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Immune subtyping of colorectal adenoma identifies a subtype with activated adaptive immunity ahead of progressing to cancer.

BACKGROUND: Colorectal adenomas (CRA) represent precursor lesions with varying risks of malignant transformation. However, molecular subtyping, particularly immune-related classification, remains underexplored in adenomas. This study aims to characterize the immune landscape of CRA through immune subtyping and evaluate its association with cancer progression, gene expression signatures, and functional pathways. METHODS: We conducted a retrospective analysis of transcriptomic data from multiple cohorts of CRA samples. Immune subtypes were identified using non-negative matrix factorization (NMF) based on immune-related genes. Diverse deconvolution algorithms were used to estimate immune cell infiltration. The immune status alteration in premalignant lesion was further consolidated by single-cell transcriptome data. Differential gene expression analysis was performed between subtypes, followed by functional enrichment analyses (Gene Ontology [GO] and Kyoto Encyclopedia of Genes and Genomes [KEGG]). RESULTS: Two distinct immune subtypes were identified: an immune-enriched subtype characterized by high lymphocyte infiltration and elevated expression of immune-related genes, and an immune-deficient subtype with suppressed immune activity. Differential expression analysis revealed significant upregulation of immune response genes (e.g., CD4, CD86, HLA-DRA) in the immune-enriched subtype. GO and KEGG analyses highlighted enrichments in leukocyte transendothelial migration, chemokine signaling, and antigen processing and presentation pathways. Single-cell result revealed an early occurrence of TIGIT activation and exhausted CD8 T cell features in adenoma when compared to normal tissue. CONCLUSION: This study delineates distinct immune subtypes within CRAs. The immune-enriched subtype demonstrates activated adaptive immunity and may reflect a higher potential for immune surveillance, while the immune-deficient subtype exhibits stromal features suggestive of progressive transformation. These findings provide insights into early immune microenvironment alterations and may inform strategies for risk stratification and immunoprevention in colorectal carcinogenesis.

Colorectal adenoma

Soluble immune checkpoint factors reflect exhaustion of antitumor immunity and response to PD-1 blockade.

BACKGROUNDPrecise stratification of patients with non-small cell lung cancer (NSCLC) is needed for appropriate application of PD-1/PD-L1 blockade therapy.METHODSWe measured soluble forms of the immune-checkpoint molecules PD-L1, PD-1, and CTLA-4 in plasma of patients with advanced NSCLC before PD-1/PD-L1 blockade. A prospective biomarker-finding trial (cohort A) included 50 previously treated patients who received nivolumab. A retrospective observational study was performed for patients treated with any PD-1/PD-L1 blockade therapy (cohorts B and C), cytotoxic chemotherapy (cohort D), or targeted therapy (cohort E). Plasma samples from all patients were assayed for soluble immune-checkpoint molecules with a highly sensitive chemiluminescence-based assay.RESULTSNonresponsiveness to PD-1/PD-L1 blockade therapy was associated with higher concentrations of these soluble immune factors among patients with immune-reactive (hot) tumors. Such an association was not apparent for patients treated with cytotoxic chemotherapy or targeted therapy. Integrative analysis of tumor size, PD-L1 expression in tumor tissue (tPD-L1), and gene expression in tumor tissue and peripheral CD8+ T cells revealed that high concentrations of the 3 soluble immune factors were associated with hyper or terminal exhaustion of antitumor immunity. The combination of soluble PD-L1 (sPD-L1) and sCTLA-4 efficiently discriminated responsiveness to PD-1/PD-L1 blockade among patients with immune-reactive tumors.CONCLUSIONCombinations of soluble immune factors might be able to identify patients unlikely to respond to PD-1/PD-L1 blockade as a result of terminal exhaustion of antitumor immunity. Our data suggest that such a combination better predicts, along with tPD-L1, for the response of patients with NSCLC.TRIAL REGISTRATIONUMIN000019674.FUNDINGThis study was funded by Ono Pharmaceutical Co. Ltd. and Sysmex Corporation.

Humans

Tumor-immune partitioning and clustering algorithm for identifying tumor-immune cell spatial interaction signatures within the tumor microenvironment.

