Browse Articles

Extrafollicular B cell responses drive pathogenic antibodies production in Heparin-induced thrombocytopenia 2259334

Abstract Introduction Heparin-induced thrombocytopenia (HIT) is a severe complication of heparin therapy caused by IgG antibodies (Abs) against platelet factor 4—heparin (PF4/H) complexes. These Abs arise rapidly, mimicking a memory response even on first exposure, yet decline quickly and recur with similar kinetics. The mechanisms remain unclear. Methods CITE-seq combined with scVDJ-seq was performed on B cells from HIT patients, non-HIT patients (NHIT) who developed PF4/H Abs without developing HIT, and healthy donors (HD). Integrated transcriptomic, surface protein, and repertoire analyses were used to define B cell subsets and clonal features. Selected clones were expressed and functionally evaluated. Results Compared to HD, HIT and NHIT patients showed expansion of activated naïve and atypical memory B cells (AtyMBCs), strongest in HIT. B cell repertoires and cloned monoclonal Abs from HIT displayed lower mutation rates, longer HCDR3s enriched for basic and tyrosine residues, broad poly- and autoreactivity, indicative of an extrafollicular (EF) response. These features were present in naïve B cells but were most pronounced in AtyMBCs. Preferential VH3—JH6 recombination and enrichment of clones bearing structural motifs associated with pathogenicity were observed in HIT naïve and AtyMBCs, along with elevated IFN-γ, TLR, and BCR signaling. Conclusion Heparin exposure selectively expands pre-existing autoreactive B cells via an EF response, driving the rapid production of pathogenic PF4/H Abs characteristic of HIT. Funding Source R01 HL130724, R01HL161127, R01HL148120, AHA 25PRE1374068 Topic Categories Immune Mechanisms of Human Disease (HUM)

Atomistic TCR-ligand interactions instruct memory T-cell differentiation 2330211

Abstract Introduction Memory T cells generate durable and rapid protection following re-exposure to an infectious pathogen or a cancerous transformation. How naive CD8+ T cells develop into memory T cells that bifurcate into long-lived central (TCM) versus effector (TEM) subsets after an antigen encounter remains ill-defined at the molecular level. Methods We dissect the T-cell receptor (TCR) repertoire of 242 murine CD8+ TCRαβ clonotypes specific for the peptide-major histocompatibility complex molecule (pMHC) comprising an immunodominant influenza A virus (IAV) epitope NP366-374 presented by H-2Db. Using single-cell transcriptomics with TCR sequencing, biophysical measurements of force-dependent TCR-pMHC interactions, in vivo memory development, and structural analyses, we integrate these data to define relationships between signaling polarity and memory fate. Results TCM and TEM polarities reflect distinct subunit-specific mechanotransduction biases: TCM-associated TCRs favor TCRβ-driven pMHC engagement, whereas TEM-associated TCRs preferentially favor TCRα-driven engagement. Moreover, “bipolar” clonotypes (TBP) capable of generating both memory subsets exhibit balanced signaling, the largest average clonal expansions, and broad heterosubtypic crossreactivity. In contrast, TCM with variegated TCR sequences predominantly form clonal singlets yet display the greatest expansion after IAV rechallenge, revealing complementary memory niche strategies. Weak, force-sensitive TCR bonds are pervasive across the repertoire, most prominently among TCM clonotypes. Subtle atomic-level differences in TCRαβ engagement of peptide and/or MHC modulate mechanical load transmission through the TCR-CD3 complex, differentially shaping downstream tyrosine phosphorylation and memory fate. Conclusion TCR diversity anticipates epitope-specific pathogen evolution, whereas divergent TCR signaling regulates memory fate with implications for adoptive T-cell immunotherapies seeking to maximize persistence and minimize functional exhaustion. Funding Source National Institutes of Health grant 1P01AI143565 Topic Categories Lymphocyte Differentiation and Peripheral Maintenance (LYM)

