Classical Dendritic Cells Research Articles

Innate and Adaptive Immunity is not Impacted by Inflammatory Bowel Disease Medications in Pregnant Women and Their Offspring

Abstract Background and Aims Inflammatory bowel disease (IBD) therapeutics and pregnancy itself are known to impact immune cell populations, but a detailed understanding of the effect of specific therapies is lacking, particularly for infants exposed in utero. With comprehensive flow cytometric assessment, we aimed to explore how IBD and its treatment impact both maternal and infant immunophenotypes and cytokine production. Methods Peripheral blood was taken for flow cytometry immunophenotyping and quantification of cytokine responses to stimulation from women with IBD and healthy controls throughout pregnancy, at delivery, and postpartum. Blood samples were also taken from the umbilical cord and peripherally from the resultant offspring at the age of 6 weeks. Results Eighteen participants (16 with IBD and 2 healthy controls) were recruited to this single-center prospective cohort study. Basal T regulatory cell population proportions were 46% lower (0.21% vs 0.39%, P = .027) in those participants exposed to ustekinumab (n = 4). No other significant differences were noted in immunophenotype according to drug therapy exposure. Basal (1.75% vs 0.47%, P = .036) and lipopolysaccharide-stimulated (72.2% vs 64.7%, P = .028) production of tumour necrosis factor by classical dendritic cells were increased 3.7- and 1.1-fold, respectively, in those with an elevated fecal calprotectin (n = 6). Basal CD4+α4β7+ (41.4% to 66.5%, P = .0043) and CD8+α4β7+ (81.2% to 93.6%, P = .007) population proportions increased 1.6- and 1.2-fold, respectively, in infants from birth to 6 weeks. Conclusions This study provides the foundation for ongoing investigation to more definitively extricate the impact of maternal IBD activity, drug exposures, and disease phenotype on infant immune system development and function. These novel data suggest that IBD pharmacotherapies may not significantly impact maternal or infant immune regulation.

Abstract 4279: FAK inhibitor APG-2449 induces immunogenic cell death and enhances anti-tumor immunity in cervical cancer through the PERK-eIF2α pathway

The focal adhesion kinase (FAK) inhibitor APG-2449, a multi-target tyrosine kinase inhibitor that also targets ALK and ROS1, has demonstrated significant potential for inducing anti-tumor immunity. In this study, we explored the effects of APG-2449 on cervical cancer, emphasizing its capacity to induce immunogenic cell death (ICD) and stimulate immune responses via the PERK-eIF2α pathway. Our findings indicate that APG-2449 enhances ATP release and calreticulin (CRT) exposure on the surface of tumor cells, which are key indicators of ICD. Moreover, treatment with APG-2449 led to a notable increase in dendritic cell (DC) maturation and promoted their differentiation into classical dendritic cells (cDCs), which are essential for antigen presentation and the subsequent activation of T-cells.In vitro co-culture models, APG-2449 effectively boosted the activation of DCs and increased the frequency of tumor-specific CD8+ T cells. These observations underscore that APG-2449 elicits a robust immunogenic response, suggesting that inhibition of FAK/ALK/ROS1 could be a promising therapeutic approach for enhancing anti-tumor immunity in cervical cancer.These results highlight the potential of APG-2449 as an innovative therapeutic agent capable of modifying the tumor microenvironment to foster an effective anti-tumor immune response via the FAK/PERK-eIF2α axis. Future studies are needed to determine the clinical efficacy of APG-2449, particularly in combination with other immunotherapies. Citation Format: Lin Zhang, Mingyue Zhang, Weihan Kang, Jing Xiao, Maple Tse, Yong Du, Dajun Yang. FAK inhibitor APG-2449 induces immunogenic cell death and enhances anti-tumor immunity in cervical cancer through the PERK-eIF2α pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4279.

