ImmunoHorizons

Immune memory responses are rapid and qualitatively distinct from primary responses. They typically develop in the presence of antigen-experienced memory T and B cells and pre-existing antibodies. Although the contribution of T and B cells to recall responses is well defined, the contribution of antibody "memory" and the mechanisms by which pre-existing antibodies modulate the development of germinal center and plasma cell responses is not precisely understood. Here we report on mechanisms that mediate antibody enhancement of germinal center (GC) and plasmablast (PB) compartments, and the parallel process by which they change the affinity threshold for B cell recruitment into immune responses. The data indicate that antibody-mediated enhancement of GC and PB responses is Fc gamma receptor (Fc{gamma}R) dependent and largely complement receptor 1 and 2 (CR1/2) independent. In contrast, the reduction in the affinity threshold for GC entry is independent of both Fc{gamma}Rs and CR1/2. SummaryCipolla et al. show that antibody can modulate immune responses via both Fc gamma receptor dependent and independent mechanisms. These mechanisms influence both the magnitude and composition of the germinal center response.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and long COVID are complex chronic conditions that often follow infectious triggers with overlapping clinical features but poorly defined pathophysiological relationships. This study aimed to identify disease-specific immune signatures through multiparameter immunophenotyping of monocytes, dendritic cells, and T-cell subsets. A total of 207 participants were included (ME/CFS: n = 103; long COVID: n = 63; healthy controls: n = 41). Peripheral blood mononuclear cells were analyzed using multiparameter flow cytometry. Statistical analyses included non-parametric testing, age-adjusted ANCOVA, correlation network analysis, and principal component analysis (PCA). Long COVID was characterized by increased M2-like monocyte polarization, elevated CD80 expression across monocyte subsets, expansion of dendritic cells, and reduced expression of activation markers, indicating persistent immune activation with features of immune exhaustion. In contrast, ME/CFS exhibited reduced costimulatory molecule expression, impaired CCR7-mediated immune cell trafficking, and less coordinated activation patterns, consistent with a state of immune suppression. Correlation network analysis revealed more extensive and integrated immune interactions in long COVID, while PCA identified distinct immunophenotypic components and enabled moderate discrimination between the two conditions. These findings demonstrate that ME/CFS and long COVID are characterized by distinct immune profiles, supporting the concept of divergent immunopathological mechanisms. The identified signatures may contribute to biomarker development and guide targeted therapeutic approaches.

Expression of the Csf1r gene in cells of the mononuclear phagocyte lineage is regulated by a conserved enhancer, the fms-intronic regulatory element (FIRE). In mice with a germ-line deletion of FIRE (Fireko) CSF1R expression is undetectable in bone marrow progenitors and classical monocytes. Fireko mice lack subpopulations of macrophages in the brain and periphery but develop normally. Here we show that loss of CSF1R expression in Fireko mice is partly overcome by CSF2 in vitro and inflammatory recruitment in vitro. Analysis of heterozygous mutant mice and deletion of the conserved AP1 motif in FIRE provide evidence that continuous receptor synthesis determines CSF1 responsiveness. The absence of macrophages in kidney and heart of Fireko mice was not associated with detectable loss of physiological function. In a model of renal injury macrophage recruitment and histopathology were similar in WT and Fireko mice. Tissue resident macrophages that were depleted in Fireko mice, including microglia, were replaced by donor-derived cells following intraperitoneal adoptive transfer of wild-type bone marrow at weaning. The Fireko mouse provides a novel platform to dissect the functions of tissue resident macrophages in development, homeostasis and pathology. Summary StatementThis study describes a unique model of selective tissue resident macrophage deficiency arising from dysregulated expression of the mouse Csf1r gene.