Mechanoporation-based Intracellular Delivery of Functional Molecules for Primary Immune Cell Engineering 2252000

Abstract Introduction Current intracellular delivery methods face significant limitations, including a restricted range of compatible molecules and cell types, as well as unintended alterations to cell biology. CellPore™ Transfection System addresses these limitations by using mechanoporation technology to efficiently deliver mRNAs, CRISPR-Cas9 ribonucleoproteins (RNPs), siRNAs, proteins and other molecules to the cytosol. Methods Recent platform enhancements, including the introduction of new cartridge sizes, have expanded compatibility to a wider range of cell types. These include unactivated and activated primary immune cells (e.g. T, NK, B and myeloid cells), hematopoietic stem and progenitor cells and pluripotent stem cells, which traditionally have been challenging to reliably engineer via conventional methods. Results In the context of immunology applications, we demonstrate efficient RNP-mediated knockout of surface MHC-I (74%) or TCRÉ’β (94%) in human T cells, and TIGIT (84%), CD16 (66%), NKG2A (81%) or NKp46 (87%) in human NK cells, with minimal impact to cell viability and function. We also demonstrate delivery of reporter mRNA and siRNA to monocytes and monocyte-derived dendritic cells for enabling transient gene expression and RNAi-mediated gene knockdown. Conclusion The CellPore™ system offers a gentle and efficient method to engineer a variety of cell types with a wide range of molecules. The simple and versatile workflow makes this a valuable tool for enabling new areas of research. Funding Source n/a Topic Categories Technological Innovations in Immunology (TECH)

Pregnancy-Associated Immune Features in COVID-19 Link Fetal Protection to Heightened Maternal Viral Risk 2334492

Abstract Introduction Pregnancy is a risk factor for increased severity of SARS-CoV-2 and other respiratory infections. The mechanisms underlying this risk have not been well-established, partly due to a limited understanding of how pregnancy shapes immune responses. Methods We assessed the differences between immune responses to SARS-CoV-2 in pregnant women and non-pregnant women, including the effects of disease severity, phase of illness (acute versus convalescent), and obesity. Using flow cytometry, single-cell multiomics, ex vivo immune cell stimulation, and unbiased immune correlative analyses. Results We found that CD8+ T cells in pregnant patients with severe/critical COVID-19 expressed elevated T cell exhaustion markers, such as PD-1 and T cell immunoglobulin and Tim-3. Further, we observed significantly down-regulated interferon-stimulated gene (ISG) responses in pregnant individuals with COVID-19 compared to non-pregnant COVID-19 counterparts. We identified altered T cell clonal expansion in pregnant patients with COVID-19, suggesting altered virus-mediated T cell responses in pregnancy. Relative to pregnant controls, COVID-19 infection in pregnancy was associated with suppressed monocyte function such as diminished cytokine and chemokine production. We also demonstrate that CD4+ and CD8+ T cells from obese pregnant women with COVID-19 produced increased inflammatory cytokine levels. Intriguingly, we found pregnancy was associated with a significantly increased level of circulating IL-27, a cytokine involved in T cell exhaustion. Using preclinical models, we demonstrated that augmented IL-27 resulted in more severe lung damage and increased mortality upon induction of respiratory viral infection, while protecting fetuses from maternal inflammation during pregnancy. Conclusion Our findings highlight mechanisms by which pregnancy influences maternal immune responses against viral infection. Funding Source Dongsun Oh was supported by a postdoctoral fellowship program (Nurturing Next-generation Researchers) through the National Research Foundation of Korea (2021R1A6A3A14044062) Topic Categories Translational and Interventional Immunology (TI)

Population Density, Vaccination Coverage, and the Persistent Burden of Influenza Mortality in the United States 2252774

