Browse Articles

Assessment of natural and anthropogenic radionuclides in marine sediments around the state of Qatar

Neoantigen-specific CD4+ T cells sustain endogenous intratumoral B cell responses to enhance anti-tumor immunity 2258511

Abstract Introduction Cancer mutations can give rise to novel tumor-specific peptides (“neoantigens”) that are recognized by T cells to attack tumors. CD4+ T cells cooperate with B cells of related antigen specificity to promote antibody production and enhance antitumor immunity. Paradoxically, tumors are frequently coated with matured antibodies that recognize unmutated epitopes despite the existence of tolerance mechanisms. We hypothesized that neoantigen-specific CD4+ T cells play a key role in coordinating polyfunctional tumor-associated B cell responses. Methods To test this, we utilized an autochthonous KP (KrasG12D/+; tp53-/-) mouse model of lung cancer initiated via delivery of Cre, and leveraged flow cytometric and histological analyses with temporal perturbations, depletions, and ELISA assay. Results Tumors expressing a single MHC-II-restricted neoantigen (mITGB1) or lacking this neoantigen (mITGB1-neg) harbored similar densities of B cells. However, B cells in mITGB1+ tumors uniquely displayed hallmarks of germinal center entry, class switching, and differentiation, and many B cells were spatially confined to clusters containing T cells. B cells persisted in mITGB1+ tumors for at least three weeks when lymphocyte entry was blocked, while B cells in mITGB1-neg tumors disappeared in this setting. Serum IgG isolated from mITGB1+ but not mITGB1-neg tumor-bearing mice showed reactivity against a non-autologous, neoantigen-deficient KP-derived cell line despite the presence of germinal center B cells in the draining lymph nodes of mITGB1-neg tumors. Finally, B cell ablation led to increased tumor burden, loss of intratumoral T cell clusters, and altered T cell composition and positioning in the tumor bed. Conclusion Our data indicate that neoantigen-specific CD4+ T cells orchestrate local B cell responses within tumors to promote anti-tumor immunity. Intratumoral lymphocyte hubs may represent unique sites of B cell selection, and function as a source of cancer-targeting antibodies and antigenic spread. Funding Source Jane Coffin Childs Fund, Hope Funds for Cancer Research Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Investigation of LOX-1 as an Immunometabolic Regulator During Lung Infection 2234171

Abstract Introduction Pneumonia is the leading cause of infectious disease related death globally. Current treatment relies on antibiotics but is limited by rising resistance and a lack of host-directed therapies. A better understanding of innate mechanisms that restore lung homeostasis is needed. Alveolar macrophages (AMs), regulate pathogen clearance, inflammation, and repair. The scavenger receptor LOX-1 is uniquely expressed on AMs and is upregulated during infection. Previously, we have shown that LOX-1 serves a protective, anti-inflammatory role in the infected airspace, with concomitant changes in genes that regulate AM metabolism, a driver of immune regulation. In this study, we investigate the role of LOX-1 in regulating AM metabolism and inflammatory signaling during lung infection. Methods AMs from healthy mouse lungs were stimulated with bronchoalveolar lavage fluid (BALF) from E. coli—infected mice, ± LOX-1 inhibition, to model the pneumonic airspace. Metabolic function was then assessed using a Seahorse XFe24 analyzer. To complement this, lung lavage cells from infected and uninfected mice were analyzed by flow cytometry with MitoTracker and MitoSOX dyes. Inflammatory signaling was evaluated by RT-qPCR following BALF stimulation. Results LOX-1 inhibition reduced maximal mitochondrial respiration and increased baseline/compensatory glycolysis in AMs following stimulation with infected BALF, indicating a shift from OXPHOS toward glycolysis. In agreement, flow cytometry revealed decreased MMP in LOX-1 inhibited AMs during lung infection. RT-qPCR of BALF-stimulated macrophages showed increased CXCL2 and IL6 expression, suggesting LOX-1 modulates inflammatory signaling, potentially via metabolic changes. Conclusion LOX-1 promotes mitochondrial respiration and suppresses excessive inflammatory signaling in AMs, highlighting a role in balancing pathogen clearance with resolution of inflammation. These findings suggest LOX-1 as a potential target for host-directed therapies in pneumonia. Funding Source This work was supported by a University of Iowa Startup Grant and NIH/NHLBI R00HL159258 Topic Categories Innate Immune Responses and Host Defense: Cellular Mechanisms (INC)