The primary route of SARS-CoV-2 entry is via respiratory epithelium. However, many COVID-19 patients developed dermatological lesions, and SARS-CoV-2 RNA has been detected in the patients skin. Inflammatory skin diseases, psoriasis and atopic dermatitis (AD), significantly increased the risk of COVID-19. To evaluate the potential role of skin in SARS-CoV-2 host interactions, we utilized 3D human skin organoids (HSO) generated from human epidermal keratinocytes, as well as neonatal skin explants. HSO were treated with cytokines involved in acute and chronic skin inflammation and cytokine storm in severe COVID-19 disease, TNF-, IL-6, IL-1{beta}, and IFN-{gamma}, individually and in combination. HSO were also treated with Th1 (TNF- + IL-17) and Th2 (IL-4 + IL-13) cocktails inducing pro-psoriasis and pro-AD HSO changes, respectively. All individual cytokines, and especially their combinations, elevated the expression of ACE2 and TMPRSS2 at mRNA/protein levels. The Th2 induced only TMPRSS2, the Th1 predominantly induced ACE2. Topically applied Spike-pseudotyped lentiviral Tomato reporter, which binds ACE2 similarly to SARS-CoV-2, successfully infected control and cytokine-treated HSO as well as neonatal skin explants. Cytokine treatment, especially TNF- + IL-6 + IL-1{beta} + IFN-{gamma} and the Th1, significantly increased viral entry. Transcriptomic analysis further revealed partial overlap between gene expression signatures induced by Spike-mediated entry in inflamed HSO and those observed in lung tissue from COVID-19 patients, supporting the biological relevance of skin models. Together, these findings demonstrate that inflammation enhances the permissiveness of human skin to SARS-CoV-2 entry, suggesting that the skin may represent a previously underappreciated interface in viral host interactions.

In mammals, most of the iron is found in the heme of red blood cells (RBCs), which must be recycled to support erythropoiesis in the bone marrow. Splenic red pulp macrophages (RPMs) play a crucial role in this process by phagocytosing senescent RBCs, metabolizing the heme and releasing iron back into the blood. Free cytoplasmic iron generates toxic reactive oxygen species, yet iron-specific adaptations of RPMs are not well documented. We previously reported that autophagy prevents ferroptosis in Langerhans cells, a cutaneous phagocyte subset. Thus, we hypothesized that autophagy may be important for the regulation of RPM metabolism and their maintenance of systemic iron homeostasis. To study this, we used Atg5flox/flox and Cd169cre mouse models to delete ATG5 in CD169+ macrophages, including RPMs. Atg5-deficient RPMs were decreased in number, and the remaining ones showed increased generation of toxic lipid peroxides. Spleens of Atg5{Delta}Cd169 mice were enlarged and contained more RBCs. Finally, autophagy impairment in RPMs exacerbated RBC loss in a model of phenylhydrazine-induced anemia. Our findings exemplify how dysregulation of macrophage metabolism alters their function and can disrupt tissue homeostasis upon challenge.

Atopic dermatitis (AD) transcriptomic studies have produced notoriously inconsistent differential gene expression (DEG) lists across cohorts, and the biological heterogeneity of non-lesional AD skin remains unresolved at the individual level --limitations that group-averaged DEG analysis is structurally incapable of addressing. We applied a geometric transcriptomic framework to 537 skin RNA-sequencing samples from four independent international cohorts, positioning each sample within a 20-dimensional disease-informative PCA space relative to a unified healthy reference cloud validated by multi-cohort batch integration (ComBat; silhouette width 0.076 across three countries). Applying a bootstrap Jaccard framework to lesional-versus-healthy comparisons, AD lesional DEG signatures were significantly more reference-sensitive than psoriasis (PSO; Jaccard 0.637 vs 0.737; non-overlapping 95% CIs), with per-gene Spearman correlation between absolute effect size and cross-reference reproducibility (rho=0.658, p<2.2x10-16) establishing that ADs instability arises from its structural dependence on smaller-effect-size transcriptomic signals -- a geometric property of AD biology, not a methodological failure of prior studies. In non-lesional skin, spectrum scores -- projections of each samples displacement from the healthy centroid onto the disease axis -- revealed that AD non-lesional (AD_NL) samples had traversed 22.6% (95% CI 15.2-29.6%) of the healthy-to-lesional axis versus 12.9% (95% CI 8.4-18.2%) for PSO non-lesional (PSO_NL; Wilcoxon p=0.012), with non-lesional skin in each disease displaced toward its own lesional pole at near-identical angles (within-disease delta-angle 1.4 degrees) but AD displaced further. Against a homeostatic boundary defined as the 95th-percentile Euclidean distance of healthy controls from their centroid, 17.2% of AD_NL samples (16/93) individually exceeded this threshold versus 2.0% of PSO_NL (1/49; OR=9.87, p=0.007), replicating across all three cohorts providing AD_NL data. Among boundary-crossing AD_NL samples, two directional patterns emerged: high-positive displacement (n=6) characterised by inflammatory pre-activation (IL-6/JAK-STAT3, IFN-alpha, TNF-alpha/NF-kB) and low/negative displacement (n=10) characterised by broad metabolic suppression and a third transcriptomic axis orthogonal to both canonical disease trajectories -- not attributable to cellular infiltration differences and undetectable by group-level analysis. These findings reframe ADs notorious transcriptomic inconsistency as a predictable consequence of effect-size architecture, establish that a reproducible subset of AD patients harbours individually measurable transcriptomic boundary escape before clinical lesion onset, and identify a biologically uncharacterised non-lesional subgroup that warrants cell-type-resolved investigation as a potential early intervention target.

