Cellular and Molecular Mechanisms of CD8+ T Cell Differentiation, Dysfunction and Exhaustion

APLNR inhibited nasopharyngeal carcinoma growth and immune escape by downregulating PD-L1

BACKGROUND

APLNR is a G protein-coupled receptor and our previous study had revealed that APLNR could inhibit nasopharyngeal carcinoma (NPC) growth and metastasis. However, the role of APLNR in regulating PD-L1 expression and immune escape in NPC is unknown.

METHODS

We analyzed the expression and correlation of APLNR and PD-L1 in NPC tissues and cells. We investigated the effect of APLNR on PD-L1 expression and the underlying mechanism in vitro and in vivo. We also evaluated the therapeutic potential of targeting APLNR in combination with PD-L1 antibody in a nude mouse xenograft model.

RESULTS

We found that APLNR was negatively correlated with PD-L1 in NPC tissues and cells. APLNR could inhibit PD-L1 expression by binding to the FERM domain of JAK1 and blocking the interaction between JAK1 and IFNGR1, thus suppressing IFN-γ-mediated activation of the JAK1/STAT1 pathway. APLNR could also inhibit NPC immune escape by enhancing IFN-γ secretion and CD8+ T-cell infiltration and reducing CD8+ T-cell apoptosis and dysfunction. Moreover, the best effect was achieved in inhibiting NPC growth in nude mice when APLNR combined with PD-L1 antibody.

CONCLUSIONS

Our study revealed a novel mechanism of APLNR regulating PD-L1 expression and immune escape in NPC and suggested that APLNR maybe a potential therapeutic target for NPC immunotherapy.

Effects of immune exhaustion and senescence of innate immunity in autoimmune disorders

Innate immune system activation is crucial in the inflammatory response, but uncontrolled activation can lead to autoimmune diseases. Cellular exhaustion and senescence are two processes that contribute to innate immune tolerance breakdown. Exhausted immune cells are unable to respond adequately to specific antigens or stimuli, while senescent cells have impaired DNA replication and metabolic changes. These processes can impair immune system function and disrupt homeostasis, leading to the emergence of autoimmunity. However, the influence of innate immune exhaustion and senescence on autoimmune disorders is not well understood. This review aims to describe the current findings on the role of innate immune exhaustion and senescence in autoimmunity, focusing on the cellular and molecular changes involved in each process. Specifically, the article explores the markers and pathways associated with immune exhaustion, such as PD-1 and TIM-3, and senescence, including Β-galactosidase (β-GAL), lamin B1, and p16ink4a, and their impact on autoimmune diseases, namely type 1 diabetes, rheumatoid arthritis, systemic lupus erythematosus, and immune-mediated myopathies. Understanding the mechanisms underlying innate immune exhaustion and senescence in autoimmunity may provide insights for the development of novel therapeutic strategies.

The CLCF1-CNTFR axis drives an immunosuppressive tumor microenvironment and blockade enhances the effects of established cancer therapies

Tumors comprise a complex ecosystem consisting of many cell types that communicate through secreted factors. Targeting these intercellular signaling networks remains an important challenge in cancer research. Cardiotrophin-like cytokine factor 1 (CLCF1) is an interleukin-6 (IL-6) family member secreted by cancer-associated fibroblasts (CAFs) that binds to ciliary neurotrophic factor receptor (CNTFR), promoting tumor growth in lung and liver cancer1,2. A high-affinity soluble receptor (eCNTFR-Fc) that sequesters CLCF1 has anti-oncogenic effects3. However, the role of CLCF1 in mediating cell-cell interactions in cancer has remained unclear. We demonstrate that eCNTFR-Fc has widespread effects on both tumor cells and the tumor microenvironment and can sensitize cancer cells to KRAS inhibitors or immune checkpoint blockade. After three weeks of treatment with eCNTFR-Fc, there is a shift from an immunosuppressive to an immunostimulatory macrophage phenotype as well as an increase in activated T, NKT, and NK cells. Combination of eCNTFR-Fc and αPD1 was significantly more effective than single-agent therapy in a syngeneic allograft model, and eCNTFR-Fc sensitizes tumor cells to αPD1 in a non-responsive GEM model of lung adenocarcinoma. These data suggest that combining eCNTFR-Fc with KRAS inhibition or with αPD1 is a novel therapeutic strategy for lung cancer and potentially other cancers in which these therapies have been used but to date with only modest effect. Overall, we demonstrate the potential of cancer therapies that target cytokines to alter the immune microenvironment.

