T Helper Research Articles

Establish a novel immune-related gene prognostic risk index (IRGPRI) associated with CD8+ cytotoxic T lymphocytes in non-small-cell lung cancer (NSCLC)

BackgroundThe aim of this study is to create an index called IRGPRI (immune-related gene prognostic risk index) that can be utilized for predicting the prognosis and assessing the efficacy of immune checkpoint inhibitors (ICIs) therapy in patients with non-small-cell lung cancer (NSCLC). MethodsDistinguishing gene expression patterns (DEGs) were detected in CD8+ cytotoxic T lymphocytes (CTLs) compared to other cellular types such as CD4 T cells, B cells, plasma cells, and CD8 Tex using the advanced technology of Single-cell RNA Sequencing (scRNA-seq). The construction of IRGPRI was accomplished by employing LASSO Cox regression analysis. We conducted a comparative analysis on clinical characteristics and molecular features, such as pathway enrichment and gene mutation, among the distinct subgroups of IRGPRI. Furthermore, we explored the correlation between immunological characteristics and IRGPRI subgroups to comprehensively assess the effectiveness of ICIs in NSCLC patients. ResultsA total of 109 genes were identified by intersecting immune-related genes with DEGs obtained from single-cell RNA sequencing data (GSE131907), specifically comparing CTLs to other cell types. From these, we selected 7 prognosis-related genes, namely TRBC1, HLA-DMA, CTSH, RAC1, CTSL, ANXA2, and CEBPB. These genes were used to construct the IRGPRI. The prognosis of patients diagnosed with NSCLC was found to be significantly better in the low-risk group compared to the high-risk group, as demonstrated by Kaplan-Meier (K-M) survival analysis. This observation was further confirmed through the utilization of data from the GEO cohort. The low-risk group demonstrated an increase in pathways linked with immune response, whereas the high-risk group exhibited a higher prevalence of pathways related to cancer. Furthermore, it was noted in the TCGA cohort that there existed a significant rise in the mutation frequency of every gene within the high-risk group as opposed to the low-risk group. Missense variation emerged as the most prevalent form of mutation. According to the analysis of immune cell infiltration and function, the comprehensive findings suggest that the group with a low risk is characterized by an increased presence of plasma cells, CTLs, T cells follicular helper, Tregs, and Dendritic cell resting. Additionally, they exhibit a higher score in terms of immune function for B cells, CD8+ T cells, checkpoint activity, T cell inhibition and stimulation. Moreover, this low-risk group demonstrates greater efficacy when treated with ICIs therapy compared to the high-risk group. ConclusionsOur research effectively developed and verified a unique IRGPRI, showcasing its association with immune-related characteristics. As a result, the potential of IRGPRI as a valuable biomarker for predicting prognosis and evaluating the effectiveness of ICIs treatment in cancer is evident.

BAFF promotes follicular helper T cell development and germinal center formation through BR3 signal.

T follicular helper (Tfh) cells represent an important subset of CD4+ T cells that is crucial to the maturation and differentiation of B cells and the production of high-affinity antibodies. Since BAFF, a vital B cell survival factor, is also crucial to B cell maturation and differentiation, we assessed the effects of BAFF on Tfh cell development and function. We demonstrate that deficiency of BAFF, but not of APRIL, markedly inhibits Tfh cell development, germinal center (GC) formation, and antigen-specific antibody production. The promoting effect of BAFF on Tfh cell development is dependent on expression of BR3 on T cells, and its promoting effect on GC formation is dependent on expression of BR3 on both T cells and B cells. BAFF directly promotes expression of the Tfh cell-characteristic genes via NF-κB signaling. This effect does need BR3 expression. Thus, BAFF not only has direct effects on B cells, but it also has direct effects on Tfh cell differentiation via engagement of BR3 which collectively promote GC formation and production of high-affinity antibodies. This dual effect of BAFF on B cells and Tfh cells may help explain the clinical utility of BAFF antagonists in the management of certain autoimmune diseases.

Variations in the germinal center response revealed by genetically diverse mouse strains.

The humoral response is complex and involves multiple cellular populations and signaling pathways. Bacterial and viral infections, as well as immunization regimens, can trigger this type of response, promoting the formation of microanatomical cellular structures called germinal centers (GCs). GCs formed in secondary lymphoid organs support the differentiation of high-affinity plasma cells and memory B cells. There is growing evidence that the quality of the humoral response is influenced by genetic variants. Using 12 genetically divergent mouse strains, we assessed the impact of genetics on GC cellular traits. At steady state, in the spleen, lymph nodes and Peyer's patches, we quantified GC B cells, plasma cells and follicular helper Tcells. These traits were also quantified in the spleen of mice following immunization with a foreign antigen, namely, sheep red blood cells, in addition to the number and size of GCs. We observed both strain- and organ-specific variations in cell type abundance, as well as for GC number and size. Moreover, we find that some of these traits are highly heritable. Importantly, the results of this study inform on the impact of genetic diversity in shaping the GC response and identify the traits that are the most impacted by genetic background.