Suppression of IFN-g expression in Treg cells is dependent on the TCR signaling pathway 2332935

Abstract Introduction Regulatory T cells (Tregs) suppress excessive immune responses but promote tumor immune evasion by limiting anti-tumor immunity. Unlike effector T cells, Tregs restrict expression of interferon-γ (IFN-γ), a key anti-tumor cytokine, through incompletely defined mechanisms. Identifying pathways that constrain IFN-γ in Tregs may enable functional reprogramming to enhance anti-tumor immunity. Methods We performed a genome-wide CRISPR/Cas9 loss-of-function screen in Tregs to identify genes involved in the suppression of IFN-γ expression. Candidate genes, including Zap70, were individually validated. Tregs were transduced with a retroviral vector carrying sgZap70 or non-targeting control (sgNT2) and cultured in vitro, with RNA-seq to assess temporal transcriptional dynamics. In vivo anti-tumor immune responses were evaluated using an adoptive T-cell transfer tumor model. Results The CRISPR screen identified Zap70 as a candidate regulator of IFN-γ suppression in Tregs. Genetic ablation of Zap70 and additional TCR pathway components resulted in a significant increase in IFN-γ expression while preserving Foxp3 expression. Time-course RNA-seq revealed a progressive upregulation of the IL-12 signaling axis components Il12rb2, Jak2, and Stat4 in Zap70-deficient Tregs. In adoptive transfer tumor models, mice receiving Zap70-deficient Tregs exhibited reduced tumor burden compared with controls. Conclusion Our data identify TCR—Zap70 signaling as a critical suppressor of a selective Il-12—Jak2—Stat4 transcriptional program in Tregs that constrains IFN-γ induction. Loss of Zap70 enables a delayed but coordinated activation of this axis while maintaining Treg lineage stability. Importantly, this transcriptional reprogramming translates into anti-tumor activity in vivo, as adoptive transfer of Zap70-deficient Tregs results in reduced tumor burden. Together, these findings establish TCR signaling in Tregs as a mechanistically defined and functionally actionable target for enhancing anti-tumor immune responses. Funding Source NIH Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Multi-omics of controlled microbial naturalization uncovers sex-dimorphic immune maturation 2254508

Abstract Introduction Mouse modeling is the cornerstone of mechanistic immunology, yet widely used laboratory mice maintained in overly hygienic environments harbor predominantly naïve immune systems that poorly emulate human immune status. “Naturalized” or “dirty” models with diverse microbial exposures promote immune maturation, but current methods lack reproducibility and broad applicability, including poor compatibility with sex-based comparisons, preventing widespread adoption. Methods We develop a controlled and reproducible naturalization method for diverse mechanistic applications, integrated with longitudinal deep multi-omics across tissues, including proteomics, scRNA/VDJ-seq, shotgun metagenomics, and spectral flow cytometry. Results The method leverages natural cecal microbiota from large cohorts of well-defined male/female pet-store mice, viably preserved for consistent administration by oral gavage to laboratory mice–with compatibility across experimental variables. The model induces broad immune activation, with sustained maturation and functional adaptation across innate and adaptive immune cells in circulation and tissues, including durable alterations to bone marrow populations. We further resolve maturation trajectories at the single-cell level, revealing unified heightened interferon signatures, expansion of age-associated atypical subsets, as well as convergent terminal differentiation of CD4+ and CD8+ T cells resembling human TEMRAs. Leveraging this model, we probe immune sex dimorphism and uncover a female bias in interferon, extrafollicular B cell, and Ly49+ cytotoxic T cell responses, in contrast to a male bias in IL-15-induced T cell bystander activation–with broad implications for human inflammation and autoimmunity. Conclusion We present a widely applicable method for mouse microbial naturalization and comprehensive multi-omics resource of controlled immune maturation–providing a natural platform for translational mechanistic discovery, including immune sex dimorphism. Funding Source PD Soros Fellowship, NIH (F30AI188889 & T32GM136651), and Yale University Topic Categories Mucosal and Regional Immunology (MUC)