METTL3-mediated HPV vaccine enhances the effect of anti PD-1 immunotherapy to alleviate the development of cutaneous squamous cell carcinoma

BACKGROUND

Cutaneous squamous cell carcinoma (cSCC) develops from epithelial keratinocytes by dysregulation of self-renewal and differentiation. Recent studies have found that the size and number of cSCC tumors gradually decrease or even disappear after HPV vaccination. However, the role of the HPV vaccine in the cSCC mechanism is poorly understood.

OBJECTIVE

The aim of this study is to investigate the effect and mechanism of the HPV vaccine in cSCC.

METHODS

Immunofluorescence was used to study the immune infiltrating cells in the tumor tissues of patients with cSCC. The effects of the HPV vaccine on cSCC cells and tissues were studied by Cell Culture, Real-time PCR, Western Blot, Cytotoxicity Assay, Enzyme-linked Immunosorbent Assay, m6A Blotting, CCK-8 Assay, m6A Ribonucleic acid Methylation Quantification and tumor transplantation.

RESULTS

The HPV vaccine enhanced the toxic effect of CD8+T cells on cSCC cells and promoted the secretion of multiple cytokines by CD8+T cells. In addition, HPV vaccines can increase tumor sensitivity to anti-PD-1 therapy by downregulating METTL3 in tumor tissue, with the combination of HPV vaccine and PD-1 monoclonal antibodies producing enhanced immune cell infiltration compared to PD-1 blockade alone.

STUDY LIMITATIONS

It is important to note the limitations of this study, including the small sample size, the construction of the mouse model, and the choice of HPV vaccine and PD-1 monoclonal antibody, which may limit the generalization of our findings to a wider population.

CONCLUSIONS

It is hoped that this research will contribute to a deeper understanding of the role of the HPV vaccine in the treatment of cSCC. HPV vaccine is expected to become an important approach to alleviate the development of cSCC.

A novel EIF3C-related CD8+ T-cell signature in predicting prognosis and immunotherapy response of nasopharyngeal carcinoma

PURPOSE

At present, dysfunctional CD8+ T-cells in the nasopharyngeal carcinoma (NPC) tumor immune microenvironment (TIME) have caused unsatisfactory immunotherapeutic effects, such as a low response rate of anti-PD-L1 therapy. Therefore, there is an urgent need to identify reliable markers capable of accurately predicting immunotherapy efficacy.

METHODS

Utilizing various algorithms for immune-infiltration evaluation, we explored the role of EIF3C in the TIME. We next found the influence of EIF3C expression on NPC based on functional analyses and RNA sequencing. By performing correlation and univariate Cox analyses of CD8+ Tcell markers from scRNA-seq data, we identified four signatures, which were then used in conjunction with the lasso algorithm to determine corresponding coefficients in the resulting EIF3C-related CD8+ T-cell signature (ETS). We subsequently evaluated the prognostic value of ETS using univariate and multivariate Cox regression analyses, Kaplan-Meier curves, and the area under the receiver operating characteristic curve (AUROC).

RESULTS

Our results demonstrate a significant relationship between low expression of EIF3C and high levels of CD8+ T-cell infiltration in the TIME, as well as a correlation between EIF3C expression and progression of NPC. Based on the expression levels of four EIF3C-related CD8+ T-cell marker genes, we constructed the ETS predictive model for NPC prognosis, which demonstrated success in validation. Notably, our model can also serve as an accurate indicator for detecting immunotherapy response.

CONCLUSION

Our findings suggest that EIF3C plays a significant role in NPC progression and immune modulation, particularly in CD8+ T-cell infiltration. Furthermore, the ETS model holds promise as both a prognostic predictor for NPC patients and a tool for adjusting individualized immunotherapy strategies.

Heterogeneity-induced NGF-NGFR communication inefficiency promotes mitotic spindle disorganization in exhausted T cells through PREX1 suppression to impair the anti-tumor immunotherapy with PD-1 mAb in hepatocellular carcinoma

BACKGROUND

The mechanism of decreased T cells infiltrating tumor tissues in hepatocellular carcinoma is poorly understood.

METHODS

Cells were separated from the single-cell RNA-sequence dataset of hepatocellular carcinoma patients (GSE149614) for cell-cell communication. Flow cytometry, EDU staining, H3-Ser28 staining, confocal immunofluorescence staining, western blotting and naked microsubcutaneous tumors were performed for the mechanism of NGF-NGFR promoting proliferation.

