Browse Articles

High‐Entropy‐Induced Polarization Discontinuity Enabling Ultrahigh and Temperature‐Stable Energy Storage in Ceramic Capacitors

ABSTRACT The development of multilayer ceramic capacitors (MLCCs) with high‐energy storage performance over a wide temperature range is critical for practical applications but remains challenging. Here, we propose a high‐entropy design to disrupt the long‐range ferroelectric order of tetragonal tungsten bronze (TTB) ceramics, inducing a polarization discontinuity composed of coexisting polar nanoregions and non‐polar regions. This unique configuration delays polarization saturation while minimizing hysteresis loss through electrostatic interactions. Consequently, the TTB‐based MLCC achieves a high recoverable energy density ( W rec ) of 15.8 J cm −3 and an ultrahigh energy efficiency ( η ) of 97.5%, yielding a record‐high figure of merit of 632 J cm −3 for TTB‐based ceramic capacitors. Furthermore, the MLCC exhibits outstanding thermal stability from 25°C to 150°C, maintaining W rec ≈ 13.04 ± 0.41 J cm −3 and η ≈ 95.43 ± 2.61%. The high‐entropy‐induced polarization discontinuity offers valuable insights into polarization modulation and provides an effective strategy for designing next‐generation high‐performance dielectrics.

Effective graph resistance as cumulative heat dissipation

Neonatal Naïve CD8+ and CD4+ T Cells Exhibit Distinct Metabolic Profiles After Activation 2309657

Abstract Introduction Neonatal immune responses differ markedly from those of adults, partly due to distinct metabolic programs within immune cells. Because cellular function is closely tied to underlying metabolic pathways, defining these early-life programs is essential for understanding age-specific immunity. We previously showed that isolated neonatal naïve CD8+ T cells have greater glycolytic capacity than adult cells. Still, it is unknown whether these differences persist when T cells are assessed directly in the more physiologic context of whole-blood—derived white blood cells. Methods We compared metabolic function of neonatal (cord blood) and adult naïve CD8+ and CD4+ T cells in activated (PMA/ionomycin) RBC-lysed white blood cells using the SCENITH (Single Cell ENergetIc metabolism by profiling Translation inHibition) assay, which quantifies reliance on glycolytic and oxidative pathways for protein (and indirectly ATP) synthesis. We also evaluated transcription factor and effector molecule expression to relate metabolic states to functional characteristics. Results Neonatal CD8+ and CD4+ T cells showed significantly lower mitochondrial dependence and higher glycolytic capacity than adult counterparts. Neonatal CD4+ T cells also demonstrated reduced glucose dependence and increased ability to use fatty acids and amino acids as alternative substrates for ATP generation. These findings indicate a more glycolytic and metabolically flexible profile in neonatal T cells. Conclusion Neonatal T cells rely more on glycolysis, less on mitochondrial respiration, and display greater flexibility in substrate use to sustain protein synthesis. Defining these age-specific metabolic programs will help distinguish normal developmental trajectories from pathogenic immune responses and may inform future age-tailored immunotherapies. Funding Source NIAID Topic Categories Immune Response Regulation: Molecular Mechanisms (IRM)

Presentation by Virally Infected Cells of Antigenic Proteins Utilized in Natural Killer Cell Antibody-Dependent Cell-mediated Cytotoxicity (ADCC) 2256335