Abstract Introduction Seasonal influenza remains a leading cause of preventable morbidity and mortality despite decades of widespread vaccination. Annual reformulation of the influenza vaccine and variable uptake rates hinder consistent population-level protection. Understanding how vaccination coverage, population density, and susceptibility interact is essential to refining prevention strategies. Methods Using published national and state-level data from 1980—2019, we analyzed influenza-associated mortality across age groups and comorbidity profiles relative to annual vaccination coverage. We further evaluated 2017 influenza mortality in relation to population density and vaccine availability to assess geographic and demographic trends. Results Despite increasing vaccination rates from 1980 to 2019, influenza-related mortality among adults ≥65 years remained unchanged. No state or national herd immunity threshold was reached during this period. Vaccine supply growth lagged behind U.S. population expansion, limiting coverage sufficient for community-level protection. In 2017, the most populous states exhibited the highest influenza-related mortality burden; however, within these states, city density did not correlate with mortality rates. Influenza deaths were concentrated where susceptible populations resided, regardless of urban or rural classification. Conclusion Our findings indicate that current annual influenza vaccination strategies have not achieved herd immunity or reduced mortality among the most vulnerable populations. To substantially decrease influenza-related deaths, vaccination efforts must prioritize achieving herd immunity within the nation’s most populous states, where transmission potential and susceptible populations are greatest. Funding Source N/A Topic Categories Vaccines and Immunotherapy (VAC)

Rapid Bioluminescent Monitoring of Granzyme B Production and Activity 2260237

Abstract Introduction Granzyme B (GZB), a serine protease secreted by cytotoxic T lymphocytes and natural killer cells, plays a critical role in immune defense by inducing apoptosis in target cells. Monitoring GZB production, e.g., during T cell activation, provides a direct functional readout of cytotoxic potential, distinguishing it from surface markers CD69 and CD25 that indicate activation status. Current methods for measuring GZB protein levels (flow cytometry and ELISA) involve multi-step, lengthy protocols. We developed a bioluminescent GZB activity assay for simplified, rapid GZB analysis to facilitate the incorporation of this functional indicator into experimental workflows. Methods The assay reaction consists of a peptide-luciferin prosubstrate and luciferase. Proteolytic cleavage by active GZB releases luciferin, which is oxidized by the luciferase enzyme. The resulting light signal is directly proportional to GZB activity. Results We used the assay to monitor GZB production during T cell activation. T cells were isolated from peripheral blood mononuclear cells and stimulated under various media conditions. Samples were collected during the activation phase on Days 1-3; culture medium and cell lysates were analyzed. GZB activity increased over time and varied by activation condition. On day 1, signals from cell lysates were ∼2 to 10-fold higher than medium background, increasing to ∼30 to 550-fold by day 3. Signals from non-activated cell lysates were not above background. GZB detected in culture medium also increased, reaching ∼11 to 106-fold above background on day 3. These results were confirmed by measuring intracellular GZB levels by flow cytometry and ELISA. GZB activity also aligned with CD69 and CD25 expression, as well as IFN-γ and TNF-α cytokine secretion. Conclusion This bioluminescent GZB activity assay provides a rapid and simple method for monitoring GZB, especially for studies requiring higher-throughput sample analysis. Funding Source Promega Corporation Topic Categories Technological Innovations in Immunology (TECH)

Uniaxial Stress Enhanced Anisotropic Magnetoresistance and Superconductivity in the Kagome Superconductor LaRu ₃ Si ₂

