Search Results (1,220)

CD8⁺ T-cell exhaustion is a key mechanism of tumor immune evasion and a major limitation of current cancer immunotherapy. However, the molecular factors sustaining dysfunctional CD8⁺ T-cell states across cancers are not fully understood. Here, we identify GPR171 as a common feature of exhausted CD8⁺ T cells across multiple solid tumors based on integrated pan-cancer single-cell transcriptomic analyses. GPR171 is enriched in exhausted CD8⁺ T cells and is closely associated with immunosuppressive and exhaustion-related gene programs. It also shows a strong association with key immune regulatory genes such as CTLA4 and NR4A2. Functional analyses suggest that reduced GPR171 activity is associated with decreased expression of exhaustion-related genes and a shift toward cytotoxic and immune-activating programs. In parallel, a CREM-centered regulatory network emerges in exhausted CD8⁺ T cells and may act in concert with GPR171-associated programs to reinforce dysfunctional states. Overall, our results identify GPR171 as a candidate marker of CD8⁺ T-cell dysfunction across cancers and provide a systematic pan-cancer single-cell characterization of its association with immunosuppressive T-cell states, supporting its potential as a therapeutic target for restoring antitumor immunity. Full article

The mucosal surfaces of the different tracts of the human body occupy a vast interface (around 400 m²), and defense at these sites represents the first line of immune defense. It is at the interface of these surfaces that a cellular and molecular crosstalk among different players is accomplished: the microbiota, the mucosal epithelial, and the immune system. Different lymphocyte populations are present on these surfaces as sentinels, ready to act upon any insult that threatens body homeostasis. One of them are the T-cell-derived intraepithelial lymphocytes (T-IELs), gatekeepers at the mucosal epithelium of the common mucosal system (MALT) (gut, lung, and urogenital tract). These lymphocytes are divided into natural, non-conventional (CD4+/CD8+, TCR αβ, γδ, αα) and induced T-IELs or conventional (CD4+/CD8+ TCR αβ). The most remarkable and distinguishing properties of these innate lymphocyte populations are a triad of attributes: innate, cytotoxic, and memory-protective immune responses. T-IELs are a disregarded population of innate cells, ready to act, for rapid microbial clearance, and an effective support for any mucosal invader. Despite this, T-IELs are an underutilized immunological target that needs further in-depth investigation into their role in inducing fast, rapid clearance of mucosal pathogens, and protective and immune memory (innate and adaptive). The present commentary aims to put into context this emerging potential of T-IELs as immunological targets. Full article

In triple-negative breast cancer (TNBC), immune checkpoint pathways play a central role in tumor immune evasion. Programmed death protein 1 (PD-1) is an inhibitory receptor expressed on T cells, while its ligand, programmed death-ligand 1 (PD-L1), is commonly expressed on tumor cells and cells within the tumor microenvironment. Their interaction suppresses T-cell activation and promotes immune escape. In this study, we evaluated the potential of small interfering RNA (siRNA) to silence PD-L1 expression in TNBC. Transcriptomic analysis of GEO datasets revealed consistent upregulation of CD274 (PD-L1) in TNBC samples. Three siRNA candidates were designed and evaluated in MDA-MB-231 cells. All siRNAs significantly reduced CD274 expression (>70%), as determined by RT-qPCR. Immunofluorescence analysis confirmed a reduction in PD-L1 protein levels (54.3 vs. 98.7 a.u.), while MTT assays demonstrated preserved cell viability at the working concentration (100 pM), supporting a non-cytotoxic and specific gene-silencing effect. These findings highlight PD-L1 as a viable molecular target and support siRNA-mediated silencing as a promising therapeutic strategy in TNBC. Full article