Abstract Introduction The presence of viral proteins in the plasma membranes of infected cells is essential for natural killer (NK) cell antibody-dependent cell-mediated cytotoxicity (ADCC). However, many enveloped viruses assemble inside cells rather than budding out through plasma membranes. Thus, the presence of viral proteins in plasma membranes of infected cells is uncertain, as is which of several viral structural proteins participates in ADCC. Their presence might represent leftover proteins after virion assembly. Methods To address external viral protein display and its sufficiency for antibody-dependent recognition, we utilized the endemic, cold-causing human coronavirus OC-43, a surrogate virus for SARS-CoV-2. We used NK-92-CD16A lymphocytes as killer cells, OC-43 from BEI, and infected, 51Cr-radiolabeled lung A549 cells as ADCC ‘targets’. Viral proteins were monitored by immunofluorescent microscopy. Antibodies to OC-43 included two monoclonal anti-spike S with human Fc’s, plasma from children who had OC-43 respiratory infections, rabbit affinity purified polyclonal anti-nucleocapsid N and S, and sera from unimmunized rabbits. Results We found that all the antibody reagents reacted with OC-43 infected cells by immunofluorescent microscopy. Labeling of external viral proteins was punctate. However, only the immune plasma and the non-immunized rabbit sera supported ADCC. The finding with anti-S was surprising since the human mAb 1249A8 anti-S could support Fc-receptor dependent phagocytosis of beads with S protein [PMID35862475]. The finding is consistent with PMID35587364, that SARS CoV-2 S was under-expressed in plasma membranes of infected cells and that depletion of anti-S from antisera from infected persons had negligible effect on ADCC. The finding with anti-N was surprising in light of PMID41060789. Conclusion Conclusions are premature but the data indicate that antibodies to the S protein alone are unlikely to support ADCC to coronavirally infected cells. Funding Source University of Nevada, Reno Foundation Award. Topic Categories Viral Immunology (VIR)

Spike-specific de novo CD8+ T cell clones exhibit robust effector phenotypes in the context of hybrid immunity 2252473

Abstract Introduction Repeated SARS-CoV-2 exposures through infections and vaccinations shape memory CD8+ T cell responses. While exposure history is known to affect CD8+ T cell differentiation, its impact on the TCR repertoire and phenotype remains unclear. Here, we analyze the TCR repertoires of SARS-CoV-2 spike-specific memory CD8+ T cells and their phenotypes in clone-dependent manner under various exposure conditions. Methods Two cohorts were enrolled: 1) individuals with infection followed by three doses of the mRNA vaccine (BNT162b2), and 2) individuals with three doses of the mRNA vaccine followed by Omicron BA.1 breakthrough infection. Antigen-reactive T cell enrichment (ARTE)-based multi-omic sequencing of spike-specific CD8+ T cells was conducted to analyze single-cell gene, protein, and TCR expressions. Results TCR repertoire analysis demonstrated that repeated antigenic exposures under hybrid immunity conditions boosted not only pre-existing “old” clones but also triggered the emergence of de novo clones. Additionally, analysis using the distance-based TCR clustering method (TCRdist) showed that de novo clones occupied a distinct region from old clones within the TCR similarity space. Phenotypic profiling showed that old clones, after repeated antigenic exposures, displayed more differentiated states, while de novo clones were less differentiated effector memory cells. Conclusion Our findings demonstrate that repeated antigenic exposures through infections and vaccinations promote differentiation of pre-existing clones. However, de novo clones can arise under hybrid immunity conditions and may functionally replace terminally differentiated pre-existing old memory clones. Funding Source n/a Topic Categories Viral Immunology (VIR)

Interrelationship of Peritoneal Fluid and Mesothelial Macrophages and Species-Specific Pathways in Their Maintenance and Repopulation 2306939

Abstract Introduction The peritoneal cavity is a clinically important immune niche that regulates serosal organ homeostasis and contributes to diseases such as peritoneal metastasis. It comprises a mesothelial surface and a fluid compartment, both enriched in macrophages. In mice, peritoneal macrophages include fluid large cavity macrophages (LCMs) and mesothelial macrophages (Mes.Macs), with mature LCMs defined by GATA6 and CD73 and thought to be replenished from monocytes through a linear LYVE1+ converting stage. However, how this paradigm applies to humans is unclear. Human peritoneal macrophages are predominantly LYVE1+ but lack GATA6 and CD73. Whether this reflects incomplete maturation, or a distinct differentiation pathway remains unknown, undermining the interpretation of murine models of human peritoneal disease. Methods Using spectral flow cytometry, fate mapping, bone marrow chimeras, and 3D imaging, we redefined peritoneal macrophage differentiation and cross-compartmental dynamics. Results We identified two parallel monocyte-LCM differentiation trajectories, overturning the prevailing linear model. A minor pathway (∼20% of monocytes) proceeds through a LYVE1+ converting stage and matures into CD73+ LCMs in a Zeb2-165 kb enhancer-dependent manner. In contrast, the dominant pathway in mice, absent in humans, bypasses the LYVE1+ stage, exhibits early CD73 expression, and directly generates GATA6+ CD73+ mature LCMs independent of the Zeb2-165 kb enhancer. We further show that fluid monocytes, but not LCMs, can differentiate into Mes.Macs in a Talin1-dependent manner, including tumor-associated Mes.Macs. Conclusion These findings redefine peritoneal macrophage ontogeny, reveal species-specific differentiation programs, and demonstrate dynamic exchange between fluid and mesothelial compartments. This work provides a framework for translating murine peritoneal immunity to human biology and highlights fluid-derived macrophages as key contributors to surface-associated pathologies such as peritoneal metastasis. Funding Source NIH/NIAID; NIH/NCI Topic Categories Hematopoiesis and Immune System Development (HEM)

