Browse Articles

Targeting IL-33 and TSLP in Asthma: Efficacy Assessment in Humanized Mouse Models 2302202

Abstract Introduction Interleukin-33 (IL-33) and thymic stromal lymphopoietin (TSLP) are key epithelial cytokines driving allergic inflammation and asthma. IL-33/ST2 signaling activates type 2 immune responses, while TSLP functions as an upstream initiator of multiple inflammatory pathways. Both cytokines are promising therapeutic targets, with several IL-33— and TSLP-directed antibodies in development. Methods To enable in vivo evaluation of human-specific drug candidates, two humanized mouse models were generated: B-hIL33/hTSLP/hTSLPR, in which human IL33, TSLP, and TSLPR replace their murine genes, and B-hIL33(C), expressing only human IL-33. An ovalbumin (OVA)—induced asthma model was established in both backgrounds. Mice received anti-human IL-33 antibody monotherapy or combination therapy with anti-human TSLP. Endpoints included eosinophil counts, serum IgE, and lung histopathology (H&E). Results Both models were successfully validated, producing only human IL-33, TSLP, and TSLPR with complete loss of murine protein expression. In OVA-challenged mice, anti-IL-33 treatment significantly decreased eosinophil infiltration and IgE levels, with lung sections showing reduced inflammatory cell accumulation and mucus secretion. Importantly, in the triple-humanized B-hIL33/hTSLP/hTSLPR mice, dual blockade of IL-33 and TSLP produced greater suppression of airway inflammation compared with monotherapy, demonstrating additive therapeutic benefit. Conclusion The B-hIL33/hTSLP/hTSLPR and B-hIL33(C) humanized mouse models provide robust platforms for evaluating IL-33— and TSLP-targeted therapies. Their validated human cytokine signaling enables meaningful preclinical assessment of monoclonal or combination strategies, supporting advancement of next-generation biologics for allergic and inflammatory diseases. Funding Source N/A Topic Categories Immediate Hypersensitivity, Asthma, and Allergic Responses (HYP)

Novel comparative models of canine tumors xenografted into mice to develop effective immunotherapies against osteosarcoma 2302620

Abstract Introduction Osteosarcoma (OSA) in dogs and humans is an aggressive form of bone cancer with limited effective treatment options for both species. Given the many aspects shared by this disease in dogs and humans, we generated preclinical models of comparative value by transplantation of canine OSA derived xenografts (CODXs) into immunocompromised mice. After finding tumor autologous canine immune cells infiltrating the CODXs, we used these models to predict anti-OSA clinical efficacy of immunotherapies targeting T cell function. Methods Canine OSA samples implanted into NOD SCID gamma (NSG) mice were tested for sustainable successive transplants. Amplification by polymerase chain reaction (PCR) of targeted canine genes was used to determine canine origin of transplanted tumors. Retention of parental OSA histology along passage of CODXs into NSG mice was studied. Infiltration of canine lymphocytes into CODXs was investigated using flow cytometry and immunohistochemistry. Finally, NSG mice hosting CODXs were treated with anti-canine CTLA-4 mAb to test anti-tumor functionality of potential canine T cells found infiltrating the CODXs. Results Two CODXs were established as consistently transplantable into successive generations of NSG mice. Canine origin of transplanted tissue across successive generations was proven by PCR. CODXs were also shown to retain parental tumor histology. Both CODX models were consistently infiltrated with canine lymphocytes positive for the T cell lineage marker CD3 across successive generations of NSG recipients. Finally, NSG mice recipients of the sixth generation of one of the two CODXs were treated with canine anti-canine CTLA-4 mAb These mice presented reduced tumor burden (p value = 0.0403) and lived longer (p value = 0.0004) than control treated mice. Conclusion CODXs established will allow pre-clinical development and evaluation of candidate drugs targeting T cell functionality for clinical care of dogs and humans suffering from OSA. Funding Source University of Missouri intra-mural funds NIH, NCI, U01 funds Topic Categories Veterinary and Comparative Immunology (VET)

