Browse Articles

VERU-111 modulates gut microbiota and offers an advantage in colorectal cancer therapeutics 2252990

Abstract Introduction The global burden of colorectal cancer (CRC) has risen, positioning it as the third most common cancer worldwide. Chemotherapies are known to disrupt the composition of gut microbiota (GM) and lead to long-term health consequences for patients. How chemotherapeutic agents alter GM is not well known. We have shown that VERU-111 suppresses CRC tumors by inducing apoptosis and targeting myeloid PD-L1 expression in an AOM/DSS-induced model of CRC. Methods This study aimed to assess changes in the GM following VERU-111 treatment. We used 16S rRNA gene amplicon sequencing as well as a metagenomic study from fecal samples of different experimental groups to evaluate the alteration of GM. We also used computational tools to predict the functional potential of microbial communities based on 16S rRNA gene sequencing data. Results The administration of VERU-111 led to a restructured microbial community characterized by increased alpha and beta diversity as compared to AOM/DSS alone. Further, VERU-111 treatment significantly increased Verrucomicrobiota compared to the AOM/DSS alone. Akkermansia muciniphila was also elevated following VERU-111 treatment, which coincides with the increased CD8+ T cell population as well as reduced PD-L1-expressing macrophages in the colon as compared to control. Moreover, the relative abundance of Ruminococcus was also diminished, which is negatively correlated with immune checkpoint blockade therapy, while Muribaculum was notably increased following VERU-111 administration. An elevated abundance of Turicibacter was detected in the VERU-111-treated group compared to the control, showing a correlation with apoptotic activity and aligning well with our in vivo observations. The metagenomic study indicated that the microbial shift by VERU-111 was associated with suppression of several cancer-related pathways. Conclusion These favorable shifts in gut microbiota suggest a therapeutic dimension of VERU-111 in treating CRC and emphasize the need for further mechanistic exploration. Funding Source NIAID R01 AI140405 Topic Categories Tumor Immunology: Checkpoints, Prevention, and Treatment (TIPT)

Hysteresis‐Free Near‐Ideal Elastic Gels

ABSTRACT The mechanical properties of covalently crosslinked gels or elastomers stem from the crosslinking of the polymer chains and entanglement. Increasing the crosslinking density of covalent networks improves their entropic elasticity but also increases their brittleness. Addressing conflicts between rigidity and toughness, large strains, elasticity, and crack extension presents a challenging task. Here, we present a spatial crosslinking (SC) strategy utilizing a spider‐like crosslinker to materialize creep‐resistant, and low‐hysteresis hydrogels under substantial deformations ( ε = 6000%). The SC approach not only boosts the entropic elasticity of the hydrogels but also disperses stress arising from fractured polymers, leading to notable enhancements in fracture strain, toughness, and crack propagation strain (8200%). Furthermore, the SC hydrogels exhibit the remarkable ability to endure 99% of the ultimate compressive strain at the fully swollen state, along with rapid rebound and creep‐free capabilities, rendering them highly promising candidates for various applications such as drift‐free sensor, artificial blood vessels, and soft robotics.

Strain‐Induced Dynamic Surface Exchange in Ternary Alloy Nanosponges for Stable PEM Water Electrolysis

ABSTRACT The anodic oxygen evolution reaction (OER) in proton exchange membrane water electrolysis (PEMWE) struggles against a persistent trilemma: achieving low iridium loading without sacrificing activity or stability. To overcome this, we design ultrafine IrRuCu ternary alloy nanosponges featuring an “artery‐capillary” hierarchical mass‐transfer network, synthesized via surfactant‐assisted ethylene glycol reduction and selective etching. This catalyst exhibits a distinct gradient core‐shell architecture, where lattice mismatch from the Cu/Ru‐rich core triggers significant tensile strain in the outer active Ir shell. Integrating a series of comprehensive in situ characterization and DFT calculations, we uncover a novel, non‐destructive strain‐induced dynamic surface exchange mechanism. Tensile strain upshifts the Ir d ‐band center from −2.3 to −1.7 eV, amplifying the covalency and electrophilicity of surface Ir‐O bonds to assemble a dense hydroxyl network at open‐circuit potential. This geometric‐electronic modulation slashes the rate‐determining * O to * OOH barrier. Active surface oxygen directly accelerates kinetics, while rapid water refilling prevents bulk dissolution. Consequently, the alloy nanosponges require a 220 mV overpotential at 10 mA cm −2 , boasting a mass‐specific activity 59.2 times that of commercial benchmarks. Demonstrating over 4500 h of stability in industrial‐scale PEMWE full‐cells, this paradigm offers a compelling route toward economical green hydrogen.

