Mechanisms Of Immune Tolerance Research Articles

Long-term immunological changes after corrective cardiacsurgery.

Infants with congenital heart disease (CHD) often undergo thymectomy during corrective cardiac surgery (CCS). The long-term immunological effects remain controversial, with concerns regarding increased susceptibility to infections, allergies, autoimmunity due to compromised immune tolerance mechanisms. This study aims to elucidate the long-term immunological effects of early thymectomy. We enrolled 22 patients who underwent thymectomy in infancy and were followed up in the Pediatric Allergy and Immunology Clinic at Marmara University. We performed demographic characteristics and detailed immunological evaluation, including immunoglobulins, vaccine responses, lymphocyte subset analyses, upregulation, proliferation of T cells and T-cell receptor excision circles (TRECs). Sixteen patients had a history of infection, including six serious infections, all in the first year. Lymphopenia was observed in 27% of patients, with a significant decrease in naive CD4+ and recent thymic emigrant T cells counts and an increase in the proportion of memory T-cells, indicating premature immune senescence. Low levels of IgG, IgA and IgM were found in 36%, 40% and 22% of patients respectively. Vaccine responses were positive in 90% of patients. TREC levels were low in all 10 patients analysed. Seven of nine patients had normal proliferation. Twenty-two percent of patients had allergic disease, and autoimmunity was not observed. Early thymectomy leads to permanent immunological changes that are indicative of early immunosenescence. It is recommended to preserve thymic tissue during surgery and requires long-term follow-up in terms of findings such as allergy and autoimmunity as well as infections due to impaired immune tolerance mechanisms.

PD-1 immunology in the kidneys: a growing relationship.

In recent years, knowledge regarding immune regulation has expanded rapidly, and major advancements have been made in immunotherapy for immune-associated disorders, particularly cancer. The programmed cell death 1 (PD-1) pathway is a cornerstone in immune regulation. It comprises PD-1 and its ligands mediating immune tolerance mechanisms and immune homeostasis. Accumulating evidence demonstrates that the PD-1 axis has a crucial immunosuppressive role in the tumor microenvironment and autoimmune diseases. PD-1 receptors and ligands on immune cells and renal parenchymal cells aid in maintaining immunological homeostasis in the kidneys. Here, we present a comprehensive review of PD-1 immunology in various kidney disorders, including renal cell carcinoma, glomerulonephritis, kidney transplantation, renal aging, and renal immune-related adverse events secondary to PD-1 immunotherapy.

Impaired tolerance of monocyte-macrophages to lipopolysaccharide in patients with coronary atherosclerosis

Atherosclerosis is a chronic disease in which lipids, cells and various proteins accumulate in the walls of the arteries, forming atherosclerotic plaques. The growth of plaques leads narrowing of the lumen of the blood vessels. Atherosclerosis is accompanied by local inflammation, while the number of hematogenous macrophages are derived from monocytes increases in the vascular wall. The reasons why the inflammatory reaction cannot be completed and becomes chronic are not clear. To resolve inflammation and protect tissues from high concentrations of cytokines that can cause apoptosis, there is a mechanism of immune tolerance of innate immunity. Lipopolysaccharide (LPS) tolerance of monocyte-macrophages is a phenomenon in which cells reduce their sensitivity to repeated exposure to LPS. This condition is characterized by a decrease in the ability of macrophages to produce proinflammatory cytokines and promotes resolution of inflammation. We hypothesized that in atherosclerosis, tolerance violations in monocyte-macrophages are possible. The study included patients who were admitted to the department of cardiac surgery, Moscow Regional Research and Clinical Institute (MONIKI). Patients were divided into patients with coronary atherosclerosis (CAD) with detected stenosis in 2 or more arteries and healthy controls without stenosis in the arteries according to the results of coronary angiography. In the present study, we examined the ability of macrophages from 13 patients with CAD and 11 patients without CAD to develop tolerance to LPS. To do this, we isolated CD14+ monocytes from the blood by positive selection using immunomagnetic separation and subjected them to two sequential LPS stimulations, immediately after cell isolation and after 6 days of culture. The secretion of cytokines TNFα, IL-1b, IL-6, IL-10, IL-8, and CCL2 was measured in cell culture supernatants using by ELISA. Our results showed impaired macrophage tolerance for CCL2 secretion and improved tolerance for IL-8 secretion in macrophages from patients with CAD compared with patients without. Since IL-8 and CCL2 are chemoattractants for other immune cells, it can be assumed that the observed impairment of macrophage tolerance to LPS in atherosclerosis increases the infiltration of other monocytes into the inflammatory site, contributing to the chronicity of inflammation.