Long-distance communication between CD8 T cells and brainstem neurons determines sickness behaviors and infection outcome 2254620

Abstract Introduction CD8 T cells are classically known for their cytotoxic role in eliminating infected, cancerous, and damaged cells. However, their potential for non-cytotoxic, long-distance, and bidirectional communication with neurons has remained unexplored. Methods Mice were intravenously infected with lymphocytic choriomeningitis virus Clone 13, as a natural model of a sustained viral infection. We combined behavioral assays, immunohistochemistry, pharmacological blockade, stereotactic ablation of specific brain neurons, flow cytometry, and single-cell RNA sequencing to dissect how CD8 T cells and neurons bidirectionally communicate during viral infection. Results Depletion of CD8 T cells abolished sickness behaviors observed one week after a systemic viral infection, while adoptive transfer of CD8 T cells into T cell and B cell-deficient mice restored these behaviors. Blocking CD8 T cell brain entry did not affect behaviors. Whole-brain c-Fos mapping revealed CD8 T cell-dependent activation of caudal nucleus of solitary tract (cNTS), including dopamine β-hydroxylase—positive (DBH+) neurons, at the peak of sickness behaviors. Ablation of these neurons attenuated sickness behaviors and enhanced effector-like CD8 T-cell responses in spleen, lung, and blood. Single-cell RNA sequencing uncovered an unconventional CD8 T cell subset co-expressing TCR-α, β, and γ chains, and enriched for IL-2 signature and cytotoxic genes following the neuronal ablation. Although viral loads decreased, the neuronal ablation caused severe, CD8 T cell-dependent, lung hemorrhage and increased mortality. Conclusion Our findings reveal a previously unrecognized systemic feedback loop wherein CD8 T cells remotely activate cNTS DBH+ neurons without entering the brain. These neurons not only drive sickness behaviors but also restrain CD8 T cell effector functions to prevent fatal immunopathology, at the expense of viral control. This immune—neural axis integrates host behavior and antiviral immunity into a single regulatory circuit. Funding Source n/a Topic Categories Neuroimmunology (NEUR)

Laplace‐Pressure‐Stabilized Rutile Solid‐Solution Catalysts for Acidic Water Oxidation: Enabling DSA‐Inspired Compositions (Adv. Mater. 46/2026)

High-accuracy lung region segmentation and injury classification using deep networks

CD4 T cell specifically deplete tissue resident alveolar macrophage 2310198

Abstract Introduction Alveolar macrophages are lung tissue resident macrophages that play a critical role clearing particles, protecting from infectious agent and inflammation. Aberrancy in the development or homeostasis of alveolar macrophage leads to lung inflammation. In the present study we tried to decipher the role of CD4 T cells in alveolar macrophage depletion and lung inflammation in kinase dead IKKa knock-in K44A (KA/KA) mice. Methods we used flow cytometry, adoptive CD4 T cells transfer and real time PCR Results We observed significant depletion of alveolar macrophages (CD11c+Siglecf+) in KA/KA mice. We thought the depletion of alveolar macrophage may be a non-specific macrophage disappearance reaction (MDR) as KA/KA lung has type II inflammation marked by increase Il4, Il13, Il5, Il33, Retnla, and Ym1 expression. We further observed the expression of Csf2 and Tgfb1 genes encoding GM-CSF and TGF-beta respectively that play a critical role in alveolar macrophage development and homeostasis were significantly reduced in KA/KA mice suggesting that the alveolar macrophage depletion is not an MDR. Not to our surprise, in KA/KA mice, we found significant reduction in the expression of Pparg gene that encodes transcription factor PPAR-gamma activated by GM-CSF and TGF-beta critical in alveolar macrophage development. Interestingly we observed no changes in the percentage of alveolar macrophages in the lungs of KA/KA; Cd4-/- as well as KA/KA; Rag-/- mice compared with wild type mice suggesting that the CD4 T cells may play a critical role in alveolar macrophage depletion. Further we observed significant depletion of alveolar macrophage in the lungs of KA/KA; Rag-/- mice that were adoptively transferred with KA/KA CD4 T cells, substantiating the role CD4 T cells in alveolar macrophage depletion. Conclusion In conclusion, CD4 T cells specifically deplete tissue resident alveolar macrophage by reducing the expression of Csf2, Tgfb1 and Pparg leading to lung inflammation in kinase dead IKKa (K44A) mice. Funding Source n/a Topic Categories Cellular Adhesion, Migration, and Inflammation (CAM)