Epitope mirroring between the malaria surface proteins PfGARP and PIESP2 identifies a knob-associated complex in infected erythrocytes

Prevalence and factors associated with conjunctivitis among patients attending an eye clinic at a regional referral hospital in Northern Uganda: a cross-sectional study

GC-independent B cells contribute to durable humoral responses and protection in mice 2309338

Abstract Introduction In mice, memory B cell heterogeneity has been established but there are no distinguishing markers based on GC-origin. How GC-independent memory B cells differ functionally from GC-derived memory B cells remains unclear. Utilizing mice models could help us better understand the memory B cells of different origins. Methods Antigen experienced IgD-IgM- B cells were sorted from Bcl6fl/fl and Bcl6fl/flCD4Cre mice and analyzed using sc-RNA seq. Antigen-specific B cells were tracked up to 6 months post immunization. GC-dependent and independent resting B cells were transferred to Rag2ko mice with follicular helper T cells and the recipient mice were immunized with the same antigen. B cells from Tcrb ko and WT mice were phenotyped. Finally, Bcl6fl/fl and Bcl6fl/flCD4Cre mice were immunized and challenged with homologous and sub-heterotypic influenza viruses. Results B cells could be grouped into 4 GC-independent and 2 GC-dependent clusters. GC B cells (GL7+CD73+) and 1 resting B cell cluster were depleted in the absence of germinal centers. Non-GC resting B cells contribute to durable antigen specific B cell populations at least 6 months after immunization. After reencountering the same antigen, both GC and non-GC antigen-experienced resting B cell populations were reactivated and gave rise to germinal centers and GC-independent reactions in Rag2ko mice. GC-dependent resting B cells and only one population of GC-independent resting B cells, were depleted in the absence of T cell help. Non-GC B cell responses were protective to challenges with the lethal dose of homologous and heterologous influenza strains after immunization. Conclusion This study establishes the GC dependent and independent B cell populations contributing to memory B cells and mature plasma cells. Further studies are required to understand the interplay between GC-linked and non-GC derived memory B cells which could inform new vaccine strategies and treatment modalities in autoimmunity and cancer. Funding Source n/a Topic Categories Lymphocyte Differentiation and Peripheral Maintenance (LYM)

Engineered Nanobodies To Induce and Visualize Antigen-Specific Tolerance in Rheumatoid Arthritis 2260631

Abstract Introduction Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by synovial inflammation, progressive joint destruction, and systemic complications. Current therapies are not curative and rely on systemic immunosuppression. This alleviates symptoms but leaves patients vulnerable to opportunistic infections and increased risk of certain cancers. RA pathogenesis is characterized by the loss of T cell tolerance and expansion of pathogenic B cells, both driven by the presentation of autoantigens by MHCII. Delivery of antigens to antigen presenting cells (APCs) under non-inflammatory conditions can impose tolerance., Methods: We present a novel strategy to selectively silence autoreactive T and B cell immune responses in a collagen-induced RA mouse model. We fused two immunodominant collagen-derived T and B cell epitopes and the corticosteroid dexamethasone to a single-domain antibody fragment (VHHMHCII) that targets APCs via their MHCII molecules. Results A single therapeutic administration of the trimodal construct halted disease progression and prevented paw swelling. Treated mice had significantly reduced pathogenic autoantibody titers against type II collagen, rheumatoid factor, and cyclic citrullinated peptide. Histological and immunohistochemical analyses revealed less fibrosis, necrosis, and edema, as well as diminished infiltration of macrophages and neutrophils. We confirmed improved cartilage preservation and reduced infiltration of pro-inflammatory T and myeloid cells. We further functionalized VHHMHCII with radioactive 89Zr. Positron emission tomography (PET) imaging employing radiolabeled VHHMHCII detected specific accumulation in secondary lymphoid organs and inflamed joints. Conclusion This suggests that the trimodal adduct acts in the inflamed joint and draining lymph nodes to impose peripheral tolerance. Engineered nanobodies to reestablish antigen-specific tolerance may provide a safer and more effective alternative to broad-spectrum immunosuppressive therapies for RA. Funding Source Rheumatology Research Foundation Topic Categories Classical and Non-Classical Antigen Presenting Cells (APC)