Immune checkpoint inhibitors (ICIs), comprising anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), anti-programmed cell death protein 1 (PD-1), and anti-programmed death-ligand 1 (PD-L1), have transformed melanoma therapy, yet the tumour microenvironment (TME), the pivotal biological interface where therapeutic efficacy, resistance, and toxicity are determined, remains incompletely characterized. This dual systematic review and meta-analysis (PROSPERO: CRD420261374242) followed PRISMA 2020 and included 58 preclinical (B16F10/C57BL/6; 46 quantitative) and 44 clinical studies (19 quantitative) to calculate pooled standardized mean differences (SMDs) for six intratumoral TME parameters. Checkpoint blockade consistently shifted the TME toward an immune-activated state, an effect that remained robust in sensitivity analyses despite substantial heterogeneity (I-squared heterogeneity statistic (I²) = 68–88%). Preclinically, ICIs significantly increased CD8⁺ T-cell infiltration (SMD = 1.45, p < 0.001), interferon-gamma (IFN-γ) (SMD = 1.78, p < 0.001), CD8/regulatory T-cell (Treg) ratio (SMD = 0.91, p = 0.005), and apoptosis (SMD = 3.54, p < 0.001) and reduced PD-L1 (SMD = −0.88, p = 0.004) and Ki-67 (SMD = −1.43, p = 0.028). Clinically, CD8⁺ infiltration and PD-L1 both increased (SMD = 0.72, p < 0.001; SMD = 0.67, p = 0.001), contrasting with the preclinical PD-L1 decrease. Meta-regression demonstrated superior anti-PD-L1 efficacy over CTLA-4 for effector parameters: IFN-γ +3.59 (p = 0.009), CD8/Treg +10.69 (p = 0.003), apoptosis +9.76 (p = 0.004), and Ki-67 −6.28 (p = 0.040). These findings establish the TME as a critical determinant of ICI outcomes, indicate that PD-L1 amplifies effector functions in the B16F10 model, and highlight translational gaps in TME reprogramming. Full article

CD19 chimeric antigen receptor (CAR) T cells have demonstrated promising outcomes in B-cell malignancies. However, using pretreated autologous T cells currently faces limitations, including compromised T-cell fitness and the challenge of manufacturing sufficient cell numbers for treatment. Consequently, natural killer (NK) cells have emerged as an alternative due to their natural ability to mediate cytotoxicity and their favorable safety profile. This study aims to generate patient autologous hematopoietic stem cell-derived NK (HSC-NK) cells and assess their therapeutic potential compared to peripheral blood NK (PB-NK) cells. We successfully cultivated HSC-NK under a 28-day, two-step differentiation and expansion protocol, achieving a cumulative 290-fold expansion using optimized memory-like cytokines and feeder cell stimulation. The expanded HSC-NK cells demonstrated a distinct phenotype (CD56⁺CD16^low), representing an immature differentiation state, characterized by a lower expression of inhibitory receptors (NKG2A, KIR2DL, and CD94) and the exhaustion markers (LAG3, PD-1, TIM-3, and CTLA-4) compared to PB-NK cells. Prominent expression of CD62L, alongside sustained expression of CD69 and CD107a, was observed, translating into NK cell proliferation, activation, and cytotoxicity against cancer cells comparable to PB-NK cells. In conclusion, generating HSC-NKs is feasible while preserving essential NK cell phenotypes and activities. Our findings emphasize the potential of HSCs as an alternative NK cell source for cancer immunotherapy. Full article

Viral vaccine development requires both mechanistic understanding of protective immunity and translational study designs that connect preclinical data with human outcomes. Animal models remain important for early assessment of safety, immunogenicity and protective efficacy, but their predictive value depends on the question being asked, the pathophysiology of infection, the immune mechanisms expected to mediate protection, and the biomarkers chosen to bridge animal and human data. This review focuses on viral vaccines and examines innate and adaptive mechanisms of vaccine-induced protection, including B cell and antibody responses, Fc-mediated functions, Fc glycosylation, T cell memory and CD8+ cytotoxic responses. We discuss common reasons for clinical failure and show how preclinical endpoints can be classified as human-counterpart, surrogate or comparative/mechanistic readouts. Influenza and COVID-19 examples illustrate how different models can be combined across discovery, challenge, transmission and late-stage bridging studies. Emerging tools such as systems serology, omics, AI/ML and new approach methods can improve candidate prioritization, but their value depends on assay standardization, biological validation and cautious interpretation. A mechanism-driven model cascade, paired with human-relevant immunological readouts, can improve preclinical interpretation and reduce the risk of advancing candidates that are unlikely to succeed in clinical trials. Full article

