Browse Articles

CXCR5 Surface Marker Expression on Human Circulating Marginal Zone B cells (MZB) is Associated with Atherosclerotic Disease 2256242

Abstract Introduction Cardiovascular disease is the world’s leading killer, emphasizing the need for more effective prevention and treatment strategies. B cells are emerging as key players that modulate atherosclerosis, with recent work from our lab indicating that human circulating MZB produce atheroprotective IgM to oxidation specific epitopes (IgMOSE). However, what markers these cells express and their association with atherosclerosis is largely unknown. Methods To address this, we measured IgM by ELISA and ran a multispectral flow cytometry panel using 47 markers on 212 peripheral blood mononuclear cell samples from patients who had also undergone intravascular ultrasound with atherosclerotic plaque characterization. The mean fluorescence intensity of 15 markers was analyzed on circulating MZB (CD27+IgM+CD21+CD1c+) and correlated with IgM and plaque characteristics. Results CXCR5 on MZB was inversely associated with IgM and positively correlated with atheroma burden (%) which retained significance following adjustment for age, sex, and total cholesterol using multiple linear regression. CCR6, CD161, and ICOS were also found to have significant associations with atheroma burden (%), calcification (%) and necrotic content (%) (respectively) using the same multiple linear regression analysis. Conclusion Specific surface markers on circulating MZB associate with atherosclerosis and plasma IgM levels. Further research is needed to determine their functional significance and utility as clinical biomarkers. Funding Source R01 AI172112, P01 HL136275, R01 HL148109 Topic Categories Cytokines and Chemokines and their Receptors (CCR)

Type 1 conventional dendritic cell mitochondrial metabolism promotes adverse tissue remodeling after organ injury 2258277

Abstract Introduction Type 1 conventional dendritic cells [cDC1] are known for their role in antiviral and cancer immune responses, yet their function in the response to tissue injury, and underlying molecular mechanisms, remains unclear. A prominent feature of tissue repair is the clearance of dying cells by efferocytosis, which fuels mitochondrial metabolism in the phagocyte. Herein, we reveal the contribution of cDC1s to adverse tissue remodeling following organ injury. Further, we discover that mitochondrial metabolism in cDC1s contributes to the maladaptive response. Methods We studied a clinically-relevant model of tissue injury and performed left anterior descending artery ligation to induce myocardial infarction [MI] using Irf8 + 32-/- [cDC1-/-] and Xcr1cre QPCfl/fl mouse lines, which disables mitochondrial metabolism in cDC1s. Echocardiography was used to track heart function over time. Acute injury was assessed using vital dyes to measure ratio of ischemic injury to the area at risk during the acute stage of injury. We evaluated cell phenotype, location, and activation by flow cytometry of the heart, spleen, and mediastinal lymph nodes [mLN] and with single cell RNA sequencing. Results cDC1 populations increased in the mLN and heart 7 days post-injury. scRNA sequencing of DC-enriched mLN on day 7 revealed an increased ratio of both resident and migratory, activated DCs and a reduction of pDCs. Concurrently, there was a reduction in the number of CD8 T cells in the injured hearts of cDC1-/- mice, by flow cytometry. cDC1 loss was associated with improved cardiovascular function on day 28 with no change in injury or function on day 7. This improvement was recapitulated in Xcr1cre/+ QPCfl/fl mice. These data indicate that cDC1 mitochondrial metabolism mediates maladaptive chronic inflammation and long-term damage in the injured heart. Conclusion Our findings more broadly implicate cDC1 mitochondrial metabolism in a maladaptive role in the resolution of chronic inflammation following tissue injury. Funding Source T32 AI007476 Topic Categories Classical and Non-Classical Antigen Presenting Cells (APC)

Time Between Implantation and Electrode Array Design Inform Electrode Impedance Dynamics and Cochlear Immunity 2309163