TLR5 activation in respiratory epithelial cells orchestrate mucosal Th17 response through both indirect and direct pathways

BackgroundFlagellin, a potent mucosal adjuvant administered via the intranasal route, has been widely recognized for its capacity to enhance immune responses against diverse pathogens. However, the effects and the underlying mechanisms by which flagellin modulates CD4+ T cell differentiation remain incompletely understood.MethodsRecombinant flagellin proteins, including full-length flagellin (SF) and a TLR5-binding deficient variant (SFΔ90–97), were produced and purified. An OT-II derived CD4+ T cell adoptive transfer model, a classical intranasal immunization model and dendritic cell (DC)-CD4+ T co-culturing system were used. The proliferation and differentiation of CD4+ T cells were analyzed using flow cytometry analysis. RNA sequencing and neutralizing antibody blocking experiments were performed to determine the essential cytokines involved in flagellin modulated Th17 differentiation.ResultsFlagellin preferentially promotes Th17 cells differentiation. Respiratory epithelial cells (RECs), acting as sentinel cells, are the first to encounter exogenous stimuli during intranasal immunization. Flagellin stimulates the secretion of various soluble cytokines by binding to TLR5 on the surface of RECs, with GM-CSF facilitating the functional activation of airway DCs. GM-CSF-conditioned DCs exhibit upregulated IL-6 expression which in turn drives the polarization of naïve CD4+ T cells toward the Th17 phenotype. Furthermore, TLR5-regulated REC-derived IL-6 synergizes with TLR5-modulated DCs to amplify Th17 polarization signals, thereby enhancing the Th17 induction.ConclusionFlagellin preferentially induced a Th17-enhanced immune response and RECs were highlighted its essential roles during this process through both indirect and direct pathways. For indirect pathway, RECs modulate DC function through GM-CSF. Moreover, RECs directly contribute to Th17 differentiation by secreting IL-6.

Conventional type 1 dendritic cells in the lymph nodes aggravate neuroinflammation after spinal cord injury by promoting CD8+ T cell expansion

BackgroundAdaptive immune response is at the core of the mechanism of secondary spinal cord injury (SCI). This study aims to explore the molecular mechanism by which classical dendritic cells (cDC1s) influence CD8+ T cell expansion in SCI.MethodsPeripheral blood samples from patients with SCI and spinal cord tissues from SCI mice were collected, and the population of cDC1 subset was analyzed by flow cytometry. In vivo, the fms-like tyrosine kinase 3 (Flt3) inhibitor quizartinib was administered to deplete cDC1s, while intraperitoneal injection of recombinant Flt3L and immunosuppressive drug FTY-720 was used to expand cDC1s and prevent T cell egress from lymph nodes (LNs), respectively. In vitro, the conditioned medium (CM) of isolated LN fibroblastic stromal cells (FSCs) and pre-DCs were co-cultured. Subsequently, FSC CM-induced DCs were stimulated and co-cultured with CD8+ T cells for proliferation assay.ResultsThe cDC1 subset was increased in the peripheral blood of SCI patients and in the injured spinal cord of SCI mice. Depletion of cDC1s decreased the proportion of infiltrating CD8+ T cells in the injured spinal cord of SCI mice and reduced the inflammatory response. The Basso Mouse Scale score of SCI mice was increased and the proportion of CD8+ T cells in blood and spinal cord tissue was decreased after FTY-720 injection. Both migratory cDC1s (CD103+) and resident cDC1s (CD8α+) were present in the LNs surrounding the injured spinal cord of SCI mice. Among them, CD103+ cells were derived from the migration of cDC1s in spinal cord tissues, and CD8α+ cDC1s were directionally differentiated from pre-DCs after co-culture with LN-FSCs. Interferon-γ promoted the secretion of Flt3L by LN-FSCs through the activation of JAK/STAT signaling pathway and enhanced the differentiation of pre-DCs into CD8α+ cells.ConclusionMigratory cDC1s and resident cDC1s promote the expansion of CD8+ T cells in LNs around the injured spinal cord and mediate the adaptive immune response to aggravate neuroinflammation in SCI.

Pulmonary and systemic effects of inhaled crystalline silica in the HOCl-induced mouse model of systemic sclerosis: An experimental model of Erasmus syndrome.

Pulmonary and systemic effects of inhaled crystalline silica in the HOCl-induced mouse model of systemic sclerosis: An experimental model of Erasmus syndrome.

Promising Cellular Immunotherapy for Colorectal Cancer Using Classical Dendritic Cells and Natural Killer T Cells.