Establishment of tissue-resident self-antigen-specific regulatory T cells protects the lung against recurrent injury 2255936

Abstract Introduction Self-reactive T cells present a threat to normal healthy tissue and are heavily regulated at steady-state by various mechanisms of peripheral tolerance. We previously reported a near-unilateral expansion of CD4+ Foxp3+ regulatory T cells (Tregs) among self-antigen-specific T cell populations during acute autoimmune lung injury which in turn limits further inflammation. Understanding the long-term consequences of this skew towards a Treg phenotype among injury-experienced self-antigen-specific T cells promises new insights into how tolerance is maintained over time and how it may be subverted during the pathogenesis of autoimmunity. Methods We utilized our novel CC10-SmUSA mouse, which expresses a model self-antigen containing multiple CD4+ T cell epitopes in lung tissue, in conjunction with peptide:MHC class II tetramers to directly identify and characterize self-antigen-specific Tregs that have previously expanded in the context of lung injury. Results Following immune-mediated lung injury, the phenotype of lung self-antigen-specific T cells remained stably enriched for Tregs in the secondary lymphoid organs (SLO) and lungs for several months. The frequency of these self-antigen-specific Tregs also remained highly elevated with populations in the lungs being tissue-resident. Upon subsequent challenge with influenza infection, previously injured mice exhibited less weight loss with a more rapid expansion of self-antigen-specific Tregs. Conclusion Our findings suggest that self-antigen-specific Tregs expanded in response to acute lung injury establish residence in the tissue and local draining lymph nodes to promote improved tissue homeostasis and resilience during future insults. Further characterization of these injury-experienced Tregs may help deepen our understanding of how immune memory develops with regard to peripheral tolerance. Funding Source National Institutes of Health/National Institute of Allergy and Infectious Diseases (NIH/NIAID); American Lung Association (ALA) Topic Categories Basic Autoimmunity (BA)

Fractalkine/CX3CL1 Functions as a Transmembrane Receptor to Promote Transendothelial Migration through glycan-dependent condensation 2257124

Abstract Introduction Biomolecular condensation provides a fundamental mechanism for organizing signaling complexes within cells. However, its occurrence on the cell surface–rich in glycans and exposed to dynamic extracellular forces–remains poorly understood. Fractalkine (CX3CL1), an endothelial membrane-bound chemokine, is heavily O-glycosylated and interacts with the monocyte receptor CX3CR1. Although fractalkine is known to mediate monocyte adhesion and migration, how its glycosylation drives condensate formation and endothelial signaling has not yet been elucidated. Methods We combined live-cell imaging, biochemical reconstitution, and a newly applied mucinase-based O-glycoproteomic approach to dissect the mechanism of fractalkine condensate formation. This strategy enabled site-specific mapping of O-glycosylation within the mucin domain and identification of key sialylated residues critical for condensate assembly. Functional analyses using glycosylation-deficient HUVEC mutants, including transendothelial migration assays, were performed to evaluate the impact of glycans on condensate formation and endothelial signaling. Results We found that endothelial membrane-bound fractalkine forms glycan-dependent condensates at the monocyte—endothelium interface. CX3CR1 engagement induces these condensates in a glycan-dependent manner. Glycoproteomic mapping revealed that a specific site of sialylated O-glycans is critical for these processes. The formation of these endothelial fractalkine condensates promotes the recruitment and activation of VEGFR2, leading to calcium influx and the upregulation of adhesion molecules, thereby enhancing monocyte transendothelial migration. Conclusion Our findings uncover a sialylation-dependent biomolecular condensate that mediates bidirectional fractalkine—CX3CR1 signaling. By recruiting and activating VEGFR2, this condensate links cell-surface glycosylation to endothelial signaling and immune cell migration, revealing a new paradigm of glycan-controlled cell-surface condensation. Funding Source n/a Topic Categories Cytokines and Chemokines and their Receptors (CCR)