Abstract Introduction Cochlear implantation (CI) outcomes can be limited due to immune-mediated foreign body responses. Previous research outlined the potential role of immunological memory in sequentially-implanted patients. Time between sequential CI and electrode array design may inform these relationships on the basis of possible long-lived memory cell decay and differential insertion trauma (thought to be greater with perimodiolar arrays), respectively. Using electrode impedance as a proxy for fibrosis, we hypothesize that longer time between CI leads to smaller increases and that perimodiolar arrays lead to higher increases in electrode impedance for the second CI. Methods Retrospective data for 79 subjects with sequential bilateral implants were obtained from the University of Iowa cohort. 12-month impedances (averaged across electrodes 5-22) were calculated and analyzed by time elapsed between implantation (six month increments) and electrode array design. Results 12-month average impedances in the first and second implant were positively correlated across all time groupings. Correlations demonstrated a bimodal strength variation across these groupings (0-6m, 0.6211; 6-12m, 0.5556; 12-18m, 0.0233; 18-24m, 0.9220; 24-30m, 0.5379; 30+m, 0.1067). A significant difference in 12 month average impedance in first versus second implant was found in perimodiolar arrays (p = 0.0020, (-936,-220Ω)) but not lateral wall arrays (p = 0.9148, (-808, 894Ω)). Conclusion Significant increases in electrode impedance were seen in perimodiolar, not lateral wall, arrays. This may be a function of differential tissue trauma upon insertion. Bimodal correlation strength variation seen in electrode impedances by implant sequence and time between CI may elucidate dynamics informing initial trauma versus delayed immunologic response with subsequent taper, though sample size is small. Further research is warranted to more fully characterize findings. Funding Source P50DC000242, R01DC018488, T35HL007485, and a Carver College of Medicine Summer Research Fellowship Topic Categories Neuroimmunology (NEUR)

Low dosage of a novel SARS-COV-2 mRNA-VLP vaccine elicits equivalent cell-mediated immunity to a licensed mRNA vaccine 2260043

Abstract Introduction mRNA-encoded virus-like particles (VLPs) are an emerging advancement in vaccine technology, enabling the self-assembly of viral antigens into structures that closely resemble native viruses. This innovative approach to conventional mRNA vaccination may boost vaccine-induced adaptive immune responses and allow for reduced dosing. To evaluate this technology, we developed AZD6563, an mRNA VLP vaccine targeting the COVID-19 XBB1.5 spike variant. Methods The phase 1 clinical study ARTEMIS-C was conducted to assess cellular immunogenicity in adults aged 18—64 years and ≥65 years following administration of AZD6563 (5 µg or 10 µg) or the licensed BNT162b2 XBB.1.5 mRNA vaccine (30 µg). Results AZD6563 drove spike-specific CD4+ and CD8+ T cell responses comparable to those elicited by higher dose of BNT162b2. Functional analysis of these cells revealed similar cytokine production profiles across groups; however, the 10µg dose of AZD6563 led to higher TCR diversity within the ≥65-year cohort. Notably, expansion of spike-specific B cells was most pronounced in the AZD6563 10µg group, with marked increases in cross-reactive XBB.1.5 spike-specific B cells that also recognized Omicron BA.4/5 and ancestral SARS-CoV-2 variants. Conclusion Collectively, these results demonstrate that AZD6563, at reduced doses, matches the cellular immunogenicity of BNT162b2 while enhancing B cell cross-reactivity and TCR diversity in older adults, supporting its potential as a next-generation COVID-19 vaccine candidate. Funding Source n/a Topic Categories Vaccines and Immunotherapy (VAC)

MAIT cells drive early hepatic fibrogenesis through a type-17 functional bias and reduced Treg cell buildup in the liver 2305794