Dual protein phosphatase promotes effector CD8+ T-cell persistence and tumor control 2241571

Abstract Introduction CD8+ T cell persistence is essential for long-term protection against cancer and infection. Immune checkpoint inhibitors improve cancer outcomes but still fail to sustain CD8+ T cell function under chronic antigen exposure. Kinases are well established in T cell-mediated tumor immunity, whereas protein phosphatases remain relatively unexplored. Here, we identify a dual protein phosphatase (DPP) that acts as a regulator of effector CD8+ T cell differentiation and persistence in tumor models. Methods DPP expression was higher in effector memory CD8+ T cells than in naïve-like and exhausted subsets across three cancer types. DPP deletion in CD8+ T cells reduced the maintenance of effector CD8+ T cells and impaired memory formation of CD8+ T cells after OVA vaccination, resulting in poor long-term tumor protection. Mechanistically, DPP deficiency in CD8+ T cells upregulated PI3K-AKT signaling and diminished FoxO1 activity, thereby limiting memory-like properties while promoting exhaustion and apoptosis. Results DPP expression was higher in effector memory CD8+ T cells than in naïve-like and exhausted subsets across three cancer types. DPP deletion in CD8+ T cells reduced the maintenance of effector CD8+ T cells and impaired memory formation of CD8+ T cells after OVA vaccination, resulting in poor long-term tumor protection. Mechanistically, DPP deficiency in CD8+ T cells upregulated PI3K-AKT signaling and diminished FoxO1 activity, thereby limiting memory-like properties while promoting exhaustion and apoptosis. Conclusion Our findings establish DPP as a novel regulator of CD8+ T cell persistence and memory formation, providing a strategy to improve the durability of cancer immunotherapy. Funding Source NRF-2022R1A2B5B03001431 Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

SMAD7-Mediated Modulation of TGF-β Signaling Drives the Emergence of ex-Tissue-Resident CD8 T Cells in Autoimmune Uveitis 2259507

Abstract Introduction Tissue-resident memory T cells (TRMs) maintain local immune surveillance, yet their persistence and potential for egress during autoimmune inflammation remain unclear. In autoimmune uveitis, recurrent flares imply dynamic circulation between the inflamed eye and peripheral blood. We hypothesized that dysregulation of TGF-β signaling within ocular TRMs could impair tissue retention and promote their release as circulating ex-TRM cells. Methods We performed paired single-cell RNA sequencing of vitreous and peripheral blood mononuclear cells from patients with autoimmune uveitis, focusing on shared TCR clones to delineate tissue—circulation transitions. Transcriptomic findings were validated by flow cytometry, cytokine assays to retinal autoantigen (IRBP), and antisense oligonucleotide knockdown of candidate signaling regulators. Results Shared CD8 T cell clones exhibited distinct compartmental signatures: vitreous clones expressed TRM-associated genes (CD69, ITGAE, ITGA1, CXCR6, ZNF683) and TGF-β—responsive regulators (PMEPA1, SMAD7), while circulating members re-expressed S1PR1, CCR7, and cytotoxic mediators, defining an ex-TRM phenotype. Flow cytometry confirmed CD8 ex-TRM and, to a lesser degree, CD4 ex-TRM cells in blood that responded to IRBP stimulation. Vitreous TRMs expressed higher SMAD7 and PMEPA1 than their circulating counterparts. SMAD7 silencing restored CD103 (ITGAE) expression, suggesting that SMAD7-mediated inhibition of TGF-β signaling reduces epithelial anchorage. Conclusion Our data reveal that SMAD7 suppresses TGF-β—driven retention cues, facilitating TRM egress from the eye into circulation as ex-TRM cells. This SMAD7—TGF-β axis defines a mechanistic link between tissue residency, egress, and systemic autoreactivity in autoimmune uveitis, highlighting a potential target for modulating chronic tissue inflammation. Funding Source DBT Wellcome Trust India Alliance, Hyderabad Eye Research Foundation Topic Categories Immune Mechanisms of Human Disease (HUM)

