The many faces of IL-7: from lymphopoiesis to peripheral T cell maintenance

Deciphering aging-associated prognosis and heterogeneity in gastric cancer through a machine learning-driven approach

Gastric cancer (GC) is a prevalent malignancy with a high mortality rate and limited treatment options. Aging significantly contributes to tumor progression, and GC was confirmed as an aging-related heterogeneous disease. This study established an aging-associated index (AAI) using a machine learning-derived gene panel to stratify GC patients. High AAI scores associated with poor prognosis and indicated potential benefits from adjuvant chemotherapy, while showing resistance to immunotherapy. Single-cell transcriptome analysis revealed that AAI was enriched in monocyte cells within the tumor microenvironment. Two distinct molecular subtypes of GC were identified through unsupervised clustering, leading to the development of a subtype-specific regulatory network highlighting SOX7 and ELK3 as potential therapeutic targets. Drug sensitivity analyses indicated that patients with high ELK3 expression may respond to FDA-approved drugs (axitinib, dacarbazine, crizotinib, and vincristine). Finally, a user-friendly Shiny application was created to facilitate access to the prognostic model and molecular subtype classifier for GC.

Lymphopoiesis is attenuated upon hepatocyte-specific deletion of the cytochrome c oxidase assembly factor Sco1

Mutations that negatively impact mitochondrial function are highly prevalent in humans and lead to disorders with a wide spectrum of disease phenotypes, including deficiencies in immune cell development and/or function. Previous analyses of mice with a hepatocyte-specific cytochrome c oxidase (COX) deficiency revealed an unexpected peripheral blood leukopenia associated with splenic and thymic atrophy. Here, we use mice with a hepatocyte-specific deletion of the COX assembly factor Sco1 to show that metabolic defects extrinsic to the hematopoietic compartment lead to a pan-lymphopenia represented by severe losses in both B and T cells. We further demonstrate that immune defects in these mice are associated with the loss of bone marrow lymphoid progenitors common to both lineages and early signs of autoantibody-mediated autoimmunity. Our findings collectively identify hepatocyte dysfunction as a potential instigator of immunodeficiency in patients with congenital mitochondrial defects who suffer from chronic or recurrent infections.

Ndrg3 is a critical regulator of peripheral T cell maturation and homeostasis

To provide protection, anticipatory T cell-dependent immunity is reliant on the generation and maintenance of a naïve T cell repertoire, which is sufficiently diverse to ensure recognition of newly encountered antigens. Therefore, under steady-state conditions, a given individual needs to maintain a large pool of naïve T cells, ready to respond to potential threats. Here, we demonstrate that N-myc downstream-regulated gene 3 (Ndrg3) is essential for naïve T cell stability. Mice with T cell-specific Ndrg3 loss are lymphopenic, with reduced numbers of conventional T cells and natural killer T cells. We show that in the absence of Ndrg3, naïve CD8+ T cells exhibit high rates of both proliferation and apoptosis, phenotypes that could be partially rescued by transgenic expression of a high-avidity T cell receptor. Furthermore, Ndrg3-deficient cells were refractory to interleukin-4, resulting in reduced Eomes induction, and a decreased virtual memory population. Our study therefore identifies Ndrg3 as an unexpected, pleiotropic regulator of T cell homeostasis.

The immune response to SARS-CoV-2 in COVID-19 as a recall response susceptible to immune imprinting: A prospective cohort study

The antibody response to SARS-CoV-2 does not follow the immunoglobulin isotype pattern of primary responses, conflicting with the current interpretation of COVID-19.

METHODS

Prospective cohort study of 191 SARS-CoV-2 infection cases and 44 controls from the second wave of COVID-19. The study stratified patients by severity and analyzed the trajectories of SARS-CoV-2 antibodies and multiple immune variables.

RESULTS

Isotype-specific antibody time course profiles to SARS-CoV-2 revealed a pattern of recall response in 94.2 % of cases. The time course profiles of plasmablasts, B cells, cTfh high-resolution subsets, and cytokines indicated a secondary response. The transcriptomic data showed that this cohort is strictly comparable to contemporary cohorts.

CONCLUSIONS

In most cases, the immune response to SARS-CoV-2 is a recall response. This constitutes a favorable scenario for most COVID-19 cases to be subjected to immune imprinting by endemic coronavirus, which, in turn, can influence the immune response to SARS-CoV-2.

Contribution of interleukins in the regulation of teleost fish immunity: A review from the perspective of regulating macrophages

Interleukins (ILs) are potent secreted regulators of a wide range of cell types and cellular activities, particularly in the immune system. They are able to participate in intercellular communication in homeostasis and disease, thereby exerting immune functions. Macrophages serve as the innate immune cells of vertebrates and play a pivotal role in defending against and eliminating external pathogens. In mammals, the immune response mounted by macrophages is intricately linked to ILs. Given the fact that teleost fish have evolved an innate immune system that closely resembles those of mammals, particularly in terms of the functionality of macrophages, raises the intriguing possibility that the regulatory function of ILs in macrophage-mediated immunity might be evolutionarily conserved across both mammal and teleost fish lineages. Consequently, from the perspective of interleukin regulation of macrophages, this review outlines the relationship between ILs and macrophages in teleost fish, and elucidates the regulatory role of ILs of immune cell function in teleost fish, thereby contributing to our understanding of the key role of these cytokines in the prevention and control of aquaculture diseases.

IL-7 promotes integrated glucose and amino acid sensing during homeostatic CD4+ T cell proliferation

Interleukin (IL)-7 promotes T cell expansion during lymphopenia. We studied the metabolic basis in CD4+ T cells, observing increased glucose usage for nucleotide synthesis and oxidation in the tricarboxylic acid (TCA) cycle. Unlike other TCA metabolites, glucose-derived citrate does not accumulate upon IL-7 exposure, indicating diversion into other processes. In agreement, IL-7 promotes glucose-dependent histone acetylation and chromatin accessibility, notable at the loci of the amino acid-sensing Ragulator complex. Consistently, the expression of its subunit late endosomal/lysosomal adaptor, MAPK and mTOR activator 5 (LAMTOR5) is promoted by IL-7 in a glucose-dependent manner, and glucose availability determines amino acid-dependent mechanistic target of rapamycin (mTOR) activation, confirming integrated nutrient sensing. LAMTOR5 deletion impairs IL-7-mediated T cell expansion, establishing that glycolysis in the absence of Ragulator activation is insufficient to support this. Clinically, CD4+ T cells from stem cell transplant recipients demonstrate coordinated upregulation of glycolytic and TCA cycle enzymes, amino acid-sensing machinery, and mTOR targets, highlighting the potential to therapeutically target this pathway to fine-tune lymphopenia-induced T cell proliferation.

A self-activated and protective module enhances the preclinical performance of allogeneic anti-CD70 CAR-T cells

Introduction

Allogeneic chimeric antigen receptor T (CAR-T) therapy, also known as universal CAR-T (UCAR-T) therapy, offers broad applicability, high production efficiency, and reduced costs, enabling quicker access for patients. However, clinical application remains limited by challenges such as immune rejection, and issues with potency and durability.

Methods

We first screened a safe and effective anti-CD70 scFv to construct anti-CD70 CAR-T cells. Anti-CD70 UCAR-T cells were then generated by knocking out TRAC, B2M, and HLA-DRA. To address the limitations of UCAR-T therapy, we developed an 'all-in-one' self-activated and protective (SAP) module, integrated into the CAR scaffold. The SAP module consists of the CD47 extracellular domain, a mutant interleukin 7 receptor alpha (IL7Rα) transmembrane domain, and the IL7Rα intracellular domain, designed to protect UCAR-T cells from host immune attacks and enhance their survival.

Results

SAP UCAR-T cells demonstrated significantly reduced immune rejection from the innate immune system, as evidenced by enhanced survival and functionality both in vitro and in vivo. The modified UCAR-T cells exhibited improved persistence, with no observed safety concerns. Furthermore, SAP UCAR-T cells maintained process stability during scale-up production, indicating the potential for large-scale manufacturing.

Discussion

Our findings highlight the SAP module as a promising strategy for the preclinical development of anti-CD70 UCAR-T, paving the way for an 'off-the-shelf' cell therapy product.

Incomplete Immune Reconstitution and Traditional Chinese Medicine in Patients with HIV/AIDS: Challenges and Perspectives

Antiretroviral therapy can reduce human immunodeficiency virus (HIV) load to undetectable levels and restore CD4+ T cells to rebuild immune function in patients with HIV. However, some patients fail to achieve immune reconstitution despite treatment. Traditional Chinese medicine is an important branch of complementary and alternative medicine for the treatment of HIV infection, and a growing number of studies has demonstrated that traditional Chinese medicine can increase CD4+ T cell counts in patients, thereby promoting immune reconstitution, ameliorating symptoms and signs, and improving quality of life. Here, we review pathogenesis in immunological non-responders and research into their treatment with traditional Chinese medicine. Furthermore, we summarize potential future research directions, including elucidation of how traditional Chinese medicine can regulate CD4+ T cells to reduce opportunistic infections and improve quality of life in immunological non-responders.