BACKGROUND: Growing evidence supports the importance of characterizing the organizational patterns of various cellular constituents in the tumor microenvironment in precision oncology. Most existing data on immune cell infiltrates in tumors, which are based on immune cell counts or nearest neighbor-type analyses, have failed to fully capture the cellular organization and heterogeneity. METHODS: We introduce a computational algorithm, termed Tumor-Immune Partitioning and Clustering (TIPC), that jointly measures immune cell partitioning between tumor epithelial and stromal areas and immune cell clustering versus dispersion. As proof-of-principle, we applied TIPC to a prospective cohort incident tumor biobank containing 931 colorectal carcinoma cases. TIPC identified tumor subtypes with unique spatial patterns between tumor cells and T lymphocytes linked to certain molecular pathologic and prognostic features. T lymphocyte identification and phenotyping were achieved using multiplexed (multispectral) immunofluorescence. In a separate hepatocellular carcinoma cohort, we replaced the stromal component with specific immune cell types-CXCR3+CD68+ or CD8+-to profile their spatial relationships with CXCL9+CD68+ cells. RESULTS: Six unsupervised TIPC subtypes based on T lymphocyte distribution patterns were identified, comprising two cold and four hot subtypes. Three of the four hot subtypes were associated with significantly longer colorectal cancer (CRC)-specific survival compared to a reference cold subtype. Our analysis showed that variations in T-cell densities among the TIPC subtypes did not strictly correlate with prognostic benefits, underscoring the prognostic significance of immune cell spatial patterns. Additionally, TIPC revealed two spatially distinct and cell density-specific subtypes among microsatellite instability-high colorectal cancers, indicating its potential to upgrade tumor subtyping. TIPC was also applied to additional immune cell types, eosinophils and neutrophils, identified using morphology and supervised machine learning; here two tumor subtypes with similarly low densities, namely 'cold, tumor-rich' and 'cold, stroma-rich', exhibited differential prognostic associations. Lastly, we validated our methods and results using The Cancer Genome Atlas colon and rectal adenocarcinoma data (n = 570). Moreover, applying TIPC to hepatocellular carcinoma cases (n = 27) highlighted critical cell interactions like CXCL9-CXCR3 and CXCL9-CD8. CONCLUSIONS: Unsupervised discoveries of microgeometric tissue organizational patterns and novel tumor subtypes using the TIPC algorithm can deepen our understanding of the tumor immune microenvironment and likely inform precision cancer immunotherapy.

Humans

HLA class I expression and tumor immune infiltration together shape colon cancer immune contexture.

BACKGROUND: The relative contribution of HLA class I molecules-including classical HLA class Ia (HLA-A, -B, -C) and non-classical HLA class Ib (HLA-E, -F, -G)-to shaping the tumor immune microenvironment in colon cancer remains insufficiently defined. We investigated how their expression patterns relate to immune infiltration and clinical outcome. METHODS: In a retrospective cohort of 280 colon cancers, we assessed HLA class Ia and class Ib expression and quantified CD45-positive immune cell infiltration by immunohistochemistry. These features were correlated with clinicopathological variables, microsatellite instability (MSI) status, and previously established genomic immune signatures. RESULTS: High HLA class Ia expression and increased CD45-positive cell infiltration were each associated with improved overall, disease-specific, and progression-free survival. CD45-positive density correlated strongly with Immunologic Constant of Rejection scores. HLA class Ia loss was more frequent in advanced stages and in MSI-H tumors. Among HLA class Ib molecules, only HLA-E expression was associated with favorable disease-specific and progression-free survival. Integrative analysis identified three immune phenotypes with distinct prognostic profiles; tumors characterized by high HLA class Ia expression, low HLA class Ib expression, and high CD45-positive infiltration had the best outcomes. CONCLUSION: Colon cancer immunogenicity is shaped by coordinated patterns of HLA class I expression and immune infiltration. Integrating HLA class Ia/Ib expression with immune cell density provides a refined stratification of tumor immune phenotypes and may support personalized immunotherapeutic decision-making.

Antigen presentation

Cancer Immune Responsiveness and MHC Class I Antigen Presentation: Mechanisms of Immune Escape and Immunotherapy Resistance in Gastrointestinal Cancers.