From Epitope to Therapy — Selecting the Right TCR 2259094

Abstract Introduction The effective design of T cell receptor (TCR)-based therapies — whether in a cellular or cell-engager format — is crucially dependent on the identification of TCRs with high specificity for the target MHC:peptide (MHCp) complex. This makes screening candidate TCRs for cross-reactivity towards off-target self-epitopes as well as ranking their affinity for the target (and off-targets) key activities on the path from epitope to therapy. Here, we present a novel, high-throughput assay for characterisation of TCR and TCR mimic molecules in terms of fine specificity (binding motif) and broader cross-reactivity towards unrelated epitopes. The assay can screen hundreds of MHCp complexes in a single run and enables easy access to essential TCR characteristics. In addition, the assay can be extended to include avidity measurements to allow TCR affinity ranking towards multiple targets. Methods TCR-coated beads were stained with pools of DNA barcode-labelled MHC Dextramer reagents carrying positional scanning peptide libraries or selected off-target peptides. Subsequent sequencing of the DNA barcodes associated with TCR binding revealed a detailed picture of the TCR binding preferences. By including MHCp complexes of known affinity towards the TCR, all MHCp could be ranked according to their TCR binding affinity. Results Using our high-throughput assay, we were able to simultaneously characterize five TCR molecules in terms of their fine specificity and cross-reactivity, while also ranking the affinity of each TCR towards the screened MHCp complexes. Conclusion Here, we demonstrate a novel assay for the characterization of TCR fine specificity, cross-reactivity, and affinity in a simple, high-throughput format. The assay enables easy assessment of TCR specificity towards MHCp complexes and is part of a larger pipeline of assays, which combines T cell/TCR discovery with TCR validation and characterisation, an essential part of the development process for TCR-based therapeutics. Funding Source Eurostars Topic Categories Technological Innovations in Immunology (TECH)

Enhancement of anti-Group A Streptococcus oxidative burst response in macrophages by polarization 2256833

Abstract Introduction Group A Streptococcus (GAS) is a human-specific bacterial pathogen that causes significant mortality during invasive infections. Human macrophages are one of the frontline defenders against GAS infection, limiting bacterial spread through phagocytosis and intracellular pathogen elimination. One mechanism macrophages use to kill bacteria is to produce reactive oxygen species (ROS). Unlike other bacterial species that can use antioxidants or enzymes to neutralize ROS, our data suggests that GAS has a novel ability to prevent ROS production altogether. Since GAS is sensitive to ROS, in this study, we aimed to increase macrophage ROS production by differentiating cells to M1 or M2 subtypes to overcome GAS ROS inhibition. Methods We first confirmed that stimulated, differentiated THP-1 macrophages produce more ROS compared to unstimulated THP-1 monocytes, but that GAS can still effectively repress ROS production. We next found that THP-1 macrophages polarized to the M1 subtype produce more ROS than the M0 and M2 subtypes, and that GAS repression of ROS was less effective in the M1 subtype. ROS production could not be upregulated in the U937 cell line, regardless of polarization. Results At early time points, THP-1 M1 macrophages more effectively eliminated GAS in intracellular killing experiments compared with M0 or M2 polarized THP-1 cells, which corresponded with the ability to produce ROS. Conclusion Overall, our results suggest that upregulation of ROS production by macrophage differentiation can enhance the ability of macrophages to kill GAS, identifying a potential route to target host cells as a treatment for GAS infection. Funding Source Fletcher Jones Science Scholarship at Occidental College Topic Categories Microbial, Parasitic, and Fungal Immunology (MPF)

miRNA-155 impacts neuroinflammation in a sex-dependent mechanism, dysregulation of the intestinal barrier, and dysbiosis 2258069