Liver metastasis and resistance to immunotherapy in microsatellite stable colorectal cancer. A literature review.

Microsatellite stable (MSS) metastatic colorectal cancer (CRC) remains predominantly managed with chemotherapy. The use of immunotherapy, whether alone or in combination with other systemic or local treatments, displays limited success, especially in the context of active liver metastases (LM). The mechanisms responsible for this resistance are not fully understood. We conducted a comprehensive search across electronic databases such as Medline, PubMed, Google Scholar and ScienceDirect. This search targeted translational studies evaluating the liver tumour immune microenvironment and immune tolerance mechanisms in CRC with LM and prospective studies that assessed immunotherapy either as a standalone treatment or in combination with other systemic or local therapies for patients diagnosed with MSS CRC. Our primary objectives included elucidating the mechanisms of resistance originating from LM in a non-systematic literature review and presenting a summary of the outcomes observed in prospective trials utilising immune checkpoint inhibitors (ICIs), with a focus on the presence of LM. There were 16 prospective trials evaluating immunotherapy for metastatic CRC comprising 1,713 patients. Response rates to immunotherapy inpatients with colorectal liver metastases (CRLM) varied from 0% to 23%. Overall, reduced or null responses to immunotherapy in the presence of liver metastasis in comparison to patients without liver involvement were observed. Studies consistently show the resistance derived from classical ICI, both alone and in combination with other systemic treatments in patients with CRLM. The design of upcoming trials using immunotherapy should consider LM as a stratification factor or contemplate excluding patients with liver involvement.

Rebalancing the Immune System to Treat Type 1 Diabetes.

In type 1 diabetes (T1D), the immune system mistakenly attacks the pancreatic islet β cells resulting in the loss of insulin secretion. Insulin-replacement therapy developed more than a century ago provided means to manage the symptoms of diabetes without addressing the root cause of the disease-the faulty immune system. A healthy immune system has built-in mechanisms to limit unwanted, excessive immune activation and prevents damages to self-tissues. These immune self-tolerance mechanisms are often impaired in autoimmune patients including those with T1Ds. Understanding how immune self-tolerance is broken in patients with T1D can inform the design of new curative therapies that correct the immune defects. In this paper, we will summarize the mechanisms of immune tolerance, review their relevance to T1Ds, and discuss novel therapeutic approaches to rebalance the immune system for the treatment of T1Ds.