The Antigen Processing and Presentation Machinery (APM) is essential for immune surveillance by enabling the presentation of antigenic peptides to T lymphocytes and facilitating the elimination of infected or transformed cells. In cancer, the integrity of this process influences cancer immune responsiveness (CIR), defined as a tumour's capacity to be recognised by the immune system and respond to immunotherapy. Tumours with intact antigen presentation pathways are more likely to generate effective antitumour responses, whereas APM defects promote immune escape and therapeutic resistance. Cancer cells frequently evade immune detection through altered antigen processing or reduced expression of major histocompatibility complex (MHC) class I molecules, limiting tumour antigen presentation to cytotoxic T lymphocytes. These alterations are increasingly recognised as determinants of response to immune checkpoint inhibitors and potential predictive biomarkers. APM defects may be reversible or irreversible. Interferon-mediated signalling can restore MHC class I expression and T-cell cytotoxicity in some tumours, whereas permanent genomic alterations affecting human leukocyte antigen (HLA) class I genes, β2-microglobulin (β2-m), or interferon-γ (IFN-γ) pathway components can severely impair antigen presentation. Emerging evidence highlights four mechanistic levels of APM perturbation: peptide generation, peptide loading, MHC class I integrity, and epigenetic regulation. Each contributes to distinct patterns of immune evasion. This review examines how MHC class I alterations influence CIR and contribute to immune evasion and immunotherapy resistance in gastrointestinal malignancies, while discussing therapeutic strategies to restore or bypass APM deficiencies.

Humans

Immune-Like Malignant Epithelial Programs Shape Tumor-Immune Interactions and Inform Prognostic Stratification in Lung Adenocarcinoma.

Lung adenocarcinoma (LUAD) is characterized by marked cellular heterogeneity, yet how malignant epithelial states contribute to immune regulation and clinical outcomes remains incompletely defined. We integrated single-cell RNA-sequencing data to map the cellular landscape of LUAD and identify malignant epithelial cells based on inferred copy-number alterations. Epithelial states were further examined through trajectory inference, transcription factor analysis, and cell-cell communication profiling. Single-cell-derived genes were subsequently integrated with TCGA and independent GEO cohorts to construct and validate a machine learning-based prognostic signature. Malignant epithelial cells displayed distinct functional programs, including an immune-like state associated with genomic instability, immune-related transcriptional activity, tumor-immune communication, and patient outcomes. The resulting immune-like malignant epithelial cell signature (IMEC-Sig) consistently stratified survival across multiple cohorts. Low IMEC-Sig scores were accompanied by greater immune infiltration, higher immune checkpoint expression, and increased immunophenoscore, whereas high scores were linked to a comparatively immunosuppressive phenotype. Pan-cancer analyses further identified KRT8 as a gene associated with unfavorable prognosis, and functional experiments showed that KRT8 silencing suppressed proliferation, migration, invasion, and colony formation in LUAD cells. Together, these findings connect malignant epithelial heterogeneity with the immune context and clinical outcomes, support IMEC-Sig as a biologically informed prognostic tool, and nominate KRT8 as a potential therapeutic target in LUAD.

Humans

Cyclin-dependent kinase 4 and 6 inhibitors and the breast cancer immune ecosystem: immune remodeling, resistance, and therapeutic reprogramming.

Cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6 inhibitors) combined with endocrine therapy have become a therapeutic backbone for hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer, yet durable disease control is frequently limited by intrinsic and acquired resistance. Canonical tumor-cell mechanisms, including retinoblastoma-pathway escape, cyclin E-cyclin-dependent kinase 2 (CDK2) activation, endocrine adaptation, and phosphoinositide 3-kinase (PI3K)-AKT-mechanistic target of rapamycin (mTOR) signaling, explain only part of this failure because they do not fully capture dynamic immune and stromal remodeling. Preclinical and translational studies indicate that early CDK4/6 inhibition can enhance antigen presentation, activate interferon-related programs, restrain regulatory T cells, and promote a T-cell-inflamed state. These effects are conditional and may not persist during prolonged treatment. Sustained therapy can instead drive heterogeneous resistant niches characterized by stromal remodeling, myeloid recruitment, checkpoint adaptation, and T-cell dysfunction. This immune-state dependence provides a rationale for immune checkpoint blockade, although clinical combinations have shown mixed efficacy and clinically relevant hepatic, pulmonary, and hematologic toxicities. Sequential or lead-in strategies therefore warrant prospective evaluation. Oxidative phosphorylation (OXPHOS) and redox adaptation may sustain selected resistant states and expose context-dependent ferroptotic vulnerabilities. Ferroptosis may connect tumor-cell killing with immune regulation, whereas nanomedicine may improve tumor-selective delivery. Both strategies remain largely preclinical and require further evaluation of pharmacokinetics, biodistribution, toxicity, manufacturability, and immune-cell safety. This Review distinguishes intrinsic from acquired resistance across interpatient, intratumoral, spatial, and temporal dimensions. It integrates tumor-cell escape with cytokine, immune, stromal, vascular, and metabolic remodeling and summarizes emerging therapeutic strategies. We further propose a candidate biomarker-informed framework that integrates genomic profiling, spatial immune architecture, circulating biomarkers, T-cell receptor (TCR) dynamics, transcriptomic and single-cell analyses, artificial intelligence (AI)-assisted multimodal integration, and longitudinal sampling. This framework is intended to support biomarker development and prospective trial design rather than current clinical decision-making, providing a translational basis for testing state-informed and sequence-aware therapeutic strategies.