HIV reservoir size and decay represent distinct dimensions of viral persistence, yet whether they are governed by shared or separable immunological mechanisms during early antiretroviral therapy (ART) remains unclear. In this study, we employed multiparameter flow cytometry and bulk RNA sequencing to analyze longitudinal immune profiles across 21 treatment-naïve people living with HIV before ART initiation and at 1 and 5 months thereafter. Our findings revealed an apparent dissociation between HIV-1 DNA levels and decay rates in peripheral blood, and the two indicators appear to be relatively independent dimensions of viral persistence. Specifically, lower HIV-1 DNA levels were associated with higher frequencies of cytotoxic and adaptive-like natural killer (NK) cell subsets, whereas faster HIV-1 DNA decay was linked to restored HIV-specific CD4+ and CD8+ T-cell responses during treatment. Notably, transcriptomic analyses uncovered divergent gene expression signatures related to B cell-associated immunity and type I interferon pathways, with individuals with higher HIV-1 DNA levels exhibiting elevated expression of immunoglobulin and interferon-stimulated genes, while faster decay correlated with enrichment of antiviral and complement-related genes. Collectively, these findings provide a preliminary characterization of immune correlates of peripheral blood total HIV-1 DNA dynamics in the early phase following ART initiation. This work offers potential immune clues for exploring the viral reservoir and generates testable hypotheses for validation in future large cohorts. Full article

Neutrophil extracellular traps (NETs) are web-like structures composed of decondensed DNA, histones, and proteins released by activated neutrophils. Originally identified as an innate defense mechanism against pathogens, NETs have since been implicated in cancer progression and immune evasion. Within the tumor microenvironment (TME), NETs suppress anti-tumor immunity through multiple mechanisms, including the physical exclusion of CD8⁺ cytotoxic T lymphocytes from the tumor interior and upregulation of exhaustion markers via checkpoint ligands. This review synthesizes current preclinical and clinical evidence on the interplay between NETs and CD8⁺ T cells across multiple malignancies, including non-small cell lung cancer, pancreatic ductal adenocarcinoma, cholangiocarcinoma, colorectal cancer, bladder cancer, hepatocellular carcinoma, skin cancer, and penile cancer. Cancer-specific mechanisms of NET-mediated immune suppression are discussed, including IL-8, IL-17, CXCL6, and TGF-β-driven NETosis pathways. Clinical data consistently demonstrate that elevated NET levels correlate with reduced CD8⁺ T cell infiltration, T cell dysfunction, and worse patient outcomes. Emerging therapeutic strategies targeting this axis are reviewed, including DNase I-mediated NET degradation, Peptidyl arginine deiminase 4 (PAD4) inhibition, CXCR2 blockade, and combination approaches with immune checkpoint inhibitors. These interventions have shown promise in restoring CD8⁺ T cell cytotoxicity and overcoming immunotherapy resistance in preclinical models. Collectively, the evidence supports the NET-CD8⁺ T cell axis as a promising prognostic and therapeutic target warranting further clinical investigation. Full article

