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MAIT cells support Treg response to UV light in healthy skin and restrain CD8 activation in lupus skin 2257500
Abstract Introduction MAIT cells are innate-like T cells enriched in barrier sites, including the skin, that exhibit both repair and inflammatory functions. UV light induces immunosuppression in healthy but not lupus (SLE) skin. We tested whether MAIT cells enable this regulatory program and how it fails in SLE. Methods B6, MAIT-deficient (Mr1-/-), and SLE (MRL/lpr or TLR7 agonist) mice (8 wks, F) were exposed to chronic UVB (50mJ/cm2 daily, x 2 or 6). Contact hypersensitivity (CHS) was induced by skin sensitization, then challenged with hapten, DNFB, 6 days later. MAITs were expanded by topical antigen, 5OPRU (1mM, every 48hr x 4). MAITs (5OPRU-loaded MR1 tetramer) and Treg were assessed by flow cytometry. Results UV exposure led to ∼5-fold expansion of MAITs and Treg in B6 skin. MAITs were required for Treg expansion; no change in Treg was seen after UV in Mr1-/- skin. Early after UV (x 2), Treg in Mr1-/- skin exhibited a fragile phenotype (NRP1loGITRloICOSloPD1hiCD69hi). After chronic UV (x 6), B6 but not Mr1-/- skin Treg upregulated immunosuppressive (ICOS, CTLA4, CD120b) and repair (ST2) proteins. UV before sensitization with DNFB prevented CHS upon challenge in B6 but not Mr1-/- skin, revealing loss of immunosuppression in the absence of MAITs. Like Mr1-/- skin, Treg did not proliferate or expand after UV in MRL/lpr skin. Instead, CD8 T cells increased ∼10-20-fold, causing a marked reduction in the Treg:CD8 ratio. Similar reduction in Treg:CD8 ratio was seen after UV in the TLR7 SLE model in Mr1-/- but not B6 skin. Topical expansion of MAITs with 5OPRU before UV restored the Treg:CD8 ratio, and CD8s in MAIT-expanded skin expressed less Ki67, CD69, PD1, and CXCR6. Conclusion In healthy skin, MAITs are required for UV-induced Treg expansion. This mechanism fails in SLE-like skin, allowing unchecked expansion and activation of CD8 T cells. Topical expansion of MAITs restores the skin immunosuppressive response to UV, revealing a novel avenue for therapeutic intervention in skin inflammatory disease. Funding Source NIAMS R01AR080641 Topic Categories Immune Response Regulation: Cellular Mechanisms (IRC)
Cancer Cell Mediated Mitochondrial Transfer Reprograms Macrophage Metabolism and Polarization 2309895
Abstract Introduction Mitochondria are regulators of cellular metabolisms, redox balance, and survival. Their dysfunction has been shown to affect cancer progression and immune regulation. Recent studies have shown mitochondria are dynamic and can be transferred between cells. However, mitochondrial transfer between tumor and immune cells is understudied. Macrophages are the most abundant immune cells in the tumor microenvironment and exhibit plasticity. Understanding how tumor cells manipulate macrophage plasticity through mitochondrial transfer could be crucial for understanding tumor immune regulation. Methods Human breast, prostate, and lung cancer cell lines were used to create bulk tumor and CSC populations. The tumor cells mitochondria were fluorescently labeled and co-cultured with human monocytes. Live cell imaging of the co-culture was used to quantify mitochondrial transfer over 48 hours. A phagocytosis inhibitor was used to identify the possible mechanism of transfer. Results Mitochondrial transfer from tumor cells to macrophages was observed in all cancer types tested. Both bulk tumor cells and CSCs showed mitochondrial transfer to macrophages. CSCs showed greater and more persistent mitochondrial donation over time. Inhibition of phagocytosis reduced mitochondrial uptake in macrophages, but did not completely inhibit transfer, indicating additional mechanisms of uptake were used. The dynamics and magnitude of mitochondrial transfer differed among tumor types, suggesting that tumor type influences immune cell organelle exchange. Conclusion This project provides evidence that tumor cells directly transfer their mitochondria to macrophages, showing a novel mechanism of tumor to macrophage communication. These findings establish the foundation to investigate how tumor mitochondria contribute to macrophage metabolic reprogramming and dichotomy. Funding Source NCI (R03CA293129) Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)
Adrenergic Signalling Drives Accumulation of Myeloid-derived Suppressor Cells in the Liver During Stress 2258331