Evaluation of the associations of interlukin-7 genetic variants with toxicity and efficacy of immune checkpoint inhibitors: A replication study of a Japanese population, based on the findings of a European genome-wide association study

AIM

Recent genome-wide association studies of European populations have identified rs16906115, a single-nucleotide polymorphism in the interleukin-7 gene, as a predictor of immune-related adverse events (irAEs) and the therapeutic efficacy of immune checkpoint inhibitors. We evaluated this single-nucleotide polymorphism in a Japanese population.

METHODS

From January 2021, we stored host DNA from individuals who received various types of immune checkpoint inhibitors. From this population, we categorized 510 participants into cases (grade ≥2 irAEs) and controls (received ≥3 immune checkpoint inhibitor doses, follow-up ≥12 weeks, no irAEs), and divided 339 hepatocellular carcinoma patients treated with atezolizumab/bevacizumab into responders and non-responders, evaluated using the modified response evaluation criteria in solid tumors. We compared the minor allele frequencies of rs16906115 between cases and controls, and responders and non-responders.

RESULTS

In the irAE prediction analysis of 234 cases and 276 controls, the minor allele frequency was 0.244 in the case group and 0.265 in the control group. This difference is not significant. In the analysis predicting the therapeutic efficacy for hepatocellular carcinoma patients, the responders had a significantly lower minor allele frequency of 0.220, compared with 0.300 for the non-responders (p = 0.022). Univariate and multivariate analyses identified the minor allele homozygosity as a significant predictor of treatment response, with odds ratios of 0.292 (p = 0.015) in the univariate analysis and 0.315 (p = 0.023) in the multivariate analysis.

CONCLUSIONS

In our Japanese cohort, no association was found between the rs16906115 minor allele and irAEs or treatment efficacy. The minor allele homozygosity may be associated with a negative therapeutic outcome.

CLINICAL TRIAL REGISTRATION

UMIN Clinical Trials Registry with the number UMIN000043798.

Memory inflation: Beyond the acute phase of viral infection

Memory inflation is confirmed as the most commonly dysregulation of host immunity with antigen-independent manner in mammals after viral infection. By generating large numbers of effector/memory and terminal differentiated effector memory CD8+ T cells with diminished naïve subsets, memory inflation is believed to play critical roles in connecting the viral infection and the onset of multiple diseases. Here, we reviewed the current understanding of memory inflated CD8+ T cells in their distinct phenotypic features that different from exhausted subsets; the intrinsic and extrinsic roles in regulating the formation of memory inflation; and the key proteins in maintaining the expansion and proliferation of inflationary populations. More importantly, based on the evidences from both clinic and animal models, we summarized the potential mechanisms of memory inflation to trigger autoimmune neuropathies, such as Guillain-Barré syndrome and multiple sclerosis; the correlations of memory inflation between tumorigenesis and resistance of tumour immunotherapies; as well as the effects of memory inflation to facilitate vascular disease progression. To sum up, better understanding of memory inflation could provide us an opportunity to beyond the acute phase of viral infection, and shed a light on the long-term influences of CD8+ T cell heterogeneity in dampen host immune homeostasis.

IL-7Rα on CD4+ T cells is required for their survival and the pathogenesis of experimental autoimmune encephalomyelitis

BACKGROUND

The IL-7 receptor alpha (IL-7Rα) binds both IL-7 and thymic stromal lymphopoietin (TSLP). IL-7Rα is essential for the development and survival of naive CD4+ T cells and their differentiation to effector/memory CD4+ T cells. Mice lacking IL-7Rα have severe lymphopenia and are resistant to experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis. However, it has been reported that IL-7Rα on peripheral CD4+ T cells is disposable for their maintenance and EAE pathogenesis, which does not align with the body of knowledge on the role of IL-7Rα in the biology of CD4+ T cells. Given that a definitive study on this important topic is lacking, we revisited it using a novel approach, an inducible knockout of the IL-7Rα gene in CD4+ T cells.

METHODS

We generated Il7rafl/fl/CD4CreERT2 double transgenic mouse line (henceforth CD4ΔIl7ra), susceptible to tamoxifen-induced knockout of the IL-7Rα gene in CD4+ T cells. CD4ΔIl7ra mice were immunized with MOG35 - 55 for EAE induction and monitored for disease development. The expression of IL-7Rα, CD4+ T cell numbers, and MOG35 - 55-specific CD4+ T cell response was evaluated in the central nervous system (CNS) and lymphoid tissues by flow cytometry. Additionally, splenocytes of CD4ΔIl7ra mice were stimulated with MOG35 - 55 to assess their proliferative response and cytokine production by T helper cells.

RESULTS

Loss of IL-7Rα from the surface of CD4+ T cells in CD4ΔIl7ra mice was virtually complete several days after tamoxifen treatment. The loss of IL-7Rα in CD4+ T cells led to a gradual and substantial decrease in their numbers in both non-immunized and immunized CD4ΔIl7ra mice, followed by slow repopulation up to the initial numbers. CD4ΔIl7ra mice did not develop EAE. We found a decrease in the total numbers of TNF-, IFN-γ-, IL-17 A-, and GM-CSF-producing CD4+ T cells and regulatory T cells in the spleens and CNS of immunized CD4ΔIl7ra mice. Tracking MOG35 - 55-specific CD4+ T cells revealed a significant reduction in their numbers in CD4ΔIl7ra mice and decreased proliferation and cytokine production in response to MOG35 - 55.

CONCLUSION

Our study demonstrates that IL-7Rα on peripheral CD4+ T cells is essential for their maintenance, immune response, and EAE pathogenesis.

Polymorphisms in the genes encoding RLR and TLR3 and CMV DNAemia in subjects coinfected with human immunodeficiency virus and cytomegalovirus

Cytomegalovirus (CMV) is a pathogen that is common worldwide and is often present in individuals infected with human immunodeficiency virus (HIV). Pattern recognition receptors (PRRs) are host sensors that activate the immune response against infectious agents. However, it is unclear whether PRR single-nucleotide polymorphisms (SNPs) are associated with the occurrence of CMV DNAemia in subjects coinfected with HIV and CMV. HIV/CMV-coinfected patients with and without CMV DNAemia were recruited for this study. The DDX58 rs10813831 and IFIH1 (rs3747517 and rs1990760) polymorphisms were genotyped using the TaqMan Allelic Discrimination Assay, whereas the DDX58 rs12006123 and TLR3 (rs3775291 and rs3775296) SNPs were analyzed using a polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assay. A mutation present in at least one allele of the DDX58 rs12006123 SNP occurred at least two times more frequently in HIV/CMV-coinfected patients with CMV DNAemia than in coinfected subjects without CMV DNAemia (OR, 2.50; 95% CI, 1.33-4.68; p = 0.004, in the dominant model). A higher level of CMV DNAemia was observed in subjects who had the heterozygous (GA) or homozygous recessive (AA) genotype for the DDX58 rs12006123 SNP compared with those who had the wild-type (GG) genotype (p = 0.0003). Moreover, in subjects with a mutation detected in at least one allele of the DDX58 rs12006123 SNP, a lower serum IFN-β concentration was found compared with those who had a wild-type (GG) genotype for this polymorphism (p = 0.024). The DDX58 rs12006123 SNP is associated with CMV DNAemia in HIV/CMV-coinfected patients.

Lrp10 suppresses IL7R limiting CD8 T cell homeostatic expansion and anti-tumor immunity

Signals emanating from the T-cell receptor (TCR), co-stimulatory receptors, and cytokine receptors each influence CD8 T-cell fate. Understanding how these signals respond to homeostatic and microenvironmental cues can reveal new ways to therapeutically direct T-cell function. Through forward genetic screening in mice, we discover that loss-of-function mutations in LDL receptor-related protein 10 (Lrp10) cause naive and central memory CD8 T cells to accumulate in peripheral lymphoid organs. Lrp10 encodes a conserved cell surface protein of unknown immunological function. T-cell activation induces Lrp10 expression, which post-translationally suppresses IL7 receptor (IL7R) levels. Accordingly, Lrp10 deletion enhances T-cell homeostatic expansion through IL7R signaling. Lrp10-deficient mice are also intrinsically resistant to syngeneic tumors. This phenotype depends on dense tumor infiltration of CD8 T cells, which display increased memory cell characteristics, reduced terminal exhaustion, and augmented responses to immune checkpoint inhibition. Here, we present Lrp10 as a new negative regulator of CD8 T-cell homeostasis and a host factor that controls tumor resistance with implications for immunotherapy.