Transplant Immunology in Liver Transplant, Rejection, and Tolerance

Liver transplantation is the most effective treatment for end-stage liver disease. Despite improvements in surgical techniques, transplant rejection remains a significant concern. The liver is considered an immune-privileged organ due to its unique microenvironment and complex interactions among various cell types. Alloimmune responses mediated by T cells and antigen-presenting cells (APCs) play crucial roles in transplant rejection. The liver’s dual blood supply and unique composition of its sinusoidal endothelial cells (LSECs), Kupffer cells (KCs), hepatocytes, and hepatic stellate cells (HSCs) contribute to its immune privilege. Alloantigen recognition by T cells occurs through direct, indirect, and semidirect pathways, leading to acute cellular rejection (ACR) and chronic rejection. ACR is a T cell-mediated process that typically occurs within the first few weeks to months after transplantation. Chronic rejection, on the other hand, is a gradual process characterized by progressive fibrosis and graft dysfunction, often leading to graft loss. Acute antibody-mediated rejection (AMR) is less common following surgery compared to other solid organ transplants due to the liver’s unique anatomy and immune privilege. However, when it does occur, AMR can be aggressive and lead to rapid graft dysfunction. Despite improvements in immunosuppression, rejection remains a challenge, particularly chronic rejection. Understanding the mechanisms of rejection and immune tolerance, including the roles of regulatory T cells (Tregs) and hepatic dendritic cells (DCs), is crucial for improving transplant outcomes. Strategies to induce immune tolerance, such as modulating DC function or promoting Treg activity, hold promise for reducing rejection and improving long-term graft survival. This review focuses on the liver’s unique predisposition to rejection and tolerance, highlighting the roles of individual cell types in these processes. Continued research into the mechanisms of alloimmune responses and immune tolerance in liver transplantation is essential for developing more effective therapies and improving long-term outcomes for patients with end-stage liver disease.

Breakdown and Repair of Peripheral Immune Tolerance in Type 1 Diabetes.

Failures in peripheral immune tolerance mechanisms create a permissive environment for autoimmune diabetes initiation and disease progression. Biomarker analyses provide tools that allow recognition of this loss of tolerance, reflecting a serial acquisition of pathogenic characteristics causally linked to islet β-cell dysfunction and death. Autoimmune effector cell activation and expansion, ineffective immune regulation, and tissue response to injury during active disease each represent challenges to homeostasis; however, they also represent targets for therapeutic intervention, with the potential for restoration of tolerance. Limited success in recent clinical trials demonstrates that tolerance in type 1 diabetes (T1D) is achievable, but currently occurs in few subjects and is not durable in most. Combining therapeutic agents to rebuild multiple immune components to restore tolerance, particularly addressing both effector and regulatory T-cell dysfunction, is needed.

Understanding the Complex Dynamics of Immunosenescence in Multiple Sclerosis: From Pathogenesis to Treatment.

Immunosenescence, the gradual deterioration of immune function with age, holds profound implications for our understanding and management of multiple sclerosis (MS), a chronic autoimmune disease affecting the central nervous system. Traditionally diagnosed in young adults, advancements in disease-modifying therapies and increased life expectancy have led to a growing number of older individuals with MS. This demographic shift underscores the need for a deeper investigation into how age-related alterations in immune function shape the course of MS, influencing disease progression, treatment effectiveness, and overall patient outcomes. Age-related immunosenescence involves changes such as shifts in cytokine profiles, the accumulation of senescent immune cells, and compromised immune surveillance, collectively contributing to a state known as "inflammaging". In the context of MS, these immunological changes disturb the intricate balance between inflammatory and regulatory responses, thereby impacting mechanisms of central immune tolerance and peripheral regulation. This paper stands out by combining the most recent advancements in immunosenescence with both pathophysiological and treatment perspectives on multiple sclerosis, offering a cohesive and accessible discussion that bridges theory and practice, while also introducing novel insights into underexplored concepts such as therapy discontinuation and the latest senolytic, neuroprotective, and remyelination therapies. Enhancing our understanding of these complexities will guide tailored approaches to MS management, ultimately improving clinical outcomes for affected individuals.