Abstract Introduction Multiple sclerosis (MS) is a chronic autoimmune and neurodegenerative disease caused by the host’s immune cells attacking the myelin sheath in the central nervous system (CNS). Recently, MS has been linked to significant modifications in gut microbial taxa and intestinal barrier dysfunction. Additionally, microRNAs (miRs), which are small, noncoding RNA regulatory sequences, influence immune cell differentiation and intestinal permeability. In the context of experimental autoimmune encephalomyelitis (EAE), a model of MS, miRNA-155 is overexpressed. Elevated levels of miRNA-155 have been shown to induce T cell differentiation into pro-inflammatory phenotypes and may also regulate the intestinal epithelial barriers. We hypothesized that increased miRNA-155 expression during EAE could lead to disruptions in the intestinal microenvironment. Methods In this project, we examined how miRNA-155 deficiency affects the MOG35-55 model of EAE in male and female C57BL/6 mice, along with its impact on EAE-induced intestinal barrier disruption and microbial dysbiosis. Results Global miRNA-155 deficiency triggered sex-dependent effects on EAE, with reduced severity in males. Moreover, miRNA-155 deficiency reversed the intestinal barrier disruption caused by EAE induction. Gut microbiota analysis revealed that, compared to wild-type controls, miRNA-155 deficiency resulted in significant alterations in gut bacterial composition, becoming more pronounced upon EAE induction. Furthermore, miRNA-155 was shown to directly modify the composition of bacteria isolated from the gut of healthy mice. Conclusion Our findings suggest early, prior to disease onset, sex-dependent effects on colonic transcriptomics and microbiota profiles in EAE mice, and that miRNA-155 plays a key role in regulating intestinal barrier function and microbiota, contributing to immune regulation in neuroinflammatory diseases. Funding Source Boise State University Topic Categories Mucosal and Regional Immunology (MUC)

A unique subset of allergen specific T helper 2 + 17 tissue resident memory cells is established in a mouse model of allergic inflammation 2257678

Abstract Introduction Asthma is one of the most common chronic respiratory diseases. Anamnestic inflammation in asthma is sustained by allergen-specific tissue-resident memory (TRM) CD4+ T cells. In addition to the Th2 pathway, components of the Th17 response have been identified as contributors to moderate and severe asthma. Of note, IL-17 — driven airway inflammation is resistant to steroids and to current treatment. A subset of antigen-specific CD4+ memory T cells co-expressing T helper 2 and T helper 17 markers (Th2 + 17 cells) is enriched in individuals with refractory asthma. Methods To investigate TRM2 cell heterogenicity in asthma, a well-established house dust mite (HDM) allergen model in mice was employed and Il13-Cre-mediated lineage-tracing of TRM2 cells was performed. Results Single cell RNA sequencing (scRNAseq) of lineage-labelled Th2-TRMs identified a major TRM2 subpopulation (Gata3+ only) and additional subpopulations that co-expressed specific markers of Th1 (TRM2 + 1), Th17 (TRM2 + 17), and Treg (TRM2+reg) lineages, which reveals significant heterogeneity of allergen-specific, Th2-TRMs in the lung. In addition, recent findings revealed that antigen-specific TRM2 + 17 cells persist in the mouse lungs for up to one year after HDM challenge and are reactivated upon subsequent allergen re-exposure. Conclusion Th2 + 17 TRMs represent a previously uncharacterized population with potential pathogenic relevance in chronic asthma. Follow-up experiments are investigating how genetic background and environmental stimuli influence the regulation and persistence of Th2 + 17 TRMs. By focusing on a novel TRM2 + 17 cell subset implicated in treatment-resistant asthma, our ultimate goal is to elucidate the mechanisms regulating this population to enable the development of effective therapeutics. Funding Source n.a. Topic Categories Immediate Hypersensitivity, Asthma, and Allergic Responses (HYP)

Interstitial macrophages prevent tuberculosis relapse by restricting Mycobacterium tuberculosis immune evasion 2333276