Abstract B010: Design of personalized neoantigen mRNA vaccines against breast cancer patients in Pakistan based on next-generation sequencing data

Abstract Breast cancer is the most common malignancy among women in Pakistan, with an outrageous increase in the incidence and mortality rate. Because of decreased effectiveness and lower survival rates, there is an urgent need for developing novel, personalized vaccines with enhanced activity. The development of a personalized mRNA vaccine illustrates a promising approach to combating the prevalence of breast cancer. We used the whole exome sequencing (WES) data of Pakistani tumor samples to predict immunogenic neoantigens. The WES data was aligned to the GRCM39 reference genome using BWA. The genome analysis toolkit (GATK) was employed for variant calling to identify somatic mutations. Using immune-bioinformatics tools, we predicted cytotoxic CD8+ T cell epitopes and helper CD4+ T cell epitopes within the identified neoantigens and designed vaccines by assembling the fusion of CTL neoepitopes, helper sequences, and adjuvants together with linkers. The Insilco ImmSim algorithm was used to examine the immune responses of the vaccine. The vaccine design was further explored by checking its simulation effect on the immune system, its physiochemical characteristics, its binding to specific immune system molecules, and cloning into an appropriate vector. In addition, molecular docking, MD simulation, and binding free energies were performed to investigate the interaction mechanism between the construct vaccine and Toll-like receptors (TLR2, TLR4, TLR7, and TLR9).By examining these factors, we aimed to ensure the vaccine's safety, stability, and ability to bind tightly to specific immune cells (class I MHC molecules), ultimately triggering a comprehensive immune response against breast cancer cells. Citation Format: Kayode Yomi Raheem, Muhammad Muddassar. Design of personalized neoantigen mRNA vaccines against breast cancer patients in Pakistan based on next-generation sequencing data [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr B010.

Targeting Polyprotein to Design Potential Multiepitope Vaccine against Omsk Hemorrhagic Fever Virus (OHFV) by Evaluating Allergenicity, Antigenicity, and Toxicity Using Immunoinformatic Approaches.

Omsk Hemorrhagic Fever Virus (OHFV) is an RNA virus with a single-stranded, positive-sense genome. It is classified under the Flaviviridae family. The genome of this virus is 98% similar to the Alkhurma hemorrhagic fever virus (AHFV), which belongs to the same family. Cases of the virus have been reported in various regions of Saudi Arabia. Both OHFV and AHFV have similarities in pathogenic polyprotein targets. No effective and licensed vaccines are available to manage OHFV infections. Therefore, an effective and safe vaccine is required that can activate protective immunity against OHFV. The current study aimed to design a multiepitope subunit vaccine against the OHFV utilizing several immunoinformatic tools. The polyprotein of OHFV was selected and potent antigenic, non-allergenic, and nontoxic cytotoxic T-lymphocyte (CTL), helper T-lymphocyte (HTL), and linear B-lymphocyte (LBL) epitopes were chosen. After screening, eight (8) CTL, five (5) HTL, and six (6) B cell epitopes were joined with each other using different linkers. Adjuvant human beta defensin-2 was also linked to the epitopes to increase vaccine antigenic and immunogenic efficiency. The designed vaccine was docked with Toll-like receptor 4 (TLR4) as it activates and induces primary and secondary immune responses against OHFV. Codon optimization was carried out, which resulted in a CAI value of 0.99 and 53.4% GC contents. In addition, the construct was blindly docked to the TLR4 immune receptor and subjected to conformational dynamics simulation analysis to interpret the intricate affinity and comprehend the time-dependent behavior. Moreover, it was predicted that immune responses to the developed vaccine construct reported formation of strong humoral and cellular immune cells. Therefore, the proposed vaccine may be considered in experimental assays to combat OHFV infections. Laboratory experiments for the above predictions are essential in order to evaluate the effectiveness, safety, and protective properties of the subject in question.

