nor progression-free survival (PFS). Conclusions: Current results suggest that SNPs rs822336, rs822337, rs822338, and rs2297136 genotypes in the PDCDL1 gene are associated with the risk of tumour invasiveness and tumour thickness in MM. Further studies on SNPs considering genetic and epigenetic factors are needed for a better understanding of malignant melanoma susceptibility and its prognosis.

Combination radiotherapy (RT) and αPD-L1 therapy has potential to enhance local and distant (abscopal) tumor control, however, clinical results in humans have been variable. Using murine melanoma models, we found RT + αPD-L1 increases intra-tumor progenitor CD8+ PD-1+ TCF-1+ T cells. This increase depends on trafficking of the PD-1+ TCF-1+ cells from the tumor-draining lymph node (TdLN) to the tumor. RT alone promotes the expansion and differentiation of the TdLN derived PD-1+ TCF-1+ cells into TIM-3+ GZMB+ TCF-1- effector-like cells in the tumor with further enhancement after the addition of αPD-L1. In the TdLN, combination therapy enriches for a novel PD-1+ TCF-1+ TOX- LY6A+ subset with expression of a type I interferon and migratory signature. This subset is able to traffic to the tumor and differentiate into TIM-3+ TCF-1- cells. Finally, we found that ablation of the PD-1+ TCF-1+ T cell population attenuates the enhanced tumor control observed with combination RT + αPD-L1. These results suggest that abscopal response failures may be secondary to impaired stimulation of TdLN CD8+ PD-1 + TCF-1+ T cells or an inability of PD-1+ TCF-1+ cells in the TdLN to traffic to the tumor.

Tumor-draining lymph nodes (TDLNs) play a crucial role in modulating tumor immune responses and influencing the efficacy of immunotherapy. However, our current understanding of the microenvironment within these lymph nodes remains limited. Tumors not only impair the anti-tumor activity of CD8+ T cells by creating an immunosuppressive microenvironment, but they also facilitate immune evasion and promote metastasis by altering the structure and function of TDLNs. Research has shown that tumor-specific memory CD8+ T cells (TTSM) within TDLNs are essential for the efficacy of immune checkpoint inhibitors, such as PD-1/PD-L1 blockers. Moreover, the abnormal structure of TDLNs, along with the presence of immunosuppressive cells-such as regulatory T cells (Tregs), regulatory B cells (Bregs), and immunosuppressive dendritic cells (DCs)-contributes to tumor-mediated immune evasion. Therefore, gaining a deeper understanding of the immune microenvironment within TDLNs is essential for improving the effectiveness of immunotherapies and developing novel therapeutic strategies. This review explores various TDLN-based therapeutic strategies, addressing the controversies surrounding lymph node dissection, the use of TDLNs as a source of tumor-infiltrating lymphocytes (TILs) for therapy, targeting immunosuppressive cells within TDLNs, and methods to reverse the structural abnormalities of TDLNs. These strategies offer valuable insights and potential directions for advancing tumor immunotherapy.

CXCR5 is a chemokine receptor that promotes B cell follicular formation and antibody production. Indeed, CXCR5 has been found to be expressed in a variety of cancers; however, the role of CXCR5 expression in clear-cell renal cell carcinoma (ccRCC) remains unclear. We aimed to determine the impact of cellular CXCR5 expression on cancer outcomes, the PD-1/PD-L1 axis, and genetic states in patients with ccRCC. First, multiplex immunofluorescence staining for CXCR5, CD4, CD8, and AE1/AE3, along with automated single-cell counting, was performed to assess cellular CXCR5 expression in ccRCC and its association with prognosis. Second, the tumour microenvironment (TME) was analysed, with a focus on the relationship between the PD-1/PD-L1 axis and CXCR5 expression. Finally, an integrated analysis of CXCR5 expression and genomic mutation information was conducted to reveal the genetic background underlying CXCR5 expression. A total of 105 ccRCC patients were included. Among the 696,964 cells analysed, the distribution of CXCR5-expressing cells was as follows: 30% CXCR5+CD4+ cells, 9% CXCR5+CD8+ cells, and 26% CXCR5+AE1/AE3+ cells. Survival analysis revealed that tumours with low-CXCR5+CD8+ cells had a poor prognosis; TME analysis revealed a relationship between low-CXCR5+CD8+ status and a highly suppressive PD-L1-positive immune environment. Genomic analysis revealed a correlation between low-CXCR5+CD8+ status and high rates of alterations in chromatin remodelling genes, including PBRM1. This study highlights the significance of CXCR5+CD8+ cells in ccRCC, demonstrating their clinical implications and revealing the immunogenomic landscape underlying CXCR5 expression.