Paxbp1 is indispensable for the maintenance of peripheral CD4 T cell homeostasis

The size and condition of the peripheral CD4 T cell population determine the capacity of the immune response. Under homeostatic conditions, the size of the peripheral CD4 T cell population is maintained through turnover and survival. However, the underlying mechanisms remain inadequately understood. Here, we observed a significant decrease in the percentage of CD4 T cells in the periphery following the targeted deletion of the Paxbp1 gene in mouse T cells. In the absence of Paxbp1, naïve CD4 T cells displayed reduced surface interleukin-7 receptor levels and a decreased capacity to respond to survival signals mediated by interleukin-7. In addition, naïve CD4 T cells deficient in Paxbp1 demonstrated impaired T cell antigen receptor signalling, compromised cell cycle entry, decreased proliferation, and increased apoptosis following stimulation, all of which contributed to the reduction in the number of peripheral CD4 T cells. Therefore, our study highlights the indispensable role of Paxbp1 in maintaining peripheral CD4 T cell homeostasis.

Expression pattern of serum interleukin-7 in elderly septic patients and its prognostic value for predicting short-term mortality

BACKGROUND

The identification of novel prognostic biomarkers in elderly septic patients are essential for the improvement of mortality in sepsis in the context of precision medicine. The purpose of this study was to explore the expression pattern and prognostic value of serum interleukin-7 (IL-7) in predicting 28-day mortality in elderly patients with sepsis.

METHODS

Patients were retrospectively enrolled according to the sepsis-3.0 diagnostic criteria and divided into the survival group and non-survival group based on the clinical outcome at the 28-day interval. The baseline characteristic data, samples for the laboratory tests, and the SOFA, Acute Physiology and Chronic Health Evaluation (APACHE II), as well as Glasgow coma scale (GCS) scores, were recorded within 24 h after admission to the emergency department. Serum levels of IL-7 and TNF-α of the patients were quantified by the Luminex assay. Spearman correlation analysis, logistic regressive analysis and receiver operating characteristic curve (ROC) analysis were performed, respectively.

RESULTS

Totally, 220 elderly patients with sepsis were enrolled, 151 of whom died in a 28-day period. Albumin (ALB), high-density lipoprotein (HDL), systolic pressure (SBP), and platelet (PLT) were found to be significantly higher in the survival group (p < 0.05). IL-7 was shown to be correlated with TNF-α in the non-survival group (p = 0.030) but not in the survival group (p = 0.194). No correlation was shown between IL-7 and other factors (p > 0.05). IL-7 and TNF-α were found to be independent risk factors associated with the 28-day mortality (OR = 1.215, 1.420). Combination of IL-7, SOFA and ALB can make an AUROC of 0.874 with the specificity of 90.77 %. Combination of IL-7 and TNF-α can make an AUROC of 0.901 with the sensitivity of 90.41 % while the combination of IL-7, TNF-α, and ALB can make an AUROC of 0.898 with the sensitivity of 94.52 %.

CONCLUSIONS

This study highlights the importance of monitoring the serum level of IL-7 and TNF-α in elderly septic patients as well as evaluating the combinations with other routine risk factors which can be potentially used for the identification of elderly septic patients with higher risk of mortality.

T Cell Homeostasis Disturbances in a Cohort of Long-Term Elite Controllers of HIV Infection

Elite controllers (ECs) are people living with HIV (PLWH) able to control HIV replication without antiretroviral therapy and have been proposed as a model of a functional HIV cure. Much evidence suggests that this spontaneous control of HIV has a cost in terms of T cell homeostasis alterations. We performed a deep phenotypic study to obtain insight into T cell homeostasis disturbances in ECs maintaining long-term virologic and immunologic control of HIV (long-term elite controllers; LTECs). Forty-seven PLWH were included: 22 LTECs, 15 non-controllers under successful antiretroviral therapy (onART), and 10 non-controllers not receiving ART (offART). Twenty uninfected participants (UCs) were included as a reference. T cell homeostasis was analyzed by spectral flow cytometry and data were analyzed using dimensionality reduction and clustering using R software v3.3.2. Dimensionality reduction and clustering yielded 57 and 54 different CD4 and CD8 T cell clusters, respectively. The offART group showed the highest perturbation of T cell homeostasis, with 18 CD4 clusters and 15 CD8 clusters significantly different from those of UCs. Most of these alterations were reverted in the onART group. Interestingly, LTECs presented several disturbances of T cell homeostasis with 15 CD4 clusters and 13 CD8 clusters different from UC. Moreover, there was a specific profile of T cell homeostasis alterations associated with LTECs, characterized by increases in clusters of naïve T cells, increases in clusters of non-senescent effector CD8 cells, and increases in clusters of central memory CD4 cells. These results demonstrate that, compared to ART-mediated control of HIV, the spontaneous control of HIV is associated with several disturbances in CD4 and CD8 T cell homeostasis. These alterations could be related to the existence of a potent and efficient virus-specific T cell response, and to the ability to halt disease progression by maintaining an adequate pool of CD4 T cells.

Intestinal tissue-resident memory T cells maintain distinct identity from circulating memory T cells after in vitro restimulation

Resident memory T (TRM) cells have been recently established as an important subset of memory T cells that provide early and essential protection against reinfection in the absence of circulating memory T cells. Recent findings showing that TRM expand in vivo after repeated antigenic stimulation indicate that these memory T cells are not terminally differentiated. This suggests an opportunity for in vitro TRM expansion to apply in an immunotherapy setting. However, it has also been shown that TRM may not maintain their identity and form circulating memory T cells after in vivo restimulation. Therefore, we set out to determine how TRM respond to antigenic activation in culture. Using Listeria monocytogenes and LCMV infection models, we found that TRM from the intraepithelial compartment of the small intestine expand in vitro after antigenic stimulation and subsequent resting in homeostatic cytokines. A large fraction of the expanded TRM retained their phenotype, including the expression of key TRM markers CD69 and CD103 (ITGAE). The optimal culture of TRM required low O2 pressure to maintain the expression of these and other TRM-associated molecules. Expanded TRM retained their effector capacity to produce cytokines after restimulation, but did not acquire a highly glycolytic profile indicative of effector T cells. The proteomic analysis confirmed TRM profile retention, including expression of TRM-related transcription factors, tissue retention factors, adhesion molecules, and enzymes involved in fatty acid metabolism. Collectively, our data indicate that limiting oxygen conditions supports in vitro expansion of TRM cells that maintain their TRM phenotype, at least in part, suggesting an opportunity for therapeutic strategies that require in vitro expansion of TRM.

The effect of physical exercise on anticancer immunity

Regular physical activity is associated with lower cancer incidence and mortality, as well as with a lower rate of tumour recurrence. The epidemiological evidence is supported by preclinical studies in animal models showing that regular exercise delays the progression of cancer, including highly aggressive malignancies. Although the mechanisms underlying the antitumorigenic effects of exercise remain to be defined, an improvement in cancer immunosurveillance is likely important, with different immune cell subtypes stimulated by exercise to infiltrate tumours. There is also evidence that immune cells from blood collected after an exercise bout could be used as adoptive cell therapy for cancer. In this Perspective, we address the importance of muscular activity for maintaining a healthy immune system and discuss the effects of a single bout of exercise (that is, 'acute' exercise) and those of 'regular' exercise (that is, repeated bouts) on anticancer immunity, including tumour infiltrates. We also address the postulated mechanisms and the clinical implications of this emerging area of research.

Cell States and Interactions of CD8 T Cells and Disease-Enriched Microglia in Human Brains with Alzheimer's Disease

Alzheimer's disease (AD) is a multi-stage neurodegenerative disorder characterized by beta-amyloid accumulation, hyperphosphorylated Tau deposits, neurodegeneration, neuroinflammation, and cognitive impairment. Recent studies implicate CD8 T cells as neuroimmune responders to the accumulation of AD pathology in the brain and potential contributors to toxic neuroinflammation. However, more evidence is needed to understand lymphocytes in disease, including their functional states, molecular mediators, and interacting cell types in diseased brain tissue. The scarcity of lymphocytes in brain tissue samples has limited the unbiased profiling of disease-associated cell types, cell states, drug targets, and relationships to common AD genetic risk variants based on transcriptomic analyses. However, using recent large-scale, high-quality single-nuclear sequencing datasets from over 84 Alzheimer's disease and control cases, we leverage single-nuclear RNAseq data from 800 lymphocytes collected from 70 individuals to complete unbiased molecular profiling. We demonstrate that effector memory CD8 T cells are the major lymphocyte subclass enriched in the brain tissues of individuals with AD dementia. We define disease-enriched interactions involving CD8 T cells and multiple brain cell subclasses including two distinct microglial disease states that correlate, respectively, to beta-amyloid and tau pathology. We find that beta-amyloid-associated microglia are a major hub of multicellular cross-talk gained in disease, including interactions involving both vulnerable neuronal subtypes and CD8 T cells. We reproduce prior reports that amyloid-response microglia are depleted in APOE4 carriers. Overall, these human-based studies provide additional support for the potential relevance of effector memory CD8 T cells as a lymphocyte population of interest in AD dementia and provide new candidate interacting partners and drug targets for further functional study.