Compromiso gástrico por enfermedad relacionada con IgG4

Introduction: IgG4-related disease (IgG4-RD) is a recently described entity, characterized by IgG4+ infiltration of plasma cells and storiform pattern sclerosis mediated by CD4+ lymphocytes and follicular helper T-cells (Tfhs). Most patients present with adenopathy and weight loss. Among the most affected sites are the pancreas, salivary and lacrimal glands, aorta, and retroperitoneum. Gastric involvement is rare. Diagnosis is based on histopathological examination of the involved organ, clinical manifestations, and serological results. Glucocorticoid therapy is the first line management. Case report: a 38-year-old male patient with symptoms suggestive of upper gastrointestinal (GI) bleeding, upper GI endoscopy revealed a gastric corpus ulcer, suspicious of an ulcerated gastric subepithelial lesion, possibly a gastrointestinal stromal tumor (GIST). Consequently, laparoscopic subtotal gastrectomy was performed. Histology was compatible with an ulcerated IgG4-related fibrosclerosing tumor. Glucocorticoid therapy was started with patient´s favorable response. Conclusion: in this paper, we will review the cases of IgG4-RD with gastric involvement reported in the literature to describe the most important features of this condition.

Targeting BTN2A1 enhances Vγ9Vδ2 T-cell effector functions and triggers tumor cell pyroptosis

Targeting BTN2A1 enhances Vγ9Vδ2 T-cell effector functions and triggers tumor cell pyroptosis

Adjuvant Use of the Invariant-Natural-Killer-T-Cell Agonist α-Galactosylceramide Leads to Vaccine-Associated Enhanced Respiratory Disease in Influenza-Vaccinated Pigs.

Invariant natural killer T (iNKT) cells are glycolipid-reactive T cells with potent immunoregulatory properties. iNKT cells activated with the marine-sponge-derived glycolipid, α-galactosylceramide (αGC), provide a universal source of T-cell help that has shown considerable promise for a wide array of therapeutic applications. This includes harnessing iNKT-cell-mediated immune responses to adjuvant whole inactivated influenza virus (WIV) vaccines. An important concern with WIV vaccines is that under certain circumstances, they are capable of triggering vaccine-associated enhanced respiratory disease (VAERD). This immunopathological phenomenon can arise after immunization with an oil-in-water (OIW) adjuvanted WIV vaccine, followed by infection with a hemagglutinin and neuraminidase mismatched challenge virus. This elicits antibodies (Abs) that bind immunodominant epitopes in the HA2 region of the heterologous virus, which purportedly causes enhanced virus fusion activity to the host cell and increased infection. Here, we show that αGC can induce severe VAERD in pigs. However, instead of stimulating high concentrations of HA2 Abs, αGC elicits high concentrations of interferon (IFN)-γ-secreting cells both in the lungs and systemically. Additionally, we found that VAERD mediated by iNKT cells results in distinct cytokine profiles and altered adaptation of the challenge virus following infection compared to an OIW adjuvant. Overall, these results provide a cautionary note about considering the formulation of WIV vaccines with iNKT-cell agonists as a potential strategy to modulate antigen-specific immunity.

Allergic Bronchopulmonary Aspergillosis (ABPA) in the Era of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Modulators.

Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity disease caused by Aspergillus fumigatus (Af), prevalent in persons with cystic fibrosis (CF) or asthma. In ABPA, Af proteases drive a T-helper cell-2 (Th2)-mediated allergic immune response leading to inflammation that contributes to permanent lung damage. Corticosteroids and antifungals are the mainstays of therapies for ABPA. However, their long-term use has negative sequelae. The treatment of patients with CF (pwCF) has been revolutionized by the efficacy of cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy. Pharmacological improvement in CFTR function with highly effective elexacaftor/tezacaftor/ivacaftor (ETI) provides unprecedented improvements in lung function and other clinical outcomes of pwCF. The mechanism behind the improvement in patient outcomes is a continued topic of investigation as our understanding of the role of CFTR function evolves. As ETI therapy gains traction in CF management, understanding its potential impact on ABPA, especially on the allergic immune response pathways and Af infection becomes increasingly crucial for optimizing patient outcomes. This literature review aims to examine the extent of these findings and expand our understanding of the already published research focusing on the intersection between ABPA therapeutic approaches in CF and the rapid impact of the evolving CFTR modulator landscape. While our literature search yielded limited reports specifically focusing on the role of CFTR modulator therapy on CF-ABPA, findings from epidemiologic and retrospective studies suggest the potential for CFTR modulator therapies to positively influence pulmonary outcomes by addressing the underlying pathophysiology of CF-ABPA, especially by decreasing inflammatory response and Af colonization. Thus, this review highlights the promising scope of CFTR modulator therapy in decreasing the overall prevalence and incidence of CF-ABPA.