Colorectal cancer (CRC) remains one of the leading causes of cancer-related morbidity and mortality around the world. Despite advances in surgery, chemotherapy, and targeted therapies, the prognosis for patients with metastatic or advanced CRC remains poor. Immunotherapies comprising immune checkpoint inhibitors showed disappointing responses in metastatic CRC (mCRC). However, cellular immunotherapy, specifically using classical dendritic cells (cDCs), may hold unique promise in immune recognition for CRC antigens. cDCs are substantial players in immune recognition and are instrumental in orchestrating innate and adaptive immune responses by processing and presenting tumor antigens to effector cells. Natural killer T (NKT) cells are insufficiently studied but unique effector cells because of their ability to bridge innate and adaptive immune reactions and the crosstalk with dendritic cells in cancer. This review explores the therapeutic potential of using both cDCs and NKT cells as a synergistic therapy in CRC, focusing on their biological roles, strategies for harnessing their capabilities, clinical applications, and the challenges within the tumor microenvironment. Both cDCs and NKT cells can be used as a new effective approach for cell-based therapies in cancers to provide a new hope for CRC patients that are challenging to treat.

Prevention of Intrauterine Adhesion with Platelet-Rich Plasma Double-Network Hydrogel.

Intrauterine adhesion (IUA) can negatively impact on pregnancy outcomes, leading to reduced pregnancy rates, secondary infertility, and an increased risk of pregnancy complications. Studies have shown that the application of platelet-rich plasma (PRP) in IUA patients is effective. However, the clinical readhesive rate of IUA after treatment is still high, especially in severe cases. Platelet-rich plasma double-network hydrogel (DN gel) is an engineered PRP double network hydrogel, which is a sodium alginate (SA) based PRP hydrogel with egg carton ion cross-linking and fibrin double network. The results of this study show that intrauterine injection of DN gel has a better effect on promoting endometrial regeneration and enhancing endometrial receptivity than PRP gel. The mechanism is analyzed through single-cell sequencing, which may be achieved by increasing the expression of neutrophils (Neut), natural killer cells (NK), and type I classical dendritic cells (cDC1) in the endometrium and inhibiting the infiltration of M2 macrophages. Overall, based on the good healing efficiency and good biocompatibility of DN gel, it is expected to become a method of treating IUA with better efficacy and faster clinical translation.

Abstract B031: Immune cell composition in surgical drain fluid as a novel prognostic marker in head and neck squamous cell carcinoma

Abstract Background: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy globally, and the vast majority of cases are treated with primary surgical resection and adjuvant therapy. Our group has pioneered the use of HNSCC circulating tumor DNA (ctDNA) in surgical effluent collected postoperatively from surgical drains (surgical drain fluid, SDF) as a novel proximal bioanalyte for measuring minimal residual disease after surgery. We now profile the immune cell composition of SDF compared to paired peripheral blood mononuclear cells (PBMCs), and correlate SDF immune cell profiles with clinical variables and oncologic outcomes in HNSCC. Method: SDF and peripheral venous blood were collected 24 hours postoperatively from 58 HNSCC patients, including 11 HPV (+) and 47 HPV (-) patients undergoing standard of care surgical resection, lymph node dissection, and adjuvant therapy. Freshly collected SDF cells and PBMCs were cryopreserved until profiling by multicolor flow cytometry for respective leukocyte compositions. Analyses were used to define the following viable CD45+ leukocyte subsets: total T cells, CD4 T-cells CD8 T-cells, Treg cells, B-cells, non- classical monocytes, classical monocytes, natural killer (NK) cells, classical dendritic cells (cDC), plasmacytoid DC (pDC), macrophages, and monocytic myeloid-derived suppressive cells (MDSCs). Immune cell percentages were correlated with clinical characteristics and cancer recurrence. Results: CD45+ leukocytes comprised >99.5% of SDF cells, with very few EPCAM+ tumor cells (< 10^-4). HPV status did not significantly affect SDF immune cell composition, and no significant differences were noted by tumor site (larynx, oral cavity, oropharynx), or extracapsular lymph node extension. Among 13 HPV (-) HNSCC patients with paired peripheral blood drawn concurrently, SDF had a higher proportion of B-cells(16.8% vs. 9%, p=0.044), NK cells(56% vs. 12%, P<0.001), monocytes(14% vs. 1%, P<0.001), and macrophages(3.1% vs. 0.46%, P<0.001) compared to PBMCs, and a lower proportion of CD4+ T cells(1% vs. 24%, P<0.001), CD8+ T cells(0.6% vs. 18%, P<0.001), MDSCs(2.1% vs. 3.4%, P=0.029), and pDCs(0.1% vs. 0.2%, P=0.014). HPV (-) HNSCC patients that went on to recur (n=9) had a significantly higher proportions of SDF monocytes (total, classical, and non- classical) and CD56dimCD16+ NK cells (all P<0.001) compared to non-recurrent patients (n=38). Patients who went on to recur also had a significantly lower proportion of SDF B-cells (P<0.001), CD56bright NK cells(P=0.01), and macrophages (P=0.018) compared to non- recurrent cases. No significant differences were noted with respect to proportions of CD3+, CD4+, CD8+ T-cells, DC, and MDSC cells. Conclusion: SDF from HNSCC patients contains unique immune cell populations and may provide new insights into postoperative tumor immunity. Differences in SDF immune cell composition by oncologic outcome in patients that go on to recur, highlighting potential prognostic and predictive applications of SDF immune cell profiling for adjuvant therapy decision-making. Citation Format: Zhongping Xu, Noah Earland, Lucien Khalil, Lazar Vujanovic, Danny Azmi Elias, Riyue Bao, Jason J. Luke, Aadel A. Chaudhuri, Jose P. Zevallos. Immune cell composition in surgical drain fluid as a novel prognostic marker in head and neck squamous cell carcinoma [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr B031.