Abstract Introduction Wound healing is a crucial process that occurs following tissue injury. While minor injuries typically resolve efficiently, more severe or repeated insults can lead to dysregulated repair and progression to fibrosis. In the liver, fibrosis can be initiated by a wide range of causes, including viral infection, alcohol, metabolic conditions, and autoimmune diseases. Mucosa-associated invariant T (MAIT) cells are a unique subset of innate-like T lymphocytes known to participate in tissue repair. However, their role in chronic liver injury and fibrosis development remains unclear. Methods To investigate the contribution of MAIT cells to hepatic fibrosis, we used the carbon tetrachloride (CCl4) mouse model in MAIT cell-enriched Mr1+/+ C57BL/6 (B6)-MAIT^CAST mice and MAIT cell-deficient Mr1-/- B6-MAIT^CAST mice. Mice were injected intraperitoneally with CCl4 or corn oil (vehicle) twice a week for 12 or 26 days to assess fibrosis progression over time. Results At day 12, CCl4-treated Mr1+/+ mice exhibited more severe liver injury, indicated by body weight loss and elevated serum alanine aminotransferase levels, compared to Mr1-/- mice. Histological analysis similarly showed increased myofibroblast activation and collagen deposition in Mr1+/+ livers at this early stage. These differences were not present at day 26, suggesting that MAIT cells predominantly influence early fibrogenesis. Flow cytometry further showed that hepatic MAIT cells upregulated PD-1 following CCl4 exposure and shifted toward a type-17 phenotype with increased IL-17A production. Moreover, CCl4-treated Mr1+/+ mice also displayed reduced hepatic regulatory T (Treg) cell accumulation compared with Mr1-/- mice, suggesting that MAIT cells suppress Treg cells during fibrosis development. Conclusion These findings identify a previously unrecognized MAIT cell—Treg cell axis that shapes a pro-fibrotic immune environment and highlight an early window in which MAIT cells act as key drivers of fibrogenesis Funding Source Cancer Research Society (CRS) Doctoral Research Award (co-funded by the Canadian Institutes of Health Research (CIHR)) Topic Categories Immune Response Regulation: Cellular Mechanisms (IRC)

Light‐Written Nonvolatile Polarization via Defect‐Engineered Charge Trapping

ABSTRACT Defect engineering offers a practical route to control interfacial charge states in polymer‐inorganic composites, yet translating this control into optically writable and non‐volatile polarization in soft dielectrics remains difficult. Here, we introduce a Polydimethylsiloxane (PDMS)‐based composite that can be written by light to form an interfacial polarization state. The design relies on FeTiO 3 (FTO) nanoparticles with oxygen‐vacancy associated trap states, whose density is tuned by spark plasma sintering to create a trap‐rich polymer‐oxide interface. Under illumination, photocarriers promote interfacial charge transfer by reducing the effective barrier at the metal‐composite contact, producing a rapid rise in interfacial charge accumulation. After the light is removed, a large fraction of the photoexcited electrons becomes immobilized, leaving a residual polarization that relaxes only slowly. We quantify the write‐relax behavior using a triboelectric nanogenerator configuration as a sensitive probe of interfacial charge transfer, and we directly visualize the photo‐written electrostatic state and its retention by Kelvin probe force microscopy. These results present defect‐mediated charge trapping as a materials‐level mechanism for light‐programmable, long‐retention polarization in soft composites, enabling remotely addressable electrostatic interfaces for soft electronic systems.

Selinexor Plus Ruxolitinib in Janus Kinase Inhibitor–Naïve Myelofibrosis: Phase III SENTRY Trial

PURPOSE Ruxolitinib improves splenomegaly and symptoms in myelofibrosis (MF) but lacks reliable clonal burden reduction. Selinexor, an oral inhibitor of exportin 1, has demonstrated activity in MF. We evaluated selinexor plus ruxolitinib versus ruxolitinib alone in Janus kinase inhibitor–naïve MF. METHODS In this double-blind, phase III trial, patients were randomly assigned (2:1) to receive selinexor plus ruxolitinib or placebo plus ruxolitinib. Coprimary end points were spleen volume reduction ≥35% (SVR35) and absolute mean change in total symptom score (AbsTSS; excluding fatigue) from baseline to week 24. RESULTS A total of 353 patients were randomly assigned. At week 24, SVR35 was achieved in 49.8% of the selinexor plus ruxolitinib group versus 28.0% of the placebo plus ruxolitinib group (difference, 21.8 percentage points; odds ratio, 2.58 [95% CI, 1.60 to 4.17]; P < .0001). Differences were evident by week 12 and through week 36. The AbsTSS coprimary end point was not met; however, symptom scores improved from baseline in both groups (−9.9 selinexor plus ruxolitinib, −10.9 placebo plus ruxolitinib), with no significant between-group difference. At a median follow-up of approximately 12 months, the overall survival (OS) hazard ratio was 0.43 ([95% CI, 0.19 to 1.00]; nominal P = .022). Grade ≥3 adverse events (AEs) occurred in 70.1% and 50.0% of patients in the selinexor plus ruxolitinib or placebo plus ruxolitinib groups, respectively, most commonly anemia, thrombocytopenia, and neutropenia. Nausea was more frequent with selinexor but predominantly low-grade and early. CONCLUSION In patients with JAK inhibitor–naïve MF, selinexor plus ruxolitinib met its coprimary end point of improved SVR35 but did not meet the AbsTSS coprimary end point, compared with placebo plus ruxolitinib. An early OS difference was observed. The safety profile was consistent with known AE profiles of the individual agents.