Lrp10 suppresses IL7R limiting CD8 T cell homeostatic expansion and anti-tumor immunity

Signals emanating from the T cell receptor (TCR), co-stimulatory receptors, and cytokine receptors each influence CD8 T cell fate. Understanding how these signals respond to homeostatic and microenvironmental cues can reveal new ways to therapeutically direct T cell function. Through forward genetic screening in mice, we discovered that loss-of-function mutations in LDL receptor related protein 10 ( Lrp10 ) caused naïve and central memory CD8 T cells to accumulate in peripheral lymphoid organs. Lrp10 encodes a conserved cell surface protein of unknown immunological function. Lrp10 was induced with T cell activation and its expression post-translationally suppressed IL7 receptor (IL7R) levels. Accordingly, Lrp10 deletion enhanced T cell homeostatic expansion through IL7R signaling. Lrp10 -deficient mice were also intrinsically resistant to syngeneic tumors. This phenotype depended on dense tumor infiltration of CD8 T cells that displayed increased memory cell characteristics, reduced terminal exhaustion, and augmented responses to immune checkpoint inhibition. Here, we present Lrp10 as a new negative regulator of CD8 T cell homeostasis and a host factor that controls tumor resistance with implications for immunotherapy.

New insights into the stemness of adoptively transferred T cells by γc family cytokines

T cell-based adoptive cell therapy (ACT) has exhibited excellent antitumoral efficacy exemplified by the clinical breakthrough of chimeric antigen receptor therapy (CAR-T) in hematologic malignancies. It relies on the pool of functional T cells to retain the developmental potential to serially kill targeted cells. However, failure in the continuous supply and persistence of functional T cells has been recognized as a critical barrier to sustainable responses. Conferring stemness on infused T cells, yielding stem cell-like memory T cells (TSCM) characterized by constant self-renewal and multilineage differentiation similar to pluripotent stem cells, is indeed necessary and promising for enhancing T cell function and sustaining antitumor immunity. Therefore, it is crucial to identify TSCM cell induction regulators and acquire more TSCM cells as resource cells during production and after infusion to improve antitumoral efficacy. Recently, four common cytokine receptor γ chain (γc) family cytokines, encompassing interleukin-2 (IL-2), IL-7, IL-15, and IL-21, have been widely used in the development of long-lived adoptively transferred TSCM in vitro. However, challenges, including their non-specific toxicities and off-target effects, have led to substantial efforts for the development of engineered versions to unleash their full potential in the induction and maintenance of T cell stemness in ACT. In this review, we summarize the roles of the four γc family cytokines in the orchestration of adoptively transferred T cell stemness, introduce their engineered versions that modulate TSCM cell formation and demonstrate the potential of their various combinations. Video Abstract.

Enhanced alloresponse to platelet transfusion due to immune dysregulation following ablative chemotherapy in mice

Introduction

Alloimmunization is common following platelet transfusion and can result in negative outcomes for recipients such as refractoriness to subsequent transfusions and rejection of transplants. Healthy people do not receive blood transfusions, and the diseases and therapies that result in a need to transfuse have significant impacts on the immunological environment to which these alloantigens are introduced. Ablative chemotherapies are common among platelet recipients and have potent immunological effects. In this study, we modeled the impact of chemotherapy on the alloresponse to platelet transfusion. As chemotherapies are generally regarded as immunosuppressive, we hypothesized that that they would result in a diminished alloresponse.

Methods

Mice were given a combination chemotherapeutic treatment of cytarabine and doxorubicin followed by transfusion of allogeneic platelets, and compared to controls given no treatment, chemotherapy alone, or transfusion alone. Alloantibody responses were measured 2 weeks after transfusion, and cellular responses and growth factors were monitored over time.

Results

Contrary to our hypothesis, we found that chemotherapy led to increased alloantibody responses to allogeneic platelet transfusion. This enhanced response was antigen-specific and was associated with increased CD4+ and CD8+ T cell responses. Chemotherapy led to rapid lymphocyte depletion followed by reconstitution, non-specific activation of transitional B cells with the highest levels of activation in the least mature subsets, and increased serum levels of B cell activating factor (BAFF).

Conclusion

These data suggest that ablative chemotherapy can increase the risk of alloimmunization and, if confirmed clinically, that additional measures to protect these patient populations may be warranted.

Characteristics of circulating immune cells in HBV-related acute-on-chronic liver failure following artificial liver treatment

BACKGROUND AND AIM

Liver failure, which is predominantly caused by hepatitis B (HBV) can be improved by an artificial liver support system (ALSS). This study investigated the phenotypic heterogeneity of immunocytes in patients with HBV-related acute-on-chronic liver failure (HBV-ACLF) before and after ALSS therapy.

METHODS

A total of 22 patients with HBV-ACLF who received ALSS therapy were included in the study. Patients with Grade I according to the ACLF Research Consortium score were considered to have improved. Demographic and laboratory data were collected and analyzed during hospitalization. Immunological features of peripheral blood in the patients before and after ALSS were detected by mass cytometry analyses.

RESULTS

In total, 12 patients improved and 10 patients did not. According to the immunological features data after ALSS, the proportion of circulating monocytes was significantly higher in non-improved patients, but there were fewer γδT cells compared with those in improved patients. Characterization of 37 cell clusters revealed that the frequency of effector CD8+ T (P = 0.003), CD4+ TCM (P = 0.033), CD4+ TEM (P = 0.039), and inhibitory natural killer (NK) cells (P = 0.029) decreased in HBV-ACLF patients after ALSS therapy. Sub group analyses after treatment showed that the improved patients had higher proportions of CD4+ TCM (P = 0.010), CD4+ TEM (P = 0.021), and γδT cells (P = 0.003) and a lower proportion of monocytes (P = 0.012) compared with the non-improved patients.

CONCLUSIONS

Changes in effector CD8+ T cells, effector and memory CD4+ T cells, and inhibitory NK cells are associated with ALSS treatment of HBV-ACLF. Moreover, monocytes and γδT cells exhibited the main differences when patients obtained different prognoses. The phenotypic heterogeneity of lymphocytes and monocytes may contribute to the prognosis of ALSS and future immunotherapy strategies.

Possible Mechanisms of Lymphopenia in Severe Tuberculosis

Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis (M. tuberculosis). In lymphopenia, T cells are typically characterized by progressive loss and a decrease in their count results. Lymphopenia can hinder immune responses and lead to systemic immunosuppression, which is strongly associated with mortality. Lymphopenia is a significant immunological abnormality in the majority of patients with severe and advanced TB, and its severity is linked to disease outcomes. However, the underlying mechanism remains unclear. Currently, the research on the pathogenesis of lymphopenia during M. tuberculosis infection mainly focuses on how it affects lymphocyte production, survival, or tissue redistribution. This includes impairing hematopoiesis, inhibiting T-cell proliferation, and inducing lymphocyte apoptosis. In this study, we have compiled the latest research on the possible mechanisms that may cause lymphopenia during M. tuberculosis infection. Lymphopenia may have serious consequences in severe TB patients. Additionally, we discuss in detail potential intervention strategies to prevent lymphopenia, which could help understand TB immunopathogenesis and achieve the goal of preventing and treating severe TB.

A mechanistically novel peptide agonist of the IL-7 receptor that addresses limitations of IL-7 cytokine therapy

Interleukin (IL)-7 is broadly active on T-cell populations, and modified versions have been clinically evaluated for a variety of therapeutic applications, including cancer, lymphopenia, and infectious diseases; and found to be relatively well-tolerated and biologically active. Here we describe novel IL-7R agonists that are unrelated in structure to IL-7, bind to the receptor subunits differently from IL-7, but closely emulate IL-7 biology. The small size, low structural complexity, and the natural amino acid composition of the pharmacologically active peptide MDK1472 allows facile incorporation into protein structures, such as the IgG2-Fc fusion MDK-703. This molecule possesses properties potentially better suited to therapeutic applications than native IL-7 or its derivatives. We compared these compounds with IL-7 for immune cell selectivity, induction of IL-7R signaling, receptor-mediated internalization, proliferation, and generation of immune cell phenotypes in human and non-human primate (NHP) peripheral blood cells in vitro; and found them to be similar in biological activity to IL-7. In cynomolgus macaques, MDK-703 exhibits a circulating half-life of 46 hr and produces sustained T-cell expansion characteristic of IL-7 treatment. In the huCD34+-engrafted NSG mouse model of the human immune system, MDK-703 induces an immune cell profile very similar to that generated by IL-7-derived compounds; including the pronounced expansion of memory T-cells, particularly the population of stem-like memory T-cells (Tscm) which may be important for anti-tumor activities reported with IL-7 treatment. Clinical administration of IL-7 and modified variants has been reported to induce anti-drug antibodies (ADAs), including IL-7 neutralizing antibodies. The novel peptide agonist reported here scores very low in predicted immunogenicity, and because the peptide lacks sequence similarity with IL-7, the problematic immunogenic neutralization of endogenous cytokine should not occur. The properties we report here implicate MDK-703 as a candidate for clinical evaluation in oncology, anti-viral and other infectious disease, vaccine enhancement, and treatment of lymphopenia.