PBMCs from people with HIV imprint diet-sensitive hepatic inflammation and lipid remodeling in NSG mice 2260261

Abstract Introduction People living with HIV (PLWH) exhibit a twofold higher risk of cardiovascular disease (CVD) compared to people without HIV (PWoH), likely due to chronic immune activation. Although inflammation is linked to CVD in PLWH, the immune mechanisms driving this risk remain poorly defined. We hypothesized that PBMCs from PLWH contain immune and metabolic signals that impose an HIV-associated cardiometabolic phenotype in vivo. To test this, we employed an immunocompromised mouse model. Methods PBMC from PLWH and PWoH were adoptively transferred into NOD scid gamma (NSG) mice and divided into two groups: high-fat diet (HFD) or standard chow diet (SCD). Body weight was monitored biweekly. Transcriptomic assessments of the liver were conducted via bulk RNA sequencing. The lipid profile was assessed by liquid chromatography-tandem mass spectrometry. Results Gene-set enrichment revealed consistent upregulation of epithelial—mesenchymal transition pathways in PLWH-PBMC recipient mice versus PWoH. On SCD, PLWH-PBMC livers had 104 DEGs compared to PWoH-PBMC (58 up/46 down), with increased inflammatory signaling, including the IL6-Jak-stat3 pathway. On HFD, differences were smaller but converged on calcium-handling/ contractile-structural programs, suggesting altered hepatic Ca²+/cytoskeletal regulation. Lipidomic analysis on HFD showed a shift toward lysosomal and storage/pro-inflammatory species in PLWH-PBMC livers compared to NSG control mice, increased bis(monoacylglycerol)phosphate, triacylglycerols, phosphatidylcholine, phosphatidylmethanol, and sphingolipid SHexCer, accompanied by reductions in mitochondrial membrane lipids (cardiolipin, monolysocardiolipin) and anti-inflammatory lipids (N-acylethanolamines, lysophosphatidylethanolamine, lysophosphatidylglycerol). Conclusion These data suggest that circulating immune cells transmit HIV-associated cardiometabolic features to target tissues in a diet-dependent manner, implicating immune lipid and calcium handling pathways as potential therapeutic targets. Funding Source n/a Topic Categories Immune Mechanisms of Human Disease (HUM)

Intravital imaging comparison of C-kit expression and co-localization with C-kit—targeting antibody in Balb/C and humanized hIgE/hFcαRI mice 2256695

Abstract Introduction Mast cells are central regulators of immune responses and play a crucial role in allergic diseases and mastocytosis. Their functional response to IgE-dependent stimulation is strongly affected by the surface expression of the high-affinity IgE receptor (FcαRI). The interaction between FcαRI and c-Kit, another key mast cell marker, is essential for their survival, maturation, and activation. Understanding how these molecules are expressed and interact in vivo is therefore critical for evaluating immune mechanisms and antibody-based therapies. This study aimed to compare the in vivo expression pattern of c-Kit and its co-localization with a c-Kit—targeting antibody between Balb/c mice and humanized hIgE/hFcαRI mice, providing insights into differential antibody—receptor interactions under physiological conditions Methods Using intravital microscopy, we continuously monitored c-Kit expression and antibody localization in the lung tissue of both mouse models for up to three days under live conditions. Results c-Kit was found to be expressed on the surface of lung epithelial cells in both groups. Following antibody drug administration, co-localization between the antibody and c-Kit expression was prominently observed, particularly one day post-treatment in hIgE/hFcαRI mice. The extent of co-localization differed significantly between models: humanized mice exhibited markedly higher antibody—c-Kit overlap, whereas Balb/c mice showed relatively weak co-localization. Conclusion These findings highlight that intravital microscopy enables direct and longitudinal visualization of antibody drug—related immune responses in living animals. The combined analysis of hFcαRI and c-Kit expression provides a valuable in vivo indicator for assessing mast cell activity, development, and therapeutic responsiveness. This underscores the unique capability of intravital imaging to bridge molecular-level interactions with physiological immune responses in real time. Funding Source n/a Topic Categories Immune Mechanisms of Human Disease (HUM)