Polymorphism can extensively reshape the genome-wide crossover landscape in Arabidopsis thaliana

Post-COVID impairment of memory T cell responses to community-acquired pathogens is associated with underlying metabolic dysfunction 2304057

Abstract Introduction Infection rates involving bacterial and viral pathogens have increased precipitously after the COVID-19 pandemic, but why rates remain high today is unclear. Mitochondrial dysfunction is known to occur post-COVID and may disrupt immune responses. Within T cells, SARS-CoV-2 infection is linked to low mitochondrial membrane potential, increased mitochondrial apoptosis, and decreased mitochondrial respiration, which together impact cellular activation and function beyond the acute phase of illness. Here, we demonstrate that decreased mitochondrial function in T cells post-COVID may contribute to higher infection susceptibility by metabolically immobilizing T cell memory responses. Methods Using donor-matched peripheral blood samples from COVID-naïve individuals who subsequently contracted COVID-19, we tracked how influenza A (IAV), Staphylococcus aureus (SA), and varicella-zoster virus (VZV) T memory cell responses are impacted by SARS-Cov-2 infection using RNA-Seq and flow cytometry. Results We found that gene expression linked to T cell activation decreased but mitochondrial redox-pathway genes increased in CD4 memory T cells post-COVID. We also observed a disordered relationship between memory T cell mobilization of glycolysis, fatty acid metabolism, and oxidative phosphorylation pathways post-COVID. Conclusion Collectively, these findings indicate that COVID-19 infection may have lasting effects on inhibiting T cell memory responses to common community-acquired pathogens, with implications for the clinical care of immunologically vulnerable populations in the post-pandemic era. Funding Source Balvi Ops Grant B48 Topic Categories Immune Mechanisms of Human Disease (HUM)

Sustained Humoral Activation through self-amplifying mRNA Vaccination Enhances Longitudinal Antibody Function in a Phase III Trial 2305471

Abstract Introduction The development and deployment of mRNA vaccines during the COVID-19 pandemic was a landmark achievement in modern medicine and ushered in a new age of vaccine innovation. The vaccines strongly elicited both neutralizing and non-neutralizing antibody responses against the viral Spike protein, but these waned over time. Self-amplifying mRNA (sa-mRNA) vaccines such as ARCT-154 can prolong antigen production and durability of humoral immune response post-immunization and can thus be administered at a lower dose. How this translates into the overall humoral architecture compared to that shaped by conventional mRNA vaccinations is unclear. Methods We analyzed serum antibody responses from a Phase III trial comparing humoral responses elicited by ARCT-154 and mRNA BNT162B2 by systems serology. All participants had received three doses of mRNA COVID-19 vaccines and were randomized to receive a booster dose of ARCT-154 or BNT162B2. Primary outcomes were to quantify waning responses against ancestral SARS-CoV-2 Spike and a panel of antigenically drifted SARS-CoV-2 variant Spikes. Results We identified that the sa-mRNA vaccine ARCT-154 elicited a unique antibody response compared to BNT162B2 defined by a sustained, activating profile to the vaccine-encoded Spike protein and a broad spectrum of drifted Spikes. Notably, potently activating FcgRIIIA-binding antibodies showed a sustained stimulation in the ARCT-154-treatment arm, and this translated to enhanced antibody-dependent natural killer cell activation (ADNKA) to both target WT Spike and the antigenically drifted BA.5 Spike, which was the predominant form of SARS-CoV-2 during the observation period. Conclusion Recipients of the sa-mRNA booster showed a temporally sustained humoral activation and an overall antibody architecture that favored pro-activating phenotypes. Our results support a model whereby prolonged antigen expression and presentation moves immune profiles towards activating phenotypes with broad antigenic coverage. Funding Source Bill and Melinda Gates Foundation INV-080712 Topic Categories Vaccines and Immunotherapy (VAC)

PI3K Delta Inhibition Alters CD8 T Cell Différentiation and Reprograms the Tumor Microenvironment Following Adoptive Immunotherapy 2247548