ABSTRACT To elucidate how kagome electronic structure governs quantum ground states, we introduce a unique approach combining in‐plane uniaxial stress tuning, magnetotransport, and first‐principles calculations to uncover its impact on superconducting and normal‐state properties in . We identify a pronounced anisotropy in both the upper critical field and the normal‐state magnetoresistance, indicating strong electronic anisotropy despite the three‐dimensional crystal structure. Furthermore, we find that the superconducting transition temperature increases under in‐plane stress applied within the kagome plane, although the enhancement is modest, reaching approximately 0.3 K at 0.6 GPa. Furthermore, the absolute magnetoresistance exhibits a pronounced increase from about 22 at zero stress to 35 at 0.6 GPa, indicating a substantial modification of the normal state above . The simultaneous enhancement of both and magnetoresistance under stress suggests a positive correlation between superconductivity and normal‐state electronic and magnetic properties in . Detailed calculations demonstrate that the stress‐induced evolution of superconductivity and magnetotransport arises from the cooperative interplay between modifications of the total density of states, kagome flat‐band physics, and anisotropic electronic response. In particular, the pronounced enhancement of magnetoresistance is closely linked to the stress‐driven downward shift of the Ru kagome‐derived flat band.

FTO promotes cancer progression by regulating VGLL4 m6A levels to activate STAT3 signaling in triple-negative breast cancer

Multi-objective collaborative optimization of conical pick group based on factor space theory

Improved natural killer cell targeting of prostate carcinoma with ATR inhibitor tuvusertib in combination with IL-15 receptor superagonist N-803 2299576

Abstract Introduction Given its role in DNA damage repair, ataxia telangiectasia and Rad3-related (ATR) represents a viable target for cancer therapy with ATR inhibitors (ATRi) demonstrating anticancer activity and synergy with other therapies. We hypothesize that the ATRi tuvusertib could induce immunogenic modulation, thereby sensitizing prostate cancer (PCa) cells to natural killer (NK) cell-mediated lysis. Methods DU145 human PCa cells were treated with tuvusertib (provided by Merck KGaA, Darmstadt, Germany; CrossRef Funder ID: 10.13039/100009945) for 48 hours. Resulting immunogenic changes were evaluated via flow cytometry. PBMC-derived NK cells were exposed to interleukin-15 (IL-15) receptor superagonist N-803 (nogapendekin alfa inbakicept; provided by ImmunityBio, Culver City, CA, USA) overnight. Tuvusertib-treated DU145 were co-cultured with NK cells (untreated or N-803-treated), PD-L1 targeting high-affinity NK (t-haNK) cells (provided by ImmunityBio), or KillerTRAIL. Anti-PD-L1 avelumab or anti-TRAIL antibody was included in select assays. Cell lysis was quantified using impedance-based real-time cell analysis. The efficacy of tuvusertib + N-803 combination therapy was assessed in DU145 tumor-bearing NU/NU mice. Results Increased expression of TRAIL-R2, ULBP-1, and PD-L1 was observed in tuvusertib-exposed DU145. Tuvusertib rendered PCa cells more susceptible to NK-mediated lysis and PD-L1-targeting by avelumab-mediated antibody-dependent cellular cytotoxicity (ADCC) and PD-L1 t-haNK cells. N-803 pretreatment of NK cells further enhanced killing of tuvusertib-treated DU145, while NK-mediated lysis was partially blocked by TRAIL signaling blockade. In the DU145 xenograft model, concurrent tuvusertib and N-803 treatment improved tumor growth inhibition and animal survival. Conclusion Immune-mediated targeting of prostate carcinoma is improved by tuvusertib ATRi which can be combined with avelumab and/or N-803. Funding Source This work was funded by the Intramural Research Program of the Center for Cancer Research, National Cancer Institute (NCI), National Institutes of Health, as well as via Cooperative Research and Development Agreements (CRADAs) between the NCI and the healthcare business of Merck KGaA, Darmstadt, Germany (CrossRef Funder ID: 10.13039/100009945) and the NCI and ImmunityBio, Culver City, CA, USA. Topic Categories Tumor Immunology: Checkpoints, Prevention, and Treatment (TIPT)