Loss of TRIM68 in intestinal epithelial cells exacerbates colitis via TAB2 ubiquitination 2305968

Abstract Introduction Inflammatory bowel diseases (IBDs) are becoming an increasingly significant public health problem, with roughly 1 in 100 Americans currently affected. Intestinal epithelial cells (IECs) serve as the first line of defense against intestinal pathogens and play a pivotal role in the initiation of colitis. TRIM68, an E3 ligase, is highly expressed in IECs, but its function in intestinal inflammation remains unclear. Methods To investigate its role, we specifically generate TRIM68 totally knockout (Trim68-/-) and IEC conditionally knockout (Trim68IEC-KO) mice. Colitis was induced using dextran sodium sulfate (DSS), and disease severity was evaluated through body weight changes, histopathological scoring, and cytokine expression analysis. Results Following dextran sodium sulfate (DSS) administration, TRIM68-deficient mice exhibited pronounced body weight loss, more severe histopathological damage, and elevated IL-6 and IL-1β expression compared with control mice. Notably, Trim68IEC-KO mice exhibited almost identical responses to Trim68-/- mice, highlighting the essential contribution of IEC expressed TRIM68. Mechanistically, TRIM68 binds to TGF-β—activated kinase 1—binding protein 2 (TAB2), an essential upstream adaptor of NF-κB signaling responsible for inducing IL-6 and IL-1β. This interaction promotes ubiquitination and degradation of TAB2, thereby dampening downstream proinflammatory cytokine induction. Conclusion Our findings reveal that TRIM68 acts as a novel negative regulator in the host innate immune response to colitis specifically within IECs. These results expand the understanding of colitis pathogenesis and suggest TRIM68 as a potential therapeutic target. Funding Source 1R56AI148215, R01AI155488 Topic Categories Innate Immune Responses and Host Defense: Molecular Mechanisms (INM)

SARS-CoV-2 vaccination protects against infection-induced autoantibody formation 2302309

Abstract Introduction SARS-CoV-2-CoV-2 infection is known to induce autoantibodies across a wide range of targets, including immune modulatory proteins and pro-thrombotic factors. It is not known if vaccination with SARS-CoV-2 mRNA vaccines would induce a similar autoantibody profile, or whether prior vaccination would protect recipients from autoantibody production upon SARS-CoV-2 infection. Methods Our group followed a cohort of over 65,000 blood donors across repeat donations in the COVID-19 era. We identified SARS-CoV-2 naïve donors who were infected without prior vaccination (n = 150) or were vaccinated then became infected (n = 100). We tested samples from the naïve time point and 6-10 weeks after infection (2 paired samples) or naïve then vaccination then infection (three samples) using a T7 bacteriophage array displaying 731,724 peptides (49 amino acids each) spanning the human proteome. Data were partitioned into five random groups and peptide comparisons between groups were performed using ranksum, with 80% used for training and 20% used for testing iteratively. Results Autoantibodies targeting 15 peptides were induced with a z-score >2 after SARS-CoV-2 infection of unvaccinated naïve donors (p < 1x10-5). Of these infection-induced autoantibodies, 1 was induced after mRNA vaccination, as well as 2 distinct vaccine induced autoantibodies. In donors who were infected after prior vaccination, autoantibody responses were blunted, targeting 7 of 15 peptides. Conclusion In contrast to SARS-CoV-2 infection of immunologically naïve individuals, SARS-CoV-2 mRNA vaccination induces only a limited autoantibody repertoire. Furthermore, prior vaccination protects against development of approximately half the autoantibodies induced by SARS-CoV-2 infection in this study. These data confirm the induction of autoantibodies following infection and underline both the safety of mRNA vaccines in terms of autoantibody induction, as well as potential protective effects of vaccination from COVID-19 associated autoimmunity. Funding Source NIH Topic Categories Viral Immunology (VIR)