Immunocyte phenotype and breast cancer risk: A Mendel randomization analysis.

Breast cancer remains a significant global health challenge. Understanding its etiological factors, particularly the role of immune system components, is crucial. This study leverages Mendelian randomization (MR) to investigate the causal relationship between various immune cell features and the risk of developing breast cancer. Utilizing two-sample MR analysis, we examined 731 immune cell features across 7 groups for their potential causal links to breast cancer. We analyzed genome-wide association studies (GWAS) data of 257,730 Europeans, comprising 17,389 cases and 240,341 controls, focusing on 24,133,589 single nucleotide polymorphisms (SNPs). Instrumental variables (IVs) were selected based on genetic associations, with rigorous statistical methods employed, including inverse variance weighting (IVW) and weighted median-based estimation. Our analysis identified 20 immunophenotypes with significant causal associations with breast cancer risk. Notably, contain B cell, mature T cell, T + B + NK (TBNK) cells, regulatory T (Treg) cell, Classic dendritic cells (cDCs), Monocyte, and Myeloid cell group features displayed positive or negative correlations with breast cancer. For instance, specific B cell phenotypes were found to have both positive and negative causal relationships with breast cancer. Additionally, reverse MR analysis revealed no significant causal effects of breast cancer on these immune characteristics. This study underscores the complex interplay between various immune cell phenotypes and breast cancer risk. The identified immunophenotypes could be potential biomarkers or targets for future therapeutic interventions. Our findings contribute to a deeper understanding of the immunological dimensions of breast cancer etiology.

CGAS activation in classical dendritic cells causes autoimmunity in TREX1-deficient mice

Detection of cytosolic DNA by the cyclic GMP-AMP (cGAMP) synthase (cGAS)-stimulator of interferon genes (STING) pathway provides immune defense against pathogens and cancer but can also cause autoimmunity when overactivated. The exonuclease three prime repair exonuclease 1 (TREX1) degrades DNA in the cytosol and prevents cGAS activation by self-DNA. Loss-of-function mutations of the TREX1 gene are linked to autoimmune diseases such as Aicardi-Goutières syndrome, and mice deficient in TREX1 develop lethal inflammation in a cGAS-dependent manner. In order to determine the type of cells in which cGAS activation drives autoinflammation, we generated conditional cGAS knockout mice on the Trex1-/- background. Here, we show that genetic ablation of the cGAS gene in classical dendritic cells (cDCs), but not in macrophages, was sufficient to rescue Trex1-/- mice from all observed disease phenotypes including lethality, T cell activation, tissue inflammation, and production of antinuclear antibodies and interferon-stimulated genes. These results show that cGAS activation in cDC causes autoinflammation in response to self-DNA accumulated in the absence of TREX1.

Classical dendritic cells contribute to hypoxia-induced pulmonary hypertension.