Single-Cell RNA-Sequencing Reveals Peripheral T Helper Cells Promoting the Development of IgG4-Related Disease by Enhancing B Cell Activation and Differentiation

Abnormal B cell differentiation plays a critical role in IgG4-related disease (IgG4-RD), but the underlying mechanism remains largely unknown. We investigated the cell landscape from three IgG4-RD retroperitoneal tissues and three control tissues using single-cell RNA-sequencing. Critical cell type or markers were further validated in the peripheral blood from the patients with IgG4-RD and healthy controls via flow cytometry as well as in the IgG4-RD and control tissue via immunofluorescence staining. The increases in B cells, plasma cells, and CD4+ T cells were found in IgG4-RD retroperitoneal tissue. Importantly, among CD4+ T cells, an increase in CD4+CXCR5-PD1hi peripheral T helper (Tph) cells with a high expression of IL-21 and TIGIT was discovered in IgG4-RD tissue, which was further validated in peripheral blood of the patients with IgG4-RD. The Tph cell and TIGIT+ Tph cell proportion were remarkably higher in active IgG4-RD patients and correlated with disease activity. Moreover, TIGIT+CD4+ cells were able to promote B cell differentiation via IL-21. Our study revealed that Tph cells are increased in IgG4-RD and probably play critical roles in B cell differentiation through TIGIT-IL-21 axis. Peripheral Tph cell and TIGIT+Tph cell are potential markers for IgG4-RD disease activity.

Harnessing the immunomodulatory effects of exercise to enhance the efficacy of monoclonal antibody therapies against B-cell haematological cancers: a narrative review

Therapeutic monoclonal antibodies (mAbs) are standard care for many B-cell haematological cancers. The modes of action for these mAbs include: induction of cancer cell lysis by activating Fcγ-receptors on innate immune cells; opsonising target cells for antibody-dependent cellular cytotoxicity or phagocytosis, and/or triggering the classical complement pathway; the simultaneous binding of cancer cells with T-cells to create an immune synapse and activate perforin-mediated T-cell cytotoxicity against cancer cells; blockade of immune checkpoints to facilitate T-cell cytotoxicity against immunogenic cancer cell clones; and direct delivery of cytotoxic agents via internalisation of mAbs by target cells. While treatment regimens comprising mAb therapy can lead to durable anti-cancer responses, disease relapse is common due to failure of mAb therapy to eradicate minimal residual disease. Factors that limit mAb efficacy include: suboptimal effector cell frequencies, overt immune exhaustion and/or immune anergy, and survival of diffusely spread tumour cells in different stromal niches. In this review, we discuss how immunomodulatory changes arising from exposure to structured bouts of acute exercise might improve mAb treatment efficacy by augmenting (i) antibody-dependent cellular cytotoxicity, (ii) antibody-dependent cellular phagocytosis, (iii) complement-dependent cytotoxicity, (iv) T-cell cytotoxicity, and (v) direct delivery of cytotoxic agents.

Retinoic Acid-Related Orphan Receptor α Is Required for Generation of Th2 Cells in Type 2 Pulmonary Inflammation

The transcription factor retinoic acid-related orphan receptor α (RORα) is important in regulating several physiological functions, such as cellular development, circadian rhythm, metabolism, and immunity. In two in vivo animal models of type 2 lung inflammation, Nippostrongylus brasiliensis infection and house dust mite (HDM) sensitization, we show a role for Rora in Th2 cellular development during pulmonary inflammation. N. brasiliensis infection and HDM challenge induced an increase in frequency of Rora-expressing GATA3+CD4 T cells in the lung. Using staggerer mice, which have a ubiquitous deletion of functional RORα, we generated bone marrow chimera mice, and we observed a delayed worm expulsion and reduced frequency in the expansion of Th2 cells and innate lymphoid type 2 cells (ILC2s) in the lungs after N. brasiliensis infection. ILC2-deficient mouse (Rorafl/flIl7raCre) also had delayed worm expulsion with associated reduced frequency of Th2 cells and ILC2s in the lungs after N. brasiliensis infection. To further define the role for Rora-expressing Th2 cells, we used a CD4-specific Rora-deficient mouse (Rorafl/flCD4Cre), with significantly reduced frequency of lung Th2 cells, but not ILC2, after N. brasiliensis infection and HDM challenge. Interestingly, despite the reduction in pulmonary Th2 cells in Rorafl/flCD4Cre mice, this did not impact the expulsion of N. brasiliensis after primary and secondary infection, or the generation of lung inflammation after HDM challenge. This study demonstrates a role for RORα in Th2 cellular development during pulmonary inflammation that could be relevant to the range of inflammatory diseases in which RORα is implicated.

IL-7 producing immunotherapy improves ex vivo T cell functions of immunosenescent patients, especially post hip fracture

Following acute stress such as trauma or sepsis, most of critically ill elderly patients become immunosuppressed and susceptible to secondary infections and enhanced mortality. We have developed a virus-based immunotherapy encoding human interleukin-7 (hIL-7) aiming at restoring both innate an adaptative immune homeostasis in these patients. We assessed the impact of this encoded hIL-7 on the ex vivo immune functions of T cells from PBMC of immunosenescent patients with or without hip fracture. T-cell ex vivo phenotyping was characterized in terms of senescence (CD57), IL-7 receptor (CD127) expression, and T cell differentiation profile. Then, post stimulation, activation status, and functionality (STAT5/STAT1 phosphorylation and T cell proliferation assays) were evaluated by flow cytometry. Our data show that T cells from both groups display immunosenescence features, express CD127 and are activated after stimulation by virotherapy-produced hIL-7-Fc. Interestingly, hip fracture patients exhibit a unique functional ability: An important T cell proliferation occurred compared to controls following stimulation with hIL-7-Fc. In addition, stimulation led to an increased naïve T cell as well as a decreased effector memory T cell proportions compared to controls. This preliminary study indicates that the produced hIL-7-Fc is well recognized by T cells and initiates IL-7 signaling through STAT5 and STAT1 phosphorylation. This signaling efficiently leads to T cell proliferation and activation and enables a T cell "rejuvenation." These results are in favor of the clinical development of the hIL-7-Fc expressing virotherapy to restore or induce immune T cell responses in immunosenescent hip fracture patients.

The Therapeutic Values of IL-7/IL-7R and the Recombinant Derivatives in Glioma: A Narrative Review

Interleukin-7 (IL-7) is essential for maintaining the immune system's defense functions by regulating the development and homeostasis of lymphocytes. Findings have shown the high efficacy of IL-7/IL-7 receptor (IL-7R)-based immunotherapy on various malignancies, with confirmation in both animal models and humans. In recent years, the progression-free survival and overall survival of patients suffering from gliomas significantly increased by introducing C7R-expressing chimeric antigen receptor (CAR)-T cells and long-acting IL-7 agonists such as NT-I7 (rhIL-7-hyFc, Efineptakin alfa). However, the effect of IL-7-based immunotherapies on the resistance of tumor cells to chemotherapy (when used simultaneously with chemotherapy agents) is still ambiguous and requires further studies. This article first reviews the pathophysiological roles of IL-7/IL-7R in tumors, focusing on gliomas. Subsequently, it discusses the therapeutic values of IL-7/IL-7R and the recombinant derivatives in gliomas.

IL-7R licenses a population of epigenetically poised memory CD8+ T cells with superior antitumor efficacy that are critical for melanoma memory

Recurrence of advanced melanoma after therapy is a major risk factor for reduced survival, and treatment options are limited. Antitumor immune memory plays a critical role in preventing melanoma recurrence and memory T cells could be a potent cell-based therapy, but the identity, and functional properties of the required immune cells are incompletely understood. Here, we show that an IL-7Rhi tumor-specific CD8+ population is critical for antitumor memory and can be epigenetically augmented to drive powerful antitumor immune responses. Using a model of functional antimelanoma memory, we found that high IL-7R expression selectively marks a CD8+ population in lymphoid organs that plays critical roles in maintaining tumor remission after immunotherapy or surgical resection. This population has intrinsic cytotoxic activity, lacks markers of exhaustion and has superior antitumor efficacy. IL-7Rhi cells have a functionally poised epigenetic landscape regulated by DNA methylation, which can be augmented by hypomethylating agents to confer improved survival and complete melanoma clearance in naive mice. Importantly, greater than 95% of tumor-specific T cells in draining lymph nodes after therapy express high levels of IL-7R. This overlap between IL-7Rhi and antigen-specific T cells allows for enrichment of a potent functional CD8+ population without determining antigen-specificity, which we demonstrate in a melanoma model without a known antigen. We identify that IL-7R expression in human melanoma is an independent prognostic factor of improved survival. These findings advance our basic understanding of antitumor memory and suggest a cell-based therapy using high IL-7R expression to enrich for a lymph node population with superior antitumor activity that can be augmented by hypomethylating agents.