Intestinal Remodeling Promotes Innate Defense During Reproduction 2259298

Abstract Introduction Mammalian reproduction requires profound maternal immune adaptations to ensure reproductive success and ultimately shape a species’ evolutionary trajectories. While systemic and placental immunity are known to shift toward tolerance during pregnancy, how maternal immunity adapts in barrier tissues, sites of frequent infection and inflammation, from pregnancy through lactation remains poorly understood. Defining these adaptations will provide fundamental knowledge to advance maternal and offspring health. Methods Using mouse models, organoid cultures and single-cell/spatial transcriptomics, we characterized intestinal immune adaptations during reproduction and studied their functional significance. Results We discovered a previously unrecognized role for eosinophils, a type of granulocyte typically associated with allergies and helminth infections, in remodeling the intestinal barrier during reproduction. From pregnancy through lactation, bone marrow-derived eosinophils accumulate in the small intestine and promote goblet cell differentiation in a stem-cell-intrinsic manner, leading to increased mucus production in the absence of infection or inflammation. This adaptation limits pathogen entry and enhances innate protection during lactation. Notably, both eosinophil accumulation and goblet cell induction persist after lactation, revealing durable remodeling of the intestinal immune and epithelial landscapes. Conclusion Our findings demonstrate that, despite a trend toward systemic immunosuppression during reproduction, the maternal intestine undergoes remodeling to enhance innate defense against enteric pathogens, a mechanism that likely benefits both mother and offspring in pathogen-rich environments. More broadly, our work establishes a framework for studying tissue immune adaptation during reproduction and highlights that tissue can retain memory of physiological states, with lasting implications for host defense and reproductive health. Funding Source Princeton University Topic Categories Mucosal and Regional Immunology (MUC)

Enabling scalable adaptive immune receptor repertoire analysis with nf-core/airrflow 2331753

Abstract Introduction Sequencing the Adaptive Immune Receptor Repertoire (AIRR) allows the characterization of immune states in health and disease, including infectious diseases, (auto)immune diseases, and cancer. Although numerous tools exist for reconstructing B and T cell receptor (BCR and TCR) sequences and inferring clonal relationships from AIRR sequencing (AIRR-seq) data, many lack scalability, efficient sample-level parallelization, or portability to high-performance computing environments. We addressed these limitations with nf-core/airrflow (https://nf-co.re/airrflow), a scalable and reproducible Nextflow-based workflow for processing bulk and single-cell AIRR-seq data. Since its implementation, we have expanded the workflow with new functionality including BCR and TCR sequence embedding using large-language models (LLM), immunoglobulin (IG) loci genotyping and support for the AIRR community germline references. Methods nf-core/airrflow integrates tools from the Immcantation Framework (immcantation.org) following BCR and TCR data analysis best practices. We recently expanded the workflow to include LLM sequence embedding with AMULETY, as well as IG loci genotyping and novel allele detection using TIgGER. We additionally provide support for the newly released AIRR Community germline reference datasets hosted in the Open Germline Receptor Database (OGRDB). Results We demonstrate the applicability of nf-core/airrflow by genotyping and generating embeddings of publicly available BCR sequencing datasets from individuals with autoimmune diseases, including systemic lupus erythematosus, type 1 diabetes and rheumatoid arthritis. Conclusion nf-core/airrflow is a comprehensive and scalable workflow for AIRR-seq data analysis, enabling a wide range of applications in immune mediated and infectious disease research and supporting the reproducible analysis of increasingly large AIRR-seq datasets. Funding Source This work was supported by the National Institutes of Health National Institute for Allergy and Infectious Diseases grant U01AI184647 to G.G. Topic Categories Computational and Systems Immunology (COMP)