Pulmonary hypertension (PH) is a chronic and progressive disease with significant morbidity and mortality. It is characterized by remodeled pulmonary vessels associated with perivascular and intravascular accumulation of inflammatory cells. Although there is compelling evidence that bone marrow-derived cells, such as macrophages and T cells, cluster in the vicinity of pulmonary vascular lesions in humans and contribute to PH development in different animal models, the role of dendritic cells in PH is less clear. Dendritic cells' involvement in PH is likely since they are responsible for coordinating innate and adaptive immune responses. We hypothesized that dendritic cells drive hypoxic PH. We demonstrate that a classical dendritic cell (cDC) subset (cDC2) is increased and activated in wild-type mouse lungs after hypoxia exposure. We observe significant protection after the depletion of cDCs in ZBTB46 DTR chimera mice before hypoxia exposure and after established hypoxic PH. In addition, we find that cDC depletion is associated with a reduced number of two macrophage subsets in the lung (FolR2+ MHCII+ CCR2+ and FolR2+ MHCII+ CCR2-). We found that depleting cDC2s, but not cDC1s, was protective against hypoxic PH. Finally, proof-of-concept studies in human lungs show increased perivascular cDC2s in patients with Idiopathic Pulmonary Arterial Hypertension (IPAH). Our data points to an essential role of cDCs, particularly cDC2s, in the pathophysiology of experimental PH.

TLR3/TRIF and MAVS Signaling Is Essential in Regulating Mucosal T Cell Responses during Rotavirus Infection.

The functions of the natural dsRNA sensors TLR3 (TRIF) and RIG-I (MAVS) are crucial during viral challenge and have not been accurately clarified in adaptive immune responses to rotavirus (RV) infection. In this study, we found that RV infection caused severe pathological damage to the small intestine of TLR3-/- and TRIF-/- mice. Our data found that dendritic cells from TLR3-/- and TRIF-/- mice had impaired Ag presentation to the RV and attenuated initiation of T cells upon viral infection. These attenuated functions resulted in impaired CD4+ T and CD8+ T function in mice lacking TLR3-TRIF signaling postinfection. Additionally, attenuated proliferative capacity of T cells from TLR3-/- and TRIF-/- mice was observed. Subsequently, we observed a significant reduction in the absolute number of memory T cells in the spleen and mesenteric lymph node (MLN) of TRIF-/- recipient mice following RV infection in a bone marrow chimeric model. Furthermore, there was reduced migration of type 2 classical dendritic cells from the intestine to MLNs after RV infection in TLR3-/- and TRIF-/- mice. Notably, RV infection resulted in attenuated killing of spleen and MLN tissues in TRIF-/- and MAVS-/- mice. Finally, we demonstrated that RV infection promoted apoptosis of CD8+ T cells in TRIF-/- and TLR3-/-MAVS-/- mice. Taken together, our findings highlight an important mechanism of TLR3 signaling through TRIF in mucosal T cell responses to RV and lay the foundation for the development of a novel vaccine.

ZBTB46 coordinates angiogenesis and immunity to control tumor outcome.

Tumor angiogenesis and immunity show an inverse correlation in cancer progression and outcome1. Here, we report that ZBTB46, a repressive transcription factor and a widely accepted marker for classical dendritic cells (DCs)2,3, controls both tumor angiogenesis and immunity. Zbtb46 was downregulated in both DCs and endothelial cells by tumor-derived factors to facilitate robust tumor growth. Zbtb46 downregulation led to a hallmark pro-tumor microenvironment (TME), including dysfunctional vasculature and immunosuppressive conditions. Analysis of human cancer data revealed a similar association of low ZBTB46 expression with an immunosuppressive TME and a worse prognosis. In contrast, enforced Zbtb46 expression led to TME changes to restrict tumor growth. Mechanistically, Zbtb46-deficient endothelial cells were highly angiogenic, and Zbtb46-deficient bone marrow progenitors upregulated Cebpb and diverted the DC program to immunosuppressive myeloid lineage output, potentially explaining the myeloid lineage skewing phenomenon in cancer4. Conversely, enforced Zbtb46 expression normalized tumor vessels and, by suppressing Cebpb, skewed bone marrow precursors toward immunostimulatory myeloid lineage output, leading to an immune-hot TME. Remarkably, Zbtb46 mRNA treatment synergized with anti-PD1 immunotherapy to improve tumor management in preclinical models. These findings identify ZBTB46 as a critical factor for angiogenesis and for myeloid lineage skewing in cancer and suggest that maintaining its expression could have therapeutic benefits.