Abstract Introduction Tuberculosis (TB) is the deadliest infectious disease worldwide, causing approximately 1.3 million deaths every year. Infection with Mycobacterium tuberculosis (Mtb), the causative bacteria of this disease, most frequently results in latent tuberculosis infection (LTBI) due to a healthy immune system that can restrict bacterial replication and prevent disease. Macrophages are the predominant host reservoir of Mtb, so elucidating the mechanisms by which they are activated and modulated to impede Mtb growth and survival is vital in understanding the course of TB relapse. Interstitial macrophages (IMs) are recruited to restrict Mtb growth and limit immune evasion after alveolar macrophages, which are the first cells to encounter Mtb, fail to eliminate this pathogen. While IMs have been implicated in the control of acute Mtb infection, their role during LTBI remained unexplored. We hypothesized that IMs contribute to maintaining latency and that their depletion during LTBI would promote Mtb reactivation, leading to TB relapse and disease. Methods To investigate this, we utilized our mouse model of paucibacillary Mtb infection that mimics LTBI in humans by infecting mice with a genetically engineered and inducible Mtb strain that results in apparent sterilization. We used clodronate liposomes administered intravenously to selectively deplete IMs during LTBI. TB relapse was established three months post-depletion. Results IM depletion during latency led to TB relapse in 26% of mice compared to 2% in control mice. This transitory depletion of IMs led to a two-fold increase in the recruitment of neutrophils to the lung. Additionally, mice that relapsed exhibited an increased frequency of pro-inflammatory IMs and a reprogramming of the pulmonary cytokine milieu, with elevated concentrations of G-CSF, GM-CSF, IL-3, IL-12, IL-13, IL-17A and KC compared to control mice. Conclusion These findings indicate that interstitial macrophages play a critical role in controlling latent Mtb and preventing TB relapse. Funding Source Potts Memorial Foundation Fellowship, American Association of University Women International Fellowship Topic Categories Microbial, Parasitic, and Fungal Immunology (MPF)

Nano‐Antenna Reactors With Spatially Coordinated Microenvironments Enable Atmospheric CO ₂ Photoreduction to C ₂ H ₆

ABSTRACT Photocatalytic CO 2 reduction to multicarbon products is often limited by inefficient proton delivery to metal nanoparticle surfaces, restricting proton‐coupled C─C coupling to a small fraction of metal‐oxide interfacial sites. Here, we report a spatially coordinated microenvironment engineering strategy to activate underutilized metal surface atoms for efficient C 2 H 6 formation, even under low CO 2 concentration. An AuCu‐CeO 2 nano‐antenna‐reactor photocatalyst is constructed where CeO 2 nanosheets serve as oxide antenna supports and Au nanoparticles act as CO 2 reduction reactors. Notably, Cu sites incorporated within Au nanoparticles function as localized water‐activation centers, creating a proton‐rich microenvironment adjacent to CO 2 reduction sites. In situ spectroscopy combined with density functional theory calculations reveals that this proton‐rich microenvironment lowers the rate‐determining *CO to *COH protonation barrier from 1.23 to 0.54 eV, promoting C─C coupling via a *CO─*COH pathway. As a result, AuCu‐CeO 2 achieves a ∼3‐fold enhancement in C 2 H 6 production under pure CO 2 compared with Au‐CeO 2 , while maintaining appreciable rates of 3.3 and 1.67 µmol g −1  h −1 at flue‐gas (15%) and atmospheric (0.03%) CO 2 levels, respectively. This work establishes a general principle for regulating proton‐coupled multi‐electron transformations on catalytic surfaces.

1-Deoxysphingolipids require very-long-chain ceramide synthesis to induce ER stress and cytotoxicity

Serum homocysteine as a novel biomarker for predicting intestinal necrosis in patients with bowel obstruction: a prospective observational study

Shaping the Mitochondrial Powerhouse in Germinal Centre B cells 2309349

Abstract Introduction B cells within the germinal centre (GC) proliferate rapidly. Nonetheless, unlike proliferating T cells, GC B cells conduct minimal glycolysis. Instead, they rely on fatty acid oxidation to fuel mitochondrial OxPhos. Reflecting this, GC B cells show increased mitochondrial mass, transcription and translation. Interestingly, mitochondria also display morphological dynamism dictated by fission and fusion events. However, mitochondrial morphology in B cells is poorly defined. Given the role of mitochondrial metabolism in the GC, we hypothesise that mitochondrial morphology is important in GC B cells. Methods To characterise morphology, mitochondria from different B cell populations were imaged with SIM microscopy. To investigate mitochondrial fusion in GC B cells, we conditionally deleted genes enabling mitochondrial fusion, Mfn1 and Mfn2, in GC B cells using Aicda-Cre (henceforth Aicda-Mfn1&2). Mice were immunised with the model antigen NP-CGG and GC responses and metabolic profiles were analysed. Single cell RNA sequencing was performed on isolated GC B cells from control and Aicda-Mfn1&2 mice. Results Relative to naïve B cells, plasma cells possess fragmented mitochondria, whereas GC B cells have fused, interconnected mitochondria. Post immunisation, Aicda-Mfn1&2 mice developed reduced GC responses and impaired somatic hypermutation and plasma cell differentiation. Loss of MFN1 and MFN2 resulted in a shift towards glucose-dependent metabolism and altered amino acid metabolism. scRNA data highlighted increased transcription of Dhrs3, suggesting a decrease in retinoic acid (RA) signalling. Addition of RA to GC B cells was associated with changes in plasma cell differentiation, mitochondrial mass and ROS production. Conclusion We have shown that mitochondrial morphology is dynamically remodelled in B cell activation and differentiation. In GC B cells, mitochondria are fused, and this fusion is essential for a robust GC response by maintaining proper metabolic pathways and retinoic acid signalling. Funding Source Kennedy trust studentship Topic Categories Lymphocyte Differentiation and Peripheral Maintenance (LYM)