Humans

Malaria: Factors affecting disease severity, immune evasion mechanisms, and reversal of immune inhibition to enhance vaccine efficacy.

Malaria is a complex parasitic disease caused by species of Plasmodium parasites. Infection with the parasites can lead to a spectrum of symptoms and disease severity, influenced by various parasite, host, and environmental factors. There have been some successes in developing vaccines against the disease recently, but the vaccine efficacies require improvement. Some issues associated with the difficulties in developing a sterile vaccine include high antigenic diversity, switching expression of the immune targets, and inhibition of immune pathways. Current vaccine research focuses on identifying conserved and protective epitopes, developing multivalent vaccines (including the whole parasite), and using more powerful adjuvants. However, overcoming the systematic immune inhibition and immune cell dysfunction/exhaustion may be required before high titers of protective antibodies can be achieved. Increased expression of surface molecules such as CD86 and MHC II on antigen-presenting cells and blocking immune checkpoint pathways (interactions of PD-1 and PD-L1; CTLA-4 and CD80) using small molecules could be a promising approach for enhancing vaccine efficacy. This assay reviews the factors affecting the disease severity, the genetics of host-parasite interaction, immune evasion mechanisms, and approaches potentially to improve host immune response for vaccine development.

Humans

Rethinking immune studies: population-level immune variations and the path forward.

Shifts in immune cell proportions underlie disease progression and immunotherapy response, positioning them as promising diagnostic biomarkers and therapeutic targets. However, these shifts also occur naturally across the lifespan and vary with demographic factors such as age and sex, which may complicate their interpretation and clinical utility. While demographic associations have been explored previously, there have been mixed results likely due to small sample sizes and cross-cohort population-specific differences. To address these limitations, we conducted a meta-analysis across 3 large, diverse cohort studies to evaluate associations between 20 immune cell subtypes, 3 informative cell ratios, and a range of sociodemographic variables such as age, sex, self-identified race and ethnicity (SIRE), and socioeconomic status. We find consistent and significant associations across all sociodemographic dimensions. Cytomegalovirus (CMV)-a key driver of immune senescence-emerged as a major contributor to variation in immune composition and CMV antibody levels were higher among women, individuals of lower socioeconomic status, and marginalized racial and ethnic groups. In addition, male sex showed similar patterns of association with immune profiles as aging, whereas race did not. These findings underscore the need to account for diverse sociodemographic factors in immunology study design and participant recruitment to avoid population-specific biases and ensure broadly generalizable results.

Humans

Characterization of the Immune Response after Oral Cholera Vaccination (OCV) and Effects of Mycophenolate Mofetil on Priming of this Immune Response-A Randomized, Placebo-Controlled Trial.

Mycophenolate mofetil (MMF) is an immunosuppressive drug widely used by solid organ transplant recipients. Although it is known that MMF suppresses immune responses, its exact effects on specific vaccinations have not been investigated yet. Mucosal vaccinations are increasingly used, such as a cholera vaccination consisting of two oral immunizations (oral cholera vaccination; OCV). This study aimed to investigate the specific immunosuppressive effects of MMF use during the first dose of OCV in a randomized, placebo-controlled trial in healthy volunteers. Moreover, the study aimed to characterize the immune response provoked by OCV in detail. This randomized, placebo-controlled, single-blind trial included 16 healthy volunteers, each receiving two doses of Dukoral® and an intranasal rechallenge. Outcome measures were serum antibody responses (IgA and IgG) and IgA levels in saliva. Additionally, peripheral blood mononuclear cells (PBMCs) of participants were investigated for ex vivo cytokine production and expression of tissue-specific homing markers after OCV. There were considerable serum IgA and IgG responses after vaccination. MMF-treated volunteers still showed a significant cholera antibody response, though data suggest a potential suppression by MMF without reaching statistical significance. There was no substantial IgA response in saliva. Investigation of PBMCs from OCV-treated participants showed a Th2 skewing with increased ex vivo production of TNF, IL-2, IL-5, IL-13, and IL-22 compared to the placebo group. Taken together, this study provides a framework for future clinical pharmacology studies building on OCV as a challenge model and for further investigation of specific effects of MMF on mucosal vaccination responses.