Despite the importance of influenza vaccination in asthma patients, the efficacy of this vaccine in asthma has not been well elucidated. We aimed to compare the efficacy of an influenza vaccine of the asthmatic and control mice. We also evaluated the efficacy of AddaVax™ as an adjuvant candidate, which is equivalent to the MF59 influenza vaccine adjuvant in the elderly.

House dust mite extracts were intranasally injected into six-week-old female BALB/c mice to induce chronic allergic asthma. Antibody responses after split-inactivated A/Puerto Rico/8/34 H1N1 influenza vaccination with or without AddaVax™ adjuvant were measured using ELISA. Homologous viral protection was determined by measuring the survival rate, lung inflammation level, and lung virus titer after challenge with the human influenza virus strain A/Puerto Rico/8/1934 H1N1. Antigen-specific T cell responses were determined using flow cytometry.

The chronic asthma mice immunized with split-inactivated A/Puerto Rico/8/34 H1N1 influenza vaccine showed significant weight loss and higher lung viral load after homologous influenza infection than naïve vaccinated mice. Antigen-specific IgG, IgG1, and IgG2a production did not differ between the naïve and asthma mice. However, serum HI titer was lower in asthma-vaccinated mice after infection. The application of AddaVax™ to a vaccine for mice with asthma enhanced the efficacy of homologous antiviral protection but elicited eosinophil infiltration in the lungs after homologous influenza virus infection.

The immune response after split inactivated A/PR8 vaccine differed between asthma and naïve mice, particularly in terms of antibody activity and T cell populations. This study enhances our understanding of how asthma status may influence the effectiveness of influenza vaccine and offers insights into the AddaVax™-induced eosinophilic inflammation, guiding the development of virus vaccine strategies for both healthy individuals and asthma patients.

While immune checkpoint blockade (ICB) has revolutionized cancer treatment, the key T-cell signaling pathways responsible for its potency remain unclear. GSK-3 is an inhibitory kinase that is most active in resting T-cells. In this study, we demonstrate that GSK-3 facilitates PD-1 blockade, an effect seen by modulating CD4 T-cell help for CD8+ CTL responses against ICB resistant tumors. We show that GSK-3 controls metabolic reprogramming towards glycolysis and synergizes with PD-1 to induce a transcriptional program that reduces suppressive CD4+ Treg numbers while generating super-armed effector-memory CD8+ CTLs that express an unprecedented 7/9 granzymes from the genome. Crucially, we found that GSK-3 cooperates with PD-1 blockade to determine the dependency of CD8+ CTLs on help from CD4+ T-cells. Our study unravels a novel cooperative PD-1 blockade-dependent signaling pathway that potentiates CTL responses against tumors, offering a new strategy to overcome immunotherapy resistance by modulating CD4+ helper and CD8+ cytotoxic functions.

This study demonstrates for the first time that GSK-3 controls the crosstalk between CD4+ and CD8+ T cells, synergizing with anti-PD-1 therapy to overcome resistance to checkpoint blockade and to generate super-armed CD8+ effector cells in cancer immunotherapy. This newly uncovered GSK-3-dependent CD4-CD8 T-cell crosstalk mechanism presents a new approach to enhance anti-PD-1 immunotherapy.

Urothelial carcinoma (UC) is frequently associated with a poor prognosis in patients with advanced disease. A strong biological rationale supports the investigation of combining antibody-drug conjugates (ADCs) with immunotherapy to overcome the occurrence of resistance and improve patient outcomes.

In this review, we illustrate the mechanisms of action of pembrolizumab and enfortumab vedotin (EV) and the immune and biological rationales underlying their synergy in mUC patients.

The results of the combination of EV and pembrolizumab represent a ray of light in the therapeutic scenario of mUC patients. A deeper understanding of the mechanisms underlying the synergistic effects of these agents will be crucial to reduce drug-resistance and further improve the outcome of mUC patients.