Abstract Introduction T cell exhaustion limits the durability of adoptive cell therapy (ACT) in solid tumors. Because PI3Kδ signaling governs T cell differentiation, we hypothesized that transient, high-dose PI3Kδ inhibition would endow T cells with durable stemness and metabolic fitness to resist terminal exhaustion and alter the immune composition of the tumor microenvironment (TME). Methods Mouse and human T cells were treated in vitro with the PI3Kδ inhibitor CAL-101 (30 uM) prior to chronic antigen stimulation and ACT into B16 melanoma. Metabolic fitness was assessed by mitochondrial dependence and spare respiratory capacity. Single-cell RNA sequencing and spatial transcriptomics profiled T cell states, spatial localization, and TME remodeling post ACT. Pathway analyses interrogated oxidative phosphorylation (OXPHOS), glycolysis, proliferation, inflammatory signaling, and myeloid composition. Results CAL-101—treated T cells acquired enhanced stemness and metabolic fitness, with increased mitochondrial dependence and spare respiratory capacity while maintaining normal basal metabolism. Under chronic stimulation, including in human T cells, they resisted terminal exhaustion and preserved stem-like properties. In tumors, treated cells preferentially differentiated into progenitor exhausted T cells (Tpex), displayed superior infiltration, and upregulated the Cxcl10/Cxcr3 axis. Tumors harboring CAL-101—treated T cells showed reduced glycolysis, OXPHOS, and proliferation alongside increased pro-inflammatory signaling and fewer immunosuppressive tumor-associated macrophages. Single-cell analysis revealed CAL-101 treated T cells concurrently increased OXPHOS, proliferation, and immune signaling pathways. Conclusion Brief PI3Kδ inhibition programs T cells with stemness and metabolic fitness that favor Tpex differentiation, resist terminal exhaustion, and remodel the TME toward an inflammatory state, supporting a practical strategy to improve ACT efficacy in solid tumors. Funding Source NIH RO1 grant: CA257954, Dartmouth TQCR Training Grant: T32CA260626 Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Defining the Role of HDAC3 Enzymatic vs. Adaptor Function in T Cells 2258602

Abstract Introduction Generation of T cells requires dynamic epigenetic alteration of histones to control gene expression at each developmental stage. Histone acetyltransferases (HATs) and histone deacetylases (HDACs) facilitate addition or removal of various acyl groups from lysine residues, including acetylation (KAc) and crotonylation (KCr). The Class I deacetylases HDAC1, HDAC2, and HDAC3 have been shown to have 3 functions: adaptor, decrotonylase, and deacetylase activity. The relative importance of each function in T cells is not known. Genetic knockout of HDAC3 in mice using CD2icre results in a severe block in T cell development and spontaneous development of severe colitis. Our lab determined that HDAC3 is required for three different aspects of this process: CD4+CD8 + (DP) cell survival, positive selection, and CD4+ lineage commitment. We generated a novel mouse model with CD2icre-mediated deletion of endogenous HDAC3 and linked re-expression of HDAC3 “VRPP” mutant mice, which maintained adaptor function but lacks enzymatic activity. Strikingly, these mice do not develop spontaneous colitis even up to one year of age. Methods We used flow cytometry to assess T cell development and maturation in the thymus, spleen, mLN, and colon of HDAC3 cKO vs. HDAC3 VRPP mice. CUT&RUN was utilized to determine differences in H3K9Ac, H3K27Ac, and H3K18Cr across CD8 and CD4 lineage genes. H&E was utilized to assess structural changes in thymus and colon. Results Similar to CD2icre HDAC3 cKO mice, HDAC3 VRPP mice have a block in positive selection due to failure to down regulate RORγt and decreased DP cell survival due to increased expression of P2RX7. Although fewer T cells are produced in HDAC3 VRPP mice, CD4+ lineage commitment is restored, likely mitigating the development of spontaneous colitis. Conclusion Our results demonstrate that HDAC3 enzymatic activity is necessary for several aspects of T cell development, while HDAC3 adaptor function is sufficient to restore CD4+ lineage commitment. Funding Source NIAID RO1 AI150100, T32 AI170478 Topic Categories Hematopoiesis and Immune System Development (HEM)

Spatial colocalization of neoantigen-expressing tumor cells and cognate T cells in cancer 2309241