Abstract Introduction Psychological stress, due to exposure to environmental and/or emotional stressors, has long been associated with immune dysfunction and immunosuppression. Previous studies have largely focused on the effects of chronic stress on conventional myeloid cells which have been shown to be afflicted by stress-induced apoptosis. However, how stress modulates immune responses elicited by unconventional myeloid cells remains poorly understood. Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature-myeloid lineage cells with potent immunosuppressive properties, commonly enriched in the tumor microenvironment. Despite their well-established role in various malignancies, mechanisms governing their accumulation and activity in stress are largely unexplored. Methods In this study, we used a prolonged restraint model to investigate the effects of chronic stress on MDSCs in the bone marrow, blood, spleen and liver of C57BL/6 mice. Cells were analyzed using a combination of flow cytometry, qPCR and histological staining. Results Here, we demonstrate that prolonged restraint results in the accumulation of MDSCs selectively in the liver. Notably, these MDSCs unusually co-express high levels of Ly6C and Ly6G, deviating from conventional monocytic (Ly6ChiLy6G-) or granulocytic (Ly6CloLy6G+) MDSC phenotypes in mice. This influx of MDSCs appears to be mediated through IL-6 and G-CSF, as well as the stress-associated neurotransmitters, norepinephrine and epinephrine. Additionally, abrogation of signalling through the IL-6R, G-CSFR and/or adrenergic receptors are successful in preventing intrahepatic MDSC accumulation. Conclusion Our findings reveal a novel stress-mediated mechanism of MDSC expansion in the liver, which may contribute to the establishment of a pre-metastatic niche or a tumor-promoting microenvironment. Understanding neuroimmune crosstalk that drives MDSC accumulation provides critical insights into how psychological stress influences cancer progression and immune evasion. Funding Source Natural Sciences and Engineering Research Council of Canada Topic Categories Neuroimmunology (NEUR)
CD4+ T cell-mediated Immune Surveillance during Intestinal Tumor Initiation 2262796
Abstract Introduction While the immune system’s role in tumor development has been broadly studied in established tumors , how the immune system can detect and kill mutated cells at early pre-cancerous stages is largely unknown. The intestine provides a unique environment to study immune responses during tumor initiation since it has a rich resident immune system. Intestinal stem cells marked by Lgr5 have been well-established as the cell-of-origin of intestinal cancer. Here, we aim to study immune surveillance of these Lgr5+ intestinal stem cells upon acquisition of the earliest oncogenic mutations. Methods To study early immune surveillance of oncogenic intestinal stem cells, we used Lgr5-GFP-CreERT2 x floxed Apc mice, since inactivating mutations in the Adenomatous polyposis coli (APC) gene are the initiating events in intestinal tumorigenesis in patients. Two weeks after inducing mutations with tamoxifen we performed single cell RNA-sequencing, immunofluorescence, and flow cytometry to characterize the cellular ecosystems in the early adenoma niche. Results Our in-depth analysis revealed an increase in IFNg-producing T helper 1 CD4+ T cells, specifically located near mutated Lgr5+ stem cells. Blockade of both IFNg and CD4 T cells leads to a decrease in stem cell death, and accelerates tiumor progression, indicating these CD4+ T cells play an anti-tumor role via IFNg. Early transformed Lgr5+ stem cells express MHC-II, suggesting direct recognition by CD4 T cells. To address this interaction in an antigen specific manner, we generated transgenic mice with CD4 T cells expressing a GFP-specific TCR. Upon adoptive transfer, these GFP-specific CD4+ T cells infiltrate the niche of oncogenic Lgr5+ cells supporting a direct recognition. Conclusion Overall, these results suggest that CD4+ T cells are early responders to early transformation of intestinal stem cells and play a part in control of early tumor development via MHCII. Funding Source n/a Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)
Zwitterionic Polymer Electrolytes With Dipole‐Rotation‐Assisted Ion Conduction for Solid Lithium Metal Batteries
ABSTRACT Solid polymer electrolytes are promising for lithium metal batteries, yet achieving both high ionic conductivity and interfacial stability remains a major challenge. Here, we report a molecular rotor strategy that addresses this trade‐off by incorporating 3‐(1‐Pyridinio)‐1‐propanesulfonate zwitterions (PP‐Z) into a polyvinylidene difluoride electrolyte. This design establishes a dipole‐rotation‐assisted ion transport mechanism distinct from conventional polymer relaxation‐dependent conduction. Molecular dynamics simulations and experiments reveal that the anchored cationic group of PP‐Z serves as a pivot, while the mobile anionic end creates a dynamic coulombic field. This configuration facilitates rapid Li + migration through coordinated intrachain transport and interchain hopping, significantly enhancing ionic conductivity (5.1 × 10 −4 S cm −1 at 25°C and 1.5 × 10 −4 S cm −1 at 0°C) and the Li + transference number (0.52). The anionic terminals further participate in Li + solvation and promote formation of a LiF‐rich solid electrolyte interphase, enabling stable cycling for 1200 h in Li||Li cells at 0.3 mA cm −2 and > 500 cycles in Li||LiFePO 4 cells at 1C (25°C). Even at 0°C, the Li||LiNi 0.8 Co 0.1 Mn 0.1 O 2 (1.8 mAh cm −2 ) pouch cell retains 85.1% capacity over 50 cycles while delivering 78.3% of its room‐temperature capacity initially.