T cell exhaustion limits effector T cell function in chronic infection and tumours1,2. The development of these hypofunctional T cells and of their precursors was considered to require stimulatory conditions that are met only after persistent exposure to antigen and inflammation. Here we show, however, that similar T cell populations exist in the early phase of acute infections1,2. At that stage, the early developing TCF1+ precursor population exhibits an unexpected diversity; it includes precursors of normal memory T cells, but also cells with phenotypic, gene-expression and epigenetic profiles that resemble those of precursors of exhausted T cells found in chronic infections. We show that high ligand affinity promotes and PD-1 signalling restricts the development of these precursors. Although the exhausted precursors are at first found frequently, they decline without being completely lost in infections that the immune system resolves. We therefore conclude that precursor T cells with at least two distinct phenotypes are pre-emptively generated irrespective of the outcome of an infection.

CD8 T cells play a critical role in antitumor immunity. However, over time, they often become dysfunctional or exhausted and ultimately fail to control tumor growth. To effectively harness CD8 T cells for cancer immunotherapy, a detailed understanding of the mechanisms that govern their differentiation and function is crucial. This review summarizes our current knowledge of the molecular pathways that regulate CD8 T cell heterogeneity and function in chronic infection and cancer and outlines how T cells respond to therapeutic checkpoint blockade. We explore how T cell-intrinsic and -extrinsic factors influence CD8 T cell differentiation, fate choices, and functional states and ultimately dictate their response to therapy. Identifying cells that orchestrate long-term antitumor immunity and understanding the mechanisms that govern their development and persistence are critical steps toward improving cancer immunotherapy.

This study examines the origin and differentiation of stem-like CD8+ T cells that are essential for sustained T cell immunity in chronic viral infections and cancer and also have a key role in PD-1 directed immunotherapy1-10. These PD-1+TCF-1+TOX+ stem-like CD8+ T cells (also known as precursors of exhausted T cells8,9) have a distinct program that enables them to adapt to chronic antigen stimulation. Here, using the mouse model of chronic lymphocytic choriomeningitis virus (LCMV) infection, we find that virus-specific stem-like CD8+ T cells are generated early (day 5) during chronic infection, suggesting that this crucial fate commitment occurs irrespective of the infection outcome. Indeed, we find that nearly identical populations of stem-like CD8+ T cells were generated early during acute or chronic LCMV infection, and that antigen was essential for maintaining the stem-like phenotype. We performed reciprocal adoptive transfer experiments to determine the fate of these early stem-like CD8+ T cells after viral clearance versus persistence. After transfer of day 5 stem-like CD8+ T cells from chronically infected mice into acutely infected mice, these cells downregulated canonical markers of the chronic stem-like CD8+ T cells and expressed markers (CD127 and CD62L) associated with central memory CD8+ T cells. Reciprocally, when day 5 stem-like cells from acutely infected mice were transferred into chronically infected mice, these CD8+ T cells functioned like chronic resource cells and responded effectively to PD-1 therapy. These findings highlight the ability of these early PD-1+TCF-1+TOX+ stem-like CD8+ T cells to adapt their differentiation trajectory to either an acute or a chronic viral infection. Importantly, our study shows that the host is prepared a priori to deal with a potential chronic infection.

In solid tumors, the tumor microenvironment (TME) is a complex mix of tumor, immune, stromal cells, fibroblasts, and the extracellular matrix. Cytotoxic T lymphocytes (CTLs) constitute a fraction of immune cells that may infiltrate into the TME. The primary function of these T-cells is to detect and eliminate tumor cells. However, due to the immunosuppressive factors present in the TME primarily mediated by Myeloid-Derived Suppressor Cells (MDSCs), Tumor associated macrophages (TAMs), Cancer Associated Fibroblasts (CAFs) as well as the tumor cells themselves, T-cells fail to differentiate into effector cells or become dysfunctional and are unable to eliminate the tumor. In addition, chronic antigen stimulation within the TME also leads to a phenomenon, first identified in chronic lymphocytic choriomeningitis virus (LCMV) infection in mice, where the T-cells become exhausted and lose their effector functions. Exhausted T-cells (Tex) are characterized by the presence of remarkably conserved inhibitory receptors, transcription and signaling factors and the downregulation of key effector molecules. Tex cells have been identified in various malignancies, including melanoma, colorectal and hepatocellular cancers. Recent studies have indicated novel strategies to reverse T-cell exhaustion. These include checkpoint inhibitor blockade targeting programmed cell death protein 1 (PD-1), T-cell immunoglobulin and mucin-domain containing-3 (Tim-3), cytotoxic T-lymphocyte associated protein 4 (CTLA-4), or combinations of different immune checkpoint therapies (ICTs) or combination of ICTs with cytokine co-stimulation. In this review, we discuss aspects of T-cell dysfunction within the TME with a focus on T-cell exhaustion. We believe that gaining insight into the mechanisms of T-cell exhaustion within the TME of human solid tumors will pave the way for developing therapeutic strategies to target and potentially re-invigorate exhausted T-cells in cancer.