Real-world treatment patterns and outcomes of patients with advanced melanoma treated with nivolumab plus relatlimab

Abstract The use of programmed death-1 (PD-1) inhibitors has been a pivotal advancement in treating advanced melanoma, yet their efficacy is limited. The approval of relatlimab (RELA), a lymphocyte activation gene 3 protein (LAG-3) antibody, in combination with nivolumab (NIVO), a PD-1 inhibitor, marked a significant stride toward enhancing treatment efficacy for metastatic and unresectable stage 3 and 4 melanoma. This combination has been shown to synergistically improve antitumor activity and effector T-cell activity in the tumor microenvironment, despite limited data on real-world outcomes. Our retrospective review at a tertiary cancer center of patients with stage 3 and 4 melanoma treated with NIVO-RELA revealed an overall response rate (ORR) of 39%, with notable improvements in median PFS and ORR, especially in first-line treated patients. Our study highlights the superior efficacy of NIVO-RELA over previous reports, demonstrating its significant potential in the treatment landscape of advanced melanoma.

Enoximone alleviates atopic dermatitis-like skin inflammation via inhibition of type 2 T helper cell development

Atopic dermatitis (AD) is an inflammatory skin disease that affects approximately 15–20 % of the children and 1–3 % of the adults worldwide. Corticosteroids and calcineurin inhibitors are used in AD therapy; however, they cause various side effects. Current studies focus on novel therapeutic targets such as phosphodiesterases (PDEs) to mitigate AD. However, the relationship between PDE3 inhibitors and AD has not yet been reported. This study aimed to investigate the therapeutic effects and pharmaceutical mechanisms of enoximone (Enox), a PDE3 inhibitor. Mice were stimulated with 2,4-dinitrochlorobenzene (DNCB) to induce AD-like skin inflammation and were topically treated with Enox for 2 weeks. Treatment with Enox reduced the dermatitis score, skin water loss, IgE production, and expression of cytokines and chemokines that were elevated by DNCB. Histologically, Enox treatment reduced the skin thickness and the infiltration of various inflammatory cells, including macrophages, mast cells, eosinophils, and type 2 T helper (Th2) cells. HuT78, a human T cell line, was used to investigate the differentiation of T cells into Th2 cells. Enox treatment decreased the expression of Th2 cytokines and GATA3, a Th2 cell marker in HuT78, and suppressed signaling pathways that play a crucial role in Th2 cell differentiation. Collectively, the results demonstrate that Enox alleviates AD-like skin inflammation by inhibiting T-cell development. Thus, Enox may be a therapeutic candidate for the treatment of AD.

Consequences of the perivascular niche remodeling for tumoricidal T-cell trafficking into metastasis of ovarian cancer.

The treatment-induced activation level within the perivascular tumor microenvironment (TME) that supports T-cell trafficking and optimal T-cell differentiation is unknown. We investigated the mechanisms by which inflammatory responses generated by tumor-specific T cells delivered to ovarian tumor-bearing mice alone or after oncolytic vaccinia virus-driven immunogenic cancer cell death affect antitumor efficacy. Analyses of the perivascular TME by spatially resolved omics technologies revealed reduced immunosuppression and increased tumoricidal T-cell trafficking and function after moderate inflammatory responses driven by a CXCR4 antagonist-armed oncolytic virus. Neither weak nor high inflammation created a permissive TME for T-cell trafficking. Notably, treatment-mediated differences in T-cell effector programs acquired within the perivascular TME contrasted with comparable antigenic priming in the tumor-draining lymph nodes regardless of the activation mode of antigen-presenting cells. These findings provide new insights into combinatorial treatment strategies that enable tumor-specific T cells to overcome multiple barriers for enhanced trafficking and control of tumor growth. .

Ipsilateral or contralateral boosting of mice with mRNA vaccines confers equivalent immunity and protection against a SARS-CoV-2 Omicron strain.

Boosting with mRNA vaccines encoding variant-matched spike proteins has been implemented to mitigate their reduced efficacy against emerging SARS-CoV-2 variants. Nonetheless, in humans, it remains unclear whether boosting in the ipsilateral or contralateral arm with respect to the priming doses impacts immunity and protection. Here, we boosted K18-hACE2 mice with either monovalent mRNA-1273 (Wuhan-1 spike) or bivalent mRNA-1273.214 (Wuhan-1 + BA.1 spike) vaccine in the ipsilateral or contralateral leg after a two-dose priming series with mRNA-1273. Boosting in the ipsilateral or contralateral leg elicited equivalent levels of serum IgG and neutralizing antibody responses against Wuhan-1 and BA.1. While contralateral boosting with mRNA vaccines resulted in the expansion of spike-specific B and T cells beyond the ipsilateral draining lymph node (DLN) to the contralateral DLN, administration of a third mRNA vaccine dose at either site resulted in similar levels of antigen-specific germinal center B cells, plasmablasts/plasma cells, T follicular helper cells, and CD8+ T cells in the DLNs and the spleen. Furthermore, ipsilateral and contralateral boosting with mRNA-1273 or mRNA-1273.214 vaccines conferred similar homologous or heterologous immune protection against SARS-CoV-2 BA.1 virus challenge with equivalent reductions in viral RNA and infectious virus in the nasal turbinates and lungs. Collectively, our data show limited differences in B and T cell immune responses after ipsilateral and contralateral site boosting by mRNA vaccines that do not substantively impact protection against an Omicron strain.IMPORTANCESequential boosting with mRNA vaccines has been an effective strategy to overcome waning immunity and neutralization escape by emerging SARS-CoV-2 variants. However, it remains unclear how the site of boosting relative to the primary vaccination series shapes optimal immune responses or breadth of protection against variants. In K18-hACE2 transgenic mice, we observed that intramuscular boosting with historical monovalent or variant-matched bivalent vaccines in the ipsilateral or contralateral limb elicited comparable levels of serum spike-specific antibody and antigen-specific B and T cell responses. Moreover, boosting on either side conferred equivalent protection against a SARS-CoV-2 Omicron challenge strain. Our data in mice suggest that the site of intramuscular boosting with an mRNA vaccine does not substantially impact immunity or protection against SARS-CoV-2 infection.