GM-CSF-IRF5 Axis as a Therapeutic Target in TLR7-Mediated Macrophage Activation Syndrome 2309192
Abstract Introduction Macrophage Activation Syndrome (MAS) is a severe systemic inflammatory disorder linked to autoimmune diseases like sJIA. It involves macrophage hyperactivation, causing tissue damage, multi-organ failure, and hematopoietic issues. Overexpression of Toll-like receptor 7 (TLR7) has been associated with MAS. Increased GM-CSF levels and IRF5 activation observed in TLR7.1 transgenic mice suggest the GM-CSF-IRF5 pathway’s role in TLR7-driven MAS. Methods WT, Irf5—/—, and GM-CSF—/—mice received topical R848 treatment to activate TLR7. Flow cytometry and imaging flow cytometry were used to quantify blood and splenic Ly6C^hi monocytes and inflammatory hemophagocytes (iHPCs). Red blood cell and platelet counts were measured with the HEMAVET analyzer. To assess disease severity, WT, TLR7.1, TLR7.1Irf5+/—, TLR7.1Irf5—/—, TLR7.1GM-CSF+/—, TLR7.1GM-CSF—/— mice were evaluated. Cytokine levels (GM-CSF, IL-12, IL-6, TNFα) were measured using LegendPlex assays across all groups. Results Topical R848 in WT mice mimicked the TLR7.1 transgenic phenotype, with significant expansion of Ly6C^hi monocytes and iHPCs, contributing to dysregulated hematopoiesis and anemia. These effects were attenuated in Irf5—/— and GM-CSF+/— mice. TLR7.1Irf5+/— and TLR7.1Irf5—/— mice showed reduced GM-CSF levels.GM-CSF deficiency partially protected against early MAS symptoms, with age-dependent effects. Irf5 deficiency resulted in a more profound rescue, markedly decreasing Ly6C^hi monocytes and iHPCs, and fully preventing anemia and thrombocytopenia, thereby restoring hematopoietic balance. Conclusion TLR7 overexpression drives excessive GM-CSF production, which in turn promotes IRF5 activation and expansion of Ly6C^hi monocytes. These cells differentiate into iHPCs, contributing to anemia and inflammatory pathology in MAS. Targeting the GM-CSF—IRF5 axis offers a promising therapeutic strategy for MAS and related autoimmune diseases. Funding Source 5R01AR076242-05 Topic Categories Basic Autoimmunity (BA)
Regulation of Microbial and Metabolic Balance in the Gut by B Cells 2309411
Abstract Introduction Mucosal microbes must be tightly regulated to prevent infection by opportunistic pathogens, promote commensal homeostasis and maintain gut health. B cells maintain microbial homeostasis through local production of antibodies. We previously reported that Myosin 18A (Myo18A), an F-actin-binding unconventional myosin, controls antibody-mediated immunity. B cell-conditional Myo18A-deficient (Myo18A BKO) mice have increased mature splenic B cells antibody-secreting cells, elevated serum IgM and IgG antibodies, development of autoantibodies, and greater B cell differentiation to plasma cells. In this study, we tested the hypothesis that Myo18A deficiency regulates gut homeostasis by altering local antibody production and composition of the gut microbiome. Methods We measured fecal IgA and conducted shotgun sequencing on colon-derived fecal samples from control Mb1cre/+ and Myo18A BKO mice followed by meta transcriptomics and metabolic pathway analysis. Results Serum and free fecal IgA were decreased and gut microbial diversity altered in Myo18A BKO mice compared to Mb1cre/+ mice. Deletion of Myo18A was associated with enrichment of Erysipelotrichaceae and a decrease in the abundance of Bifidobacterium pseudolongum. As the former is linked to metabolic disorders and inflammatory diseases, and the latter has beneficial roles in health by suppressing diseases such as non-alcoholic fatty liver disease, our data are consistent with poorer gut health in Myo18A BKO mice. Accordingly, Myo18A BKO mice had enlarged livers and significantly higher liver triglyceride levels compared to Mb1cre/+ mice. Analysis of metabolic pathways revealed perturbation of acetate and adenosine metabolism in the fecal environment of Myo18A BKO mice, which further points to an altered gut barrier and pro-inflammatory environment. Conclusion Taken together, our results suggest that B cell Myo18A maintains gut health by regulating commensal diversity and metabolic balance. Funding Source NIH Topic Categories Mucosal and Regional Immunology (MUC)
Preserving neutrophils in single cell sequencing — our experience with a multi-center cohort 2309567
Abstract Introduction Neutrophils are the most abundant innate immune cells, yet they remain underrepresented in single-cell studies because they are not captured in PBMC preparations and rapidly deteriorate in whole blood. To address this gap, we generated a high-quality single-cell neutrophil atlas from patients with ANCA-associated vasculitis and related rheumatic diseases. Methods Fresh whole blood was collected from participants enrolled in three ethics-approved observational studies at collaborating university hospitals. Single-cell profiling was performed using the standard 10x Genomics workflow optimized for unfixed material. To define quality control parameters, we conducted a time-series analysis of neutrophil retention (2—28 hours post-collection) and compared fresh versus frozen aliquots from matched samples. Results Frozen samples showed marked neutrophil loss. Beyond 6 hours post-collection, cells exhibited reduced viability, increased autoreactivity, and transcriptional alterations, including ICAM-1 upregulation indicative of artifactual activation. After optimizing processing parameters, we generated a robust neutrophil atlas comprising 168 samples and 1.2 million cells, capturing disease-relevant states in ANCA-associated vasculitides. We here provide first evidence for early developmental stages (promyelocytes: DEFA3, MPO; myelocytes: RTN, LCN2, CYBB), immature neutrophils (MME), activated subsets (S100A8, S100A9, MMP9), interferon-responsive populations, and exhausted phenotypes related to disease phenotype and severity of ANCA-associated vasculitides. Conclusion Immature neutrophil substates, which are largely absent in healthy donors, are essential for understanding autoimmune pathology. Processing fresh whole blood within 6 hours is critical to preserve native transcriptomic states and prevent activation artifacts such as ICAM-1 induction, underscoring processing time as a key variable in neutrophil single-cell studies. Funding Source I’m employee of Evotec International GmbH Topic Categories Technological Innovations in Immunology (TECH)