Airway B cells regulate neutrophilic inflammation via Fas:FasL pathways during respiratory Mycoplasma infection 2255833

Abstract Introduction Neutrophils are frontline effectors in bacterial pneumonia, providing rapid phagocytosis, degranulation, and NET formation to control pathogens, yet persistent or dysregulated neutrophil activity drives tissue injury and worsens outcomes. We recently showed neutrophils to be maladaptive during Mycoplasma infection while B cells appeared to modulate neutrophil dynamics through an unknown mechanism. Methods We combined targeted B cell depletion, passive transfers, high-parameter flow cytometry, and mixed-bone marrow chimera mice to assess the mechanisms by which B cells regulate neutrophilic inflammation during Mycoplasma infection. Outcome measures included neutrophil counts, Fas expression and apoptotic status, B cell localization and FasL expression, bacterial burden and histopathology. Results Passive transfer of hyperimmune serum failed to alter neutrophilia, lung pathology or pathogen load in Mycoplasma infected mice, implicating an antibody-independent regulatory mechanism. B cell depletion reproduced exacerbated neutrophilia. CXCL13-deficient bone marrow chimera mice, which lack luminal B cell recruitment to airway, but not to lung interstitium, exhibited exacerbated neutrophilia similar to B-cell depleted mice, supporting a contact-dependent regulatory mechanism. Screening of death receptors identified the Fas-FasL axis as the likely pathway for B-cell mediated killing of neutrophils. ∼21% of luminal B cells expressed FasL, and ∼73.6% of Fas+ neutrophils were found to be pre-apoptotic. Conclusion Altogether, these data define a previously undescribed Fas-FasL dependent mechanism by which airway recruited B cells regulate neutrophilic inflammation in the lung, highlighting cellular targets for immunomodulatory intervention in neutrophil-driven respiratory disease. Funding Source Funds made available by the Center of Excellence for Vaccine Research, NIH-NIAID T32AI007363 Topic Categories Immune Response Regulation: Cellular Mechanisms (IRC)

Real‐Space Mapping of Emergent Correlated Electronic States With Scanning SQUID Microscopy

ABSTRACT Scanning superconducting quantum interference device (SQUID) microscopy provides ultrahigh magnetic field sensitivity and has emerged as a powerful real‐space probe for correlated quantum phenomena in condensed matter. By reducing the superconducting loop to submicron regime, scanning SQUID microscopy achieves magnetic field sensitivities on the order of ≈10 nT Hz −1/2 while simultaneously enabling spatial resolution below 50 nm, allowing direct visualization of local magnetic textures and current distributions. Unlike the conventional SQUID measurements that can only probe spatially averaged magnetic responses of bulk samples, the scanning‐probe technique enables the detection of tiny, spatially inhomogeneous magnetic signals associated with emergent electronic states. This review focuses on recent progress in applying scanning SQUID microscopy to topological materials, magnetic systems, and unconventional superconductors, with an emphasis on the underlying mechanisms that can be uniquely revealed by real‐space magnetic imaging based on scanning SQUIDs. We discuss how scanning SQUID measurements have revealed phenomena that are inaccessible to bulk probes, including chiral edge currents in topological insulators, coexistence/competition between superconductivity and ferromagnetism, and anomalous flux quantization in multiband superconductors. Finally, we outline the future directions and challenges of scanning SQUID, with particular focuses on understanding correlated quantum phenomena and guiding the design of quantum information devices.