HIV outcome changed drastically with antiretroviral (ARV) therapy, especially after the introduction of second-generation integrase strand transfer inhibitors (INSTIs). Despite these advances, however, chronic immune activation and exhaustion, marked by programmed cell death 1 (PD-1) and programmed death ligand 1 (PD-L1) upregulation, persist in patients. This study investigates the impact of various ARV regimens on these immune exhaustion markers in newly diagnosed HIV patients over 12 months, taking into consideration cardiovascular risk.

This study included 58 newly diagnosed patients with HIV at Pomeranian Medical University, Szczecin, Poland. Participants received ARV regimens classified as INSTI + tenofovir alafenamide, INSTI + tenofovir disoproxil fumarate, or non-INSTI-based (VARIA). Flow cytometry was used to assess PD-1 and PD-L1 expression on CD3+, CD3+CD4+, CD3+CD8+ and CD19+ lymphocytes. Statistical analyses included Wilcoxon paired tests, Kruskal-Wallis tests and multivariate regression, with validation through residual analysis and linear discriminant analysis (LDA).

INSTI-based regimens were linked to higher PD-1 expression on CD3+ and CD3+CD4+ lymphocytes, indicating increased immune exhaustion. Conversely, non-INSTI regimens were associated with lower PD-1 levels, suggesting better retention of immune function. A positive correlation between cardiovascular risk a prediction model to estimate 10-year fatal and non-fatal cardiovascular disease (SCORE2) and PD-1 expression was observed. However, the modest explanatory power of the models suggests variability in the effects of different ARV regimens.

This study challenges the assumption that INSTI-based ARV regimens are universally superior, suggesting that non-INSTI therapies may better preserve immune function by reducing PD-1 expression. These findings highlight the potential benefits of non-INSTI regimens in improving long-term clinical outcomes in HIV treatment, warranting further research.

Immune checkpoints are critical regulators of T-cell exhaustion, impairing their ability to eliminate antigens present during chronic viral infections. Current immune checkpoint inhibitors (ICIs) used in the clinic aim to reinvigorate exhausted T cells; yet, most patients fail to respond or develop resistance to these therapies, underscoring the need to better understand these immunosuppressive pathways. PSGL-1 (Selplg), a recently discovered immune checkpoint, negatively regulates T-cell function. We investigated the cell-intrinsic effects of PSGL-1, PD-1, and combined deletion on CD8+ T cells during chronic viral infection. We found that combined PSGL-1 and PD-1 (Selplg-/-Pdcd1-/-) deficiency in CD8+ T cells increased their frequencies and numbers throughout chronic infection compared to the wild type. This phenotype was primarily driven by PD-1 deficiency. Furthermore, while PD-1 deletion increased virus-specific T-cell frequencies, it was detrimental to their function. Conversely, PSGL-1 deletion improved T-cell function but resulted in lower frequencies and numbers. The primary mechanism behind these differences in cell maintenance was driven by proliferation rather than survival. Combined PSGL-1 and PD-1 deletion resulted in defective T-cell differentiation, driving cells from a progenitor self-renewal state to a more terminal dysfunctional state. These findings suggest that PD-1 and PSGL-1 have distinct, yet complementary, roles in regulating T-cell exhaustion and differentiation during chronic viral infection. Overall, this study provides novel insights into the individual and combined roles of PSGL-1 and PD-1 in CD8+ T-cell exhaustion. It underscores the potential of targeting these checkpoints in a more dynamic and sequential manner to optimize virus-specific T-cell responses, offering critical perspectives for improving therapeutic strategies aimed at reinvigorating exhausted CD8+ T cells.IMPORTANCEOur findings provide a comprehensive analysis of how the dual deletion of PD-1 and PSGL-1 impacts the response and function of virus-specific CD8+ T cells, revealing novel insights into their roles in chronic infection. Notably, our findings show that while PD-1 deletion enhances T-cell frequencies, it paradoxically reduces T-cell functionality. Conversely, PSGL-1 deletion improves T-cell function but reduces their survival. Whereas the combined deletion of PSGL-1 and PD-1 in CD8+ T cells improved their survival but decreased their function and progenitor-exhausted phenotypes during infection. We believe our study advances the understanding of immune checkpoint regulation in chronic infections and has significant implications for developing more effective immune checkpoint inhibitor (ICI) therapies.