Sterile and Non-sterile Induction of Neuroinflammation Attenuated by Pre-habilitative Resistance Exercise 2300012
Abstract Introduction Resistance exercise (RE) has been demonstrated to improve cognition in both human and animal studies related to Alzheimer’s Disease (AD). Previous research also suggested that cognitive impairment increases vulnerability to rapid cognitive decline following acute systemic inflammation. However, these mechanisms involved remain poorly understood. This study aimed to investigate how pre-habilitative RE modulates systemic inflammatory responses and its effects on neuroinflammation and cognitive decline. Methods 5-month-old female non-transgenic (nTg) and 3xTg-AD mice were subjected to a five-week RE ladder-climbing regimen prior to either laparotomy under sevoflurane anesthesia or lipopolysaccharide (LPS) injection. Following a three-day recovery period, we evaluated cognition and learning using the novel-object recognition (NOR), Y-maze, and fear-conditioning (FC) tests, focusing on the discrimination index, spontaneous alternation percentage, and freezing behavior. Brain tissue was collected for Western blot (WB) analysis, qPCR, or fixed in neutral-buffered formalin for immunohistochemical assessment. Results In both models of inducing systemic inflammation, RE-trained nTg mice showed significant reductions in pro-inflammatory cytokines, microglial activation, and cognitive deficits compared to sedentary controls. RE-trained 3xTg-AD mice displayed significantly improved discrimination and freezing percentages against their sedentary counterparts, with notable decreases in inflammatory cytokines and apoptotic signaling pathways. This provides compelling evidence that pre-habilitative RE mitigated neuropathologies and cognitive decline in the AD model. Conclusion Pre-habilitative RE can reduce neuroinflammation and cognitive changes induced by both non-sterile and sterile models of systemic inflammation. Furthermore, pre-habilitative RE can ameliorate exacerbation of AD-like phenotype triggered by such acute inflammatory challenges. Funding Source n/a Topic Categories Neuroimmunology (NEUR)
Life-History Traits in the Context of Immunology: An Interactive Module 2310199
Abstract Introduction Eco-immunology is an interdisciplinary field that examines the immune function in ecological and evolutionary contexts. Interest in this understudied field has increased due to effects of climate change, novel pathogens, and One Health concerns. By integrating immunology with ecology and evolution, an explanation of life-history trade-offs in population can be addressed. To address gaps in traditional biology curriculum, we developed an interactive module focused on immunological and evolutionary fitness and life-history trade-offs. By utilizing graphs and static models, this resource integrates immunology, ecology, and evolution while helping students develop their skills in quantitative and scientific reasoning. Methods Students completed a pre-assessment to determine a baseline understanding of eco-immunology concepts and competencies. They then completed an interactive module that introduced the concepts related to evolutionary and immunological fitness and life history trade-offs using graphs and static models. After completing the module, students completed a post-assessment that contained the same questions as the pre- and a survey on self-perception of their understanding. Results The percentage of relative frequency was determined on a five-point likert scale for each competency and concept. Most students reported agree, with few reporting strongly disagree or disagree for both competencies and concepts. Overall test scores and individual question responses were compared using a Wilcoxon matched-pairs signed rank test. Overall test scores showed a significant increase from pre- to post-assessment. Question based analysis indicated a significant gain on questions 1-7 but not question 8. Conclusion Overall test scores indicate students performed better on the post-assessment after completing the module. Most students were also in agreement of their increased understanding of various concepts and competencies after completing the interactive module. Funding Source NSF award # 2316260 Topic Categories Immunology Education and Communication (EDU)
Natural Chlamydia trachomatis Immunity Highlights CPAF as a Key Vaccine Target 2258359