Diverse Clinical and Immunological Profiles in Patients with IPEX Syndrome: a Multicenter Analysis from Turkey.

Immunodysregulation, Polyendocrinopathy, Enteropathy, and X-linked syndrome (IPEX), caused by pathogenic FOXP3 variants, is a rare autoimmune disorder with diverse clinical features, including early-onset diabetes, eczema, and enteropathy. Atypical cases show milder symptoms and unique signs, requiring different treatments. Therefore, there are ambiguities in the accurate diagnosis and management of IPEX. We sought to present clinical, genetic, and immunological assessments of 12 IPEX patients with long-term follow-up to facilitate the diagnosis and management of the disease. Clinical findings and treatment options of the patients were collected over time. Lymphocyte subpopulations, protein expressions, regulatory T (Treg) and circulating T follicular helper (cTFH) cells, and T-cell proliferation were analyzed. Predominant presentations included autoimmunity (91.6%), failure to thrive (66.7%), and eczema (58.3%). There were four classical and eight atypical IPEX individuals. Allergic manifestations were more common in atypical patients. Notably, chronic diarrhea demonstrated heightened severity compared to other manifestations. Four patients (33.3%) demonstrated eosinophilia, and nine (75%) showed high serum IgE levels. Most patients exhibited normal percentages of Treg cells with reduced CD25, FOXP3, and CTLA-4 expressions, corrected after hematopoietic stem cell transplantation (HSCT). Compared to healthy controls, the TH2-like skewing accompanied by reduced TH17-like responses was observed in cTFH and Treg cells of patients. Overall, nine patients (75%) received immunosuppressants (ISs), and six (50%) underwent HSCT, which was the only treatment revealing sustained control. Sirolimus was used in six patients and showed better control than other ISs. The first cohort from Turkey with long-term follow-up results, comparing typical and atypical cases, provides insights into the outcomes of different therapeutic modalities and T- cell subtype changes in IPEX syndrome.

Investigating immune dysregulation and hub genes in septic cardiomyopathy development

Septic cardiomyopathy is a life-threatening heart dysfunction caused by severe infection. Considering the complexity of pathogenesis and high mortality, the identification of efficient biomarkers are needed to guide clinical practice. Based on multimicroarray analysis, this study aimed to explore the pathogenesis of septic cardiomyopathy and the related immune landscape. The results showed that septic cardiomyopathy resulted in organ dysfunction due to extreme pro- and anti-inflammatory effects. In this process, KLRG1, PRF1, BCL6, GAB2, MMP9, IL1R1, JAK3, IL6ST, and SERPINE1 were identified as the hub genes regulating the immune landscape of septic cardiomyopathy. Nine transcription factors regulated the expression of these genes: SRF, STAT1, SP1, RELA, PPARG, NFKB1, PPARA, SMAD3, and STAT3. The hub genes activated the Th17 cell differentiation pathway, JAK-STAT signaling pathway, and cytokine‒cytokine receptor interaction pathway. These pathways were mainly involved in regulating the inflammatory response, adaptive immune response, leukocyte-mediated immunity, cytokine-mediated immunity, immune effector processes, myeloid cell differentiation, and T-helper cell differentiation. These nine hub genes could be considered biomarkers for the early prediction of septic cardiomyopathy.

Adenosine A2B receptor activation regulates the balance between T helper 17 cells and regulatory T cells, and inhibits regulatory T cells exhaustion in experimental autoimmune myositis.