THP1-based cybrid cells with various mtDNA mutations differ by the ability to form inflammatory response

Most age-related human diseases are accompanied by chronic inflammation. Modern research is aimed at studying the principles of the formation of the immune response. The reasons why the local inflammatory reaction cannot be resolved and becomes a sluggish chronic form are still unknown. Immune cells secrete cytokines in response to pathogens. To avoid cell death as a result of high concentrations of cytokines and resulting tissue damage, there is a mechanism of innate immune tolerance. Innate immune tolerance involves a decrease in the secretion of proinflammatory cytokines in response to repeated exposure to a pathogen. It is known that mitochondria play an important role in the formation of the immune response. Consequently, impaired mitochondrial function can lead to impaired immune response. To control the quality of mitochondria in the cell, there is a mechanism – mitophagy. Previously, we have created cybrid lines based on the monocytic cell line THP-1. Cybrids were obtained by fusion of THP-1 cells (mitochondria were removed) with platelets from patients. Each of the cybrid lines had the THP-1 nuclear genome and an individual patient’s mitochondrial genome. In our study, we decided to study the ability of cells carrying different mitochondrial genomes to generate a proinflammatory response, as well as to form tolerance in the future. For this purpose, we chose a model of ecdotoxin tolerance. Thus, we stimulated the cybrid lines twice with lipopolysaccharide and then assessed the secretion of the cytokines TNFα, IL-1β, IL-6, IL-8, and CCL2 using ELISA. The cybrids demonstrated two levels of proinflammatory response: high and low. Moreover, cybrids with a high proinflammatory response either did or did not develop tolerance upon repeated stimulation. In our study, cells that differed from each other only in mitochondrial genome demonstrated three types of reactions upon the induction of immune tolerance to LPS. Future studies will improve our understanding of the mechanisms of mitochondrial involvement in pathological processes. It is likely that studies of deficient mitophagy and the role of certain mtDNA mutations in its development will yield promising results.

Multi-Layered Mechanisms of Immunological Tolerance at the Maternal-Fetal Interface.

Pregnancy represents an immunological paradox where the maternal immune system must tolerate the semi-allogeneic fetus expressing paternally-derived Ags. Accumulating evidence over decades has revealed that successful pregnancy requires the active development of robust immune tolerance mechanisms. This review outlines the multi-layered processes that establish fetomaternal tolerance, including the physical barrier of the placenta, restricted chemokine-mediated leukocyte trafficking, lack of sufficient alloantigen presentation, the presence of immunosuppressive regulatory T cells and tolerogenic decidual natural killer cells, expression of immune checkpoint molecules, specific glycosylation patterns conferring immune evasion, and unique metabolic/hormonal modulations. Interestingly, many of the strategies that enable fetal tolerance parallel those employed by cancer cells to promote angiogenesis, invasion, and immune escape. As such, further elucidating the mechanistic underpinnings of fetal-maternal tolerance may reciprocally provide insights into developing novel cancer immunotherapies as well as understanding the pathogenesis of gestational complications linked to dysregulated tolerance processes.

TAX1BP1/A20 inhibited TLR2-NF-κB activation to induce tolerant expression of IL-6 in endothelial cells

The inflammatory cascadedriven by interleukin-6 (IL-6) plays a crucial role in the initiation and progression of chronic inflammatory conditions such as atherosclerosis. Research has demonstrated that prolonged exposure to inflammatory stimuli leads to the development of “immune tolerance” in specialized immune cells such as monocytes and macrophages, serving as a mechanism to prevent tissue damage and curb the inflammatory cascade. However, our recent investigation revealed that immune tolerance did not effectively regulate the production of IL-6 in human umbilical vein endothelial cells (HUVECs) when stimulated by a Toll-like receptor 2 (TLR2) ligand Pam3CSK4, which is a potent activator of the pro-inflammatory transcription factor NF-κB. Furthermore, the negative regulator of NF-κB signaling, A20, was ineffective in suppressing TLR2-induced IL-6 synthesis in this context. Notably, all A20 auxiliary molecules, with the exception of TAX1BP1, were found to be significantly expressed in HUVECs. DNA methylation in TAX1BP1 was confirmed in GEO database. According to the information provided, it is hypothesized that altered DNA methylation in HUVECs could potentially lead to decreased expression of TAX1BP1, thereby impeding A20′s capacity to modulate continuous activation of the TLR2-NF-κB pathway. This may consequently lead to unregulated production of IL-6, evading immune tolerance mechanisms. Subsequent investigations suggested that demethylating TAX1BP1 could enhance its expression, potentially reducing the endogenous IL-6 levels induced by repeated TLR2 stimulation and restoring A20′s inhibitory role in NF-κB signaling. Additionally, over-expression of TAX1BP1 coulddecrease the production of atherosclerosis-associated cytokines like IL-6, MCP-1, ICAM-1, and VCAM-1, while increasing NO release following repeated Pam3cks4 stimulation, along with enhanced co-localization of TAX1BP1 and A20. These findings indicate that inducing immune tolerance in endothelial cells may effectively suppress endogenous IL-6 production and halt the IL-6-mediated inflammatory cascade, with TAX1BP1/A20 identified as crucial components in this process.These insights provide novel perspectives and potential targets for therapeutic strategies in inflammatoryimmunological disorders involving the overproduction of IL-6.