Abstract Introduction Our previous studies identified Chlamydia trachomatis (CT)-specific IFNg-producing CD4+ T cells as correlates of protection from reinfection, whereas higher antibody titers marked exposure, and CPAF (CT858) emerged as an immunodominant T cell target. Methods We analyzed IFNg ELISPOT responses to seven CT antigens (CT005, CT372, CT486, CT529, CT681, CT858, CT871) in 79 women stratified as FU- (n = 48), who completed ≥3 of 4 follow-up visits and remained CT-negative, or FU + (n=31), who tested CT-positive at any visit within one year. Frequencies of positive responders and summed antigen responses were compared using Fisher’s exact or Chi-squared tests. Correlations between total antigen-specific IFNg responses and anti-CT IgG titers were assessed by Spearman analysis, and Wilcoxon tests compared response magnitudes by antibody titer (≤1:64 vs > 1:64). Antigen-specific antibody levels (CT529, CT681, CT858) were correlated with corresponding T cell responses, and CPAF-specific responses were further analyzed by anti-CPAF antibody levels (< 45% vs ≥ 45%). Results IFNg responses were most frequent to CT858 (n = 34) and CT529 (n = 34), followed by CT005 (n = 22), CT486 (n = 16), CT681 (n = 11), CT871 (n = 6), and CT372 (n = 4). Response frequencies and magnitudes did not differ between FU- and FU+ groups. In FU+ participants, IFNg responses correlated with anti-CT IgG titers (Rho=0.4, P = 0.03), a pattern not observed in FU- women. Among women with low anti-CT IgG titers, higher IFNg responses were detected in FU- compared with FU+ groups (P = 0.03), whereas no difference was seen among those with high titers. Among women with low anti-CPAF IgG, higher CPAF-specific IFNg responses showed a trend toward protection from reinfection (P = 0.19 for FU- vs FU+). Conclusion These findings indicate that natural infection elicits CT-specific IFNg T cell responses, yet reinfection still occurs. Stronger T cell responses, particularly to CPAF, were linked to lower reinfection risk, supporting CPAF as a key target for CT vaccine design. Funding Source NIAID U19AI144181, T32AI007001, American Association of Immunologists Intersect Fellowship Program for Computational Scientists and Immunologists Topic Categories Vaccines and Immunotherapy (VAC)
Liver metastasis limits immunotherapy efficacy by dismantling systemic anti-tumor T cell responses through unconventional antigen presentation 2263569
Abstract Introduction Liver is a well-known site of peripheral immune tolerance induction. Because it processes antigen-rich blood from the gut, the liver has evolved mechanisms to limit over-reaction to food and commensal antigens. When cancer metastasizes to liver, it likely hijacks this tolerogenic function, leading to tolerance to tumor antigens. This tolerance can systemically dampen anti-tumor immunity allowing the cancer to spread and jeopardizing responses to immunotherapy. This is a significant clinical problem as liver is a common site of metastasis. Despite this, liver metastases are treated with the same regimens as other visceral metastases. A significant knowledge gap exists regarding how this tolerance is induced and how it can be reversed. Methods To understand the process of liver induced immune tolerance to tumor antigens, we have established a model demonstrating that the presence of liver metastasis suppresses antigen specific anti-tumor immune responses systemically. Results We found that this suppression is mediated by the induction of regulatory T cells (Tregs) and dysfunction of circulating tumor specific effector CD8 T cells. To uncover which antigen presenting cell (APC) is responsible for tolerizing T cells in the liver, we have generated a single cell transcriptomic dataset of tumor antigen carrying APCs from different tumor-bearing organs (liver, lung, and breast). This analysis has revealed that, in addition to professional APCs, the liver contains resident APCs, such as liver sinusoidal endothelial cells (LSECs), capable of phagocytosing, processing, and presenting antigens on MHCII and MHCI. Conclusion Our data suggests that cancer cells residing in the liver leverage its physiological function and exploit hepatic tolerogenic APCs to suppress anti-tumor immune responses. Using various mouse models, we are dissecting which of these APCs are responsible for inducing Tregs and CD8 T cell dysfunction. Funding Source Parker Institute for Cancer Immunotherapy Topic Categories Classical and Non-Classical Antigen Presenting Cells (APC)
Nanoporous Carbon Coating of Separator Boosts Rate Capability of Cathodes in Lithium‐Ion Batteries
ABSTRACT High rate capability of cathodes in lithium‐ion batteries (LIBs) is essential for fast rechargeability of electric vehicles. Herein, we report that coating the cathode side of the separator with a layer of nanoporous carbon significantly improves the rate capability of LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC) and LiFePO 4 (LFP) cathode materials, where NMC and LFP deliver 121 mAhg −1 and 125 mAhg −1 at 2 Ag −1 (∼12 C), respectively. To elucidate the underlying mechanism, we investigate the interfacial behavior and charge transfer kinetics using the distribution of relaxation times (DRT) from electrochemical impedance spectroscopy. Our DRT results show an increased relaxation time for mass transport and indicate a more populated charge storage in the diffuse layer of the electrical double layer (EDL). Simulations on ion transport behavior using a size‐modified Poisson–Nernst–Plank equation reveal that the nanopore‐confined EDLs produce an exclusion effect that increases Li‐ion transport resistance in over‐confined pores. These results support the experimentally observed increase in performance for coatings with expanded pore sizes and further indicate that the carbon layer enhances both (de)lithiation processes by promoting a more uniform and consistent gradient of Li‐ions in the EDL.