Background: The tumor immune microenvironment, particularly the role of cytotoxic CD8+ T lymphocytes, is crucial in cancer progression but remains poorly understood in pituitary neuroendocrine tumors (PitNETs). The significance of CD8+ cell infiltration varies across PitNET subtypes, suggesting a complex interplay with tumor cell lineage. This study aimed to characterize the distribution of CD8+ tumor-infiltrating lymphocytes across different PitNET subtypes defined by the current WHO classification and to explore their association with clinicopathological features. Methods: We conducted a retrospective study on 40 surgically resected PitNETs. All cases were classified based on immunohistochemical expression of pituitary hormones and lineage-specific transcription factors (PIT-1, TPIT, SF-1). CD8+ lymphocyte density was quantified using immunohistochemistry and calculated as cells/mm². Exploratory statistical analysis was performed based on non-parametric tests to compare CD8+ cell density across tumor subtypes and with parameters like tumor size, invasiveness (Knosp grade), and proliferation index (Ki-67). Findings are to be treated as observational trends. Results: The highest density of CD8+ lymphocytes was observed in plurihormonal PIT-1-positive tumors [17.61 cells/mm² (IQR: 17.61–60.36)], followed by somatotroph [13.2 (6.6–15.72)] and mammosomatotroph [13.83 (0–21.38)] tumors. A difference in CD8+ density was found between PIT-1-positive and PIT-1-negative tumors (n1 = 34, n2 = 6, U = 49.5, p_exact = 0.050, r = 0.33); the medium effect size indicates a possible lineage-related trend. Another difference was observed between SF-1-positive and SF-1-negative tumors (p = 0.025), with SF-1 lineage tumors showing the lowest infiltration. No correlations were found between CD8+ density and tumor size, Knosp grade, or Ki-67 index. Conclusions: The distribution of intratumoral CD8+ T lymphocytes in PitNETs is highly heterogeneous and appears to be strongly dictated by the transcription factor-defined tumor lineage rather than by traditional clinicopathological markers of aggressiveness. PIT-1 lineage tumors harbor a more active immune microenvironment, while SF-1 lineage tumors are relatively ‘immune-poor’. These findings highlight the immunological diversity of PitNETs and support further investigation of the tumor immune landscape. Collaborative multi-institutional studies are required to validate these trends. Full article

Background/Objectives: Tuberculosis, caused by Mycobacterium tuberculosis, remains a major global health challenge requiring novel prevention strategies. This study aims to developed an immunoinformatics-guided framework coupled with experimental screening to prioritize for multi-epitope mRNA vaccine design. Methods: Eight immunologically relevant antigens were computationally analyzed to predict cytotoxic (CTL) epitopes and helper T lymphocyte (HTL) epitopes. Population coverage, immune simulation, molecular docking, and normal mode analysis (NMA) were performed in silico. To evaluate peptide immunoreactivity, human IFN-γELISPOT assays were conducted using the candidate peptides, though HLA restriction was not experimentally validated. Results: The workflow identified 14 candidate CTL and 8 HTL epitopes, yielding an estimated global population coverage of 82.6% (60.7% in China; 51.2% in Indonesia). Immune simulations predicted robust humoral and Th1-associated cellular responses, though sustained CD8⁺ memory responses appeared limited. Docking and NMA suggested favorable structural interactions with TLR3 and TLR4. Crucially, the IFN-γ ELISPOT assay validated eight reactive epitopes that partially coincided with computational predictions within the tested donor group. Conclusions: This study establishes an integrated computational–experimental workflow for T cell epitope prioritization. The identified reactive epitopes provide a preliminary immunological basis and candidate pool for the future design and evaluation of multi-epitope mRNA vaccine strategies against tuberculosis. Full article

Lymph nodes are central hubs of immune regulation and coordination, serving as primary sites for antigen presentation, lymphocyte activation, and the orchestration of adaptive immune responses. The composition and activation state of lymph node-resident immune cells critically shape both local and systemic immunity. Comprehensive immunophenotyping of these populations is therefore essential for understanding immune organization and functional heterogeneity. Here, we present an optimized protocol for the characterization of mouse lymph node-associated immune populations using 14-color multiparametric flow cytometry. The method combines lymph node isolation based on anatomical landmarks with mechanical dissociation and enzymatic digestion to generate high-quality single-cell suspensions suitable for downstream analysis. Furthermore, the described flow cytometry panel and gating strategy enable reliable identification and quantification of major lymphoid subsets, including helper CD4⁺ and cytotoxic CD8⁺ T cells with their differentiation states, as well as natural killer (NK) cells across distinct maturation stages. Although optimized for assessing lymphocyte maturation after lipopolysaccharide (LPS) challenge, the protocol serves as a reproducible platform for broad immunophenotyping of T and NK cell subsets in mouse lymphoid tissues under experimental conditions. Full article