Progestogen-driven B7-H4 contributes to onco-fetal immune tolerance

Immune tolerance mechanisms are shared in cancer and pregnancy. Through cross-analyzing single-cell RNA-sequencing data from multiple human cancer types and the maternal-fetal interface, we found B7-H4 (VTCN1) is an onco-fetal immune tolerance checkpoint. We showed that genetic deficiency of B7-H4 resulted in immune activation and fetal resorption in allogeneic pregnancy models. Analogously, B7-H4 contributed to MPA/DMBA-induced breast cancer progression, accompanied by CD8+ Tcell exhaustion. Female hormone screening revealed that progesterone stimulated B7-H4 expression in placental and breast cancer cells. Mechanistically, progesterone receptor (PR) bound to a newly identified -58 kb enhancer, thereby mediating B7-H4 transcription via the PR-P300-BRD4 axis. PR antagonist or BRD4 degrader potentiated immunotherapy in a murine B7-H4+ breast cancer model. Thus, our work unravels a mechanistic and biological connection of a female sex hormone (progesterone) to onco-fetal immune tolerance via B7-H4 and suggests that the PR-P300-BRD4 axis is targetable for treating B7-H4+ cancer.

Microparticles incorporating dual apoptotic factors to inhibit inflammatory effects in macrophages

New approaches to treat autoimmune diseases are needed, and we can be inspired by mechanisms in immune tolerance to guide the design of these approaches. Efferocytosis, the process of phagocyte-mediated apoptotic cell (AC) disposal, represents a potent tolerogenic mechanism that we could draw inspiration from to restore immune tolerance to specific autoantigens. ACs engage multiple avenues of the immune response to redirect aberrant immune responses. Two such avenues are: phosphatidylserine on the outer leaflet of the cell and engaging the aryl hydrocarbon receptor (AhR) pathway. We incorporated these two avenues into one acetalated dextran (Ace-DEX) microparticle (MP) for evaluation in vitro. First phosphatidylserine (PS) was incorporated into Ace-DEX MPs and evaluated for cellular association and mediators of cell tolerance including IL-10 production and M2 associated gene expression when particles were cultured with peritoneal macrophages (PMacs). Further PS Ace-DEX MPs were evaluated as an agent to suppress LPS stimulated PMacs. Then, AhR agonist 2-(1′H-indole-3′-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) was incorporated into Ace-DEX MPs and expression of M2 and IL-10 genes was evaluated in PMacs. Further the ITE and PS Ace-DEX MPs (PS/ITE MPs) were evaluated for suppression of T cell priming and Th1 polarization. Our results indicate that the PS/ITE-MPs stimulated anti-inflammatory cytokine expression and suppressed inflammation following LPS stimulation of PMacs. Moreover, PS/ITE MPs induced the anti-inflammatory enzyme IDO1 and suppressed macrophage-mediated T cell priming and Th1 polarization. These findings suggest that PS and ITE-loaded Ace-DEX MPs could be a promising therapeutic tool for suppressing inflammation.