Lysophosphatidylcholine (LPC 18:2) Reprograms the Tumor Immune Microenvironment to Potentiate Immune Checkpoint Blockade 2309882
Abstract Introduction Lysophosphatidylcholine (LPC) is a bioactive lipid with emerging immunomodulatory properties, but its potential as an adjuvant to immune checkpoint blockade (ICB) is poorly understood. We hypothesized that LPC could reprogram the tumor microenvironment to boost the efficacy of anti—PD-1/anti—CTLA-4 therapy. Methods Using syngeneic mouse models of MCA205 fibrosarcoma, MC38 colon adenocarcinoma, and CMT167 lung carcinoma, tumors were established bilaterally and treated with IgG control, ICB (anti—PD-1 + anti—CTLA-4), or ICB plus LPC18:2. Tumor growth, survival, serum cytokines, flow cytometry, and bulk RNA-seq were used to characterize treatment responses. Results Across models, ICB + LPC consistently reduced tumor growth compared with ICB alone, with an increased fraction of long-term responders. Bulk RNA-seq of MC38 tumors revealed that ICB alone modestly induced interferon response and antigen-presentation pathways, while addition of LPC produced a much stronger and more coherent transcriptional program. Gene-set and GO enrichment analyses showed marked up-regulation of adaptive immunity, T-cell cytotoxicity, and both MHC class I and II antigen-processing pathways, alongside interferon-stimulated IRG/GBP modules and DNA-sensing genes. Jaccard similarity analysis demonstrated that LPC specifically amplifies and consolidates these immune modules rather than introducing unrelated pathways. Conclusion Together, these data support a model in which LPC enhances ICB by reprogramming myeloid and antigen-presenting cell compartments to drive stronger interferon signaling and T-cell effector function. Ongoing 10x Genomics 3’ scRNA-seq of CD45+ tumor-infiltrating cells will define the precise cellular states and circuits engaged by LPC in combination with checkpoint blockade. Funding Source NIH R01 CA256133(2007105000403) Topic Categories Tumor Immunology: Checkpoints, Prevention, and Treatment (TIPT)
ImmunoFoundation: A Multimodal Deep Learning Approach to Immunogenicity Prediction 2310036
Abstract Introduction Predicting immunogenicity remains a critical challenge in vaccine design, autoimmunity treatment, and pharmaceutical development. Current AI tools rely on limited data inputs, typically only class-I MHC-peptide sequences, missing crucial structural and biochemical information. We developed the ImmunoFoundation Model (IFM), a multimodal deep learning system that integrates not only peptide sequences, 3D molecular structures, and biochemical properties but also TCR-MHC-peptide (class-II and class-I) to achieve superior immunogenicity prediction and enable peptide optimization for therapeutic applications. Methods IFM comprises three modules: (1) ESM3 transformer for embedding antigen-peptide, MHC, and TCR sequences from vast biomedical data; (2) geometric scattering transformer networks to capture molecular structure from AlphaFold3-predicted peptide-MHC complexes; (3) Autoencoder for biochemical property embedding including surface area and thermal stability. Cross-modal attention layers integrate these representations. Training utilized IEDB, VDJdb, McPAS-TCR, and TCR3d datasets totaling >300,000 samples across MHC class I and II. Results The preliminary model achieved state-of-the-art performance on CEDAR cancer neoepitope datasets. Attention mechanism analysis revealed structural motifs influencing immunogenicity, distinguishing between KRAS G12V and G12D mutants. The model successfully predicted vaccine cassette immunogenicity and identified key peptide-MHC interaction sites. Current IFM development shows improved multimodal integration with enhanced predictive accuracy across viral and cancer peptide immunogenicity tasks. Conclusion IFM represents a paradigm shift in immunogenicity prediction by comprehensively modeling the complex antigen-MHC-TCR interaction system. Its generative capabilities enable peptide optimization for cancer vaccines and personalized immunotherapy, with potential applications in autoimmunity treatment and biologics development. Funding Source Yale Colton Center for Autoimmunity Topic Categories Computational and Systems Immunology (COMP)
17b-Estradiol Potentiates the Type I Interferon Signature and Pro-inflammatory Cytokine Profile in SLE via ERa Signaling 2309771