Abstract We055: Role of Classical Dendritic Cells in the Sterile Inflammatory Response Following Myocardial Infarction

Myocardial infarction and the subsequent development of chronic ischemic cardiomyopathy is the most common cause of congestive heart failure. Infarction is associated with an intense sterile inflammatory response which can lead to adverse remodeling over the long term. Dendritic cells (DCs) are antigen presenting cells that function as a bridge between innate and adaptive immunity. Precursor DCs give rise to several distinct classical DC (cDC) subsets that mediate a variety of functions. The cDC1 subset is essential for cross-presentation of antigens to CD8 + T cells, while the cDC2 lineage is a potent inducer of CD4 + T cell proliferation. The aim of the study was to characterize the profile of the cDC populations present during the various stages of the development of chronic ischemic cardiomyopathy. We hypothesized that cDCs are essential mediators of chronic LV remodeling in the period following ischemic myocardial injury. We sought to determine which specific cDC subtype (cDC1 vs cDC2) forms the predominant population in the heart and secondary lymphoid tissues following ischemic injury. Adult male C57BL/6 (WT) mice underwent non-perfused myocardial infarction by ligating the left anterior descending artery (LAD) to induce sterile injury, with sham operated mice used as controls. Left ventricular (LV) remodeling was assessed by echocardiography at 1 w and 8 w following surgery. Alterations in cDC1 (CD45+CD11c+CD103-XCR1-) and cDC2 (CD45+CD11c+CD103+XCR1+) profile were examined by flow cytometry. When compared with the sham operated mice, mice with ischemic cardiomyopathy following LAD ligation exhibited the following features. There is an initial influx of cDC2 into the myocardium 1 w after MI (mean of 3.0% vs 0.26% of CD45 + leukocytes, p=0.02). This is followed by a subsequent influx of cDC1 into the myocardium 4 weeks after MI (mean of 1.98% vs 0.16% of CD45 + leukocytes, p=0.001). This influx of cDC into the heart is accompanied by an egress of cDC from the spleen (mean of 0.37% vs 0.76% of CD45 + leukocytes, P=0.001) at 4 weeks following MI. In conclusion, the findings of our study suggest that there is an initial influx of cDC2 followed by a more sustained influx of cDC1 into the myocardium in the weeks following an infarct. Antigen presentation by cDC likely plays a critical role in driving the inflammatory response and inducing chronic LV remodeling in the period following MI.

An IL-23-STAT4 pathway is required for the proinflammatory function of classical dendritic cells during CNS inflammation

Although many cytokine pathways are important for dendritic cell (DC) development, it is less clear what cytokine signals promote the function of mature dendritic cells. The signal transducer and activator of transcription 4 (STAT4) promotes protective immunity and autoimmunity downstream of proinflammatory cytokines including IL-12 and IL-23. In experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), Stat4-/- mice are resistant to the development of inflammation and paralysis. To define whether STAT4 is required for intrinsic signaling in mature DC function, we used conditional mutant mice in the EAE model. Deficiency of STAT4 in CD11c-expressing cells resulted in decreased T cell priming and inflammation in the central nervous system. EAE susceptibility was recovered following adoptive transfer of wild-type bone marrow-derived DCs to mice with STAT4-deficient DCs, but not adoptive transfer of STAT4- or IL-23R-deficient DCs. Single-cell RNA-sequencing (RNA-seq) identified STAT4-dependent genes in DC subsets that paralleled a signature in MS patient DCs. Together, these data define an IL-23-STAT4 pathway in DCs that is key to DC function during inflammatory disease.

Causal relationship between immune cell phenotypes and risk of biliary tract cancer: evidence from Mendelian randomization analysis.

Biliary tract cancer stands as a prevalent illness, posing significant risks to human health, where immune cells are pivotal in both its development and recovery processes. Due to the diverse functionalities exhibited by different immune cell phenotypes within the organism, and the relatively limited research on their relationship with biliary tract cancer, this study employed Mendelian randomization (MR) to explore their potential association, thereby aiding in a better understanding of the causal link between immune cell phenotypes and biliary tract cancer. In this study, the causative association of 731 immunophenotype with biliary tract cancer was established using publicly accessible genome-wide association study (GWAS) genetic data through two-sample MR analysis. Sensitivity analyses assess horizontal pleiotropy and heterogeneity of the study findings. Among the 731 immunophenotypes examined, a total of 26 immune cell phenotypes were found to exhibit positive results, indicating a significant association with the risk of biliary tract cancer. We confirmed that among these 26 types of immune cells, there are primarily 13 types of B cells; three types of classical dendritic cells (CDCs), including CD80 on myeloid DC, HLA DR on myeloid DC, and Myeloid DC %DC; one type of mature stage T cell,CD4RA on TD CD4+; six types of regulatory T cells; and three types of myeloid cells.