Structural basis of anti-MHC-I antibody blocking of inhibitory NK cell receptors in tumor immunity 2299676

Abstract Introduction Anti-MHC-I mAbs in human and murine systems can stimulate immune responses to tumors and infections by competitively blocking inhibitory signals delivered by MHC-I-specific inhibitory receptors of several inflammatory cell types (Panda, A.K. et al. J Immunol, 2020). Previous work showed that anti-MHC-I mAbs could activate immune responses by blocking the interactions of HLA with inhibitory receptors like leukocyte immunoglobulin-like receptors LILR (Panda, A.K. et al. Cancer Immunol. Res., 2025). Methods Here, we determined the structure of a broadly reactive anti-human MHC-I mAb, B1.23.2, in complex with the MHC-I molecule HLA-B*44:05 by both X-ray crystallography and cryo-electron microscopy (cryo-EM) (Jiang J. et al. Commun. Biol. 2025, in review) Results The determined structure revealed that B1.23.2 binds to a conserved region on the MHC-I molecule that overlaps with the binding sites for killer immunoglobulin-like receptors (KIRs), indicating the binding competition between anti-MHC-I mAb and KIRs. These studies prompted experiments evaluating B1.23.2 treatment in the human KLM-1 pancreatic cancer model using humanized (NSG-IL15) mice, providing evidence of tumor growth suppression by these anti-MHC-I mAbs. Conclusion We proposed a mechanism of anti-MHC-I mAb blocking NK cell inhibitory receptors, which is distinct from other checkpoint mAb mechanisms. These results provide new insights into the structural basis of how anti-MHC-I antibodies can be used in cancer immunotherapy by specifically targeting inhibitory receptor interactions. Funding Source This work was supported by the Division of Intramural Research, NIAID, NIH. Topic Categories Classical and Non-Classical Antigen Presenting Cells (APC)

Photoreforming and Photoelectroreforming of Waste‐Derived Feedstocks for Solar‐Driven Production of Fuels and Chemicals

ABSTRACT Photoreforming and photoelectroreforming have emerged as promising strategies for the solar‐driven valorization of waste‐derived feedstocks, offering a sustainable route to fuels and commodity chemicals. Unlike conventional thermochemical and biological processes, these photocatalytic and photoelectrocatalytic approaches operate under mild conditions, leveraging solar energy to activate complex organic substrates. Recent advances in artificial photosynthesis, including catalyst design, reaction engineering, and interfacial charge dynamics, have shown promise in improving selectivity and efficiency, yet fundamental challenges remain. Precise control over reaction pathways and suppression of undesirable side reactions remain difficult due to complex charge transfer kinetics, competing surface reactions, and limited stability under operational conditions. Addressing these challenges requires rational catalyst design to optimize charge transport, modulation of redox environments to enhance selectivity, and development of reactor architectures that maximize photon utilization and mass transfer efficiency. This review critically examines the mechanistic principles governing photocatalytic and photoelectrocatalytic waste valorization and discusses the central catalytic challenges. Finally, key challenges in process integration and scale‐up are assessed, and future directions are outlined for practical implementation of photoreforming in circular carbon and hydrogen systems.