Bulk RNAseq of cardiac myosin-specific CD4 and CD8 T cells reveals distinct transcriptomic profiles between myocarditis-resistant and susceptible mice 2256473

Abstract Introduction We recently generated T cell receptor (TCR) transgenic (Tg) mice specific to cardiac myosin heavy chain-α (Myhc-α 334—352) on both myocarditis-resistant (C57BL/6) and susceptible (A/J) genetic backgrounds. While functional antigen-specific TCRs were expressed in both CD4+ and CD8+ T cells, the T cells from naïve Tg C57BL/6 mice did not respond to Myhc-α 334-352. In contrast, both cell types from A/J mice spontaneously responded to the antigen, suggesting their underlying molecular mechanisms might differ. Methods Using flow cytometrically sorted cells from naïve C57BL/6 and A/J Tg mice, we performed bulk RNA sequencing on CD4+ and CD8+ T cell subsets. Differentially expressed genes (DEGs), gene ontology (GO), and Kyoto encyclopedia of genes and genomes (KEGG) pathways, Gene set enrichment analysis (GSEA) of GO and KEGG, and transcription factor (TF) network analyses were performed to identify pathways and regulators of immune responses. Results Principal component analysis distinguished CD4+ from CD8+ T cells and revealed distinct transcriptomic profiles between C57BL/6 and A/J mice. KEGG enrichment analysis indicated downregulation of pathways related to viral myocarditis and autoimmune conditions in C57BL/6 compared to A/J mice. GSEA of GO revealed that negative regulation of heart contraction and positive regulation of cardiac muscle hypertrophy were negatively enriched in CD4+ T cells from C57BL/6 mice. TF network analysis revealed unique TFs that have a role in autoimmunity, T cell activation, tolerance, and regulatory T cells. Conclusion Our data provide new insights into the transcriptomic profiles that may contribute to the genetic resistance mechanisms for developing cardiac autoimmunity. Funding Source 5R21AI142281-02 Topic Categories Basic Autoimmunity (BA)

Interrogating immune niches in a murine GBM model under radiation therapy 2335073

Abstract Introduction Adult glioblastoma (GBM) is the most aggressive primary brain tumor in adults, with a median survival of approximately 14 months. Standard of care, surgical resection followed by radiation therapy (RT) and temozolomide, has remained largely unchanged since 2005. A major barrier to therapeutic progress is limited understanding of how distinct immune populations within the tumor microenvironment (TME), particularly microglia and peripherally derived macrophages, respond to therapy. Methods We developed an immunocompetent, autochthonous adult GBM mouse model driven by EGFRvIII expression with loss of PTEN and CDKN2A. Tumor-bearing mice received a single 8 Gy dose of whole-brain radiation. Immune profiling was performed seven days post-treatment using immunohistochemistry, single-cell RNA sequencing, and spatial transcriptomics to assess myeloid composition and treatment-induced changes within the TME. Results RT-treated tumors exhibited reduced tumor burden compared to untreated controls, along with increased accumulation of IBA1+ myeloid cells. Single-cell RNA sequencing identified brain-resident microglia and peripherally derived macrophages as the dominant immune populations in both treatment groups. RT induced a relative enrichment of CD49d+ peripheral macrophages. Transcriptomic analyses revealed ontogeny-specific responses to RT, with peripheral macrophages enriched for inflammatory, angiogenic, and lipid-associated gene programs consistent with a disease-associated phenotype. Conclusion Ongoing spatial transcriptomic analysis using 10x Genomics Visium HD will spatially resolve microglia and peripheral macrophages within the TME and adjacent non-tumor brain regions. Together, this integrated approach defines myeloid heterogeneity in GBM and provides insight into how distinct immune populations respond to radiation therapy. Funding Source CIRM Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Distinct Humoral Response Development to Measles Virus across Vaccine Platforms 2251461