Humans

Pre-treatment polyfunctionality percentage (PFA) of CD8+ T cells is associated with development of immune-related adverse events (irAEs) in patients receiving immune checkpoint inhibitors (ICIs).

INTRODUCTION: Immune checkpoint inhibitors (ICIs) have improved cancer survival, but immune-related adverse events (irAEs) occur frequently and can have devastating consequences. There are no validated methods to evaluate risk of irAEs prior to initiation of ICIs. MATERIALS AND METHODS: We conducted a pilot study evaluating the ability of blood-based, single-cell secretomic analysis to characterize irAEs. A total of 10 patients with thoracic malignancies who were scheduled to receive ICIs were enrolled. Each patient had a pre-ICI blood sample drawn as well as a sample at the time of irAE development or 12 weeks after ICI initiation, whichever came first. Utilizing IsoPlexis's IsoLight system, polyfunctionality percentages (PFAs) and strength indices (PSIs) were analyzed for CD4+ and CD8+ T cells. RESULTS: Five patients developed irAEs and 5 patients did not develop irAEs. Pre- and post-ICI CD8+ T cell PFA was significantly elevated in patients who developed irAEs compared with those who did not (p = 0.017 and p = 0.014, respectively). CONCLUSIONS: In this pilot study, pre-ICI CD8+ T cell PFA was associated with development of irAEs. While this is a pilot study, this is a first step toward developing a blood-based, streamlined assay to assess risk of irAEs prior to initiation of ICIs. Validation in larger cohorts is warranted.

Humans

Integrated Cytokine and Immune Cell Profiling Reveals a Distinct Immune Signature Associated with High-Altitude Pulmonary Edema.

High-altitude pulmonary edema (HAPE) is a rapidly progressive, life-threatening disorder arising in otherwise healthy individuals upon ascent to high altitude, yet the mechanisms underlying maladaptive vascular leak remain poorly defined. Although elevated pulmonary arterial pressure and capillary stress failure are recognized as central hemodynamic drivers, accumulating evidence indicates that innate immune dysregulation is an equally critical, largely unexplored determinant of HAPE. To systematically delineate the immune and molecular programs that distinguish pathological responses to hypobaric hypoxia from acclimatization, peripheral blood along with clinical details was collected from low-altitude controls (LA-Cntrl, number of participants, (n = 19), healthy high-altitude sojourners (HA-Cntrl, n = 47), and HAPE patients (n = 90). Plasma proteomic markers were quantified using a targeted panel, while monocyte and dendritic cell subsets in peripheral blood mononuclear cells were immunophenotyped by multicolor flow cytometry. HA-Cntrl subjects displayed an anti-inflammatory profile, marked by the suppression of CXC chemokine receptor 3 axis chemokines. HAPE patients, in contrast, exhibited a pro-inflammatory, vascular injury signature, with elevated levels of inflammatory interleukins and myeloid and chemotactic factors. This inflammatory signature was accompanied by the expansion of classical monocytes, implicating a myeloid vascular program associated with HAPE.

Humans

Dynamic balance of CRISPR-Cas immunity and resistance plasmid anti-immunity mediated by a bifunctional protein AcrIE10.

Despite targeting by CRISPR-Cas system, antimicrobial resistance plasmids are prevalent in clinical isolates of carbapenem-resistant Klebsiella pneumoniae which represent a major public health threat. A stable co-existence of plasmids and CRISPR-Cas systems is mediated by anti-CRISPR (Acr) proteins. Here, we report that previously identified AcrIE10 encoded by a resistance plasmid combines two functions: it inhibits CRISPR immunity by directly binding Cas7* subunit through its Acr domain, and acts as an Acr-associated (Aca) protein that self-represses the transcription of Acr locus. AcrIE10 is an example of an Aca protein that utilizes N-terminal ribbon-helix-helix (RHH) domain to specifically recognize the inverted repeat (IR) region in its own promoter. Crucially, a dimerization of AcrIE10 dimers is required for the effective binding to the IR and self-repression, while stoichiometry-dependent interaction with Cas7* facilitates transition to de-repressed state. These findings elucidate molecular mechanisms by which AcrIE10 operates as a dual functionAcr-Aca protein to achieve a delicate balance between host CRISPR-Cas immunity and plasmid anti-defense.