Design Principles for Fluid Molecular Ferroelectrics

ABSTRACT Fluid molecular ferroelectrics are a new class of organic materials where ferroelectricity is found in conjunction with 3D fluidity whilst still retaining spontaneous polarization values comparable to their traditional solid‐state counterparts. One of the major challenges for soft condensed matter physics is predicting whether a fluid molecular material will form ferroelectric phase with nematic or smectic order. Through the synthesis of 45 systematically varied molecules, and by analogy to solid molecular ferroelectrics, it is shown that subtle hydrogen–fluorine (H/F) substitution(s) allows for tuneable syn ‐parallel pairing motifs resulting in either specific pairings, leading too geometrically constrained lamellar order, or diversified pairings, stabilising nematic ordering. Large‐scale, fully atomistic molecular dynamics simulations reveal that smectic ferroelectricity emerges from discrete lateral pairing modes, whereas nematic phases arise from a multiplicity of equivalent polar configurations. Together, these findings establish experimentally validated design principles for fluid molecular ferroelectrics and provide a predictive framework for engineering functional polar fluids.

Corisin induces proteostasis stress to drive epithelial injury and pulmonary fibrosis

A follicular helper-like program enables T cell tolerance to ingested antigen 2309672

Abstract Introduction Extrathymic T cell tolerance towards innocuous antigen is mediated by 3 complementary mechanisms: deletion, anergy and peripheral regulatory T cell (pTreg) induction. Recent studies suggest that a follicular helper T cell (Tfh)-like program underlies T cell tolerance; yet the mechanisms by which it influences anergy and pTreg differentiation remain poorly understood. Methods Key elements of Tfh program (PD-1 and BCL6) are knocked out in donor mice. We use a mouse model of antigen-specific oral tolerance whereby naïve donor chicken ovalbumin (Ova) reactive CD4+ T cells are adoptively transferred into secondary hosts which are then fed Ova ad libidum in drinking water. 7 to 21 days later, donor T cell responses are analyzed in mesenteric lymph nodes by flow cytometry and scRNA-seq. Results We demonstrate that CD4+ T cell anergy and pTreg are sequentially engaged, suggesting a two-stage process. First, T cells enter a multipotent ‘proto-anergic’ state, characterized by Tfh-ike features, most notably induction of BCL6 and PD-1 (Stage 1). Then, they proceed to terminal tolerogenic states, becoming either terminally anergic or pTreg (Stage 2). Strikingly, we found that tolerance is broken in the absence of PD-1 or BCL6; T cells fail to become anergic and proceed to effector differentiation. PD-1 is also required for pTreg induction, suggesting its key role in extrathymic T cell tolerance. We also learned that BCL6 promotes survival and stemness of T cells responding to ingested antigen, ultimately enabling them to take on terminal tolerogenic fates. Moreover, pTreg generated in the absence of BCL6 appear prone to losing FOXP3, indicating that BCL6 is required for lineage stability. Conclusion These data establish that cells responding to innocuous antigen acquire Tfh-like features, specifically expression of PD-1 and BCL6, which combine to mediate T cell anergy and pTreg development, thereby driving transition from Stage 1 to Stage 2 tolerance and, in turn, preventing deleterious effector responses. Funding Source n/a Topic Categories Immune Response Regulation: Cellular Mechanisms (IRC)

CMV-specific clonal expansion of Th1, GZMK+ CD8+, and TEMRA T cells revealed by human PBMC profiling 2257482