Abstract Introduction Tumor neoantigens have emerged as promising candidates for personalized immunotherapies, however, confirming their presentation and immunogenicity remains challenging due to low neoantigen expression and limited detection sensitivity. Moreover, the spatial organization of neoantigen-specific T cell clones relative to their target tumor cells and other cell types within the tumor microenvironment remains incompletely defined due to technological limitations. To bridge this gap, we developed Slide-GoTags. Methods Slide-GoTags integrates single-nucleus spatial transcriptomics with targeted genotyping and TCR sequencing from a single 20 µm tissue section. Slide-tags spatial barcoding and the 10x Genomics 5’ droplet-based platform are followed by targeted RNase H—dependent PCR and long-read sequencing, enabling genotypes and TCR repertoires to be linked to gene expression profiles and spatial coordinates via shared cell barcodes. Results Slide-GoTags was applied to murine and human tumors, revealing colocalization of clonally expanded, neoantigen-specific T cells with tumor cells expressing their cognate neoantigen, validated by known neoantigen-TCR pairs. T cell functional state and clonotype avidity were linked to neoantigen proximity. Moreover, we identified IFN-γ—rich immunogenic niches consistently enriched for neoantigen-specific progenitor-exhausted T cells, marked by enhanced local T cell activation, clonal expansion, and immune-modulatory interactions with antigen-presenting cells within the TME. Spatially resolved receptor—ligand analysis revealed co-stimulatory and inhibitory interactions that shape immune engagement and regulation within these niches. Conclusion In this study, we define the spatial architecture of neoantigen directed T cell immunity shaped by proximity to neoantigen expressing tumor cells, TCR avidity, and receptor-ligand interactions within tumors, providing a framework for spatially informed TCR deorphanization and the development of personalized T cell therapy. Funding Source This work was supported in part by the NIH/NCI (CA276865), the Mark Foundation for Cancer Research Endeavor Award, the Dana-Farber/Harvard Cancer Center Kidney SPORE (P50CA101942), and the Dana-Farber/Harvard Cancer Center Support Grant (P30CA006516). A.N Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Investigating the Role of Interferon Signaling in the Malformation of the Down Syndrome Lung 2260174

Abstract Introduction Down Syndrome (DS) is the most prevalent chromosomal abnormality worldwide, affecting 1 in every 700 live births. Although typically noted for its neurological implications, individuals with DS exhibit severe pulmonary malformations as well, including poor branching, impaired alveolar formation, and low lung mass. The triplication of chromosome 21 (HSA21) in DS results in the overexpression of several immunological genes found on HSA21, including four of the six interferon (IFN) receptor genes. Increased IFN receptor expression constitutively activates the IFN signaling pathway, fostering an antiproliferative environment during development. Given that dysregulated IFN signaling has been linked to impaired cardiogenesis in DS mouse models, we hypothesize that hyperactive IFN signaling similarly impairs human pulmonary development. Methods Although mechanistically useful, animal models prove incomplete in fully recapitulating a chromosomal disorder such as DS. Thus, we have utilized Trisomy HSA21 (T21) induced pluripotent stem cells (iPSCs) to establish a DS Branching Lung Organoid (BLO) model that recapitulates key hallmarks of pulmonary development, including branching, budding, and epithelial differentiation. Using this model, we aim to investigate how dysregulated IFN signaling contributes to pulmonary malformation in DS. Results iPSCs derived from an individual mosaic for DS, providing both diploid (D21) and triploid (T21) isogenic cell lines, were used to generate BLOs. We hypothesize that T21 induces impairments to healthy BLO morphogenesis that can be corrected when proper IFN signaling is restored. Conclusion Given that the lungs continue to form through early childhood, interventions given to infants immediately following birth have displayed efficacy in facilitating healthy pulmonary development. Thus, studying how lung malformations arise in the development of DS may offer insight into restorative therapies for these individuals, ultimately curbing high pulmonary associated mortality. Funding Source R01HL165259-03S1 Topic Categories Cytokines and Chemokines and their Receptors (CCR)

DEC-205—Targeted Antigen Delivery Enhances T Cell Immunity in a Murine Model of West Nile Virus Encephalitis 2260788