Longitudinal associations between physiological characteristics and performance in elite speed climbers

A User-Friendly, Modality-Agnostic, Scalable Pipeline for High-Dimensional Immune Data Across Cytometry and Imaging Platforms 2310246

Abstract Introduction High-dimensional immune profiling technologies, including flow cytometry, mass cytometry, spatial proteomics, and fluorescence imaging, generate complex datasets that remain challenging to analyze in a unified and reproducible manner. Existing analytical approaches often require substantial computational expertise and are limited to specific platforms, creating barriers for broad adoption by wet-lab scientists and clinicians. There is a need for user-friendly, modality-agnostic pipelines that enable scalable analysis. Methods We developed a user-friendly, modality-agnostic pipeline for end-to-end analysis of high-dimensional immune data across cytometry and imaging platforms. The pipeline is built on robust and widely adopted R and Python packages and is delivered through an intuitive graphical user interface (GUI). The pipeline supports standard data formats, including FCS, MCD, and TIFF files The pipeline provides standardized, scalable workflows for data preprocessing, visualization, and downstream analysis, while remaining extensible for advanced users. Results To demonstrate functionality and versatility, the pipeline was applied to a practice dataset examining immune cell infiltrates in early colorectal cancer lesions. The pipeline enabled efficient preprocessing, visualization, and comparative analysis of high-dimensional immune profiles, illustrating its ability to handle complex cytometric and spatial data within a unified analytical framework. Conclusion Our GUI guided pipeline lowers technical barriers to high-dimensional immune data analysis by providing a scalable, user-friendly, and modality-agnostic framework. By enabling reproducible and interpretable analysis across cytometry and imaging platforms, our pipeline facilitates biological discovery and supports the broader adoption of advanced immune profiling technologies in translational and clinical research. Funding Source R01CA258882, HT94252510707 Topic Categories Computational and Systems Immunology (COMP)

Investigating the Susceptibility of Peripheral Immune Cells to Human Respiratory Syncytial Virus (RSV) Infection 2256601

Abstract Introduction Respiratory syncytial virus (RSV) infects nearly all children by two years of age and causes up to 199,000 childhood deaths annually worldwide. A hallmark of RSV infection is its ability to cause recurrent disease throughout life, suggesting inadequate long-term cellular immunity. Current understanding of RSV-induced immune responses is largely derived from murine models, which are only semi-permissive to infection and resistant to reinfection, limiting their translational relevance. Although RSV has been shown to infect B cells and monocytes in mice, the full extent of RSV’s interaction with diverse human immune cell subsets remains unclear. Methods To address this gap, we are using human peripheral blood mononuclear cells (PBMCs) to define how T cells, B cells, monocytes, dendritic cells, and natural killer (NK) cells respond to RSV infection. We hypothesize that specific PBMC subsets become differentially infected and that their susceptibilities change over the course of infection due to cellular maturation and cytokine-driven modulation. Results Our data shows approximately 10% excess PBMC death during RSV infection, with 1—2% of cells identified as RSV-positive by flow cytometry. Infectious viral particles are detected predominantly within cells over a 6-day infection period. Imaging flow cytometry confirms that RSV actively infects all five immune cell subsets and induces distinct phenotypic changes. Among these, monocytes exhibit the highest susceptibility, showing markedly greater viral uptake than T cells and other subsets. Conclusion These findings provide the first comprehensive evidence that RSV targets multiple human immune cell populations ex vivo, leading to cell-type—specific alterations. The insights gained from this study will set the stage for developing a novel co-culture system integrating adult human nasal organoids with isolated human immune cells to establish a more physiologically relevant model for studying cell-mediated immune responses to RSV infection. Funding Source This research was supported in part by the National Institutes of Health grants Human Biomimetics for Mucosal Infections: 2 U19 Al116497 and Integrated Genomics of Mucosal Infections: U19 Al144297. Topic Categories Viral Immunology (VIR)

Spatial stochasticity in lymph node microdomains optimizes host protection and enforces self-tolerance 2257248