Abstract Introduction As measles incidences increase globally, it is imperative to elucidate the features of a protective humoral response. Methods In this study, a phage-display immunoprecipitation sequencing technology, VirScan, was employed to evaluate viral epitope coverage by antibodies raised to infection of rhesus macaques with wild-type (WT) measles virus (MeV), or after vaccination with a live-attenuated MeV vaccine (LAMV), the triple measles mumps rubella vaccine (MMR) or a novel recombinant MeV hemagglutinin protein-based vaccine (rMeVH). Vaccinated animals were also challenged with WT MeV to measure antibody epitope reactivity during a recall. Results The results demonstrate that WT MeV infection elicited antibodies with a broader epitope reactivity profile than LAMV-containing vaccines. The rMeVH vaccine not only resulted in a narrow H-protein specific antibody profile, but induced specificities that were distinct from those induced to WT MeV or LAMV. All vaccinated animals expanded the breadth of their MeV-specific antibody binding repertoires following WT MeV challenge. The MeV-specific VarScore, a measure of overall antigen-binding, was positively correlated with total IgG titers assessed by ELISA, avidity, and neutralizing titer. Conclusion These results demonstrate the large effects of vaccination platforms on the breadth and fine-specificity of anti-measles induced humoral responses. Funding Source NIH Topic Categories Vaccines and Immunotherapy (VAC)

Large-scale Network Analysis of the T cell Beta Chains in the AIRR Knowledge Commons 2309927

Abstract Introduction Biological networks (or graphs) are generic data structures where nodes represent biological or other entities and each edge connects two nodes to represent a relationship between them. Examples include sequence similarity networks with nodes being sequences and edges being a similarity (distance) score between the two sequences, and receptor-epitope specificity networks with receptors and epitopes as nodes where an edge between them indicates the receptor has specificity for that epitope. Analysis of the structure and composition of these networks can provide insight into the underlying biology. Methods We built and analyzed a set of networks for human T cell receptor beta chain (TCRB) sequences in the Adaptive Immune Receptor Repertoire Knowledge Commons (AKC). Starting with ∼357M TCRB junction AA sequences across all studies, subjects, diseases, and V/J genes, we acquired ∼169M unique sequences and built a similarity network for edit distance equal to 1. The resultant similarity network has ∼169M nodes and ∼1.7B edges. Results Analysis of the degree distribution shows that the similarity network does not follow a power law or a log-normal distribution (i.e., is not scale-free). Connected component analysis of the similarity network produces ∼32M components with ∼31M of those components comprising a single isolated node. The single largest component contains ∼131M nodes and, when excluding the isolated nodes, this component represents over 98% of the unique TCRB junction AA sequences in the AKC. This suggests the biological interpretation that, at the population level, many junction sequences are similar to each other. Conclusion We will analyze other large-scale networks built from the AKC and discuss their biological interpretation. In particular, we will incorporate epitopes with known receptor specificity and compare those receptor-epitope networks. Furthermore, we will partition and compare networks between subject demographics, diseases, and other study metadata. Funding Source The research described is supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health under award number U24AI177622. Topic Categories Computational and Systems Immunology (COMP)

Reprogramming the Immunosuppressive Microenvironment in Triple‐Negative Breast Cancer via FAP‐Targeted Nanoprobes for Multimodal Imaging and Photothermal Therapy