Abstract Introduction Targeted immunotherapies aimed at enhancing antiviral T cell responses are of particular interest for treating neurotropic viral infections such as West Nile Virus (WNV), which lacks a licensed human vaccine. Previous studies have shown that DEC-205+ dendritic cells (DCs) in the central nervous system (CNS) play a role in reactivating antiviral immunity during WNV infection. Methods Methods to investigate this: a hybrid scFv antibody targeting DEC-205 and conjugated to a peptide from the WNV NS4b protein was administered to mice infected with WNV-TX. Poly I:C was co-delivered as an adjuvant to promote DC maturation. Immunological outcomes were assessed by quantifying co-stimulatory molecule expression (CD40, CD80, CD86) on DCs and evaluating T cell activation markers and cytokine profiles. Results Mice receiving the DEC-205—NS4b scFv showed increased expression of activation markers and higher levels of pro-inflammatory cytokines, suggesting enhanced antiviral immunity. Conclusion These findings support targeted DC-based strategies as a promising approach for future WNV vaccine development. Funding Source Cal Poly Pomona Project Hatchery Topic Categories Immune Response Regulation: Cellular Mechanisms (IRC)

Rethinking Cardiovascular Events, End Points, and Surveillance in Oncology Trials

High-throughput engineering of bispecific antibodies to enhance macrophage-mediated cytotoxicity of B-cell lymphoma

Abstract Macrophages are critical effectors of antibody therapies for lymphoma, but the best targets to engage their function remain unknown. Here, we develop a ‘tactical surfaceome profiling’ strategy to define a comprehensive repertoire of surface antigens on B-cell lymphoma that can be targeted with antibodies to provoke macrophage attack. Across both mouse and human systems, we identify multiple unappreciated targets of opsonization as well as putative immune checkpoints. We incorporate this information into a high-throughput engineering strategy, creating 156 bispecific antibodies and identifying dozens that stimulate macrophage-mediated cytotoxicity. A heterodimeric scFv-Fc format enables our approach; it is superior to conventional bispecific antibody design and offers enhanced activity while reducing developmental complexity. Among the therapeutics we create, a bispecific comprising a SIRPα decoy domain and a CD38-targeting arm (WTa2d1xCD38) exhibits maximal efficacy with reduced risk of toxicity. This bispecific stimulates robust anti-tumor responses in xenograft models of aggressive B-cell lymphoma and shows benefits over anti-CD20 antibody rituximab. Our approach can be applied to other cancers to leverage anti-tumor responses by macrophages or other immune cells.

Characterizing Immune Cell Sexual Dimorphism in Intracranial Aneurysm via Rat IA Model and Spatial Transcriptomics 2306413

Abstract Introduction Intracranial aneurysm (IA) prevalence in the general population can be as high as 3%. Most IAs are diagnosed incidentally. However, IAs can cause subarachnoid hemorrhage and are responsible for high mortality and morbidity. No effective medical therapy is available for IA. Female sex is a known risk factor for IA formation and rupture. In addition, the rupture risk escalates in postmenopausal women, suggesting that low estrogen level promotes ruptures. This study investigates whether immune cell sexual dimorphism in IA exists and whether it promotes IA formation, growth, and rupture. Subsequently, the study will evaluate how low estrogen exacerbates aneurysms by defining the responsible pathways. Methods We will perform spatial transcriptomics (GeoMx DSP) on formalin-fixed, paraffin-embedded aneurysm tissues from established rat IA models that can reproduce human pathology. The study comprises six groups, each containing three rats: the control male and female groups, the male and female aneurysm-induction groups, the induction after ovariectomy group, and the induction after ovariectomy and hormone replacement group. The GeoMx morphology markers are CD68, α-smooth muscle actin, and androgen receptor. The findings will be validated in human IA tissues from both sexes using single-cell spatial transcriptomics. Results The preliminary data demonstrate CD68+ macrophages infiltrating a male aneurysm on GeoMx immunofluorescent images. Two male control arteries showed no infiltration. The study aims to identify sexual dimorphism in macrophages by analyzing ontogeny, transcriptomic profiles, and interactions with lymphocytes, such as Th17 CD4+ T cells. The study also examines the relationships among other innate and adaptive immune cells in the context of IA, across sex and hormonal status. Conclusion Understanding the immune cell sexual dimorphism and its contribution to IA will aid the development of therapeutics tailored to women and postmenopausal women, who experience the greatest disease burden. Funding Source Joint support from Seoul National University College of Medicine Physician Scientist Training Program and the MD-PhD/Medical Scientist Training Program through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea. Topic Categories Translational and Interventional Immunology (TI)