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive subtype of ALL characterized by unfavorable clinical outcomes. Despite significant progress in deciphering the genetic and epigenetic landscapes of T-ALL, the underlying molecular mechanisms, particularly in non-early T-cell precursor (non-ETP) T-ALL, remain incompletely understood. In this study, functional assays were performed using three well-characterized non-ETP T-ALL cell lines. In vivo therapeutic efficacy was evaluated using non-ETP T-ALL xenograft models. Transcriptomic profiling was performed by RNA sequencing (RNA-seq) followed by bioinformatic analysis. Publicly available clinical datasets from T-ALL patients were mined to analyze survival outcomes. We found that activation of CD40 ligand (CD40LG) or CD28 accelerates cell-cycle progression and enhances the migratory capacity of non-ETP T-ALL cells, with CD40LG uniquely upregulating CXCR4 to mediate bone marrow tropism. Further RNA-seq and functional validation identified Rho GTPase signaling, specifically RhoA/Rac1/Rac2, as a pivotal downstream effector of CD40LG/CD28, leading to therapeutic resistance to PI3K inhibition. Pharmacological blocking RhoA or Rac1 using small-molecule compounds not only induces remarkable cytotoxicity but also sensitizes resistant cells to PI3K inhibitors, both in vitro and in vivo. Clinically, elevated expression of CD40LG, CD28, RHOA, or RAC2 correlates with poor prognosis in non-ETP T-ALL patients. These findings uncover a novel CD40LG/CD28-Rho GTPase axis as a key driver of pathogenesis and a potential therapeutic vulnerability in non-ETP T-ALL, providing a new target for precision intervention and a promising strategy to overcome therapeutic resistance. Full article

Background: Cutaneous melanoma (CM) is a highly immunogenic malignant neoplasm. It features high mutational burden and intense lymphocytic infiltration, supporting the use of immunotherapies, especially inhibitors of the programmed cell death protein 1 (PD-1) checkpoint. Despite advances with anti-PD-1 therapies, such as nivolumab and pembrolizumab, many patients still experience resistance. This result highlights additional immunosuppressive mechanisms within the tumor microenvironment (TME) that limit T-lymphocyte-mediated responses. Objectives: The aim was to discuss the immunologic and metabolic bases of PD-1- and CD73-mediated pathways and evidence that CD73 inhibition can boost PD-1 inhibitor efficacy by acting on convergent immunosuppressive pathways. Methods: We conducted a narrative literature review focusing on tumor immunosuppression, purinergic signaling and checkpoint inhibitor-based immunotherapy. Results: The purinergic pathway, mediated by the ectonucleotidase CD73, is a critical regulator of tumor immunosuppression. CD73 converts extracellular adenosine monophosphate (AMP) into adenosine. This adenosine accumulates in the hypoxic and inflamed TME, exerting immunosuppressive effects. Adenosine acts as a “metabolic brake,” inhibiting proliferation, cytokine production, and cytotoxic activity of CD8⁺ T lymphocytes and natural killer (NK) cells. It also promotes the expansion of regulatory T cells (Tregs) and tumor progression. This axis may limit responses to PD-1 blockade, suggesting that complementary pathways are active. Conclusions: Integration of PD-1 and CD73 pathways suggests that CD73 inhibition may enhance PD-1 blockade by targeting convergent immunosuppressive mechanisms. This supports the exploration of combination strategies to broaden the benefits of immunotherapy in CM. Full article