Idiopathic inflammatory myopathy (IIM) is a systemic autoimmune disease characterized by skeletal muscle involvement. This study aimed to investigate the role of adenosine receptor signalling pathways in the development of experimental autoimmune myositis (EAM). An ecto-5'-nucleotidase (CD73) inhibitor, adenosine receptor agonists, a hypoxia-inducible factor-1α (HIF-1α) inhibitor or a vehicle were administered to control and EAM mice. Murine splenic CD4+ or regulatory T cells (Tregs) were isolated using magnetic beads and subsequently stimulated with an adenosine A2B receptor agonist, a HIF-1α inhibitor, or vehicle in vitro. In cross-sectional studies, we collected 64 serum samples (69% female, 49±9years), 63 peripheral blood samples (70% female, 50±11years), and 34 skeletal muscle samples (71% female, 63±6years) from patients with IIM. Additionally, 35 serum samples and 30 peripheral blood samples were obtained from age- and sex-matched healthy controls, and six quadriceps muscle samples were collected from patients with osteoarthritis to serve as the normal group. Patients with IIM exhibited increased CD73 [dermatomyositis (DM), polymyositis (PM): P<0.01; immune-mediated necrotizing myopathy (IMNM): P<0.0001] and adenosine deaminase (ADA) expression (DM: P<0.001; PM, IMNM: P<0.0001) in the skeletal muscles, and serum ADA levels [56.7 (95% CI: 53.7, 58.7) vs. 198.8 (95% CI: 186.2, 237.3) ng/μL, P<0.0001]. Intervention with a CD73 inhibitor exacerbated (P=0.0461), whereas adenosine receptor agonists (A1: P=0.0009; A2B: P<0.0001; A3: P=0.0001) and the HIF-1α inhibitor (P=0.0044) alleviated skeletal muscle injury in EAM mice. Elevated expression of programmed cell death protein-1 (PD1: P=0.0023) and T-cell immunoglobulin and mucin-domain containing-3 (TIM3: P<0.0001) in skeletal muscles of patients with IIM were correlated with creatine kinase levels (PD1, r=0.7072, P<0.0001; TIM3, r=0.4808, P=0.0046). PD1+CD4+ (r=0.3243, P=0.0115) and PD1+CD8+ (r=0.3959, P=0.0017) T cells were correlated with Myositis Disease Activity Assessment Visual Analogue Scale scores (muscle) in IIM. The exhausted Tregs were identified in the skeletal muscles of patients with IIM. Activation of the A2B adenosine receptor downregulated HIF-1α (protein or mRNA level, P<0.01), resulting in decreased T helper cell 17 (Th17) (13.58% vs. 5.43%, P=0.0201) and phosphorylated-signal transducer and activator of transcription 3 (p-STAT3)+ Th17 (16.32% vs. 6.73%, P=0.0029), decreased exhausted Tregs (PD1+ Tregs: 53.55% vs. 40.28%, P=0.0005; TIM3+ Tregs: 3.93% vs. 3.11%, P=0.0029), and increased Tregs (0.45% vs. 2.89%, P=0.0006) in EAM mice. The exhausted T cells may be pathogenic in IIM,andthe activation of adenosine A2B receptor signalling pathway can regulate Th17/Treg balance and inhibit Tregsexhaustion, thereby slowing EAM disease progression.

Abstract B073: Organ-specific diversity of tumor immune microenvironment in metastatic pancreatic cancer

Abstract Pancreatic ductal adenocarcinoma (PDAC) that is refractory to treatment frequently leads to extensive systemic and multi-organ metastases. PDAC is characterized as an immune “cold” cancer; however, the persistence of this “cold” tumor immune microenvironment (TIME) across distant metastases, and the mechanisms by which metastases influence their respective TIME, remain poorly understood. In this study, we conducted spatial protein expression profiling of the TIME using the Nanostring GeoMx Digital Spatial Profiling (DSP) platform. We employed a 43- plex panel on 54 tissue samples, including 14 primary tumors and 40 matched metastases from organs commonly affected by PDAC metastases (liver, lung, and peritoneum), obtained through a rapid (“warm”) autopsy program. We quantified protein expression in three cellular compartments: PanCK+ epithelial cells, α-SMA+ fibroblasts, and CD45+ immune cells, across 181 regions of interest (ROIs). Our analysis revealed a significant enrichment of CD45+ immune cells in lung metastases compared to other organ sites, with a notably lower presence of these cells in liver metastases. Focusing on the immune cell compartment, we analyzed the CD45 segments for further investigation. After normalization using housekeeping proteins, including Histone H3, GAPDH, and ribosomal protein S6, we found that the immune profiles were most distinct between liver and lung metastases. Specifically, liver metastases exhibited the greatest deviation in immune profile compared to primary PDAC, lung, and peritoneal metastases. We scored protein expression signatures for various immune cell subsets based on specific marker expressions. When comparing liver to lung metastases, scores for T cells, myeloid cells, checkpoint markers, macrophages, and interferon signaling were significantly lower in the liver, underscoring the immune “coldness” of the liver metastasis environment. Our cohort included six untreated patients and nine patients treated with chemotherapies. We compared protein expressions in each organ site between untreated and treated patients. Notably, treatment induced divergent expression patterns of multiple proteins between liver and lung metastases. While treatment significantly reduced the expression of several immune markers, including CD45 (total immune), CD3 (T cell), CD4 (T helper cell), CD45RO (memory T cell), CD163 (M2 macrophage), and B7-H3 (checkpoint marker), in lung metastases, these markers were significantly upregulated in liver metastases of treated patients. This finding indicates a pronounced divergence in TIME modulation in response to treatment between liver and lung metastases, potentially fostering a treatment-resistant environment in PDAC patients with multi- organ metastasis. Consequently, this urges the need to develop tailored therapeutic strategies for PDAC metastasis, taking into account the distinct immune landscapes of different metastasis sites. Citation Format: Jimin Min, Vittorio Branchi, Kimal I Rajapakshe, Nisha Narayanan, Guangsheng Pei, Linghua Wang, Jean L Grem, Thomas C Caffrey, Paul M Grandgenett, Michael A Hollingsworth, Paola A Guerrero, Anirban Maitra. Organ-specific diversity of tumor immune microenvironment in metastatic pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B073.