T cell development in the thymus is a tightly regulated process where epigenetic modifications, such as histone 3 lysine 27 acetylation (H3K27ac), play a crucial role in controlling the activation of genes. The epigenetic regulation of human mucosal-associated invariant T (MAIT) cell development is unknown; we mapped the regulatory chromatin landscape in the three developmental stages of thymic MAIT cells to identify the regulatory elements and enhancer activity involved in thymic maturation and analysed whether these chromatin dynamics are associated with the acquisition of effector programs in developing MAIT cells. Utilising cleavage under target and tagmentation (CUT&Tag), genome-wide H3K27ac profiles were generated and combined with transcriptome data from thymic MAIT cells, which revealed how developmental shifts in enhancer activity correspond to changes in gene expression. In total, 41,958 genomic regions with H3K27ac signal were identified in MAIT cells across the three development stages, of which 1,200 regions showed acetylation changes during differentiation from stage 1 to stage 3. At dynamic regions, the greatest differences were observed between stage 1 and stage 3, highlighting a progressive gain or loss of H3K27ac during MAIT cell development. Overall, MAIT cell maturation was associated with the gradual accumulation of H3K27ac at promoters and enhancers, which closely correlated with gene expression changes during development. Stage-specific enrichment of H3K27ac was observed at key transcription factor gene loci involved in MAIT cell development, including ZBTB16 (PLZF), EOMES, RUNX3, NFATC2, FOXO1, TGIF1, IRF1, and MAF genes. Epigenetic remodelling was also observed at cytokine and cytokine receptors (IL7R, IL18R1, IL23R, IFNG), chemokines and chemokine receptors (CCL4, CCL5, CCR5, CCR9, CXCR4, CXCR6), as well as several surface molecules with known immunological function. Our work reveals a previously uncharacterised epigenetic profile of human MAIT cells that regulates and inuences their development.

Th1 cells are viewed as a cornerstone of immunity to fungi and other intracellular pathogens. Despite the widely accepted role of Th1 cells in antifungal resistance, the development of protective strategies harnessing them is stunted by a limited understanding of how best to promote their development. We and others have reported a requisite role for Th17 cells in resistance to fungi. We have long been puzzled about how to reconcile seminal roles for both Th1 and Th17 subsets. Here we report that Th17 cells convert into polyfunctional Th1 cells producing multiple cytokines, including IFN-{gamma}, TNF and GM-CSF when we used adjuvant formulations that include glucopyranosyl lipid adjuvant (GLA) to enhance antifungal immunity. GLA induced plastic Th17 cells that convert into polyfunctional Th1 memory cells.