Mendelian Causes of Autoimmunity: the Lupus Phenotype.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that is characterized by its large heterogeneity in terms of clinical presentation and severity. The pathophysiology of SLE involves an aberrant autoimmune response against various tissues, an excess of apoptotic bodies, and an overproduction of type-I interferon. The genetic contribution to the disease is supported by studies of monozygotic twins, familial clustering, and genome-wide association studies (GWAS) that have identified numerous risk loci. In the early 70s, complement deficiencies led to the description of familial forms of SLE caused by a single gene defect. High-throughput sequencing has recently identified an increasing number of monogenic defects associated with lupus, shaping the concept of monogenic lupus and enhancing our insights into immune tolerance mechanisms. Monogenic lupus(moSLE) should be suspected in patients with either early-onset lupus or syndromic lupus, in male, or in familial cases of lupus. This review discusses the genetic basis of monogenic SLE and proposes its classification based on disrupted pathways. These pathways include defects in the clearance of apoptotic cells or immune complexes, interferonopathies, JAK-STATopathies, TLRopathies, and T and B cell dysregulations.

Antigen-specific Fab profiling achieves molecular-resolution analysis of human autoantibody repertoires in rheumatoid arthritis

The presence of autoantibodies is a defining feature of many autoimmune diseases. The number of unique autoantibody clones is conceivably limited by immune tolerance mechanisms, but unknown due to limitations of the currently applied technologies. Here, we introduce an autoantigen-specific liquid chromatography-mass spectrometry-based IgG1 Fab profiling approach using the anti-citrullinated protein antibody (ACPA) repertoire in rheumatoid arthritis (RA) as an example. We show that each patient harbors a unique and diverse ACPA IgG1 repertoire dominated by only a few antibody clones. In contrast to the total plasma IgG1 antibody repertoire, the ACPA IgG1 sub-repertoire is characterised by an expansion of antibodies that harbor one, two or even more Fab glycans, and different glycovariants of the same clone can be detected. Together, our data indicate that the autoantibody response in a prominent human autoimmune disease is complex, unique to each patient and dominated by a relatively low number of clones.

Factors Governing B Cell Recognition of Autoantigen and Function in Type 1 Diabetes.

Islet autoantibodies predict type 1 diabetes (T1D) but can be transient in murine and human T1D and are not thought to be directly pathogenic. Rather, these autoantibodies signal B cell activity as antigen-presenting cells (APCs) that present islet autoantigen to diabetogenic T cells to promote T1D pathogenesis. Disrupting B cell APC function prevents T1D in mouse models and has shown promise in clinical trials. Autoantigen-specific B cells thus hold potential as sophisticated T1D biomarkers and therapeutic targets. B cell receptor (BCR) somatic hypermutation is a mechanism by which B cells increase affinity for islet autoantigen. High-affinity B and T cell responses are selected in protective immune responses, but immune tolerance mechanisms are known to censor highly autoreactive clones in autoimmunity, including T1D. Thus, different selection rules often apply to autoimmune disease settings (as opposed to protective host immunity), where different autoantigen affinity ceilings are tolerated based on variations in host genetics and environment. This review will explore what is currently known regarding B cell signaling, selection, and interaction with T cells to promote T1D pathogenesis.