Background/Objectives: Hepatocellular carcinoma (HCC) is challenging to treat with chemotherapy. Immunotherapy has shown moderate responses in inflammatory and immunosuppressive tumor environments. Hepatic cytochrome P450 monooxygenases (CYPs) play a crucial role in xenobiotic and drug metabolism, as well as lipid and steroid metabolism. We aimed to investigate whether CYP expression and various parameters of the innate and adaptive immune system are prognostic factors for the survival of HCC patients. Methods: HCC biopsies (n = 370) from The Cancer Genome Atlas (TCGA) database were analyzed using Kaplan–Meier statistics and the KMPlotter algorithm. Parameters such as immune cell infiltration, DNA mutation rates, and neoantigen load were selected for survival analysis and subjected to hierarchical cluster analysis. The expression of candidate CYP genes in tumors was compared to that in normal liver tissues. Furthermore, tumor infiltration of innate immune cells (basophilic and eosinophilic granulocytes, natural killer cells), adaptive immune cells (CD4+ memory and CD8+ cytotoxic T cells, regulatory T cells, type 1 and type 2 helper T cells), and mesenchymal stem cells was examined. Results: High expression of CYP19A1 and CYP26B1 was associated with shorter survival, whereas high expression of CYP3A5, CYP3A43, CYP7A1, and CYP27A1 was linked to longer survival. Mutation rates combined with CYP expression showed a correlation with five out of six CYP genes, while a high neoantigen load produced less definitive results. A specific cluster exhibiting high CYP expression and immune cell counts or mutation/neoantigen rates was associated with shorter survival, while another cluster was linked to longer survival. Conclusions: CYPs involved in the metabolic regulation of HCC, including CYP3A5, CYP3A43, CYP7A1, CYP19A1, CYP26B1, and CYP27A1, were found to have prognostic value for patient survival. Combined signatures that include CYP expression, mutational rates, and immune cell infiltration into tumors further enhanced the prognostic value for patient survival. This suggests that CYPs may influence the creation of a tumor-specific metabolic microenvironment that impacts immune functions. These combined signatures could be utilized for patient stratification to personalize tumor treatment and develop novel combination therapies aimed at optimizing treatment outcomes, such as combining transarterial chemoembolization (TACE) with immune checkpoint inhibitors. Full article

Non-Hodgkin lymphoma (NHL) encompasses a biologically diverse group of malignancies for which the integration of precision medicine has markedly reshaped therapeutic strategies. Recent advances in molecular profiling, target identification, and drug development have led to the introduction of highly selective agents capable of overcoming resistance mechanisms and improving outcomes in relapsed or refractory disease. This review highlights three targeted therapies—pirtobrutinib, brentuximab vedotin, and belinostat—and their evolving roles in modern NHL management. Pirtobrutinib, a next-generation, non-covalent Bruton tyrosine kinase (BTK) inhibitor, demonstrates preserved activity in patients previously treated with covalent BTK inhibitors (BTKi), addressing a critical unmet need in B-cell lymphomas. Brentuximab vedotin, an antibody–drug conjugate targeting CD30, has significantly improved therapeutic precision by delivering cytotoxic agents directly to lymphoma cells and has become a central component of treatment for CD30-expressing NHL subtypes. Belinostat, a broad-spectrum histone deacetylase (HDAC) inhibitor, offers a mechanistically distinct epigenetic approach, particularly in peripheral T-cell lymphomas (PTCL), where conventional chemotherapy has limited efficacy. Together, these agents exemplify three complementary paradigms of precision oncology in NHL: kinase signaling inhibition, antigen-directed cytotoxic delivery, and epigenetic modulation. This review synthesizes current evidence, clinical trial data, and future perspectives regarding the integration of pirtobrutinib, brentuximab vedotin, and belinostat into evolving treatment paradigms. Cumulatively, these therapies illustrate both the progress and the ongoing challenges of biomarker-driven treatment in NHL, including resistance mechanisms, toxicity management, optimal therapeutic sequencing, and variability in evidence maturity across targeted strategies. While pirtobrutinib and brentuximab vedotin are supported by increasingly robust clinical evidence in selected lymphoma subtypes, the role of belinostat remains constrained by modest response rates and limited randomized data, underscoring the continued need for biomarker refinement and more precisely individualized therapeutic approaches in NHL precision medicine. Full article