Regulatory T (Treg) cells are central mediators of immune tolerance and are generally considered to rely predominantly on mitochondrial metabolism rather than glucose-driven glycolysis. To define the role of glucose metabolism in Treg cells, we investigated the contribution of the hexose transporters GLUT1 and GLUT3. Genetic ablation of GLUT1 in T cells or selectively in Treg cells had minimal impact on Treg cell numbers, phenotype or immune homeostasis, indicating that GLUT1 is largely dispensable in this lineage. By contrast, deletion of GLUT3 in T cells resulted in a marked reduction in Treg cell numbers. However, it remained unclear whether this reduction reflected diminished IL-2 production by GLUT3-deficient conventional T cells or a cell-intrinsic requirement for GLUT3 in Treg cells. To investigate this, we generated mice with Treg cell-specific deletion of GLUT3. These animals developed severe systemic inflammation accompanied by lethal cellular and humoral autoimmunity. Mechanistically, GLUT3-deficient Treg cells exhibited reduced glycolytic activity and mitochondrial respiration, leading to impaired suppressive function and defective effector and follicular Treg cell differentiation. Collectively, our findings demonstrate a non-redundant requirement for GLUT3 in Treg cell metabolic fitness and immune regulation, refining the prevailing view that Treg cells operate largely independently of glucose metabolism. Our data further suggest that therapeutic strategies targeting glucose uptake and glycolysis in autoimmune and inflammatory diseases should account for potential adverse effects on Treg cell-mediated immune tolerance.

Cell-mediated immune responses are crucial for protecting the host against Toxoplasma gondii infection. However, impaired immunity, such as T-cell exhaustion, is a common phenomenon during chronic infection. This may represent a strategy employed by T. gondii to evade host defenses. T-cell immunoglobulin and mucin-domain containing 3 (Tim-3) is an important regulatory molecule involved in cell-mediated immunity. This study examined the expression of Tim-3 and the effects of its blockade in a mouse model of toxoplasmosis. In mice with chronic T. gondii infection, we found that Tim-3 is highly expressed in both cyst-bearing and non-cyst-bearing tissues, and its expression correlates with the parasite burden. Blocking the Tim-3 pathway with an anti-Tim-3 antibody enhances the immune response, resulting in elevated levels of cytokines (IFN-{gamma}, IL-12p70, IL-2, IL-9) and the chemokine CXCL1 in the serum, increased leukocyte infiltration (CD3+, CD14+ cells) in the brain, and downregulation of Tim-3 expression in microglial cells. As a result, the anti-Tim-3 treatment resulted in a 62% reduction in the number of tissue cysts and a trend towards an increase in the homeostatic signature, P2RY12, in microglia. Our study provides proof of concept for an anti-Tim-3 approach in treating chronic T. gondii infection and potentially other brain-residing pathogens.

BackgroundHumans and mice display elevated levels of IL-27, an immunosuppressive cytokine shown to increase during neonatal bacterial sepsis and compromise survival. This study explores two hypotheses for regulation of IL-27 expression: 1) decreased DNA methylation in newborns that contributes to increased expression of IL-27 genes; 2) neonatal hormones regulate IL-27 expression through upstream hormone response elements (HREs). MethodsWhole genome methyl-seq analysis of neonatal and adult blood-derived macrophages identified differentially methylated regions (DMRs) at steady-state. Quantitative PCR (qPCR) measured expression of IL-27 genes (IL27p28 and EBI3) in human and murine neonatal macrophages stimulated in vitro with synthetic glucocorticoid or progesterone. Confocal microscopy and chromatin immunoprecipitation (ChIP) of glucocorticoid receptor (GR) assessed translocation into the nucleus and binding to the EBI3 promoter. ResultsThe IL-27p28 promoter contained DMRs that were increased in the neonatal cohort. The analysis did not identify DMRs within the EBI3 promoter. Dexamethasone stimulation increased EBI3 gene expression in human and murine neonatal macrophages. GR localized to the nucleus in response to dexamethasone and was enriched at the EBI3 upstream regulatory region. ConclusionThese data suggest glucocorticoid (GC) signaling increases EBI3 expression. This has importance in the context of antenatal GC administration that may increase IL-27 levels. Impact Statement{blacksquare} Elevated expression of IL-27 in early life impairs the host response to invasive bacterial infection in neonates. {blacksquare}Understanding the regulatory mechanisms contributing to increased IL-27 during the neonatal period is necessary to reduce susceptibility to infection in this vulnerable population. {blacksquare}The methylation status of the IL-27 genes in macrophages from neonatal and adult blood donors does not suggest regulation of differential expression with age. {blacksquare}Glucocorticoids are a signal that can induce EBI3 gene expression in a GR-dependent manner. {blacksquare}Glucocorticoid therapy for premature infants may increase IL-27 expression and promote enhanced susceptibility to infection.