ABSTRACT Triple‐negative breast cancer (TNBC) poses a major clinical challenge because of its aggressive behavior, high likelihood of metastasis, and absence of specific therapeutic targets. The immunosuppressive tumor microenvironment, largely influenced by cancer‐associated fibroblasts (CAFs) through fibroblast activation protein (FAP)‐mediated extracellular matrix (ECM) remodeling and cytokine secretion, contributes to TNBC's resistance to immunotherapy. In response to this challenge, we have developed FAP‐targeted nanoprobes (FAP‐IR1061) that incorporate second near‐infrared (NIR‐II) fluorescence/magnetic resonance (MR)/photoacoustic (PA) imaging capabilities alongside highly efficient NIR‐II photothermal conversion for precision theranostics. This platform facilitates a tripartite therapeutic approach: (1) selective ablation of CAFs and dismantling of the ECM to overcome physical barriers; (2) spatiotemporal induction of immunogenic cell death through the release of damage‐associated molecular patterns; (3) functional repolarization of tumor‐associated neutrophils toward antitumor N1 phenotypes. When used in conjunction with anti‐programmed cell death protein 1 (αPD‐1) therapy, this strategy achieves over 80% suppression of both primary and distant tumors by enhancing the infiltration of cytotoxic T lymphocytes. Collectively, these effects promote the establishment of long‐term antitumor immune memory, which facilitates tumor eradication and prevents tumor recurrence.

Surface‐Selective Nucleation of Polymeric Resists for Bottom‐Up Nanofabrication

ABSTRACT Bottom‐up micro/nanofabrication complements photolithography in multilayer, 3D, and cost‐effective manufacturing, but lacks resist patterning technology with photoresist‐level reproducibility, processability, and universality. Here, we explore a surface‐selective nucleation (SSN) effect to derive polymeric resist patterns with nanoscale resolution, inherent 3D compatibility, low defect density, clean lift‐off, and broad applicability across fabrication platforms. The SSN phenomenon is achieved through solution‐phase polymerization of dual‐ended acrylic monomers on prepatterned substrates and surface‐mediated creation of area‐dependent nucleation barriers using adsorption inhibitors and chain terminators, which synergistically modulate surface and bulk free energy of nucleation, respectively. The resulting resist forms a coherent resin film physically adhered to the substrate, while featuring tunable thickness (13–150 nm) and minimal surface roughness (0.91 nm). This method delivers 15 nm linewidth patterning with 99.97% coverage across wafer‐scale arrays within 10 s and demonstrates high compatibility with mainstream thin‐film deposition techniques (e.g., e‐beam evaporation, sputtering, and atomic layer deposition).

Non-caveolar caveolin - 1 in retinal Müller glia promotes innate immune responses

A hybrid framework for occupational risk prioritization in construction projects using monte carlo simulation and utility theory

P-Glycoprotein induction in Plasma cells drives treatment resistance in Lupus Nephritis via IL-17/TAK-1/C/EBP-β pathway 2258946

Abstract Introduction Despite advances in lupus nephritis (LN) management, many patients fail to respond to first-line therapy or relapse after remission. Overexpression of P-glycoprotein (p-gp) on Plasma cells (PCs) and T-helper 17 lymphocytes (Th17) cells may contribute to disease activity and drug-resistant phenotype in LN. Objective Evaluation of role of IL-17 mediated pathway (IL-17/TAK-1/C/EBP-β pathway) in upregulation of P-gp expression in PCs and lymphocytes of LN and their contribution in the refractoriness to standard treatment. Methods The expression of P-gp on PCs and Th17 cells from LN patients were analysed. U266B1 plasma cells were treated with rIL-17, rIL-6+sIL-6R, or their inhibitors–anti-IL-6 plus anti-IL-17, IL-17 plus (5Z)-7-oxozeaenol (TAK-1 inhibitor), or IL-17 plus ST101 (C/EBP-β inhibitor). Plasma concentrations of NGAL, IL-17, IL-6, TNF-α, CXCL12, and CXCL13 were quantified by ELISA. Results 49 LN patients (refractory n = 11; active n = 20; inactive n = 18) and 15 healthy controls were studied. Frequencies of CD38+CD138+ PCs, and P-gp+ PCs, Th17, P-gp+Th17, were significantly elevated in refractory and active LN compared with inactive LN and controls, which decreased after 3 months of standard therapy. IL-17, IL-6, TNF-α, CXCL12, and NGAL levels were elevated in plasma and declined post-treatment (P < 0.001). In vitro, IL-6 + IL-17 stimulation induced P-gp expression in plasma cell line, In pre treatment strategy, expression of P-gp was significantly suppressed by anti-IL-6 + anti-IL-17, or by IL-17 inhibition combined with (5Z)-7-oxozeaenol or ST101.While, in the post treatment strategy, expression of P-gp was not significantly decreased when treated with anti-IL-6 + anti-IL-17 or IL-17 inhibition combined with (5Z)-7-oxozeaenol or ST101. Conclusion IL-17 upregulates P-gp via the IL17/TAK-1/C/EBP-β pathway, contributing to therapeutic refractoriness in LN. Targeting IL-17 signaling axis represent a novel therapeutic approach for refractory LN. Funding Source n/a Topic Categories Therapeutic Approaches to Autoimmunity (THER)