KRAS inhibition triggers coordinated neoplastic and immune remodeling in the tumor microenvironment

Abstract KRAS inhibitors are a novel, recently approved class of small molecules that target cancers with KRAS mutations, and understanding molecular mechanisms by which these inhibitors stimulate anti-tumor immunity will improve patient outcomes. In this study, we utilized a multi-omic approach combining single-cell RNA-seq, spatial transcriptomics, and flow cytometry to define cell signatures and signaling events associated with response in a murine model expressing KRAS-G12C tumors. Treatment with KRAS inhibitors but not MEK inhibitors drove neoplastic differentiation toward cell states with increased oxidative stress and extracellular matrix remodeling capacity. These changes were accompanied by spatially-defined Notch and Integrin signaling patterns between neoplastic, stromal, and classical dendritic cell (cDC) niches, leading to accelerated cDC maturation and CD8 effector T-cell activation. Our multi-omic design distills the complex cellular consequences and intercellular communication patterns in the tumor microenvironment following KRAS inhibition and provides a framework for contextualizing and validating disease-relevant signatures to guide therapeutic strategy.

Imbalance of cell differentiation clusters associated with contamination of biological media by lanthanides in workers of the titanium and rare metals recovery and distillation workshop

The professional activity of a person, depending on the working conditions, modifies the regulation of a single homeostatic mechanism, ultimately forming a breakdown of adaptation associated with an imbalance of immunological 
 parameters.
 The study aims to evaluate changes in the surface molecules of leukocytes of the immune system specifically induced by the presence of lanthanides in workers in the production environment.
 The authors examined 88 people working in the metallurgical industry. The observation group consisted of 24 people with an average work experience of 7.4±0.9 years, the comparison group included 64 people with an average work experience of 7.3±0.9 years. The scientists determined the identification of membrane markers (CD11a, CD277+, CD304+) by flow cytometry, and they also identified specific IgG to lanthanides by allergosorbent testing.
 Excessive concentrations of lanthanides in the blood are formed in workers of the titanium and rare metals recovery and distillation workshop, which are reliably associated with indicator indicators of cellular differentiation of immune regulation clusters: inhibition of expression of immunological phenotypes CD11a, CD304+, CD277+, hyperproduction of specific IgG class reagins to lanthanides. The established immunological scenario is characteristic of the phenotypic characteristics of classical dendritic cells involved in autoimmune inflammatory reactions during the formation of vascular disorders of the central nervous system in workers in these production conditions.
 The results obtained indicate that under conditions of industrial exposure to rare earth metals (lanthanides), workers in the workshop for the recovery and distillation of titanium and rare metals form maladaptive processes of disorders of immune regulation and expression of mediators of cellular differentiation, the markers of which include inhibition of cellular immunity associated with neurovascular mediators (CD11a, CD277+, CD304+), hyperproduction of specific IgG to lanthanides.
 Ethics. The study was approved by the Ethics committee of Federal Scientific Center for Medical and Preventive Health Risk Management Technologies. All patients were informed about the purpose of the study, and voluntary informed consent was obtained.

A generalizable and easy-to-use COVID-19 stratification model for the next pandemic via immune-phenotyping and machine learning.

The coronavirus disease 2019 (COVID-19) pandemic has affected billions of people worldwide, and the lessons learned need to be concluded to get better prepared for the next pandemic. Early identification of high-risk patients is important for appropriate treatment and distribution of medical resources. A generalizable and easy-to-use COVID-19 severity stratification model is vital and may provide references for clinicians. Three COVID-19 cohorts (one discovery cohort and two validation cohorts) were included. Longitudinal peripheral blood mononuclear cells were collected from the discovery cohort (n = 39, mild = 15, critical = 24). The immune characteristics of COVID-19 and critical COVID-19 were analyzed by comparison with those of healthy volunteers (n = 16) and patients with mild COVID-19 using mass cytometry by time of flight (CyTOF). Subsequently, machine learning models were developed based on immune signatures and the most valuable laboratory parameters that performed well in distinguishing mild from critical cases. Finally, single-cell RNA sequencing data from a published study (n = 43) and electronic health records from a prospective cohort study (n = 840) were used to verify the role of crucial clinical laboratory and immune signature parameters in the stratification of COVID-19 severity. Patients with COVID-19 were determined with disturbed glucose and tryptophan metabolism in two major innate immune clusters. Critical patients were further characterized by significant depletion of classical dendritic cells (cDCs), regulatory T cells (Tregs), and CD4+ central memory T cells (Tcm), along with increased systemic interleukin-6 (IL-6), interleukin-12 (IL-12), and lactate dehydrogenase (LDH). The machine learning models based on the level of cDCs and LDH showed great potential for predicting critical cases. The model performances in severity stratification were validated in two cohorts (AUC = 0.77 and 0.88, respectively) infected with different strains in different periods. The reference limits of cDCs and LDH as biomarkers for predicting critical COVID-19 were 1.2% and 270.5 U/L, respectively. Overall, we developed and validated a generalizable and easy-to-use COVID-19 severity stratification model using machine learning algorithms. The level of cDCs and LDH will assist clinicians in making quick decisions during future pandemics.