This review explores the emerging role of T cell exhaustion in allergic diseases and allergen immunotherapy (AIT). It aims to synthesize current knowledge on the mechanisms of T cell exhaustion, evaluate its potential involvement in allergic inflammation, and assess its implications as a novel biomarker for predicting and monitoring AIT efficacy.

Recent studies highlight that T cell exhaustion, characterized by co-expression of inhibitory receptors (e.g., PD-1, CTLA-4, TIM-3), diminished cytokine production, and altered transcriptional profiles, may suppress type 2 inflammation in allergic diseases. In allergic asthma, exhausted CD4 + T cells exhibit upregulated inhibitory receptors, correlating with reduced IgE levels and airway hyperreactivity. During AIT, prolonged high-dose allergen exposure drives allergen-specific Th2 and T follicular helper (Tfh) cell exhaustion, potentially contributing to immune tolerance. Notably, clinical improvements in AIT correlate with depletion of allergen-specific Th2 cells and persistent expression of exhaustion markers (e.g., PD-1, CTLA-4) during maintenance phases. Blockade of inhibitory receptors (e.g., PD-1) enhances T cell activation, underscoring their dual regulatory role in allergy. T cell exhaustion represents a double-edged sword in allergy: it may dampen pathological inflammation in allergic diseases while serving as a mechanism for AIT-induced tolerance. The co-expression of inhibitory receptors on allergen-specific T cells emerges as a promising biomarker for AIT efficacy. Future research should clarify the transcriptional and metabolic drivers of exhaustion in allergy, validate its role across diverse allergic conditions, and optimize strategies to harness T cell exhaustion for durable immune tolerance. These insights could revolutionize therapeutic approaches and biomarker development in allergy management.

Recent breakthroughs in tumor immunotherapy have confirmed the capacity of the immune system to fight several cancers. The effective means of treating cancer involves accelerating the death of tumor cells and improving patient immunity. Dynamic changes in the tumor immune microenvironment alter the actual effects of anti-tumor drug production and may trigger favorable or unfavorable immune responses by modulating tumor-infiltrating lymphocytes. Notably, CD8+ T cells are one of the primary tumor-infiltrating immune cells that provide anti-tumor response. Tumor cells and tumor stem cells will resist or evade destruction through various mechanisms as CD8+ T cells exert their anti-tumor function. This paper reviews the research on the regulation of tumor development and prognosis by cancer stem cells that directly or indirectly alter the role of tumor-infiltrating CD8+ T cells. We also discuss related immunotherapy strategies.

Background/Objectives: Acute otitis media is a common pediatric infection caused primarily by nontypeable Haemophilus influenzae. With rising antibiotic resistance, vaccines are essential for combating this public health issue. Although the PD-1/PD-L1 pathway has been extensively studied for its role in tumor immunity, its impact on mucosal immunity, particularly in vaccine responses, is unclear. Methods: BALB/c mice were intranasally immunized with nontypeable H. influenzae outer membrane protein and treated with anti-PD-L1 antibodies. Immune responses were evaluated in middle ear mucosa (MEM), the cervical lymph node, and the spleen using an enzyme-linked immunosorbent assay, an enzyme-linked immunospot assay, and flow cytometry. The effects on CD4+ T cells, T follicular helper (Tfh) cells, and B-cell differentiation were analyzed. Results: Anti-PD-L1 antibody treatment increased CD3+CD4+CD185+ (CXCR5+) Tfh cells in MEM, which play a crucial role in supporting B-cell activation and antibody production. This correlated with a significant increase in IgA- and IgG-producing cells in MEM, which enhanced local bacterial clearance. Although B-cell activation and differentiation into plasmablasts were observed in MEM, no significant changes were noted in the cervical lymph node and spleen, suggesting a localized enhancement of mucosal immunity. Conclusions: Anti-PD-L1 antibodies promoted Tfh cell expansion and B-cell differentiation in MEM, leading to enhanced antibody production and improved bacterial clearance. These findings suggest that PD-L1 blockade can potentiate mucosal vaccine-induced immunity by strengthening local humoral responses. This supports its potential application in developing intranasal vaccines for acute otitis media.