Abstract Introduction Cytomegalovirus (CMV) is a common herpesvirus that establishes lifelong latency and becomes increasingly prevalent with age. Methods We systematically characterized CMV-associated immune remodeling by analyzing six human cohorts (two newly built) using single-cell RNA sequencing, T cell receptor (TCR) sequencing, and flow cytometry. Results Beyond the well-known expansion of CD4+/CD8+ TEMRA, adaptive NK, and γδ T cells, CMV(+) adults exhibited increased frequencies of GZMK+ CD8+ T cells and atypical B cells, alongside a reduction of CD56dim NK cells. Longitudinal profiling of an individual who seroconverted revealed rapid CMV-driven shifts in circulating immune cell frequencies. Single-cell TCR data analyzed using a large database of CMV-associated clones combined with predictive modeling (CMVerify), identified novel CMV-specific clonal expansions reproducible across two independent cohorts. In the CD8+ lineage, CMV-specific clones were enriched in GZMK+ CD8+ and CD8+ TEMRA cells, while in the CD4+ lineage, Th1 cells showed clonal expansion alongside CD4+ TEMRA cells. Conclusion This integrative study revealed how latent CMV alters the cellular and clonal landscape, defining Th1 and GZMK+ CD8+ cells as newly recognized elements of the latent CMV response in humans. Funding Source Funding provided by the T32 Training Program in Precision Genetics of Aging, Alzheimer’s Disease and Related Dementias — (1T32AG062409-01A1) Topic Categories Computational and Systems Immunology (COMP)

Central role of IL-10 in CNS-protection from Inflammatory Damage during Cryptococcus Meningoencephalitis 2253926

Abstract Introduction Cryptococcus neoformans meningoencephalitis (CM) is a highly lethal fungal disease. Th1/IFN-g are crucial for fungal clearance but are also profoundly damaging in the brain. In CM patients with inflammatory syndromes (c-IRIS/c-PIIRS), elevated T-cell responses and elevated IFN-g in cerebrospinal fluid were markers of poor prognosis and brain damage. The cytokine IL-10 is one of the major anti-inflammatory factors produced by immune cells, but its role in CM and PIIRS is unknown. Methods Using an established murine model of CM/PIIRS, we applied fungal burden analysis, flow cytometry, immunofluorescence microscopy, and single-cell RNA sequencing to assess the effects of IL10 deficiency on inflammation and pathology during CM. Additionally, a murine coma and behavioral scale (MCBS) was used to assess neurological health. IL-10-/- mice were compared to wild-type C57BL/6 counterparts. Results Our investigation revealed that: 1) IL-10 is induced in the CM brain; 2) regulatory T cells are the major source of this cytokine in the brain. Compared to WT mice, IL-10-/- mice with CM exhibited: 1) drastically worsened weight loss and neurological status of the infected mice, inducing 100% mortality despite enhanced fungal clearance; 2) increased CD45+ leukocyte infiltration into the brain, with a notable expansion of T-cells; 3) enhanced activation and inflammatory cytokine (IFN-γ and TNF-α) production by CD4+ T cells in the CNS; and 4) accelerated recruitment of monocytes and increased iNOS upregulation in these cells as well as in the resident microglia. Pathological examination further revealed increased neuronal damage in IL-10-/- mice with CM with severe depletion of the synaptic protein Syt7 at the perimeter of cryptococcal lesions and intense staining of cleaved caspase-3 in neurons, a marker of neuronal apoptosis. Conclusion These results collectively indicate that IL-10 plays a critical role during CM as an essential immunoregulatory factor protecting the brain from inflammatory damage. Funding Source U.S. Department of Veterans Affairs to MAO (1I01BX000656) U.S.Department of Veterans Affairs to MAO (1IK6BX003615) Topic Categories Immune Response Regulation: Molecular Mechanisms (IRM)

Immune congestion drives dural sinus failure and lethal intracranial pressure in cerebral malaria 2308981