GM-CSF and IL-7 fusion cytokine engineered tumor vaccine generates long-term Th-17 memory cells and increases overall survival in aged syngeneic mouse models of glioblastoma

Age-related immune dysfunctions, such as decreased T-cell output, are closely related to pathologies like cancers and lack of vaccine efficacy among the elderly. Engineered fusokine, GIFT-7, a fusion of interleukin 7 (IL-7) and GM-CSF, can reverse aging-related lymphoid organ atrophy. We generated a GIFT-7 fusokine tumor vaccine and employed it in aged syngeneic mouse models of glioblastoma and found that peripheral vaccination with GIFT-7TVax resulted in thymic regeneration and generated durable long-term antitumor immunity specifically in aged mice. Global cytokine analysis showed increased pro-inflammatory cytokines including IL-1β in the vaccinated group that resulted in hyperactivation of dendritic cells. In addition, GIFT-7 vaccination resulted in increased T-cell trafficking to the brain and robust Th-17 long-term effector memory T-cell formation. TCR-seq analysis showed increased productive frequency among detected rearrangements within the vaccinated group. Overall, our data demonstrate that aging immune system can be therapeutically augmented to generate lasting antitumor immunity.

Severe persistent mycobacteria antigen stimulation causes lymphopenia through impairing hematopoiesis

Miliary tubersculosis (TB), an acute systemic blood disseminated tuberculosis mainly caused by Mycobacterium tuberculosis (M. tuberculosis), can cause signs of lymphopenia in clinical patients. To investigate whether/how persistent mycobacteria antigen stimulation impairs hematopoiesis and the therapeutic effect of interleukin-7 (IL-7), a mouse model of Mycobacterium Bovis Bacillus Calmette-Guérin (BCG) intravenous infection with/without an additional stimulation with M. tuberculosis multi-antigen cocktail containing ESAT6-CFP10 (EC) and Mtb10.4-HspX (MH) was established. Consistent with what happened in miliary TB, high dose of BCG intravenous infection with/without additional antigen stimulation caused lymphopenia in peripheral blood. In which, the levels of cytokines IFN-γ and TNF-α in serum increased, and consequently the expression levels of transcription factors Batf2 and IRF8 involved in myeloid differentiation were up-regulated, while the expression levels of transcription factors GATA2 and NOTCH1 involved in lymphoid commitment were down-regulated, and the proliferating activity of bone marrow (BM) lineage^- c-Kit⁺ (LK) cells decreased. Furthermore, recombinant Adeno-Associated Virus 2-mediated IL-7 (rAAV2-IL-7) treatment could significantly promote the elevation of BM lymphoid progenitors. It suggests that persistent mycobacteria antigen stimulation impaired lymphopoiesis of BM hematopoiesis, which could be restored by complement of IL-7.

Implication of IL-7 receptor alpha chain expression by CD8+ T cells and its signature in defining biomarkers in aging

CD8+ T cells play an important role in host defense against infections and malignancies as well as contribute to the development of inflammatory disorders. Alterations in the frequency of naïve and memory CD8+ T cells are one of the most significant changes in the immune system with age. As the world population rapidly ages, a better understanding of aging immune function or immunosenescence could become a basis for discovering treatments of illnesses that commonly occur in older adults. In particular, biomarkers for immune aging could be utilized to identify individuals at high risk of developing age-associated conditions and help monitor the efficacy of therapeutic interventions targeting such conditions. This review details the possible role of CD8+ T cell subsets expressing different levels of the cytokine receptor IL-7 receptor alpha chain (IL-7Rα) and the gene signature associated with IL-7Rα as potential biomarkers for immune aging given the association of CD8+ T cells in host defense, inflammation, and immunosenescence.

Interleukin-7 enhances in vitro development and blastocyst quality in porcine parthenogenetic embryos

Interleukin-7 (IL-7), a vital factor that affects cell development, proliferation, and survival, plays an important role in oocyte maturation. However, its role in embryonic development remains unknown. Therefore, in this study, we aimed to investigate the effects of IL-7 supplementation on in vitro culture (IVC) of porcine embryos after parthenogenetic activation (PA) based on characteristics such as cleavage, blastocyst formation rate, intracellular glutathione (GSH) and reactive oxygen species (ROS) levels in cleaved embryos, total cell number, apoptosis rate, and cell lineage specification in blastocysts. Immunofluorescence revealed that IL-7 and its receptor, IL-7Rα (IL-7R) localized in the cytoplasm of porcine parthenote embryos. By supplementing the IVC medium (PZM5) with various concentrations of IL-7, an optimal concentration that enhanced embryonic development, promoted intracellular GSH, and decreased ROS levels in the cleavage stage during porcine embryo IVC was determined. Investigation of mRNA expression patterns via qRT-PCR suggested that IL-7 possibly regulated maternal mRNA clearance and zygotic genome activation. Furthermore, IL-7 supplementation reduced blastocyst apoptosis, enhanced the expression of the inner cell mass marker SOX2, and phosphorylated STAT5 levels in the blastocysts. Moreover, it altered the transcription patterns of genes that regulate apoptosis, IL-7 signaling, and development. Thus, we demonstrated the localization of IL-7 and IL-7R in porcine preimplantation embryos in vitro for the first time. Furthermore, we suggest that IL-7 supplementation can be employed to enhance embryonic development and blastocyst quality based on the activation of the transcripts of genes that are involved in developmental competence and IL-7 signaling during in vitro porcine embryo development following PA.

IL7 genetic variation and toxicity to immune checkpoint blockade in patients with melanoma

Treatment with immune checkpoint blockade (ICB) frequently triggers immune-related adverse events (irAEs), causing considerable morbidity. In 214 patients receiving ICB for melanoma, we observed increased severe irAE risk in minor allele carriers of rs16906115, intronic to IL7. We found that rs16906115 forms a B cell-specific expression quantitative trait locus (eQTL) to IL7 in patients. Patients carrying the risk allele demonstrate increased pre-treatment B cell IL7 expression, which independently associates with irAE risk, divergent immunoglobulin expression and more B cell receptor mutations. Consistent with the role of IL-7 in T cell development, risk allele carriers have distinct ICB-induced CD8+ T cell subset responses, skewing of T cell clonality and greater proportional repertoire occupancy by large clones. Finally, analysis of TCGA data suggests that risk allele carriers independently have improved melanoma survival. These observations highlight key roles for B cells and IL-7 in both ICB response and toxicity and clinical outcomes in melanoma.

RNA Metabolism in T Lymphocytes

RNA metabolism plays a central role in regulating of T cell-mediated immunity. RNA processing, modifications, and regulations of RNA decay influence the tight and rapid regulation of gene expression during T cell phase transition. Thymic selection, quiescence maintenance, activation, differentiation, and effector functions of T cells are dependent on selective RNA modulations. Recent technical improvements have unveiled the complex crosstalk between RNAs and T cells. Moreover, resting T cells contain large amounts of untranslated mRNAs, implying that the regulation of RNA metabolism might be a key step in controlling gene expression. Considering the immunological significance of T cells for disease treatment, an understanding of RNA metabolism in T cells could provide new directions in harnessing T cells for therapeutic implications.

The Role of IL-7 and IL-7R in Cancer Pathophysiology and Immunotherapy

Interleukin-7 (IL-7) is a multipotent cytokine that maintains the homeostasis of the immune system. IL-7 plays a vital role in T-cell development, proliferation, and differentiation, as well as in B cell maturation through the activation of the IL-7 receptor (IL-7R). IL-7 is closely associated with tumor development and has been used in cancer clinical research and therapy. In this review, we first summarize the roles of IL-7 and IL-7Rα and their downstream signaling pathways in immunity and cancer. Furthermore, we summarize and discuss the recent advances in the use of IL-7 and IL-7Rα as cancer immunotherapy tools and highlight their potential for therapeutic applications. This review will help in the development of cancer immunotherapy regimens based on IL-7 and IL-7Rα, and will also advance their exploitation as more effective and safe immunotherapy tools.

Transcriptional coregulator Ess2 controls survival of post-thymic CD4+ T cells through the Myc and IL-7 signaling pathways

Ess2, also known as Dgcr14, is a transcriptional co-regulator of CD4+ T cells. Ess2 is located in a chromosomal region, the loss of which has been associated with 22q11.2 deletion syndrome (22q11DS), which causes heart defects, skeletal abnormalities, and immunodeficiency. However, the specific association of Ess2 with 22q11DS remains unclear. To elucidate the role of Ess2 in T-cell development, we generated Ess2 floxed (Ess2fl/fl) and CD4+ T cell-specific Ess2 KO (Ess2ΔCD4/ΔCD4) mice using the Cre/loxP system. Interestingly, Ess2ΔCD4/ΔCD4 mice exhibited reduced naïve T-cell numbers in the spleen, while the number of thymocytes (CD4-CD8-, CD4+CD8+, CD4+CD8-, and CD4-CD8+) in the thymus remained unchanged. Furthermore, Ess2ΔCD4/ΔCD4 mice had decreased NKT cells and increased γδT cells in the thymus and spleen. A genome-wide expression analysis using RNA-seq revealed that Ess2 deletion alters the expression of many genes in CD4 single-positive thymocytes, including genes related to the immune system and Myc target genes. In addition, Ess2 enhanced the transcriptional activity of c-Myc. Some genes identified as Ess2 targets in mice show expressional correlation with ESS2 in human immune cells. Moreover, Ess2ΔCD4/ΔCD4 naïve CD4+ T cells did not maintain survival in response to IL-7. Our results suggest that Ess2 plays a critical role in post-thymic T-cell survival through the Myc and IL-7 signaling pathways.