Abstract A050: MDSC-derived transmembrane TNF is a central regulator of stromal inflammation and T-cell dysfunction in pancreatic cancer

Abstract INTRODUCTION: Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy characterized by stromal inflammation and T-cell dysfunction. Neutrophilic/granulocytic myeloid-derived suppressor cells (gMDSC) infiltrate early in PDAC development and contribute to a highly immunosuppressive tumor microenvironment (TME). We have previously shown that gMDSC-derived tumor necrosis factor (TNF) is a novel regulator of therapeutic resistance in the PDAC TME, and pharmacological targeting of transmembrane (tm)TNF-TNFR2 signaling can reprogram the TME to improve chemosensitivity. Here we dissect the functional consequences of gMDSC-derived tmTnf on cancer-associated fibroblast (CAF) skewness and CD8+ T-cell function. METHODS: To assess global effects of tmTNF in orthotopically and subcutaneously injected KPC models of PDAC, we compared T-cell/CAF phenotypes in littermate vs transgenic mice overexpressing exclusively tmTnf (tmTnfOE)—in which site-directed mutagenesis of TNF cleavage sites renders tmTNF uncleavable, resulting in systemically overexpressed tmTNF signaling. To investigate effects of gMDSC-derived tmTnf in vitro, J774M cells that phenocopy gMDSCs were engineered to overexpress exclusively tmTnf (J-tmTnfOE) or wild-type Tnf (J-TnfWT) following CRISPR/cas9 silencing of endogenous Tnf (J-TnfKO). These cells were co-cultured with dual reporter CAFs (Il6GFP=inflammatory iCAF; Acta2dsRed=myofibroblastic myCAF) and CD8+ T-cells followed by cell trace violet proliferation assay, flow cytometry phenotyping, and IFNγ ELISA. RESULTS: Compared to littermate controls, flank and orthotopic KPC tumor-bearing tmTnfOE mice displayed accelerated tumor kinetics and volume, respectively, as well as increase in stromal fibrosis and collagen deposition (Trichrome/Sirius Red). Flow cytometric phenotyping revealed increased proportion of iCAF (PDPN+Ly6C+) vs myCAF (PDPN+Ly6C-) in tmTNFOE vs littermate mice. Moreover, intratumoral gMDSCs isolated from tmTNFOE mice augmented CAF-Il6GFP:Acta2dsRed ratios ex vivo. CD8+ T-cell phenotyping revealed higher proportions of CD39+Ly108- dysfunctional and KLRG1+CD127- short-lived effector T-cells (SLEC), with concurrent reduction in CD127+KLRG1- memory progenitor effector T-cells (MPEC), in tmTnfOE compared with littermate tumors. Using confocal microscopy in vitro, we confirmed that transmembrane sequestration of Tnf was more pronounced in J-tmTNFOE vs J-TnfWT, with complete loss of subcellular Tnf in J-TnfKO cells. To define the precise contribution of gMDSC-tmTNF on CAF/T-cell skewness, co-culture of J-tmTnfOE with dual-reporter CAFs resulted in striking induction in CAF-Il6GFP compared with J-TnfKO-CAF co-cultures. Moreover, J-tmTnfOE significantly restrained CD8+ T-cell proliferation, MPEC differentiation, and IFN-γ release relative to J-TnfKO. CONCLUSIONS: gMDSC-tmTnf is a central regulator of inflammatory CAF polarization and CD8+ T-cell dysfunction in PDAC. Selective pharmacologic or genetic strategies to disrupt gMDSC-tmTNF derived signaling in the TME may improve chemoimmunotherapy sensitivity in PDAC. Citation Format: Andrew M Adams, Haleh Amirian, Christine I Rafie, Karthik Rajkumar, Erin Dickey, Harper M Marsh, Manan Patel, Siddharth Mehra, Nagaraj Nagathihalli, Nipun Merchant, Yoon S Yap, Luisa Cimmino, Erietta Stelekati, Anna Bianchi, Jashodeep Datta. MDSC-derived transmembrane TNF is a central regulator of stromal inflammation and T-cell dysfunction in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A050.