Abstract Introduction Cerebral malaria (CM) is a severe manifestation of Plasmodium falciparum infection affecting young children and causing hundreds of thousands of deaths each year in Africa. CM progresses rapidly after coma onset, creating a narrow therapeutic window for intervention. Because CM often fails to respond to antimalarial therapy and no adjunctive therapies exist, there is an urgent need to define disease mechanisms and develop fast-acting rescue strategies. Although infected red blood cells in cerebral vasculature were once thought to drive CM by obstructing blood flow, studies in a mouse model revealed a central role for CD8+ T cells in pathogenesis. Our work showed similarities between mice and humans in MRI-defined brain pathology and CD8+ T cell accumulation, supporting development of a therapeutic now in Phase I/IIa trials in African children. Yet it remains unclear how meningeal immune and vascular interactions initiate the rapid neurological decline and lethal intracranial pressure spike characteristic of CM. Methods Here, we combined intravital imaging, electron microscopy, light-sheet imaging, and immunohistochemistry to assess structural and immune cell-mediated changes in the endothelial cells of the dural venous sinuses that drain fluids from the meninges, brain, and skull. Results We identified immune cell-mediated changes in sinus architecture, porosity, vasodilation, and flow that precipitated intracranial pressure (ICP) elevation and death. Notable remodeling of sinus endothelial cell morphology and dynamic behavior occurred before clinical symptom onset, suggesting an early compensatory response to relieve immune congestion and stabilize ICP. As disease progressed, this compensatory capacity was exceeded, leading to abrupt loss of sinus regulation and neurological decline. Conclusion These findings reveal a key neurovascular failure point in CM and highlight a druggable meningeal interface for rapid therapeutic intervention to prevent fatal intracranial pressure crises. Funding Source Intramural research program of the National Institutes of Allergy and Infectious Diseases/NIH Topic Categories Neuroimmunology (NEUR)

Macrophage metabolic reprogramming facilitates viral entry and pyroptosis 2307659

Abstract Introduction The respiratory virus SARS-CoV-2 has posed a significant health burden since its emergence. The virus primarily infects and replicates in epithelial cells in the respiratory tract, but SARS-CoV-2 viral RNA has also been detected in macrophages isolated from patients with COVID-19. However, how SARS-CoV-2 enters macrophages remains unclear. Methods To address this gap, we assessed the metabolic changes that SARS-CoV-2 induces in monocyte-derived and tissue resident macrophages and how this affects transcriptional responses and viral entry. Results Our studies suggest that SARS-CoV-2 triggers a TLR2-dependent pathway encompassing IRG1, an enzyme that produces the metabolite itaconate, and NRF2, a transcription factor, which is necessary for effective viral entry into macrophages. Through this mechanism, SARS-CoV-2 induces the NRF2 gene target Macrophage associated receptor with collagenous structure (MARCO) for entry. MARCO is a scavenger receptor that is basally expressed by tissue-resident macrophages and facilitates efferocytosis of unopsonized particles and pathogens. MARCO expression increases in macrophages following SARS-CoV-2 treatment in a TLR2, IRG1, and NRF2-dependent manner. Furthermore, SARS-CoV-2 is unable to effectively enter MARCO-deficient macrophages, suggesting that MARCO serves as an alternative viral entry receptor. Our data shows that MARCO is required for pyroptosis following SARS-CoV-2 infection. In vivo, pre-treatment of mice with an anti-MARCO blocking antibody reduces the severity of COVID-19. To understand how MARCO expression is regulated during infection, I determined that anti-viral type I IFN negatively regulates MARCO via inhibition of NRF2. Conclusion Together, these novel findings suggest that SARS-CoV-2 metabolically reprograms macrophages to induce MARCO expression and promote viral entry and pyroptosis in the absence of IFN signaling. This work identifies a novel, druggable host-pathogen interaction that dictates the severity of respiratory virus infection. Funding Source NIH/NIAID T32 AI095213 Topic Categories Viral Immunology (VIR)

A Novel Balloon Procedure for Generating Physiologically and Clinically Relevant Orthotopic Colorectal Cancer Mouse Model 2259578