Immunoregulation via Cell Density and Quorum Sensing-like Mechanisms: An Underexplored Emerging Field with Potential Translational Implications

Quorum sensing (QS) was historically described as a mechanism by which bacteria detect and optimize their population density via gene regulation based on dynamic environmental cues. Recently, it was proposed that QS or similar mechanisms may have broader applications across different species and cell types. Indeed, emerging evidence shows that the mammalian immune system can also elicit coordinated responses on a population level to regulate cell density and function, thus suggesting that QS-like mechanisms may also be a beneficial trait of the immune system. In this review, we explore and discuss potential QS-like mechanisms deployed by the immune system to coordinate cellular-level responses, such as T cell responses mediated via the common gamma chain (γc) receptor cytokines and the aryl hydrocarbon receptors (AhRs). We present evidence regarding a novel role of QS as a multifunctional mechanism coordinating CD4⁺ and CD8⁺ T cell behavior during steady state and in response to infection, inflammatory diseases, and cancer. Successful clinical therapies such as adoptive cell transfer for cancer treatment may be re-evaluated to harness the effects of the QS mechanism(s) and enhance treatment responsiveness. Moreover, we discuss how signaling threshold perturbations through QS-like mediators may result in disturbances of the complex crosstalk between immune cell populations, undesired T cell responses, and induction of autoimmune pathology. Finally, we discuss the potential therapeutic role of modulating immune-system-related QS as a promising avenue to treat human diseases.

Antisense modulation of IL7R splicing to control sIL7R expression in human CD4+ T cells

The interleukin 7 receptor (IL7R) is strongly associated with increased risk to develop multiple sclerosis (MS), an autoimmune disease of the central nervous system, and this association is likely driven by up-regulation of the soluble isoform of IL7R (sIL7R). Expression of sIL7R is determined by exclusion of the alternative exon 6 from IL7R transcripts, and our previous work revealed that the MS risk allele of the SNP rs6897932 within this exon enhances the expression of sIL7R by promoting exclusion of exon 6. sIL7R potentiates the activity of IL7, leading to enhanced expansion of T cells and increased disability in the experimental autoimmune encephalomyelitis (EAE) murine model of MS. This role in modulating T cell-driven immunity positions sIL7R as an attractive therapeutic target whose expression could be reduced for treatment of MS or increased for treatment of cancers. In this study, we identified novel antisense oligonucleotides (ASOs) that effectively control the inclusion (anti-sIL7R ASOs) or exclusion (pro-sIL7R ASOs) of this exon in a dose-dependent fashion. These ASOs provided excellent control of exon 6 splicing and sIL7R secretion in human primary CD4⁺ T cells. Supporting their potential for therapeutic targeting, we showed that lead anti-sIL7R ASOs correct the enhanced exon 6 exclusion imposed by the MS risk allele of rs6897932, whereas lead pro-sIL7R ASOs phenocopy it. The data presented here form the foundation for future preclinical studies that will test the therapeutic potential of these ASOs in MS and immuno-oncology.

A Proposed Link Between Acute Thymic Involution and Late Adverse Effects of Chemotherapy

Epidemiologic data suggest that cancer survivors tend to develop a protuberant number of adverse late effects, including second primary malignancies (SPM), as a result of cytotoxic chemotherapy. Besides the genotoxic potential of these drugs that directly inflict mutational burden on genomic DNA, the precise mechanisms contributing to SPM development are poorly understood. Cancer is nowadays perceived as a complex process that goes beyond the concept of genetic disease and includes tumor cell interactions with complex stromal and immune cell microenvironments. The cancer immunoediting theory offers an explanation for the development of nascent neoplastic cells. Briefly, the theory suggests that newly emerging tumor cells are mostly eliminated by an effective tissue immunosurveillance, but certain tumor variants may occasionally escape innate and adaptive mechanisms of immunological destruction, entering an equilibrium phase, where immunologic tumor cell death "equals" new tumor cell birth. Subsequent microenvironmental pressures and accumulation of helpful mutations in certain variants may lead to escape from the equilibrium phase, and eventually cause an overt neoplasm. Cancer immunoediting functions as a dedicated sentinel under the auspice of a highly competent immune system. This perspective offers the fresh insight that chemotherapy-induced thymic involution, which is characterized by the extensive obliteration of the sensitive thymic epithelial cell (TEC) compartment, can cause long-term defects in thymopoiesis and in establishment of diverse T cell receptor repertoires and peripheral T cell pools of cancer survivors. Such delayed recovery of T cell adaptive immunity may result in prolonged hijacking of the cancer immunoediting mechanisms, and lead to development of persistent and mortal infections, inflammatory disorders, organ-specific autoimmunity lesions, and SPMs. Acknowledging that chemotherapy-induced thymic involution is a potential risk factor for the emergence of SPM demarcates new avenues for the rationalized development of pharmacologic interventions to promote thymic regeneration in patients receiving cytoreductive chemotherapies.

Therapeutic Effect of Anti-CD52 Monoclonal Antibody in Multiple Sclerosis and Its Animal Models Is Mediated via T Regulatory Cells

The objective of this study is to determine the mechanism of action of anti-CD52 mAb treatment in patients with relapsing-remitting multiple sclerosis (RRMS). Experimental autoimmune encephalomyelitis (EAE), an animal model of the disease, was used to address the role of T regulatory cells (Tregs) in the anti-CD52 mAb-induced suppression of the disease. In vitro studies on PBMCs from RRMS patients and matched healthy controls determined the effect of IL-7 on the expansion of CD4+CD25+CD127- Tregs and induction of their suppressive phenotype. This study using EAE animal models of MS has shown that mouse anti-CD52 mAb suppression of clinical disease was augmented by coadministration of IL-7 and partially reversed by anti-IL-7 mAb. In vitro human studies showed that IL-7 induced expansion of CD4+CD25+CD127- Tregs and increased their FOXP3, GITIR, CD46, CTLA-4, granzyme B, and perforin expression. Anti-CD52 mAb treatment of mice with relapsing-remitting EAE induced expansion of Foxp3+CD4+ Tregs and the suppression of IL-17A+CD4+ and IFN-γ+CD4+ cells in peripheral immune organs and CNS infiltrates. The effect was detected immediately after the treatment and maintained over long-term follow-up. Foxp3+CD4+ Treg-mediated suppression of IL-17A+CD4+ and IFN-γ+CD4+ cells in the spinal cord infiltrates was reversed after inducible Foxp3 depletion. Our results demonstrated that the therapeutic effect of U.S. Food and Drug Administration-approved anti-CD52 mAb is dependent on the presence of Tregs.

Longitudinal analysis reveals age-related changes in the T cell receptor repertoire of human T cell subsets

A diverse T cell receptor (TCR) repertoire is essential for protection against a variety of pathogens, and TCR repertoire size is believed to decline with age. However, the precise size of human TCR repertoires, in both total and subsets of T cells, as well as their changes with age, are not fully characterized. We conducted a longitudinal analysis of the human blood TCRα and TCRβ repertoire of CD4⁺ and CD8⁺ T cell subsets using a unique molecular identifier–based (UMI-based) RNA-seq method. Thorough analysis of 1.9 × 10⁸ T cells yielded the lower estimate of TCR repertoire richness in an adult at 3.8 × 10⁸. Alterations of the TCR repertoire with age were observed in all 4 subsets of T cells. The greatest reduction was observed in naive CD8⁺ T cells, while the greatest clonal expansion was in memory CD8⁺ T cells, and the highest increased retention of TCR sequences was in memory CD8⁺ T cells. Our results demonstrated that age-related TCR repertoire attrition is subset specific and more profound for CD8⁺ than CD4⁺ T cells, suggesting that aging has a more profound effect on cytotoxic as opposed to helper T cell functions. This may explain the increased susceptibility of older adults to novel infections.

The generation and application of antigen-specific T cell therapies for cancer and viral-associated disease

Immunotherapy with antigen-specific T cells is a promising, targeted therapeutic option for patients with cancer as well as for immunocompromised patients with virus infections. In this review, we characterize and compare current manufacturing protocols for the generation of T cells specific to viral and non-viral tumor-associated antigens. Specifically, we discuss: (1) the different methodologies to expand virus-specific T cell and non-viral tumor-associated antigen-specific T cell products, (2) an overview of the immunological principles involved when developing such manufacturing protocols, and (3) proposed standardized methodologies for the generation of polyclonal, polyfunctional antigen-specific T cells irrespective of donor source. Ex vivo expanded cells have been safely administered to treat numerous patients with virus-associated malignancies, hematologic malignancies, and solid tumors. Hence, we have performed a comprehensive review of the clinical trial results evaluating the safety, feasibility, and efficacy of these products in the clinic. In summary, this review seeks to provide new insights regarding antigen-specific T cell technology to benefit a rapidly expanding T cell therapy field.