PSIV-23 Transcriptomic analysis revealed the mechanisms of resilience and susceptibility to nonalcoholic steatohepatitis in dairy goats under high-concentrate diet

Abstract Liver health is vital for growth and health of ruminants, which can directly affect their performance. High-concentrate diet (HCD) feeding, a common practice to meet the energy requirements for animal production and growth, has been known to induce liver damage, including nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH) in ruminants. To date, the regulatory mechanisms of liver metabolic dysfunctions in ruminants induced by HCD are not well defined. To elucidate molecular regulatory mechanisms underlying liver dysfunction in ruminants, we compared liver transcriptome and single-cell transcriptome of dairy goats that had varied responses to the HCD, aiming to underpin the key mechanisms behind resilience and susceptibility to NASH in ruminants. After feeding 30 dairy goats with low-concentrate diet (LCD, n = 15, defined as Con) or high-concentrate diet (HCD, n = 15) for 6 wk, 10 of them developed NASH (defined as NASH), while the other 5 did not showed any NASH symptom (defined as NASH-tolerance, NASH-T) under HCD. Liver tissues were collected to extract RNA. The paired-end RNA-seq library was sequenced with a NovaSeq6000 sequencer (Illumina). Real-time quantitative PCR was conducted to verify the significantly different genes among groups. Liver single-cell transcriptome was performed using 10×Genomics Chromium system. Liver transcriptome analysis revealed that the expression level of genes involved in the interleukin (IL)-17 signaling pathway, including IL-17A (P = 0.035; 0.001), Act1 (P = 0.036; 0.002), FOSB (P = 0.041; 0.048) and IL-1β (P = 0.022; 0.002) in the NASH group were significantly greater than those in the Con and NASH-T groups. Hepatic single-cell RNA sequencing identified seven cell types in the liver, including hepatocytes, macrophages, T cells, endothelial cell, natural killer (NK) cell, hepatic stellate cells (HSCs), B cells. In T cell subset, significantly decreased T helper 17 (TH17) cells and increased regulatory T (Treg) cells were detected in the NASH group compared with Con and NASH-T groups. In TH17 cell, the expression levels of IL-17A (P = 0.004; 0.009) and IL-23R (P = 0.007; 0.01; the surface antibodies of TH17 cells) in NASH group were significantly greater than those in the Con and NASH-T groups. The expression levels of Foxp3 (P &amp;lt; 0.001; 0.013), IL-2R (P &amp;lt; 0.001; 0.001), CTLA-4 (P = 0.005; 0.017) and CD127 (P = 0.004; 0.009; the surface antibodies of Treg cells) in NASH group were significantly less than those in the Con and NASH-T groups. Our results revealed the role of liver immune cells in maintaining tolerance to NASH in dairy goats under HCD, which provides new understanding in pathogenesis of NASH under HCD. Further studies are needed to identify major factors that drive the changes of ratio of TH17/Treg cell.

Immunologic markers for vitiligo

Questions of the etiology and pathogenesis of vitiligo remain open to this day. Of the majority of hypotheses for the development of vitiligo, the leading role today belongs to the autoimmune theory. The most relevant for solving issues of both therapy and diagnosis of the disease are studies devoted to the immunological mechanisms accompanying the development of vitiligo. The article describes both immunological markers of autoimmune diseases of satellites and changes in immunity during the disease itself. The question of the activity of the process sometimes causes great difficulties, both for the doctor, and the patient himself sometimes cannot say for sure whether there is a growth of foci, especially with a widespread process. In the article we touched upon the issues of consideration and immunological markers, which, according to pilot studies, can serve as laboratory indicators of activity. The roles of interleukin 17, imbalance between subpopulations of T-helper lymphocytes type 1 (Th 1) or Th 17 and Tregs and Th 2, cytokine imbalance, JAK1 and JAK2 kinases, CXCL 9, CXCL 10, granzyme B are described.