The impairment of MTCH2 accelerates autoreactive B cell expansion by enhancing Oxidative Phosphorylation in SLE 2307315

Abstract Introduction In systemic lupus erythematosus (SLE), aberrant B cell activation is fueled by elevated oxidative phosphorylation (OXPHOS), yet checkpoints restraining this metabolic hyperactivity remain undefined. We identify mitochondrial carrier homolog 2 (MTCH2),as a critical metabolic gatekeeper that limits OXPHOS-driven autoreactive B cell expansion and maintains germinal center (GC) tolerance in autoimmunity. Methods We analyzed metabolic profiles of B cells from SLE patients and healthy controls using scRNA-seq. B cell-specific MTCH2-deficient mice (Mb1-Cre; Mtch2fl/fl) were subjected to pristane-induced lupus. GC responses, BCR repertoire, and somatic hypermutation (SHM) were assessed by flow cytometry, and BCR sequencing. Mechanistic studies employed immunoprecipitation and GTPase activity to define the MTCH2—FUNDC2 axis, and a high-throughput screen identified a pharmacological agonist. Results B cells from SLE patients exhibited an OXPHOS signature and concomitantly downregulated MTCH2. B cell-specific MTCH2 deletion in mice exacerbated lupus, with expanded GCs, elevated autoantibodies. Sc-metabolic profiling revealed profound metabolic reprogramming across B cell subsets, with dark-zone GC B cells exhibiting the highest OXPHOS activity. This metabolic rewiring skewed the BCR, promoting the clonal expansion of autoreactive cells with excessive SHM. Mechanistically, MTCH2 governed mitochondrial dynamics via the FUNDC2—MFN1/2 axis which led to dysregulated mitochondrial fusion and B cell activation threshold. Pharmacological upregulation of MTCH2 by agonist restored mitochondrial homeostasis and ameliorated lupus in vivo. Conclusion We establish MTCH2 as a pivotal metabolic checkpoint that restrains autoreactive B cell expansion. Loss of MTCH2 disrupts GC tolerance, driving clonal dominance of autoreactive B cells and accelerating systemic autoimmunity. Targeting the MTCH2 axis represents a clinically translatable strategy to reinstate metabolic control and restore immune tolerance in SLE. Funding Source National Natural Science Foundation of China ( 82230060, 32141004, 32430036, 32441093) Topic Categories Basic Autoimmunity (BA)

JAM-A deficiency alters dendritic cell phenotype in a mouse model of food allergy 2333769

Abstract Introduction Food allergy is a growing health concern affecting over 220 million people worldwide. The intestinal epithelial barrier is crucial to food tolerance as its disruption can activate immune cells in the lamina propria and lead to allergic reactions. Junctional Adhesion Molecule A (JAM-A) is a key tight junction protein that maintains barrier integrity. Our previous work showed that JAM-A-/- mice had heightened anaphylaxis compared to wild-type (WT), with males exhibiting stronger Th2 responses than females. Methods Since JAM-A is also expressed on dendritic cells (DCs), we investigated how JAM-A on DCs impacts their differentiation and maturation. Bone marrow DCs from WT and JAM-A-/-mice were cultured with GM-CSF and then stimulated with TLR ligands. Results JAM-A-/- females display elevated IL-12, IL-6 and TNF expression, suggesting a Th1-skewed phenotype. In contrast, JAM-A-/- males exhibit higher MHCII, CD80, and CD86 expression than WT, indicating enhanced antigen-presenting capacity. In addition, naïve JAM-A-/- mice had increased frequencies of live lymph node DCs, indicating a potential role in T-cell priming. Conclusion Overall, our results suggest that BMDCs from male mice are skewed toward a pro-allergic Th2 response. Funding Source NIH Topic Categories Immediate Hypersensitivity, Asthma, and Allergic Responses (HYP)