Abstract Introduction Regulatory T cells (Tregs) respond more strongly to self antigens than conventional T cells (Tconvs), effectively preventing autoimmunity. However, Treg reactivities to foreign antigens, and their relative strength compared to Tconvs, remain less understood. Because Tconv self-reactivity promotes their sensitivity to foreign antigens, we hypothesized that Tregs–being even more self-reactive–would be the most sensitive to foreign stimuli, a prediction we experimentally validated. This finding raises a fundamental paradox: how can Tconvs overcome Treg suppression to mount effective immune responses against pathogens? To address this, we developed and experimentally tested a mathematical theory grounded in spatially localized T cell decision-making within lymph nodes - a framework we term spatial stochasticity. Methods We quantified self- and foreign-reactivity distributions of endogenous, polyclonal Tconvs and Tregs using reporter mice that measure TCR signaling strength and MHC-II tetramers. We then applied high-resolution, multiplexed 3D imaging of optically cleared lymph nodes to directly test predictions in situ. Results Remarkably, Tregs exhibited higher sensitivity not only to self but also to foreign antigens compared to Tconvs. In a well-mixed lymph node where Tconvs and Tregs compete globally, such an advantage would imply that Tregs always dominate, precluding productive pathogen responses. However, our data and modeling indicate that lymph nodes are not well-mixed but instead organized into numerous microdomains–where small numbers of T cells are stochastically sampled to compete locally–thereby breaking this global advantage and allowing rare, highly responsive Tconvs to initiate effector responses. Conclusion Spatial stochasticity redefines self/non-self discrimination as a spatially distributed, probabilistic, population-based decision process across lymph node microdomains. As a result, Tregs provide quality control during infections by selecting the most competitive T cell clones. Funding Source Jane Coffin Childs Memorial Fund for Medical Research Topic Categories Computational and Systems Immunology (COMP)

Cataloging Epitope Data: A glimpse into the manual curation efforts of the IEDB team in 2026 2309343

Abstract Introduction The Immune Epitope Database and Analysis Resource (IEDB, iedb.org) and its sibling resource, the Cancer Epitope Database and Analysis Resource (CEDAR, cedar.iedb.org), are platforms created and maintained for the benefit of the scientific community, allowing open access to organized epitope data that is then utilized to power the associated epitope prediction tools. Methods The foundation of the curation process is in staying current with published research literature, our primary source of epitope data, and in structuring the data according to associated data ontologies. The process for inputting data includes identification, categorization, curation, peer review, and systemic quality control and validation steps. Results The curation process results in databases that reflect the epitope literature in the areas of infectious disease, autoimmunity, allergy, transplantation, and cancer. Here, we detail the data input process with a focus on the manual curation efforts of the expert curation team, including the recent addition of CAR-T cell epitopes, updates to non-peptidic curation, and new quality-control processes for cell lines. Conclusion These improvements help ensure end-users are getting the greatest benefit possible from the IEDB and CEDAR. Funding Source NIH/NIAID (75N93019C00001), and NIH/NCI (U24CA248138) Topic Categories Technological Innovations in Immunology (TECH)

Therapeutic Evaluation of a C3-Targeting Small Nucleic Acid Drug in a Spontaneous Humanized C3 Glomerulopathy Mouse Model 2256845

Abstract Introduction Complement component C3 is central to the activation of the alternative pathway (AP), and its dysregulation drives C3 glomerulopathy, a severe renal autoimmune disease that lacks effective therapies. Methods To enable translational studies, we established a humanized C3G model, B6-hC3 mC3 KO, which overexpresses human C3 while lacking the endogenous murine C3. These mice spontaneously develop progressive glomerulopathy resembling human C3G pathology. Small nucleic acid drugs were administered to mice to evaluate drug efficacy. Results The disease phenotype observed in humanized C3 transgenic mice appears to arise from a dysfunctional interaction between human C3 protein and murine complement proteins, resulting in uncontrolled AP activation. Subcutaneous administration of C3-targeting small nucleic acid drugs effectively reduced serum C3 and plasma C3a levels, and downregulated the ratio of Ba (the activated fragment of complement factor B, CFB) to CFB, indicating suppression of AP hyperactivation. After 6 weeks of treatment, renal histology showed markedly reduced deposition of hC3 and diminished inflammatory cell infiltration. Conclusion B6-hC3 mC3 KO mice reproduce key immunopathological features of C3G and serve as a powerful platform for mechanistic studies and preclinical evaluation of complement-targeted therapeutics. Funding Source n/a Topic Categories Innate Immune Responses and Host Defense: Cellular Mechanisms (INC)