Klebsiella pneumoniae

The Addition of Concurrent Immune Checkpoint Inhibitors for Chemoradiotherapy With Consolidative Immune Checkpoint Inhibitors in Unresectable Cancers: A Systematic Review and Meta-Analysis.

Following the success of chemoradiotherapy (CRT) combined with consolidative immune checkpoint inhibitors (ICIs) in locally advanced tumors, over 30 ongoing randomized controlled trials (RCTs) are investigating the potential benefits of adding concurrent ICIs. To investigate the differences in efficacy and safety between adding and not adding concurrent ICIs to CRT followed by consolidative ICIs, a literature search was conducted in PubMed, Embase, and the Cochrane Library, incorporating RCTs comparing CRT combined with consolidative ICIs versus CRT alone, or CRT with both concurrent and consolidative ICIs versus CRT alone. The primary outcomes were overall survival (OS) and progression-free survival (PFS). To reduce potential bias, an additional mirror-design analysis was performed through network meta-analysis. A total of 13 RCTs comprising 6868 patients and 14 cohort studies comprising 4724 patients were included. While patients treated with CRT and consolidative ICIs demonstrated significantly superior OS and PFS to patients treated with CRT alone in RCTs (HR of OS, 0.743, 95% CI, 0.654-0.843; HR of PFS, 0.674, 95% CI, 0.577-0.786), CRT and concurrent-plus-consolidative ICIs did not improve OS and PFS compared with CRT alone (HR of OS, 0.942, 95% CI, 0.782-1.134; HR of PFS, 0.880, 95% CI, 0.752-1.030). Significant differences were detected in OS (p = 0.038) and PFS (p = 0.017) between CRT combined with consolidative ICIs treatment versus CRT combined with concurrent and consolidative ICIs treatment from RCTs. In conclusion, adding concurrent ICIs may dampen the survival benefits of CRT combined with consolidative ICIs. This evidence informs future RCT design strategies.

Humans

Multi-omics analysis reveals stage-associated differences in gut immunity and microbiota between juvenile and adult common carp (Cyprinus carpio).

In vertebrates, the development of intestinal immunity is closely associated with dynamic changes in the gut microbiota. However, stage-associated differences in intestinal immunity and gut microbial communities remain poorly characterized in teleost fish. In this study, transcriptomic analysis combined with 16S rRNA gene sequencing was employed to characterize intestinal immunity and gut microbial communities in juvenile and adult common carp (Cyprinus carpio). Transcriptomic profiling revealed marked developmental differences in intestinal immune function. Juvenile carp exhibited a predominantly innate immune phenotype, characterized by elevated expression of pro-inflammatory cytokines, antimicrobial peptides, and lysozyme-related genes. This immune profile was accompanied by enhanced mucosal barrier function and a relatively pro-inflammatory intestinal environment. In contrast, adult carp displayed increased expression of genes associated with adaptive immunity, suggesting that adult common carp exhibit relatively stronger adaptive immune characteristics than juvenile fish. Gut microbiota analysis demonstrated significant stage-dependent differences in microbial diversity and community composition. Juvenile fish were enriched with bacterial taxa potentially associated with innate immune activation, whereas adult fish harbored distinct microbial communities linked to intestinal homeostasis and barrier maintenance. Furthermore, correlation analyses identified significant associations between specific microbial taxa and innate immune-related gene expression, suggesting a close association between gut microbiota composition and intestinal immune characteristics in juvenile and adult common carp. Collectively, these findings reveal stage-associated differences in intestinal immunity and gut microbial communities between juvenile and adult common carp, thereby providing insights into intestinal immune characteristics at different developmental stages in teleost fish.

Animals

Epigenetic Gene Networks Governing Immune State Transitions Across the Lifespan.