Activation of formyl peptide receptor 2 enhances host defense against antifungal-resistant Candida glabrata 2258812

Abstract Introduction Opportunistic fungi such as Candida glabrata cause severe, drug-resistant infections in immunocompromised patients. Neutrophils are key to controlling candidiasis, but C. glabrata can evade their defenses. Enhancing neutrophil activity may therefore provide therapeutic benefit. The formyl peptide receptor (FPR) family, highly expressed in neutrophils, regulates their activation, but its role in fungal infection remains unclear. Here, we investigated whether the FPR2 agonist WKYMVm could boost host defense against antifungal-resistant C. glabrata under immunocompromised conditions Methods An immunocompromised mouse model was established using cyclophosphamide to mimic bloodstream infection with antifungal-resistant C. glabrata, and the therapeutic efficacy of WKYMVm was evaluated through survival, organ CFU, histology, and cytokine analyses. Emergency granulopoiesis was assessed by flow cytometry and qRT-PCR, autophagy by western blot and CYTO-ID staining, and neutrophil function and glycolytic activity by functional, metabolic, and molecular assays. Results WKYMVm administration improved survival in immunocompromised mice infected with C. glabrata, while reducing organ fungal burden and tissue damage. It increased neutrophil production and promoted autophagy-dependent maturation, yielding functionally active cells. Additionally, WKYMVm enhanced neutrophil immune functions through GLUT1-mediated metabolic activation, augmenting ROS production, degranulation, migration, and phagocytosis. Conclusion These findings indicate that FPR2 activation strengthens host defense against C. glabrata infection in immunocompromised mice by promoting neutrophil production, maturation, and functional activation. Overall, FPR2 activation represents a promising therapeutic approach for combating infections caused by antifungal-resistant fungi. Funding Source n/a Topic Categories Microbial, Parasitic, and Fungal Immunology (MPF)

Antibody-mediated intracellular neutralization as a correlate of risk for rotavirus gastroenteritis in vaccinated infants 2256577

Abstract Introduction Rotavirus vaccines are highly effective in high-income countries at reducing severe gastroenteritis, but show poor efficacy in low- and middle-income regions. The reasons for this discrepancy remain unclear, creating an urgent need for improved vaccines and reliable correlates of protection. Traditional serum IgA ELISAs and neutralization assays do not fully capture the breadth of antibody-mediated immunity to rotavirus. Mounting evidence suggests that antibodies targeting the internal capsid protein VP6 may mediate an additional intracellular layer of protection following viral entry, a mechanism not routinely assessed in vaccine evaluation. Methods We have developed a novel intracellular neutralization assay to measure antibody activity against internal rotavirus proteins exposed only after viral entry. Our assay was validated and optimized for human serum samples collected from infants enrolled in a phase III rotavirus vaccine trial. We evaluated intracellular neutralization as a correlate of risk for gastroenteritis in infants receiving the standard live-attenuated vaccine (Rotarix) compared to a candidate non-replicating rotavirus vaccine (NRRV). Results Infants vaccinated with Rotarix had a significantly higher intracellular neutralization response post-vaccination than those receiving NRRV. This finding contrasted with conventional neutralization assays, in which NRRV appeared superior. Importantly, Rotarix provided greater protection against clinical disease. Among Rotarix-vaccinated infants, intracellular neutralization was significantly boosted by vaccination in controls but not in those who developed gastroenteritis. Conclusion This intracellular neutralization assay captures a previously unmeasured component of antibody-mediated protection against rotavirus. We have demonstrated its value as a correlate of risk for rotavirus gastroenteritis in vaccinated human infants, and future work will evaluate its wider role as a correlate of protection. Funding Source PATH, Wellcome Trust Topic Categories Vaccines and Immunotherapy (VAC)