Abstract 6522: Epigenetic modulation decreases myeloid suppression to improve response to immune checkpoint inhibition in breast cancer

Abstract Immune checkpoint inhibitors (ICIs) promote a durable anti-tumor immune response. Unfortunately, many patients with breast cancer are thought to be intrinsically resistant. One potential mechanism of resistance is a myeloid suppressed tumor microenvironment (TME). Targeting myeloid suppression is under investigation as a therapeutic strategy to sensitize tumors to ICI. In our trial, NCI-9844, we demonstrated that the combination of the epigenetic modulator, entinostat with ICIs—nivolumab (anti-PD-1) + ipilimumab (anti-CTLA-4), leads to a 25% objective response rate in patients with advanced breast cancer. Work in our preclinical models showed entinostat decreases suppressive function by myeloid derived suppressor cells (MDSCs). We hypothesized that entinostat decreases intra-tumoral MDSC suppression via the STAT3/AP-1 axis and drives cellular shifts within the TME to improve response to ICI. Here, we examined expression of upstream, downstream, and interacting factors within the STAT3 pathway in MDSCs treated with entinostat. Macro-dissected lung metastases from entinostat treated NeuN mice revealed differential gene expression of AP-1 subunits JunB and FOSL1 in MDSCs identified by single cell RNA sequencing (scRNAseq). Western blot of isolated intratumoral MDSCs from lung metastases revealed decreased STAT3 phosphorylation upon entinostat treatment. In an entinostat treated MDSC-like cell line, J774M, JunB phosphorylation and FOSL1 were both decreased. scRNAseq also revealed decreased gene expression of STAT3 upstream receptors IL4RA and IFNGR1 and increased expression of STAT3 negative regulator SOCS3. Chromatin immunoprecipitation sequencing is planned to further narrow the molecular mechanism of action. Cell-cell communication analysis of scRNAseq data was performed to evaluate the contribution of entinostat treated macrophages, dendritic cells (DCs), and natural killer (NK) cells on MDSC function. We observed increased frequency of DC populations (classic DC2s and Ccr7 DCs). Following combined treatment with entinostat + ICIs, we also found increased DC to T cell signaling strength for receptor-ligand pairs involved in T cell activation, including Tnfsf9__Tnfrsf9, Cd70_Cd27, H2-dmb2_Cd4, and Cd80_Cd28. Analysis of macrophage-T cell interactions revealed a synergistic decrease in signaling associated with immunosuppression after combined treatment, such as Cd80_Ctla4, Tnf_Tnfrsf1b, and Entpd1_Adora2a. Suppressive function of treated sub-populations of macrophages is planned to determine functional effect of findings. Finally, we are using imaging mass cytometry and bulk RNA sequencing to evaluate proposed mechanisms in patient specimens (NCI-9844). The goal of this work is to identify the molecular and cellular mechanisms driving myeloid suppression of the TME thereby identifying potential therapeutic targets. Citation Format: Aaron G. Baugh, Edgar Gonzalez, Jesse Kreger, Yingtong Liu, Batul Al-Zubeidy, Ludmila Danilova, Sarah M. Shin, Valerie H. Narumi, Sofi Castanon, Julie Jang, Elana J. Fertig, Ashley Cimino-Mathews, Elizabeth M. Jaffee, Vered Stearns, Roisin M. Connolly, Won Jin Ho, Adam MacLean, Evanthia T. Roussos Torres. Epigenetic modulation decreases myeloid suppression to improve response to immune checkpoint inhibition in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6522.