GATA3 expressing CD4 T cells promote intestinal graft-versus-host disease 2306818

Abstract Introduction Hematopoietic cell transplantation (HCT) is a curative therapy for blood cancers but is complicated by graft-versus-host disease (GVHD), where donor CD4+ T helper (Th) cells drive gut pathology. Defining factors that drive pathogenic Th cell differentiation in the gut promises to inform therapies that mitigate GVHD without impacting the beneficial anti-cancer activity of HCT therapy. In our work, we identified GATA3 as a key transcription factor that may facilitate the development of gut pathogenic Th cells after HCT. We hypothesized that Th cell deletion of GATA3 will impair pathogenic Th cell differentiation and improve clinical outcomes in a murine GVHD model. Methods Using a murine allo-HCT model, we transplanted T cell-depleted bone marrow from WT C57BL/6 donors and splenocytes from C57BL/6-Gata3fl/fl Rosa26ERT2-Cre donors into irradiated BALB/c recipients. Donor cell GATA3 deletion was induced via tamoxifen treatment of recipient mice. Disease severity, intestinal pathology, donor cell trafficking, cytokine/granzyme expression, and innate immune infiltration were assessed by clinical scoring, histology, flow cytometry, and ex vivo Th cell stimulation. Results GATA3 deletion reduced intestinal GVHD pathology and impaired early donor T cell trafficking and persistence in the gut. While IFN-γ and IL-17A production were largely unaffected in early timepoints, GATA3 was required for heightened granzyme A expression, sustained GM-CSF production and chronic GM-CSF-driven intestinal eosinophilia at later timepoints. Analysis of human GVHD samples exhibited enrichment of eosinophil chemotactic pathways, mirroring murine findings. Conclusion GATA3 promotes intestinal GVHD by supporting donor T cell gut infiltration, granzyme A expression, and sustained GM-CSF-dependent eosinophilia. These findings identify GATA3 as a key regulator of pathogenic Th responses and a potential therapeutic target for mitigating intestinal GVHD. Funding Source Purdue Institute for Cancer Research Topic Categories Transplantation Immunology (TRAN)

Analysis of Langerhans Cells and CGRP-Expressing Neurons Interaction in Human Skin 2250360

Abstract Introduction Langerhans cells (LCs) are closely associated with sensory nerve fibers in the skin and express neurotransmitter receptors, enabling interaction with the peripheral nervous system. The neuropeptide Calcitonin Gene-Related Peptide (CGRP) may regulate the antigen-presenting function of LCs, providing evidence of regulatory mechanisms mediating interactions between the immune and nervous systems in the skin. However, the skin is a complex structure influenced by diverse intrinsic and extrinsic factors, which play a critical role in the body’s response to skin diseases. Hence, this study aims to evaluate the interaction between LCs and CGRP-expressing neurons in human skin with respect to age, body mass index (BMI), smoking habits, and anatomical region differences. Methods In this study, skin tissue samples were obtained from 60 volunteers aged 20 to 70 years. For general histological analyses, samples were stained with toluidine blue, Masson’s trichrome, and hematoxylin-eosin, while immunofluorescent evaluations included CD207, CD1a, and CGRP immunostaining. Results Consequently, smoking status and BMI did not cause statistically significant changes in the number of mast cells (MCs), the density of LCs, or the number of CGRP-expressing nerve endings. However, MC density increased in sun-protected older skin and sun-exposed aged (photoaged) skin compared to sun-protected young skin Conclusion . In photoaged skin, while LC density decreased, CGRP-expressing nerve fiber density increased. The present data are crucial for understanding neuroimmunological regulation in the skin and for elucidating how cellular coordination is both maintained and disrupted. Topical formulations of CGRP antagonists or agonists, if shown to be effective, will enhance our understanding of various skin disorders and contribute to the development of novel therapeutic approaches. Funding Source This project was a PhD thesis and was supported by the Scientific and Technological Research Council of Turkey (TÜBİTAK) under the grant number 1059B142100173. Topic Categories Neuroimmunology (NEUR)