Abstract 1159: Machine learning integrating spatial omics uncovers humoral immunity patterns in intratumoral tertiary lymphoid structures in pancreatic cancer pathologic responders

Abstract Background: In pancreatic ductal adenocarcinoma (PDAC), rare long-term survivors correlate with high intratumoral tertiary lymphoid structure (TLS) density. This finding prompted our investigation of clinically viable strategies to induce TLS in patients with immune-excluded tumors. We previously reported the induction of intratumoral TLS following administration of a neoadjuvant GM-CSF-secreting allogeneic vaccine (GVAX) to PDAC patients (NCT00727441). However, no clinical benefit was observed, likely owing to immune tolerance mechanisms governing the PDAC tumor microenvironment (TME). We previously observed upregulation of both the PD-1 and 4-1BB pathways with GVAX, and thus in a subsequent neoadjuvant trial combined GVAX with PD-1 blockade and 4-1BB agonism (NCT02451982) which was associated with pathologic responses. We hypothesized this combination strategy induced TLS of higher maturity and anti-tumor activity compared to GVAX alone. Methods: To explore how this therapeutic strategy affected TLS morphology and intercellular crosstalk, we leveraged the Visium spatial transcriptomics platform and a 35-marker customized TLS panel for imaging mass cytometry. We generated cellular and molecular maps of the TME after neoadjuvant treatment in 26 PDAC patients (GVAX n=19, GVAX+aPD1 n=2, GVAX+aPD1+a41BB n=5). To compare TLS maturation in parallel with secondary lymphoid organ-mediated tumor immunity, we also profiled tumor-adjacent lymph nodes. We applied unsupervised learning with non-negative matrix factorization (NMF) and trained AI-enabled image classification models to characterize cellular states within tissue structures of interest. Results: We identified spatial gene expression NMF patterns in PDAC TLS spanning across distinct morphologies and neoadjuvant treatment arms. Intratumoral TLS after GVAX were found to propagate activated B cells expressing immunoglobulins that infiltrated into malignant cellular niches. TLS NMF patterns were also associated with autoimmune disease signatures, such as diabetes, in a subset of patients. We scored TLS using tumor-draining lymph nodes as a reference and found increased maturation of TLS after PD-1 blockade, while addition of 4-1BB agonism significantly boosted the cytotoxic NK/T cell compartment compared to GVAX alone. Conclusions: We present machine learning approaches for spatial multi-omics analysis to characterize the TLS-enriched TME. We mined genome-wide spatial TLS gene expression patterns elucidating the spatial dynamics of humoral immunity of rare immunotherapy pathologic responders in PDAC. Altogether our findings shed light on the plasticity of TLS in neoadjuvant immunotherapy and suggest future immunotherapy approaches should target both humoral and cytotoxic NK/T cell compartments to augment responses in solid tumors. Citation Format: Dimitrios N. Sidiropoulos, Sarah M. Shin, Alexander Girgis, Daniel H. Shu, Janelle Montagne, Atul Deshpande, Jeanette A. Johnson, Lucie Dequiedt, Victoria Jacobs, Aleksandra Ogurtsova, Guanglan Mo, Xuan Yuan, Genevieve Stein-O’Brien, Mark Yarchoan, Qingfeng Zhu, Ashley Kiemen, Elizabeth M. Jaffee, Lei Zheng, Won Jin Ho, Robert Anders, Elana J. Fertig, Luciane T. Kagohara. Machine learning integrating spatial omics uncovers humoral immunity patterns in intratumoral tertiary lymphoid structures in pancreatic cancer pathologic responders [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 1159.

Immune rebalancing at the maternal-fetal interface of maternal SARS-CoV-2 infection during early pregnancy.

The current coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2) remains a threat to pregnant women. However, the impact of early pregnancy SARS-CoV-2 infection on the maternal-fetal interface remains poorly understood. Here, we present a comprehensive analysis of single-cell transcriptomics and metabolomics in placental samples infected with SARS-CoV-2 during early pregnancy. Compared to control placentas, SARS-CoV-2 infection elicited immune responses at the maternal-fetal interface and induced metabolic alterations in amino acid and phospholipid profiles during the initial weeks post-infection. However, subsequent immune cell activation and heightened immune tolerance in trophoblast cells established a novel dynamic equilibrium that mitigated the impact on the maternal-fetal interface. Notably, the immune response and metabolic alterations at the maternal-fetal interface exhibited a gradual decline during the second trimester. Our study underscores the adaptive immune tolerance mechanisms and establishment of immunological balance during the first two trimesters following maternal SARS-CoV-2 infection.