Antigen-specific CD8 T cells are primed in the bone marrow by migratory myeloid DCs bringing antigen from the brain following inflammatory injuries 2260619

Abstract Introduction Bone marrow (BM) is the primary immune organ responsible for stem cell maintenance. Neurotropic infections elicit sequestration of T cells within the BM. Changes of the BM niche during brain viral infections are unknown. Intracranial infection with the neurotropic Theiler’s Murine Encephalomyelitis Virus (TMEV) in C57BL/6 mouse is cleared by 30 days due to generation of an antigen-specific CD8 T cell response. Methods We used brain viral infection and injury models to test T cell responses against brain antigens in the bone marrow. Results We determined that 1-10% of CD8 T cells present in the sternal, femoral, and cranial BM were virus antigen-specific 7 days post intracranial infection. Over 70% of these CD8 T cells were tissue resident. We determined antigen-specific CD8 T cells were generated in the BM within 4 days of infection. Continuous treatment with FTY720, which sequesters T cells outside of the blood, did not eliminate antigen-specific CD8 T cells in any BM compartment. CD8 T cells in the BM established durable memory populations and were reactivated upon antigen reencounter. In the memory phase (200 days post brain TMEV infection), bone marrow resident CD8 T cell could be reactivated upon cognate peptide delivery. Such reactivation of antigen specific memory CD8 T cells caused an increase in lineage-, Sca-1+, ckit + (LSK) cells in the BM in a CD8 dependent manner. Similarly, injection of the model antigen AF488-conjugated OVA mixed with Poly IC into the brain recapitulated antigen specific CD8 T cell generation within the bone marrow and further demonstrated the antigen presenting cell involved in the response to be a CD103 expressing myeloid DC. We conclude that viral infections and inflammatory stimulation in the brain induce in situ effector and memory T cell responses within the BM which is associated with significant stem cell dysregulation. Conclusion Our data paves the way for crucial studies of BM resident antigen-specific CD8 T cells in health and disease. Funding Source NIH K99/R00 Topic Categories Viral Immunology (VIR)

Intranasal administration of a pan-reactive influenza antibody reveals Fc-independent mode of protection 2259232

Abstract Introduction Monoclonal antibodies protect through two core mechanisms: their antigen-binding fragment (Fab) directly binds and neutralizes viral antigens, while the fragment crystallizable domain (Fc) engages Fcγ receptors to activate immune effector functions. We investigated and segregated the relative contribution of each antibody domain to immune protection by comparing peripheral/systemic versus local/mucosal delivery within a mouse model of antibody prophylaxis against influenza virus Methods We performed intranasal versus intravenous delivery of CR9114, the broadest known human influenza antibody, which engages a conserved epitope on the hemagglutinin stem to provide protection against both influenza A and influenza B viruses within pre-clinical challenge models. Mice received either wild-type CR9114, Fc-silenced mutants (LALA, N297Q), or the bivalent antigen-binding F(ab’)₂ fragment alone (no Fc domain) 24 hours before lethal challenge with influenza A/H1N1, A/H3N2, A/H5N1, B/Yamagata, or B/Victoria viruses. Survival and weight change were measured to determine protection and median effective doses (ED50). Results Intranasal delivery of CR9114 resulted in an increase in potency against lethal influenza A/H1N1, A/H5N1, A/H3N2, B/Yam and B/Vic compared to intravenous administration, up to 50-fold. Systemic protection required an intact Fc domain, whereas intranasal protection remained strong even with Fc-silenced or Fc-depleted formats. The F(ab’)₂ fragment alone conferred full prophylaxis when delivered locally but was ineffective systemically. Conclusion These findings reveal that the route of antibody delivery determines its mechanism of protection. Local mucosal delivery achieves potent Fc-independent immunity, which was also seen in the absence of conventional neutralization activity, offering a new strategy for antibody-based prevention of influenza and other respiratory infections. Funding Source Leyden Laboratories B.V. Topic Categories Mucosal and Regional Immunology (MUC)