Abstract Introduction Systemic Lupus Erythematosus (SLE) is a life-threatening autoimmune disease with a profound female predominance, yet the molecular nexus between sex hormones and inflammatory pathways remains poorly defined. This study aims to identify and validate E2-responsive candidate genes and signaling networks that drive SLE pathogenesis. Methods Peripheral blood mononuclear cells (PBMCs) from SLE patients (n = 3) and healthy controls (n = 3) were treated in vitro with physiological concentrations of 17b-estradiol. We utilized Gene-chip transcriptomic analysis to identify differentially expressed genes (DEGs). Cytokine profiles (IL-6, IL-12, IL-17, IL-21) were quantified in patient plasma via ELISA and correlated with systemic E2 levels. T cell activation (CD69) and cytokine production (IFN-g) were assessed by flow cytometry. Results Plasma levels of pro-inflammatory cytokines (IL-6, IL-12, IL-17, and IL-21) were significantly elevated in SLE patients and positively correlated with endogenous E2 concentrations. In vitro E2 stimulation differentially upregulated pathways involved in G-protein coupled receptor (GPCR) signaling, apoptosis, and TNF/IFN-mediated inflammation. Notably, E2 treatment induced a 30-fold increase in IL-1 expression in SLE PBMCs compared to a 7-fold increase in healthy controls. Gene-chip analysis identified TNFAIP3 (A20) as a key E2-responsive ISG. Furthermore, E2 significantly increased the frequencies of activated CD3+CD69+ and IFNg+ T cells. These effects were abrogated by simultaneous ERa inhibition, establishing an ERa dependent mechanism for ISG and cytokine dysregulation. Conclusion Our findings demonstrate that 17b-estradiol acts as a potent rheostat for the IFN signature and pro-inflammatory milieu in SLE. The hyper-responsiveness of SLE PBMCs to E2-induced IL-1 and ISG expression provides a mechanistic basis for the sexual dimorphism observed in SLE. Targeting the E2-ERa signaling axis may represent a viable strategy for attenuating the inflammatory cascade in SLE patients. Funding Source This work was supported by the NIH grants AR54034, AI 083894,AI65645, I01 BX 005887-01 to RPS; UCLA Senate Core Grant to BHH and RPS; UCLA Oppenheimer Clinical Seed Grant and American Autoimmune Related Disease Association grant to RPS. Topic Categories Immune Mechanisms of Human Disease (HUM)
The allo-antigen specificity of a T cell driving acute cellular rejection of a kidney allograft 2302494
Abstract Introduction While alloreactive CD8+ T cells are the main drivers of direct acute cellular rejection (ACR), their targets are poorly understood. Old models posit that TCRs on alloreactive T cells bind their targets non-specifically. However, recent data suggest that many alloreactive T cells are allospecific, recognizing unique peptide-allo-HLA complexes. Using scRNA/TCR-seq we showed that kidney biopsies from ACR patients had limited numbers of clonally expanded CD8+ T cells (CD8EXP). Here, our aim was to identify the alloantigens recognized by the CD8EXP TCRs. Methods K562 cells singly expressing donor mismatched class I HLA proteins, HLA-A*32:01 and -B*14:01, were used to stimulate Jurkat cells expressing the CD8EXP TCRs. An A*32:01 responsive TCR was used to screen an A*32:01 yeast display library. Hits from the screen were used in a molecular mimicry search (MimicMaker) of the K562 transcriptome to find potential targets. Hits from the search were compared to peptides identified by immunopeptidomics, tested for their ability to stimulate the patient-derived TCR, and mapped to the donor kidney transcriptome. Results The clone 7 TCR responded to A*32:01 on K562 cells only, indicating HLA restriction. Clone 7 failed to respond when co-cultured with A*32:01+ T2 cells in the presence of rationally designed peptides, confirming allospecificity. Yeast display screening yielded 5 highly stimulatory peptides. A MimicMaker scan of the K562 transcriptome for mimics of these peptides, along with peptidomics, identified 72 candidate targets. From these, only a single peptide strongly stimulated clone 7. This peptide is likely the biologically relevant target of the clone 7 TCR. Its source protein is highly expressed in the donor kidney. Conclusion Our interdisciplinary approach has allowed us to identify a target of a patient-derived allospecific TCR. Broader deployment of this approach is likely to yield further success, paving the way for improving transplant outcomes by linking alloreactive TCRs to their targets. Funding Source R21AI91060, R21AI169863, T32GM145773 Topic Categories Transplantation Immunology (TRAN)
HLA Gene Editing of the Type I Diabetes Susceptible DQ8 Allele Inhibits Hybrid Insulin Peptide Binding and T Cell Activation 2310163
Abstract Introduction The risk for developing T1D is strongly associated with HLA-DQ8 in humans and I-Ag7 in NOD mice, both of which have an alanine at position 57 and an asparagine in position 82. In the NOD mouse model, replacing alanine (A) with aspartic acid (D) renders the mice resistant to diabetes, suggesting that the edit should block binding of autoantigens. Here, we compared the T1D-specific gene edit (A57D) with a universal approach replacing the invariant asparagine (N) with leucine (L) at position 82 (N82L). Asparagine forms hydrogen bonds with the peptide backbone near the N-terminus of a peptide and appears to be critical for all high-affinity peptide binding. Methods DQ8, DQ8(A57D) and DQ8(N82L) edits were cloned individually into the K562 cell line. HIP-11, a T1D pathogenic peptide, was synthesized with a biotinylated polyethylene-3 linker on the N-terminus. K562 transfectants were cultured with biotinylated peptide overnight. Peptide binding was detected with streptavidin-PE and analyzed by flow cytometry. The T cell transductant (GSE.8E3), which was generated by cloning the HIP-11-specific T cell receptor from a T1D patient, was co-cultured with HLA-transfected K562 cells plus HIP-11 and T cell activation measured using an NFAT reporter. Results Replacing alanine at position 57 with aspartic acid in DQ8 reduced HIP-11 peptide binding by 37%. In contrast, replacing asparagine at position 82 with leucine reduced HIP-11 peptide binding by 87%. However, both edits completely blocked T cell activation of HIP-11-specific T cells. Conclusion The global (N82L) gene edit in DQ8 reduced binding of HIP-11 more effectively than the A57D edit. However, both gene edits blocked the activation of a HIP-11 pathogenic T1D T cell line. These findings support the potential development of HLA gene editing to treat T1D. Funding Source n/a Topic Categories Therapeutic Approaches to Autoimmunity (THER)