NLRP3 inflammasomes modulate sleep responses to S. pneumoniae in mice 2253065

Abstract Introduction S. pneumoniae is a common bacterial infection in humans that induces inflammation in the lung and brain affecting sleep and electroencephalogram (EEG) slow-wave-activity (SWA). S. pneumoniae infections can potentially be fatal and cause meningitis especially in vulnerable population such as young children, older adults, and individuals with compromised immune systems. NLRP3 inflammasomes are critical regulators of homeostatic sleep and SWA responses to toxin challenge. Consequently, we aimed to investigate if NLRP3 inflammasomes are involved in sleep and SWA to S. pneumoniae in mice lacking NLRP3. Methods NLRP3 knockout (KO) mice and wild-type (WT) controls were implanted with electrodes for polysomnography (PSG) recordings. Baseline sleep was recorded for 24 H. Thereafter, mice were infected intranasally with S. pneumoniae, and PSG was recorded for 3 days. Results Baseline sleep and SWA were not significantly reduced in NLRP3 KO mice compared to WT mice. WT mice had increased non-rapid-eye movement sleep (NREMS) and SWA responses within the first 24 H post-infection that continued to increase for the next 2 days compared to baseline values. NLRP3 KO mice exhibited enhancements in NREMS and SWA after infection, although these changes were smaller and delayed when compared to WT mice. Conclusion These data suggest that NLRP3 inflammasomes are involved in the progression of sleep and SWA responses to S. pneumoniae. Funding Source Department of Veteran Affairs I01BX005379 (MRZ) and I21RX003722 (MRZ) Topic Categories Neuroimmunology (NEUR)

Rv2140c is targeted by follicular helper T cells in M.tuberculosis exposed γ Interferon Release Assay negative populations in Uganda and South Africa 2299672

Abstract Introduction Mycobacterium tuberculosis (Mtb) remains a leading cause of death worldwide. IFNγ Release Assay (IGRA) is widely used to diagnose Mtb infection by measuring the IFNγ response to Mtb antigens. However, healthy IGRA- individuals with high Mtb exposure (“resisters”) have shown evidence of infection and make Mtb-specific responses that differ from IGRA+ individuals. Human CD4 T cells are critical in controlling Mtb. IFNγ-expressing Th1 cells are largely believed to be the major protective subset. Resisters’ negative response to IGRA suggests alternative protective mechanisms of CD4 T cells. This study aims to profile the antigen-specific CD4+ T cell responses in Mtb-exposed IGRA- individuals. Methods We performed TCR sequencing on Ugandan resisters and IGRA+ individuals. TCR repertoires were analyzed with GLIPH3 algorithm we recently developed to identify resister-specific TCRs. Mtb antigenic ligands were discovered by a new T cell epitope discovery platform. Antigen-specific CD4+ T cells were then isolated using peptide-MHC multimers covering the discovered antigenic peptide, and characterized by single-cell multi-omics and Flow Cytometry. Results We identified 24 TCR specificity groups uniquely enriched in resisters. Two ligand peptides were decoded from Mtb antigens Rv2140c and ESAT6. In a parallel South African cohort, in IGRA- individuals, we detected T cell responses to ESAT6, the antigen used in IGRA test, and a robust response to Rv2140c. Notably, Rv2140c-specific CD4 T cells were predominantly follicular helper cells (Tfh), which correlated with protection from Mtb in mice, whereas IGRA+ individuals showed primarily Th1 responses. Conclusion We identified a novel Mtb antigen associated with protection, highlighting its potential as vaccine candidate. ESAT6-specific responses in IGRA- individuals confirmed underlying Mtb infection, indicating the limitations of IGRA tests. The predominance of Tfh cells reveals new protective human T cell mechanism against Mtb beyond the classic Th1 response. Funding Source Bill & Melinda Gates Foundation Topic Categories Microbial, Parasitic, and Fungal Immunology (MPF)

Characterization of Neuroinflammatory Response in BALB/c Mice After Exposure to Aerosolized Yersinia pestis 2253118