An Immunological Wildfire: Trichomonas vaginalis sparks pyroptosis in ectocervical cells 2257413

Abstract Introduction Trichomonas vaginalis (Tv) is a eukaryotic parasite that causes the most common sexually transmitted infection, trichomoniasis. Increased inflammation during Tv infection is predicted to drive comorbidities like cervical cancer, but the underlying inflammatory mechanism at play is unclear. Pyroptosis is a form of cell death that releases proinflammatory cytokines. It involves caspase-1 cleavage of Interleukin-1β (IL-1β) cytokine and gasdermin D (GSDMD), which generates a gasdermin N-terminal fragment (GSDMD-NT). GSDMD-NT oligomerization forms pores on the cell membrane, prompting cytokine release and cellular rupture. We hypothesize that Tv damages ectocervical epithelial cells (Ect1) via GSDMD-mediated pyroptosis. Methods To test whether Tv induces GSDMD-mediated pyroptosis, we generated Ect1 GSDMD-knockout (GSDMD KO) cells and measured cytolysis via lactate dehydrogenase assay. Furthermore, we assayed Ect1 GSDMD KO and WT cell supernatants for differential release of proinflammatory cytokines via enzyme-linked immunosorbent assay (ELISA). In parallel, we sought to identify additional microenvironment-altering proteins released via GSDMD pores during Tv-induced pyroptosis using quantitative proteomics and western blot analysis. Results Upon Tv infection, we noted a striking 25% decrease in cytolysis of GSDMD KO cells compared to WT. Furthermore, cell supernatant analysis via ELISA showed a dramatic 53% decrease in IL-1β and a 25% decrease in IL-18 cytokine release in GSDMD KO cells compared to WT. Finally, quantitative proteomics demonstrated the selective release of potential microenvironment-altering proteins via GSDMD-NT pores. We further validated the differential release of these proteins via western blots. Conclusion Collectively, we show that Tv triggers GSDMD-mediated pyroptosis in Ect1 cells. To our knowledge, this is the first evidence showing that Tv triggers pyroptosis in Ect1 cells and that female reproductive tract cells, not just immune cells, can undergo robust pyroptosis. Funding Source Rees-Stealy Research Foundation Fellowship Topic Categories Microbial, Parasitic, and Fungal Immunology (MPF)

Rapid Neurochemical Signaling from Regulatory T cells Reveals a Novel Dimension of Immune Modulation 2258988

Abstract Introduction Neurochemicals are key mediators of neuro-immune crosstalk, modulating communication between immune cells and neurons. Dysregulation of this bidirectional communication has been implicated in neuroinflammatory and neurodegenerative diseases. While immune cells possess the machinery to synthesize and respond to neurochemicals, the mechanisms and dynamics of neurochemical signaling, especially from T cells, remain poorly understood. Among T cells, regulatory T cells (Tregs) are crucial in maintaining immune homeostasis through well-established suppressive functions. However, their potential involvement in rapid neurochemical communication remains unexplored. This project addresses that gap by investigating the dynamics of neurochemical signaling from Tregs. Prior studies have shown that these neurochemicals can influence Treg function, suggesting a potential therapeutic approach for neurological disorders. Methods To characterize real-time neurochemical signaling from Tregs, we used fast scan cyclic voltammetry (FSCV) which offers excellent temporal and spatial resolution. The study also investigated activation-mediated neurochemical secretion on this timescale using both artificial and biological activators including ionomycin, phytohemagglutinin-L (PHA-L), and interferon-beta (IFN-β). To validate the FSCV findings, we used mass spectrometry for neurochemical identification, qPCR for gene expression analysis, and flow cytometry to assess the phenotype and activation state. Results Our findings demonstrated the first sub-second release of neurochemicals from in vitro cultures of Tregs, revealing the neuronal-like dynamics and providing insight into how different activation pathways influence sub-second neurochemical signaling. Conclusion This work establishes a framework for connecting sub-second neurochemicals fluctuations to changes in Treg activation, expands the current paradigm of immune regulation and lays the foundation for therapeutic targeting of neuroimmune interactions. Funding Source NIH R21AG086735 Topic Categories Immune Response Regulation: Cellular Mechanisms (IRC)