Diffuse large B-cell lymphoma (DLBCL), the most common aggressive lymphoma, encompasses histologically similar but genetically distinct cancers. Recent genetic studies have defined at least six molecular subtypes, yet none account for Epstein-Barr virus (EBV), despite 5-15% of DLBCLs being EBV-associated. By reanalyzing published whole-exome and RNA-sequencing data from 481 tumors, we identified 19 EBV-positive cases. These were significantly enriched in the BN2 subtype (6/19), while most (11/19) remained unclassified. In BN2 tumors, several subtype-defining mutations were reduced in frequency among EBV-positive cases, supporting the hypothesis that EBV oncogenes substitute for specific cellular alterations and may confound DLBCL classification algorithms. Extending our analysis to cell lines, we found that the widely used Val cell line harbors the B95-8 laboratory EBV strain; other EBV-positive lines appeared authentic but modeled only non-BN2 subtypes and expressed an atypical viral latency III program, whereas some DLBCL tumors expressed the atypical latency III program and others latency I or II. Together, these findings demonstrate that EBV-positive DLBCL, like DLBCL itself, is not a single disease, and that current in vitro models only partially capture its biological heterogeneity. Key pointsO_LIEBV-positive DLBCL is not a single disease and EBV status can impact genetic-based classifications. C_LIO_LICurrent EBV-positive DLBCL cell lines do not adequately capture tumor complexity; we determined that Val is a problematic cell line. C_LI

BackgroundCompanion canines need advances in therapeutic options for solid tumor malignancies. Prior studies established feasibility of autologous natural killer (NK) cell infusions in canines with solid tumors; however, autologous products are limited by dysfunctional immunity and a manufacturing process that delays care. Allogeneic NK cells offer the possibility of "off-the-shelf" therapy to be administered from healthy donors. MethodsPeripheral blood mononuclear cells (PBMCs) were isolated from healthy canine donors via density gradient separation. NK cells were expanded with recombinant human IL-2 and canine IL-21 with the addition of K562 feeder cells transfected with CD137 ligand and membrane bound human IL-15. Additional experiments included IL-12 in the expansions. In vitro potency was assessed via co-culture with the D17-mKate2 canine osteosarcoma cell line. Three canines were enrolled in a phase 1 trial infusing ex vivo expanded allogeneic NK cells after lymphodepletion. ResultsFlow cytometric analysis confirmed successful expansion of canine NK cells with up to 50% of cells demonstrating NKp46+ after 14 days of expansion. Residual T cell numbers varied based on donor. The addition of IL-12 led to increased NK cell expansion. Incucyte demonstrated potency with increasing osteosarcoma cell death at higher effector to target ratios. Three canines with metastatic/refractory solid tumors were successfully lymphodepleted and infused with allogeneic NK cell products. The canines tolerated the infusions well. ConclusionsCanine allogeneic NK cells were successfully expanded and activated ex vivo, demonstrated potency in vitro, and safety in vivo. Further studies will optimize the NK cell product and escalate dosing to reach the maximal tolerable dose.

The establishment of mixed hematopoietic chimerism is a promising way to induce immune tolerance for islet replacement therapy and to treat the underlying autoimmunity in Type 1 diabetes (T1D). Mixed chimerism not only promotes effective thymic negative selection of autoreactive cells but also restores regulatory T cell (Treg) function and peripheral tolerance. In the current study, we determined that a novel class of donor-derived CD8+CD44+CD122+ Tregs (d-CD8+CD122+ Tregs) plays a crucial role in controlling autoimmunity in non-obese diabetic (NOD) mice with induced mixed chimerism. Using adoptive T cell transfer experiments, we showed that d-CD8+CD122+ Tregs abrogate autoimmunity by selectively depleting the exogenously injected diabetogenic T cells in Recombination-Activating Gene deficient NOD mice. These d-CD8+CD122+ Tregs from NOD chimeras show upregulation of Helios, Programmed cell death protein 1, perforin, granzyme-B, CD39, Folate receptor 4, and downregulation of proinflammatory markers like Scart1 and Scart2. Using in vitro assays, we show that d-CD8+CD122+ Tregs respond specifically to a Complementarity-Determining Region-3 peptide sequence derived from T cell receptors of islet antigen-specific autoreactive T cells. Thus, mixed chimerism might be a method to revitalize CD8+CD122+ Tregs which are decreased in number and functionality in NOD mice. Similarly, we found that individuals with T1D have a deficiency in CD8+CD122+ Tregs, suggesting a potential loss of regulatory function accompanies disease onset. Revitalizing CD8+CD122+ Tregs may offer a new therapeutic strategy of restoring immune tolerance in autoimmune diabetes. One sentence summary Inducing mixed donor chimerism in NOD mice generates donor-derived CD8+CD122+ Tregs that suppress autoimmunity and restore immune tolerance by selectively eliminating autoreactive T cells.