Immune function across development, tissue repair, aging, and disease depends not only on signaling pathways but also on epigenetic architectures that determine whether coordinated transcriptional programs can be accessed and resolved. Increasing evidence indicates that epigenetic gene networks regulate the accessibility and reversibility of semi-stable immune states, shaping plastic, homeostatic, reparative, and degenerative configurations. We propose the concept of epigenetic transition windows, defined as temporally and contextually restricted intervals during which epigenetic constraints are relaxed, permitting coordinated and reversible transitions between immune states. During development, these windows are broad and support immune tolerance and adaptive plasticity. In adulthood they become spatially and temporally restricted, preserving stability while enabling conditional adaptation. With aging, they progressively narrow, contributing to chronic inflammation, impaired repair, and increased vulnerability to neurodegeneration. Conversely, pathological persistence of regulatory permissiveness may underlie immune evasion and sustained plasticity in cancer. We outline operational genomic readouts for quantifying transition windows, including chromatin accessibility variance, enhancer switching dynamics, reversibility metrics, and cross-cell coordination indices, and derive experimentally testable predictions that distinguish this model from pathway-centric or damage-centric explanations. By reframing immune dysfunction as a failure of regulated state transition rather than excessive signaling alone, this framework integrates inflammaging, trained immunity, immune resolution failure, and tumor immune escape within a unified regulatory architecture and provides a systems-level perspective on immune adaptability across the lifespan.

Epigenesis, Genetic

A genome-wide survey reveals a diverse array of enhancers coordinate the Drosophila innate immune response.

To defend against microbes, animals regulate a complex immune response. The Drosophila innate immune system deploys a large transcriptional induction of signaling proteins, antimicrobial effectors, and other critical immune factors. This transcriptional response is encoded in enhancers, cis-regulatory sequences that modulate gene expression by binding transcription factors (TFs). While enhancers and transcription factor binding sites (TFBS) have been identified for several immune responsive genes in Drosophila, most enhancers that regulate immune-induced genes are unknown. By identifying enhancers, we can understand how their composition controls expression and contributes to infection outcome. We employed STARR-seq (Self Transcribing Active Regulatory-Region sequencing) in a hemocyte-like cell line to identify immune-specific enhancers across the D. melanogaster genome and performed ATAC-seq in hemocytes extracted from adult flies to assess the chromatin state of these enhancers before and after immune stimulus. We identified thousands of enhancers responsive to IMD stimulation, one of the two primary immune signaling pathways in Drosophila. As expected, immune enhancers are enriched for motifs of Relish, an NF-κB factor, and Kay/Jra, a bZip heterodimer pair, involved in the Imd and JNK pathways respectively, compared to enhancers active in unstimulated cells. However, when grouping enhancers by their target gene's expression timing or functional role or by the enhancers' chromatin accessibility pre- or post-stimulus, different groups of TFBS motifs are enriched, suggesting distinct regulatory logic for different parts of the immune response. Identification and characterization of the diverse array of enhancers that regulate the innate immune response expands our understanding of how animals fight infections.

Drosophila immunity

Trade-off between antibacterial immune defense and oogenesis progression in female Drosophila melanogaster.

Trade-offs between reproduction and immunity are common in animals, potentially due to preferential allocation of limiting resources. In Drosophila melanogaster, mating stimulates egg production but also triggers a rapid and persistent decrease in female immune defense. Proteins essential for both processes are produced in fat body tissue, which may result in competition for cellular resources that could drive a functional trade-off between reproduction and immune defense. We predicted that arrest of oogenesis prior to egg provisioning would alleviate postmating immune suppression because cellular stress would be relieved, but that postmating immune suppression would be observed in genotypes that fully provision eggs even if fertility is compromised. In the present study, we test these predictions by evaluating postmating immune competence in mated D. melanogaster mutants that arrest oogenesis either prior to, or subsequent to, vitellogenesis. Consistent with our prediction, we find that mated female immune defense is maintained when egg development is arrested prior to vitellogenesis. We find that progression through the vitellogenic stages of oogenesis results in postmating immune suppression, except in the case of a mutant with an egg-retention phenotype, where we infer that the failure to lay eggs results in feedback that inhibits subsequent egg development. We additionally show that elimination of yolk protein synthesis in the fat body and follicle cells of the ovary partially restores female immune capacity. Nevertheless, females that lack yolk protein genes still experience partially reduced immune capacity after mating, suggesting that other reproductive demands also suppress immune defense.

Animals