Programmed cell death protein 1 (PD-1) is a critical immune checkpoint receptor and a target for cancer immune checkpoint inhibitors (ICI). We investigated PD-1 transcript expression across cancer types and its correlations to clinical outcomes. Using a reference population, PD-1 expression was calculated as percentiles in 489 of 514 patients (31 cancer types) with advanced/metastatic disease. PD-1 RNA expression varied across and within cancer types; pancreatic and liver/bile duct malignancies displayed the highest rates of high PD-1 (21.82% and 21.05%, respectively). Elevated CTLA-4, LAG-3, and TIGIT RNA expression were independently correlated with high PD-1. Although high PD-1 was not associated with outcome in immunotherapy-naïve patients (n = 272), in patients who received ICIs (n = 217), high PD-1 transcript expression was independently correlated with prolonged survival (hazard ratio 0.40; 95%CI, 0.18-0.92). This study identifies PD-1 as an important biomarker in predicting ICI outcomes, and advocates for comprehensive immunogenomic profiling in cancer management.

This study aimed to explore the potential correlation between the metabolic intermediate L-2-hydroxyglutarate (L-2-HG) and T cell exhaustion, as well as the underlying mechanisms involved. In this study, we investigated the presence of exhausted T (Tex) cells in patients under certain conditions: HIV infection, chronic leukemia, and hepatocellular carcinoma. To gain insights into the epigenetic signatures and transcriptome changes in Tex cells, we employed a combination of RNA-seq and ATAC-seq analyses. To evaluate the impact of L-2-HG on mitochondrial function, differentiation, and antitumor capacity of Tex cells, we utilized in vitro cell culture experiments and animal tumor models. We observed mitochondrial depolarization and metabolic dysfunction in Tex cells, accompanied by a significant reduction in L-2-HG levels. Moreover, altered epigenetic characteristics were observed in Tex cells, including a substantial increase in H3K27me3 abundance. Culturing Tex cells with L-2-HG demonstrated improved mitochondrial metabolism, reduced H3K27me3 abundance, and enhanced memory T cell differentiation. In a mouse melanoma tumor model, L-2-HG-treated CD8+ T cells for adoptive therapy led to significantly reduced tumor volume and significantly enhanced effector function of T cells. The study revealed that L-2-HG acted as an immune metabolite through epigenetic modifications of Tex cells.

Cancer is one of the most important challenges worldwide with an increasing incidence. However, most of patients with malignant cancer receiving traditional therapies have tumor recurrence and short-term 5-year survival. Herein, a novel Cu2O-MnO@PEG (CMP) nanomaterial is developed to treat tumors. CMP directly mediates cuproptosis in tumor cells. Meanwhile, CMP potentiates anti-tumor immune responses in the tumor microenvironment (TME) to induce tumor regression. CMP improves the tumor antigen processing and presentation of dendritic cells and tumor-associated macrophages, and further promotes CD8+ T cell responses, especially for cytotoxic CD8+ T cells and transitory exhausted CD8+ T cells. Additionally, CMP downregulates the proportion of Treg cells and CTLA-4 expression on Treg cells. Notably, CMP induces systemic immune responses against distant tumors and long-term immune memory. Furthermore, CMP synergized with PD-L1 mAb promotes tumor inhibition and sustains the anti-tumor efficacy post PD-L1 mAb treatment. Collectively, this strategy has the clinically therapeutic potential for tumors by facilitating cuproptosis in tumor cells and anti-tumor immune responses.