Many intracellular pathogens stimulate host cell stress by directly or indirectly causing an imbalance in host nutrients; depletion of amino acid pools in particular can act as a danger signal to infected cells. Using a restrictive host model of Salmonella enterica serovar Typhi (S. Typhi) infection, we identify early induction the integrated stress response (ISR) by viable bacteria, but not heat-killed bacteria. Genetic deletion of the amino acid sensing ISR kinase GCN2 (also known as EIF2AK4) prevented early ISR activation during S. Typhi infection, and murine macrophages lacking GCN2 show impaired bacterial clearance and decreased cytokine output. Supplementation of wildtype C57BL/6 murine macrophages with only the non-essential amino acid asparagine was sufficient to suppress S. Typhi-induced ISR activation and deletion of S. Typhi ansB, encoding an asparaginase, prevented ISR activation during infection. Pharmacological inhibition of mammalian target of rapamycin (mTOR), the other major amino acid sensing pathway in eukaryotic cells, prevented GCN2 activation and ISR induction in murine macrophages, indicating an upstream role for mTOR in signaling to GCN2. These findings suggest a role for the ISR in macrophage innate immune responses to S. Typhi infection and highlight a potential difference in nutrient-dependent signaling between the S. Typhi-susceptible human host and the restrictive murine host centered around asparagine, mTOR, and GCN2.

Helminths are parasitic worms that secrete a variety of immune-regulating molecules to modulate the hosts inflammatory responses, enabling them to persist within the host over a long period of time, even decades. Their capacity to control host responses has prompted research into helminth-derived molecules as potential therapies for controlling excessive immune and inflammatory activity across a range of diseases. This systematic review with cross-study quantitative analysis aims to synthesize the published data on helminth-derived immunomodulatory peptides/polypeptides/proteins (HDIPs) with a focus on determining the extent of their disease-modifying and anti-inflammatory potential in in vivo animal models of inflammatory disease. In accordance with PRISMA 2020 guidelines, a predefined systematic search of the PubMed, Web of Science and Medline databases identified relevant studies published up to February 2026, and 65 articles were included after screening. We found that, although the HDIPs were assessed in multiple different disease models, most published studies assessed their potential in mouse models of colitis, asthma, arthritis and sepsis. Twenty species from which >65 isolated HDIPs were derived were tested in these models, with the trematode, Fasciola hepatica, and the nematode, Acanthocheilonema viteae, the most explored species. A common property of the HDIPs was the ability to significantly reduce disease severity across the in vivo animal models of inflammatory disease, underpinned by a decrease in pro-inflammatory cytokine levels and an increase in anti-inflammatory cytokine levels. Overall, this systematic review with cross-study quantitative analysis not only synthesizes the existing literature in this field but also highlights the disease-modifying and anti-inflammatory potential of HDIPs for a range of diseases in which immunoregulatory therapeutics may improve disease outcomes. It also encourages accelerated advancement of these helminth-derived molecules into first-in-human clinical trials.