Graft Protective and Intercellular Immunomodulatory Effects by Adoptive Transfer of an Agonistic Anti-BTLA mAb (3C10) Induced CD4+CD25+ Regulatory T Cells in Murine Cardiac Allograft Transplant Model

We demonstrated that an agonistic anti-B and T lymphocyte attenuator antibody (3C10) prolonged cardiac survival by inducing regulatory T cells (Treg). However, the mechanisms of immune tolerance in the recipients remained unclear. In this study, we investigated the graft-protective and intercellular immunomodulatory effects of adoptive transfer (AT) of 3C10-induced Tregs in a murine cardiac allograft transplant model. Thirty days after transplantation of a C57BL/6 heart into the primary 3C10-treated CBA recipients, splenic CD4+CD25+ cells from these recipients (3C10/AT group) or naïve CBA mice (no-treatment group) were adoptively transferred into secondary CBA recipients with a C57BL/6 heart. To confirm the requirement for 3C10-induced Tregs, we administered an anti-interleukin-2 receptor alpha antibody (PC-61) to secondary CBA recipients. Additionally, histologic and fluorescent staining, cell proliferation analysis, flow cytometry, and donor-specific antibody (DSA) measurements were performed. 3C10/AT-treated CBA recipients resulted in significantly prolonged allograft survival (median survival time [MST], >50 days). Allografts displayed prolonged function with preservation of vessel structure by maintaining high numbers of splenic CD4+CD25+Foxp3+ Treg and intramyocardial CD4+Foxp3+ cells. DSA levels were suppressed in 3C10/AT-treated CBA recipients. Moreover, PC-61 administration resulted in a shorter MSTs of cardiac allograft survivals, a detrimental increase in DSA production, and enhanced expression of programmed cell death (PD)-1. AT of 3C10-induced Tregs may be a promising graft-protective strategy to prolong allograft survival and suppress DSA production, driven by the promotion of splenic and graft-infiltrating Tregs and collaboration with PD-1+ T cells and Treg.

BMI1 overexpression is correlated with a poor prognosis and immune infiltration in hepatocellular carcinoma

Abstract Background Owing to the occurrence of primary or secondary tolerance, the efficacy of immunotherapy for hepatocellular carcinoma (HCC) patients is limited. Therefore, the mechanism underlying this tolerance needs to be further investigated. B cell–specific Moloney murine leukemia virus integration site 1 (BMI1) is associated with cancer stem cell tumorigenesis, progression, and the maintenance of the self-renewal. However, the effect of BMI1 expression on immune infiltration and prognosis in HCC is still unclear. Methods To assess the relationship between BMI1 expression and HCC prognosis and immune infiltration, the GEPIA database, TIMER database, and K-M plotter were used. TIMER database was used to determine the levels of BMI1 in various tumor tissues and corresponding normal tissues, and examine the association between BMI1 expression and tumor-infiltrating immune cells. GEPIA database was applied to determine BMI1 expression in various tumor tissues and corresponding normal tissues. K-M Plotter was used to study the relationships among BMI1 expression, clinicopathological features, and survival rates. Results BMI1 expression was markedly higher in various solid tumors compared with that in the respective normal tissues, including HCC, and high expression led to poor relapse-free survival and overall survival in HCC patients. BMI1 overexpression was also correlated with the infiltration of immune cells (eg, B cells, CD8+ T cells, CD4+ T cells, dendritic cells, neutrophils, and macrophages) and positively associated with different subsets of T cells, monocytes, and M1 macrophages, among others. Conclusions This study demonstrates that high BMI1 expression is strongly correlated with immune infiltration and poor prognosis in HCC. Increased expression of BMI1 might thus be a potential mechanism of immune tolerance in this disease.