Abstract Introduction The tumor microenvironment (TME) plays a crucial role in influencing therapeutic interventions in colorectal cancer (CRC). Current CRC mouse models, like cecal-wall injection, develop tumors from the outer cecal wall instead of natural colon mucosa, thereby failing to mimic human CRC development and differing in tumor immune profiling. Methods Here, we present a non-surgical balloon procedure that induces localized mucosal abrasion to enable tumor cell adhesion, resulting in physiologically relevant tumors originating from the mucosal lining, like human CRC. Human scRNA sequencing data were used to analyze immune profiling in CRC patients. MSI-like and MSS-like tumors were generated using MC38 and CT26 cell lines in syngeneic mouse. Treatment was initiated 6 days after tumor cell inoculation. Results This method achieved high tumor success rates (70-100%) with minimal mortality and reduced invasiveness in both immunocompromised and immunocompetent mice. Interestingly, these tumors exhibited human CRC immune profiles, displaying immunosuppressive “cold” microenvironments in MSS-like tumors and immunogenic “hot” microenvironments in MSI-H-like models. Furthermore, these models faithfully recapitulate human therapeutic responses: a combination of 5-FU and anti-PD1 enhances anti-tumor immunity in MSS-like tumors by reducing immunosuppression, while anti-PD1 monotherapy restores cytotoxic T-cell function in MSI-H-like tumors. Conclusion This balloon procedure provides a highly reproducible and accessible platform for generating orthotopic CRC models that recapitulate human tumor physiology, the native immune TME, and therapeutic responsiveness, offering a valuable tool for translational research. Funding Source n/a Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Flow Cytometric Evaluation of SYTO 9 Green Staining in Empty and Loaded Lipid Nanoparticles Using the CytoFLEX nano Flow Cytometer 2302379

Abstract Introduction Lipid nanoparticles (LNPs) have emerged as nanoscale carriers for therapeutic agents, including mRNA vaccines and gene therapies. Accurate methods for characterizing nucleic acid encapsulation within these particles are essential for LNP development and quality control. This study presents an optimized flow cytometric protocol that uses SYTO 9 Green, a nucleic acid-binding dye, to differentiate and quantify nucleic acid-loaded versus empty LNPs with high sensitivity using the CytoFLEX nano Flow Cytometer. Methods We optimized a SYTO 9 Green staining protocol and applied it to empty and loaded LNP samples (Cytiva-sourced LNP1/LNP2 and UBC-sourced siRNA-LNPs). A sequential gating strategy was used to ensure single-particle detection by excluding debris and doublets. Dye titration experiments (ranging from 25 µM down to 3.125 µM SYTO 9 Green) were performed, along with critical controls, including unstained LNPs and SYTO 9 Green dye-only samples. Results Our results demonstrate that SYTO 9 Green staining enabled clear, concentration-dependent discrimination between loaded and empty LNPs. Loaded LNPs exhibited strong fluorescence signals, with positive staining efficiency peaking at optimal dye concentrations. Staining efficiency varies across concentrations, reflecting a complex interplay between dye-to-target binding, nucleic acid content, and potential quenching effects. In contrast, empty LNPs consistently showed minimal background staining (< 1% positive events). Unstained LNPs and dye-only controls presented negligible positive events, confirming that the observed signals are attributable to nucleic acid targets. Conclusion These findings highlight the combined use of the CytoFLEX nano Flow Cytometer and optimized SYTO 9 Green staining as a sensitive, robust approach for precise, multiparametric characterization of nucleic acid encapsulation in LNPs. Funding Source n/a Topic Categories Technological Innovations in Immunology (TECH)

Constructive Electroluminescence Interference for Ultra‐Efficient and Narrowband Perovskite‐Organic Tandem LEDs

ABSTRACT The integration of solution‐processed perovskite light‐emitting diodes (PeLEDs) with vacuum‐deposited organic light‐emitting diodes (OLEDs) in tandem architectures offers a promising pathway toward next‐generation displays. However, directly stacking electroluminescent units with dissimilar optoelectronic characteristics often results in electroluminescence losses and spectral broadening. To achieve efficient and narrowband tandem emission, we first develop high‐performance green PeLEDs as the bottom subunit through rational trap‐state management. By precisely optimizing device efficiency‐impedance matching, we realize synchronous operation of the PeLED and OLED subunits at their respective maximum efficiencies, producing constructive electroluminescence interference and yielding significant efficiency enhancement. Moreover, delicate regulation of the relative emission contributions ensures optimal spectral overlap and superposition, leading to markedly strengthened narrowband output. Using this strategy, tandem devices integrating PeLEDs with two representative OLEDs deliver record‐breaking external quantum efficiencies of 52.3% and 54.8%, with narrow full widths at half maximum of 22 and 24 nm, respectively. This work establishes a fundamental design principle for tandem light‐emitting diodes that simultaneously overcome limitations in EL efficiency and color purity in advanced display technologies.