BackgroundIn the course of testing mAb-based therapies to eradicate the persistent reservoir of HIV infection, we investigated the efficacy and mode of killing of HIV-infected cells by two categories of cytotoxic immunoconjugates (CICs) targeted by the same mAb, an immunotoxin (IT) and antibody-drug conjugate (ADC). MethodsWe performed metabolic and transcriptional analyses of treatment effects on the persistently-infected cell line H9/NL4-3. Cells were treated with CICs consisting of the anti-gp41 mAb 7B2 conjugated to either deglycosylated ricin A chain (dgA) or to the highly cytotoxic anthracycline derivative PNU-159682. At intervals up to 24 hr, intracellular metabolites were quantified by 1H nuclear magnetic resonance spectroscopy, and the transcriptome analyzed by RNA-Seq. ResultsSix hr post treatment, 7B2-dgA elicited both metabolic and transcriptional alterations, whereas 7B2-PNU treated cells did not differ from untreated cells. 7B2-dgA treated cells exhibited elevated intracellular levels of many amino acids, and activation of gene pathways for apoptosis, intracellular signaling, and immune activation. By 24 hr, both 7B2-dgA and 7B2-PNU treated cells differed markedly from untreated. Many of the changes observed following 7B2-PNU treatment at 24 hr were similar to those observed at 6hr following 7B2-dgA, likely indicating processes involved in cell death, but a number of alterations were unique to either IT or ADC treated cells. ConclusionsAn IT and ADC showed both similarities and differences in their cytotoxic effects. These results raise the question of whether the mode of cell killing could be a determinant of clinical efficacy. Although these studies were aimed at targeting the persistent reservoir of HIV infection, they have relevance for the design of CICs to treat cancer and other conditions. SUMMARYThe use of cytotoxic immunoconjugates, wherein an antibody is attached to a cellular poison, is effective in the treatment of cancer and other conditions. We seek to extend these results to treating HIV and other chronic viral infections. We analyzed the molecular mechanisms of cell killing when the same antibody was attached to different toxic structures. We report that each immunoconjugate induced both common and distinct patterns of killing. Such differences may have clinical relevance.

NLRP3 inflammasome is a cytosolic multi-protein complex that plays a crucial role in the immune system, responding to various exogenous and endogenous stimuli by triggering protective inflammatory responses. However, aberrant NLRP3 inflammasome activation is implicated in numerous inflammatory diseases. Therefore, the NLRP3 inflammasome is an important pharmacological target for the treatment of multiple diseases. In this context, we screened various US-FDA-approved drugs for NLRP3 inflammasome inhibition. We found that among various drugs, minoxidil hydrochloride (MXL) effectively inhibits NLRP3 inflammasome, evidenced by reduced secretion of IL-1{beta} and IL-18 in J774A.1 cells treated with MXL. The IC50 values of MXL for inhibition of IL-1{beta} and IL-18 were calculated to be 1.2 and 1.06 {micro}M, respectively. MXL was found to prevent ASC oligomerization, thereby inhibiting the NLRP3 inflammasome and leading to CASP1 cleavage. Further investigation revealed that MXL also utilizes AMPK-mediated autophagy to modulate NLRP3 inflammasome activity. Using siAMPK and bafilomycin A1, an end-stage autophagy inhibitor, we elucidated crosstalk between the NLRP3 inflammasome and autophagic pathways, which was modulated by MXL. Furthermore, we demonstrated the efficacy of MXL in two different mouse models of inflammation, involving the NLRP3 inflammasome. MXL at doses of 10 and 20 mg/kg effectively inhibited the activation of NLRP3 inflammasome by monosodium urate in the air pouch model and by ATP in the peritoneal inflammation model, as evidenced by reduced secretion of 1{beta} and IL-18 in the lavage. Our study identifies MXL as a potent NLRP3 inflammasome inhibitor, warranting further investigation as a potential therapeutic agent for inflammatory diseases.