Xenophagocytosis blockade enhances interspecies chimerism 2258754
Abstract Introduction Organ shortage remains a major challenge in transplantation medicine. Interspecies blastocyst complementation seeks to generate human organs in livestock by creating an empty organ niche for donor pluripotent cells. Yet donor chimerism often falls at early embryonic stages. We tested whether an innate immunologic barrier emerging with embryonic macrophages causes this drop and whether overcoming it improves donor chimerism. Methods We generated rat to mouse and human to mouse chimeras by injecting donor pluripotent stem cells into blastocyst stage embryos. Donor contribution was quantified by imaging, droplet digital PCR, and flow cytometry, and host myeloid states by index sorted single cell RNA sequencing. Mechanism tests included macrophage depletion or impairment (PU.1 or Csf1r knockout), receptor genetics (Axl knockout), and tuning eat me versus do not eat me cues on donors (BCL2, mouse CD47). Results Donor chimerism declined as macrophages appeared at E9.5 to E11.5. Host macrophages contained donor EGFP puncta while targeted donor cells lacked cleaved caspase 3, consistent with phagoptosis; we term this xenogeneic clearance xenophagocytosis. Depleting host macrophages increased rat and human donor contribution. Xenogeneic donor cells displayed elevated surface phosphatidylserine sensed by Axl on host macrophages. Knocking out Axl in the host increased donor chimerism in mouse embryos. Donor mouse CD47 overexpression increased chimerism. Conclusion An Axl dependent xenophagocytosis checkpoint restricts interspecies chimerism by enabling macrophages to remove viable xenogeneic cells with high surface phosphatidylserine. Targeting this checkpoint improves donor persistence and provides routes to increase the efficiency of blastocyst complementation for human organ generation. Funding Source NIH (R01DK121851) the Ludwig Foundation the Leducq Foundation the Centers for Clinical Application Research on Specific Disease/Organ of the Research Center Network for Realization of Regenerative Medicine, funded by the Japan Agency for Medical Research and Development (AMED_JP23bm1123041) and the Japan Society of the Promotion of Science Topic Categories Transplantation Immunology (TRAN)
Farnesol regulation of the Immune-Gut-Brain Axis in the context of CNS inflammatory demyelination 2267098
Abstract Introduction Experimental models and clinical evidence suggest multifactorial and bidirectional interactions between the gut and the central nervous system (CNS). A third player, the immune system, has recently been identified in these interactions, with research showing a link between the gut microbiome and inflammatory conditions, including those affecting the CNS. In this study, we make the case that farnesol, a naturally produced isoprenoid intermediate of the mevalonate pathway, plays a key signaling player that links the gut and its microbiota, the immune system, and the CNS. Interestingly, farnesol has been studied extensively as a quorum-sensing regulator of fungal biofilms and for its antibacterial effects. Methods Using experimental autoimmune encephalomyelitis (EAE) and in vitro systems, we tested the effects of orally administering farnesol using corn oil as a delivery vehicle on the integrity of the intestinal barrier, the gut mucosal immune compartment, and the microbiome and mycobiome composition, quantified ex vivo and in vitro by 16S rRNA and ITS sequencing, respectively. Results C57BL/6 mice induced with EAE, treated with farnesol, showed reduced disease severity, linked to effects on the gut barrier integrity and modifications on the phenotype of monocyte-derived macrophages, reduced proinflammatory cytokine production, such as TNF-α, and the composition of the gut microbiome and mycobiome of EAE mice. Furthermore, farnesol directly impacts the microbial composition when cultured in vitro. Importantly, corn oil administration resulted in significant modifications in gut microbes. Conclusion Our study indicates that farnesol should be considered as a significant modulator of the immune-gut-brain axis. Furthermore, corn oil should not be an optimal delivery method. Corn oil-free delivery methods based on lipidic micelles are now being tested in our laboratory. Funding Source National Institutes of Health (Grant number R15AI191202) Topic Categories Therapeutic Approaches to Autoimmunity (THER)