Abstract Introduction Plague, caused by the bacterium Yersinia pestis, can present as several forms including bubonic, septicemic, pneumonic, and meningitis. Plague meningitis is considered rare and has been estimated to occur in 6-11% of documented cases, mostly observed in pediatric patients 15 years old or younger. Furthermore, most cases are tied to inadequate or no antibiotic treatment of bubonic cases. To date, there have been few reports describing neurologic plague in the mouse model of pneumonic plague. Methods We used the BALB/c mouse model of exposure to aerosolized Y. pestis to characterize the pathogenic effects in the CNS resulting from pneumonic plague. Here we use a multifaceted approach analyzing tissue homogenates, tissue slides, transcriptomic, and cytokine data of mice exposed to aerosolized Y. pestis CO92, collected at 24-hour intervals for three days. Results We find that Y. pestis is present in brain homogenates, but histology indicates that it is bound to the capillaries inside the cerebellum, cerebrum, and nasal turbinates. However, transcriptomic data targeting mouse neuroinflammatory responses indicates dysregulation of several gene pathways including those associated with CNS cells such as astrocytes, oligodendrocytes, and microglia. Furthermore, there is a cytokine response to pneumonic plague in brain tissues. Conclusion Although Y. pestis does not breach the capillaries resulting in meningitis in our model, we find evidence of a neuroinflammatory response within the CNS of mice. Funding Source DTRA-JSTO Topic Categories Neuroimmunology (NEUR)

Local immune networks promote respiratory IgA responses after mucosal vaccination 2260370

Abstract Introduction Mucosal immunization and respiratory IgA offer significant promise in protecting against airborne pathogens, including SARS-CoV-2. However, the conditions and mechanisms that lead to the robust induction of respiratory IgA responses following mucosal vaccination remain poorly understood. Methods In this project, we established SARS-CoV-2 breakthrough infection and mucosal adenovirus-based booster vaccination models. Using genetic mouse models and various in vivo and in vitro blockade or depletion approaches, we further investigated the mechanisms regulating respiratory IgA responses. Results Here we found that a mucosal adenovirus-based booster vaccination in mouse models revealed that respiratory booster immunization elicited markedly stronger and more durable respiratory IgA, T cell response, and protective immunity against SARS-CoV-2, supporting the promise of respiratory mucosal vaccination. Mechanistically, we identified that local CD4+ T cells support respiratory IgA production by promoting IgA+ B cell class switching, proliferation, and survival in situ. This T cell help depended on interactions between local Blimp-1+ T-bet+ Th1 cells and B cells, mediated through ICOS/CD40L/MHC-II engagement and IL-21 signaling. Furthermore, lung macrophages contributed to the mucosal IgA response via TGF-β production. Consequently, mucosal administration of SARS-CoV-2 Spike-encoding mRNA encapsulated in pulmonary surfactant (PS)- incorporated lipid nanoparticles designed to target lung macrophages elicited a stronger mucosal IgA response. Conclusion Our results uncover a local cellular network supporting enhanced mucosal IgA responses, with implications for the development of optimal mucosal immunization strategies against SARS-CoV-2 and other respiratory pathogens such as H5N1 influenza. Funding Source AI147394, AG069264, AI112844, HL170961, AI154598, AI176171 to J.S., AI67986, AI177467 to Hui.H; U54CA260582 to S.L.L; R01AI168684 to G. Z.; S.L.L was also supported by a fund provided by an anonymous private donor to The Ohio State University. Topic Categories Mucosal and Regional Immunology (MUC)

Structure of a MenB de-N-acetyl polysialic acid antibody and mechanism of immune cell inhibition

Quercetin ameliorates iron overload-induced liver injury via NRF2/GPX4 pathway

YY1 regulates B cell lineage plasticity via transcriptional, miRNA post-transcriptional, and epigenetic mechanisms 2299696