Protocol for a Sepsis Model Utilizing Fecal Suspension in Mice: Fecal Suspension Intraperitoneal Injection Model

Background

Various animal models of sepsis have been developed to optimize sepsis treatment. However, therapeutic agents that were successful in animal models were rarely effective in human clinical trials. The cecal ligation and puncture (CLP) model is currently the gold standard for sepsis studies. However, its limitations include the high variability among researchers and the difficulty in comparing animals with different cecum shapes and sizes. In this study, we established a protocol for the creation of a simple and accessible sepsis rodent model using fecal suspensions that minimized differences in technical effects among researchers and individual differences in animals.

Methods

A mouse model of sepsis using fecal suspension intraperitoneal injection (FSI) was created using fresh stool excreted within 24 h. The collected fresh stool was dissolved in saline solution and filtered. The obtained fecal suspension was injected intraperitoneally into the mice. Moreover, fecal suspensions with different concentrations were prepared, and the survival rates were compared among the fecal suspensions for each concentration. To assess the validity of the FSI as a sepsis model, CLP and FSI with similar mortality rates were compared pathologically, physiologically, immunologically, and bacteriologically. Histopathological comparison was evaluated by hematoxylin-eosin and Gram staining of the parenchymal organs. Physiological evaluation was performed by comparing the respiratory rate, body temperature, and blood gas analysis results. Immunological assessment was performed using multiplex analysis. Bacteriological comparisons were performed by culturing ascites fluid.

Results

The FSI model increased mortality in proportion to the fecal suspension concentration. The mortality rate was reduced with antibiotic administration. In various comparative experiments conducted using the FSI and CLP models, both models showed findings consistent with sepsis. Furthermore, the FSI model showed less variability among the individuals in each test.

Conclusion

This is the first detailed and accurate report of a protocol for creating a sepsis model using fecal suspension. The FSI model is a minimally invasive and accessible sepsis rodent model. Its clinical validity as a sepsis model was proven via histological, physiological, microbiological, and immunological evaluation methods. The FSI model minimizes individual differences between mice and helps to conduct accurate studies after the onset of sepsis.

Emerging Strategies in TCR-Engineered T Cells

Immunotherapy of cancer has made tremendous progress in recent years, as demonstrated by the remarkable clinical responses obtained from adoptive cell transfer (ACT) of patient-derived tumor infiltrating lymphocytes, chimeric antigen receptor (CAR)-modified T cells (CAR-T) and T cell receptor (TCR)-engineered T cells (TCR-T). TCR-T uses specific TCRS optimized for tumor engagement and can recognize epitopes derived from both cell-surface and intracellular targets, including tumor-associated antigens, cancer germline antigens, viral oncoproteins, and tumor-specific neoantigens (neoAgs) that are largely sequestered in the cytoplasm and nucleus of tumor cells. Moreover, as TCRS are naturally developed for sensitive antigen detection, they are able to recognize epitopes at far lower concentrations than required for CAR-T activation. Therefore, TCR-T holds great promise for the treatment of human cancers. In this focused review, we summarize basic, translational, and clinical insights into the challenges and opportunities of TCR-T. We review emerging strategies used in current ACT, point out limitations, and propose possible solutions. We highlight the importance of targeting tumor-specific neoAgs and outline a strategy of combining neoAg vaccines, checkpoint blockade therapy, and adoptive transfer of neoAg-specific TCR-T to produce a truly tumor-specific therapy, which is able to penetrate into solid tumors and resist the immunosuppressive tumor microenvironment. We believe such a combination approach should lead to a significant improvement in cancer immunotherapies, especially for solid tumors, and may provide a general strategy for the eradication of multiple cancers.

NFAT Factors Are Dispensable for the Development but Are Critical for the Maintenance of Foxp3+ Regulatory T Cells

The transcription factors of the nuclear factor of activated T cell (NFAT) family play a crucial role in multiple aspects of T cell function. It has recently been reported that NFATs play an important role in the suppressive function of CD4⁺CD25⁺Foxp3⁺ regulatory T (T_reg) cells. In this study, we have investigated the role of NFATs in the thymic development of T_reg cells in mice. We show that NFAT factors are dispensable for the development of Foxp3⁺ T_reg cells in the thymus but are critical for the maintenance of both the phenotype and survival of T_reg cells in the thymus as well as in peripheral lymphoid organs. Specifically, the homeostasis of CD4⁺CD25⁺Foxp3⁺ but not the CD4⁺CD25⁻Foxp3⁺ fraction is severely perturbed when NFAT signaling is blocked, leading to a strongly reduced T_reg population. We underscored this intriguing effect of NFAT on CD4⁺CD25⁺Foxp3⁺ T_reg cells to the disruption of survival signals provided by interleukin 2 (IL-2). Accordingly, blocking T_reg cell death by abolishing the activity of pro-apoptotic Bcl-2 family member Bim, compensated for the survival defects induced due to a lack of NFAT-IL-2-IL-2R signaling. Inhibition of NFAT activity led to a strong reduction in the number of Foxp3⁺ T_reg cells; however, it did not influence the level of Foxp3 expression on an individual cell basis. In addition, we show a differential effect of IL-2 and IL-7 signaling on Foxp3⁺ T_reg versus CD4⁺CD25⁻ T cell development, again underlining the dispensability of NFAT signaling in the development, but not in the maintenance of Foxp3⁺ T_reg cells.

Surviving the Storm: Cytokine Biosignature in SARS-CoV-2 Severity Prediction

Simple Summary

The world has been stricken mentally, physically, and economically by the COVID-19 virus. However, while SARS-CoV-2 viral infection results in mild flu-like symptoms in most patients, a number of those infected develop severe illness. These patients require hospitalization and intensive care. The severe disease can spiral downwards with eventual severe damage to the lungs and failure of multiple organs, leading to the individual’s demise. It is necessary to identify those who are developing a severe form of illness to provide early management. Therefore, it is crucial to learn about the mechanisms and chemical mediators that lead to critical conditions in SARS-CoV-2 infection. This paper reviews studies regarding the individual chemical mediators, pathways, and means that contribute to worsening health conditions in SARS-CoV-2 infection.

Abstract

A significant part of the world population has been affected by the devastating SARS-CoV-2 infection. It has deleterious effects on mental and physical health and global economic conditions. Evidence suggests that the pathogenesis of SARS-CoV-2 infection may result in immunopathology such as neutrophilia, lymphopenia, decreased response of type I interferon, monocyte, and macrophage dysregulation. Even though most individuals infected with the SARS-CoV-2 virus suffer mild symptoms similar to flu, severe illness develops in some cases, including dysfunction of multiple organs. Excessive production of different inflammatory cytokines leads to a cytokine storm in COVID-19 infection. The large quantities of inflammatory cytokines trigger several inflammation pathways through tissue cell and immune cell receptors. Such mechanisms eventually lead to complications such as acute respiratory distress syndrome, intravascular coagulation, capillary leak syndrome, failure of multiple organs, and, in severe cases, death. Thus, to devise an effective management plan for SARS-CoV-2 infection, it is necessary to comprehend the start and pathways of signaling for the SARS-CoV-2 infection-induced cytokine storm. This article discusses the current findings of SARS-CoV-2 related to immunopathology, the different paths of signaling and other cytokines that result in a cytokine storm, and biomarkers that can act as early signs of warning for severe illness. A detailed understanding of the cytokine storm may aid in the development of effective means for controlling the disease’s immunopathology. In addition, noting the biomarkers and pathophysiology of severe SARS-CoV-2 infection as early warning signs can help prevent severe complications.

Physical Exercise Restrains Cancer Progression through Muscle-Derived Factors

Simple Summary

The benefits of physical exercise against cancer onset and progression, as well as the adverse effects of physical inactivity have changed the way that we utilize exercise for cancer patients. Nevertheless, although guidelines of various scientific societies and organizations propose exercise as a complementary intervention during cancer therapies, the exact cellular and molecular mechanisms by which exercise acts against cancer have not yet been elucidated. In the present review, we analyze the factors which either are secreted from skeletal muscle or are regulated by exercise and can restrain cancer evolution. We also describe the exercise-induced factors that counteract severe side effects of cancer treatment, as well as the ways that muscle-derived factors are delivered to the target cells.

Abstract

A growing body of in vitro and in vivo studies suggests that physical activity offers important benefits against cancer, in terms of both prevention and treatment. However, the exact mechanisms implicated in the anticancer effects of exercise remain to be further elucidated. Muscle-secreted factors in response to contraction have been proposed to mediate the physical exercise-induced beneficial effects and be responsible for the inter-tissue communications. Specifically, myokines and microRNAs (miRNAs) constitute the most studied components of the skeletal muscle secretome that appear to affect the malignancy, either directly by possessing antioncogenic properties, or indirectly by mobilizing the antitumor immune responses. Moreover, some of these factors are capable of mitigating serious, disease-associated adverse effects that deteriorate patients’ quality of life and prognosis. The present review summarizes the myokines and miRNAs that may have potent anticancer properties and the expression of which is induced by physical exercise, while the mechanisms of secretion and intercellular transportation of these factors are also discussed.