Engineered Nanobodies to Direct and Visualize Durable Tolerance 2260248

Abstract Introduction Current treatments for autoimmunity and allergy manage symptoms rather than cure disease. We propose a curative nanobody-based approach that selectively silences pathogenic responses to specific antigens/allergens while preserving protective immunity, i.e., durable antigen-specific immune tolerance. We also developed nanobody tools to map antigen processing and T cell responses in vivo, enabling precise visualization and quantification of tolerance induction at the molecular and cellular levels. Methods We developed an engineering-based solution using alpaca-derived nanobodies (VHHs) that recognize all MHC class II molecules (VHH MHCII). We covalently conjugated disease- or allergen-specific peptides-derived from myelin, insulin, and citrullinated collagen, as well as the model antigen ovalbumin (OVA) and house dust mite allergen to VHH MHCII together with the anti-inflammatory drug dexamethasone (VHH MHCII-antigen-DEX). Results A single dose of these trimodal conjugates induced durable, antigen-specific tolerance by promoting deletion, anergy, and regulatory differentiation of antigen-specific T cells. VHH MHCII-Myelin-DEX reversed experimental autoimmune encephalomyelitis, VHH MHCII-collagen-DEX halted arthritis progression, and intranasal delivery of VHH MHCII-OVA-DEX reduced OVA-specific IgG/IgE, mast cell activation, and airway inflammation. Conclusion This approach imposed long-lasting tolerance in prophylactic and therapeutic settings while maintaining systemic heterotypic immunity. Complemented by newly developed anti-idiotypic nanobodies specific for myelin- and OVA-specific TCRs, functionalized for fluorescence and positron emission tomography (PET) imaging, we achieved real-time visualization of antigen processing and tolerance induction. Together, these tools reveal how APC networks orchestrate tolerance and establish a modular platform for antigen- and allergen-specific immunotherapy. The available human-specific version of VHH MHCII enables translation to a clinical setting. Funding Source Boston Children’s Hospital Faculty Development and Pilot Grants, NIH R24OD035556, NIH R01AI182177, NIH R01CA255216, Breakthrough T1D Career Development Award, Lupus Research Alliance Innovative Award, Charles H. Hood Foundation Child Health Grant, Rheumatology Research Foundation Innovative Award, National Multiple Sclerosis Foundation Career Transition Fellowship, and American Lung Association & American Academy of Allergy, Asthma, and Immunology (AAAAI) Allergic Respiratory Disease Research Award Topic Categories Therapeutic Approaches to Autoimmunity (THER)

Inflammatory arthritis irAE may represent a unique autoimmune disease primarily driven by T cells, but likely not autoantibodies 2251377

Abstract Introduction The underlying immunopathogenesis of inflammatory arthritis (IA) immune-related adverse event (irAE) remains obscure. Unlike rheumatoid arthritis (RA), where autoantibodies and B cell dysfunction are central features, the contribution of humoral immunity to IA-irAE is unclear. Methods Here, we performed immunophenotyping of peripheral blood from IA-irAE patients, and compared them with seronegative RA patients, ICI-treated patients without irAE, and healthy controls. Results IA-irAE was marked with increased cytotoxic gene expression and metabolic activation in T cells, and reduced CXCR3 and CCR6 expression in CD4+ T cells. Contrary to seronegative RA, IA-irAE patients displayed no significant elevation in autoantibody levels or atypical CD11c+CD21⁻ B cells. IA-irAE was further characterized by elevated levels of IL-6, IL-12, and type I IFN, which correlated with the T cell activation phenotypes. Conclusion Altogether, our findings define IA-irAE as a disease with certain immunological features distinctive from RA, representing a potentially T cell driven, autoantibody-independent autoimmunity. These results offer insights into immune tolerance breakdown and therapeutic targeting in irAEs. Funding Source National Institute of Arthritis and Musculoskeletal and Skin Diseases Mark E. and Mary A. Davis Initiative in Rheumatoid Arthritis Research Mayo Foundation for Medical Education and Research Topic Categories Basic Autoimmunity (BA)