Abstract Introduction YY1 is essential for embryogenesis, cell proliferation, and lineage differentiation. It regulates genes via co-activators, co-repressors, or PcG complexes. In hematopoiesis, YY1 controls stem cell differentiation, and its loss at the pro-B stage halts B-cell development. Methods Bulk RNA-seq of WT and YY1-KO pro-B cells was analyzed for QC, alignment, and differential expression (edgeR), and their miRNA list was identified via miRDeep2, targets were predicted with TargetScan, and their functional enrichment and pathways were performed through the clusterProfiler package. Further, scRNA-seq and scATAC-seq (Seurat and Signac) confirmed lineage-specific changes in expression and chromatin accessibility at these targets. Results Upregulated miRNAs in YY1-KO pro-B cells (miR-1194, miR-714, miR-712-5p, and miR-712-3p) target key genes involved in B-cell regulation. Their elevated expression is associated with repression of B-cell-related signaling, suggesting a role in the reduced B-cell commitment observed in YY1-deficient cells. Consistently, scRNA-seq analysis of YY1-KO pro-B cells cultured on OP9-DL4 feeders showed decreased expression of B-lineage genes such as Pla2g12a and Map3k4, which was further supported by reduced chromatin accessibility in scATAC-seq data. In contrast, downregulated miRNAs (miR-3473, miR-696, and miR-762) regulate genes involved in monocyte, macrophage, and T-cell pathways. Their reduced expression in YY1-KO pro-B cells correlated with increased expression of alternative-lineage genes, including Cxcl2, Fhl2, and Il1b miRNA targets. Consistent with increased expression for downregulated miRNA targets in YY1-KO pro-B cells, scATAC-seq also revealed increased chromatin accessibility at these loci, indicating activation of non-B-lineage differentiation programs. Conclusion Multi-omics integration across RNA-seq, miRNA, scRNA-seq, and scATAC-seq datasets allowed the construction of YY1-dependent regulatory networks that reveal how YY1 influences B-cell lineage plasticity. Funding Source n/a Topic Categories Computational and Systems Immunology (COMP)

Reprogramming the tumor microenvironment: endowing T with the ability to degrade the extracellular matrix 2259469

Abstract Introduction Despite the remarkable success of chimeric antigen receptor (CAR) T cell therapy in hematological cancers, the clinical experience with solid tumors has not been encouraging. Preclinical and clinical data support that the tumor-specific extracellular matrix (ECM) presents a physical barrier restricting the entry of immune cells like T cells into the tumor microenvironment (TME). ECM-degrading enzymes like heparanase and MMP7 have been explored; however, these enzymes are also associated with tumor growth, metastasis, and poor prognosis in several cancers. We focused on the collagenase MMP8 since it: (1) exhibits the best catalytic efficiency (kcat/KM) with the ability to degrade a broad range of collagens and also aggrecan, gelatins, fibronectin, and laminin, (2) MMP8 is secreted only by immune cells, and (3) MMP8 expression is not prognostic in any cancer. Methods Donor-derived T cells and second generation CAR T cells targeting CD19, HER2, and GD2 were engineered with and without MMP8. Proliferative and migratory exhaustion upon exposure to mechanical stress was evaluated in vitro. Matrigel-embedded tumor organospheroids were used to assess infiltration and cytotoxicity functions of the T cells. In vivo, xenograft models and immunohistochemistry evaluated safety, tumor rejection, and TME remodeling. Results T cells exposed to cross-linked ECM exhibited both proliferative and migratory exhaustion but this defect was rescued by secretion of MMP8. Parental T cells showed poor ECM penetration, while enzyme-expressing T cells demonstrated enhanced infiltration, migration, and tumor killing in vitro. MMP8-CAR T cells showed robust infiltration in multiple tumor models in vivo and eradicated HEY-A8 tumors and extended survival beyond 100 days, outperforming parental CAR T cells. Conclusion MMP8-engineered T cells offer a stoffer a promising strategy to overcome physical barriers in solid tumors, enhance infiltration, and unlock their full anti-tumor potential. Funding Source CDMRP(CA240991P2), CPRIT(RP240439) Topic Categories Tumor Immunology: Checkpoints, Prevention, and Treatment (TIPT)