Anemia is one of the most debilitating and frequent complications of inflammatory bowel diseases (IBD) and is often treated with iron supplementation, which has limited efficacy. Damaged intestinal barrier function is a hallmark of IBD and causes the translocation of endotoxins from gut bacteria into the bloodstream. In a previous study in mice, we reported that endotoxin suppresses erythropoiesis by reprogramming erythroblastic island macrophages (EBI M{varphi}). Here, we show that IBD patients and mice with acute colitis developed endotoxemia associated with anemia. Endotoxemia in IBD patients was negatively correlated with blood erythrocyte counts. In line with this, mice with acute colitis caused by drinking water containing dextrin sodium sulphate (DSS) had endotoxemia together with anemia characterized by reduced red blood cell counts, hemoglobin content and hematocrit., and reduced medullary erythropoiesis which was in part compensated by increased extramedullary erythropoiesis. As the endotoxin receptor TLR4 is expressed by CD169+ gut-resident macrophages and erythroid island macrophages in the bone marrow, we tested the hypothesis that TLR4 expressed by these CD169+ macrophages mediate both inflammatory colitis and anemia. Indeed, mice with conditional deletion of the Tlr4 gene specifically in CD169+ tissue-resident macrophages were protected from DSS-induced anemia and colitis. In addition, treatment of DSS mice with the TLR4 inhibitor C34 abated inflammation and anemia. These results suggest that endotoxins leaking from the inflamed gut may play a crucial role in IBD and associated anemia and that drugs targeting TLR4 may protect against IBD-associated anemia. Key pointsO_LIPatients with IBD and mice with acute colitis are anemic with increased endotoxemia and inflammation. C_LIO_LIEndotoxemia is inversely correlated with blood erythrocyte counts in IBD patients. C_LIO_LIConditional deletion of endotoxin receptor gene Tlr4 specifically in CD169+ tissue-resident macrophages or administration of synthetic TLR4 inhibitor significantly reduced colitis-induced anemia in mice. C_LI

To explore the mechanism of Hsa_circ_0000629 adsorbing miR-212-5p/ nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) through sponge in bronchial asthma. Twenty BALB/C mice were randomly divided into a normal control group and an asthma group. Pathological changes in lung tissue were observed via HE staining. Human bronchial epithelial cells (16HBE) were transfected with Hsa_circ_0000629 overexpression group (Hsa_circ_0000629-over), Hsa_circ_0000629 siRNA (Hsa_circ_0000629-si), mimic NC, miR-212-5p mimic, inhibitor NC, miR-212-5p inhibitor, and LPS+Hsa_circ_0000629 si. LPS-induced asthmatic cell models (LPS group) and untransfected 16HBE cells (NC group) served as controls. qRT-PCR was used to measure Hsa_circ_0000629, miR-212-5p and NLRP3 expression. ELISA assessed interleukin 18 (IL-18), interleukin 1{beta} (IL-1{beta}), interleukin 6 (IL-6) and tumor necrosis factor - (TNF-) levels. Cell proliferation and the apoptosis were evaluated by EDU assay and flow cytometry, respectively. Western blot analyzed Cleaved-caspase 1, 3 and 9 proteins expression. Dual-luciferase assay verified the binding sites of Hsa_circ_0000629 to miR-212-5p and NLRP3 to miR-212-5p. HE staining revealed inflammatory cell infiltration, bronchial wall thickening, smooth muscle hyperplasia, and alveolar destruction in asthmatic mice. Compared with the controls, Hsa_circ_0000629 and NLRP3 expression were significantly increased, while miR-212-5p expression was decreased in asthmatic lung tissues. In 16HBE cells, Hsa_circ_0000629-over and LPS groups showed elevated Hsa_circ_0000629 and NLRP3 expression but reduced miR-212-5p levels. Silencing Hsa_circ_0000629 in LPS-treated cells (LPS+Hsa_circ_0000629-si) reversed these effects. Overexpression of miR-212-5p counteracted Hsa_circ_0000629-induced NLRP3 upregulation, while miR-212-5p inhibition enhanced NLRP3 expression. LPS exposure increased TNF-, IL-18, IL-6, and IL-1{beta} levels, reduced cell proliferation, and promoted apoptosis. These changes were attenuated by Hsa_circ_0000629 silencing or miR-212-5p overexpression. Western blot confirmed that Hsa_circ_0000629 overexpression upregulated Cleaved-Caspase 1, 3, and 9, whereas miR-212-5p mimic or Hsa_circ_0000629-si reversed this trend. Dual-luciferase assays demonstrated targeted interactions among Hsa_circ_0000629, miR-212-5p, and NLRP3. Interference with Hsa_circ_0000629 expression can alleviate LPS induced apoptosis in 16HBE cells and inhibit the expression of inflammatory factors by targeting the miR-212-5p/NLRP pathway, which may be a new target for the treatment of asthma.