RESULTS

The present study has revealed that during the process of T-cell infiltration from adjacent tissues to tumor tissues, an inefficiency in NGF-NGFR communication occurs in the tumor tissues. Importantly, NGF secreted by tumor cells interacts with NGFR present on the membranes of the infiltrated T cells, thereby promoting the proliferation through the activation of mitotic spindle signals. Mechanistically, the mediation of mitotic spindle signal activation promoting proliferation is executed by HDAC1-mediated inhibition of unclear trans-localization of PREX1. Furthermore, PD-1 mAb acts synergistically with the NGF-NGFR communication to suppress tumor progression in both mouse models and HCC patients. Additionally, NGF-NGFR communication was positively correlates with the PD-1/PDL-1 expression. However, expressions of NGF and NGFR are low in tumor tissues, which is responsible for the invasive clinicopathological features and the disappointing prognosis in HCC patients.

CONCLUSION

Inefficiency in NGF-NGFR communication impairs PD-1 mAb immunotherapy and could thus be utilized as a novel therapeutic target in the treatment of HCC patients in clinical practice.

Modeling the neuroimmune system in Alzheimer's and Parkinson's diseases

Parkinson's disease (PD) and Alzheimer's disease (AD) are neurodegenerative disorders caused by the interaction of genetic, environmental, and familial factors. These diseases have distinct pathologies and symptoms that are linked to specific cell populations in the brain. Notably, the immune system has been implicated in both diseases, with a particular focus on the dysfunction of microglia, the brain's resident immune cells, contributing to neuronal loss and exacerbating symptoms. Researchers use models of the neuroimmune system to gain a deeper understanding of the physiological and biological aspects of these neurodegenerative diseases and how they progress. Several in vitro and in vivo models, including 2D cultures and animal models, have been utilized. Recently, advancements have been made in optimizing these existing models and developing 3D models and organ-on-a-chip systems, holding tremendous promise in accurately mimicking the intricate intracellular environment. As a result, these models represent a crucial breakthrough in the transformation of current treatments for PD and AD by offering potential for conducting long-term disease-based modeling for therapeutic testing, reducing reliance on animal models, and significantly improving cell viability compared to conventional 2D models. The application of 3D and organ-on-a-chip models in neurodegenerative disease research marks a prosperous step forward, providing a more realistic representation of the complex interactions within the neuroimmune system. Ultimately, these refined models of the neuroimmune system aim to aid in the quest to combat and mitigate the impact of debilitating neuroimmune diseases on patients and their families.

T cell exhaustion dynamics in systemic autoimmune disease

Unlike in infection and cancer, T cell exhaustion in autoimmune disease has not been clearly defined. Here we set out to understand inhibitory protein (PD-1, Tim3, CTLA4, Lag3) expression in CXCR5- and CXCR5+ CD8 and CD4 T cells in systemic lupus erythematosus. CXCR5+ CD8 and CD4 T cells express PD-1 and engage B cells in germinal center reactions, leading to autoantibody formation in autoimmunity. We hypothesized that CXCR5+ CD8 T cells develop an exhausted phenotype as SLE autoimmunity expands from initial to chronic, self-perpetuating disease due to chronic self-antigen exposure. Our results indicate that there is no exhaustion frequency differences between sexes, although disease kinetics vary by sex. CXCR5+ CD8 T cells express primarily IFNγ, known to promote autoimmune disease development, whereas CXCR5-CD8 T cells express TNFα and IFNγ as disease progresses from 2-6 months. Tim3 is the highest expressed inhibitory marker for all CD4 and CD8 T cell populations demonstrating potential for terminally exhausted populations. CTLA4 expression on CD4 T cells suggests potential tolerance induction in these cells. We identified exhaustion phenotypes within autoimmune disease that progress with increasing lupus erythematosus severity and possibly provide a feedback mechanism for immunological tolerance.

Highlights

CXCR5- and CXCR5+ CD8 T cells expand with rate of disease in SLE mouse model.CXCR5+ CD8 T cells are low contributors to TNFα disease progression unlike CXCR5-CD8 T cells but may increase disease mechanisms through high IFNγ production.Inhibitory markers upregulate in frequency with the highest amounts seen in Tim3+ populations. Tim3+Lag3+ expression may be an indicator of terminal differentiation for all populations.Inhibitory marker expression frequency was unrelated to sex.

A transcriptional evaluation of the melanoma and squamous cell carcinoma TIL compartment reveals an unexpected spectrum of exhausted and functional T cells

Introduction

Significant heterogeneity exists within the tumor-infiltrating CD8 T cell population, and exhausted T cells harbor a subpopulation that may be replicating and may retain signatures of activation, with potential functional consequences in tumor progression. Dysfunctional immunity in the tumor microenvironment is associated with poor cancer outcomes, making exploration of these exhausted T cell subpopulations critical to the improvement of therapeutic approaches.

Methods

To investigate mechanisms associated with terminally exhausted T cells, we sorted and performed transcriptional profiling of CD8+ tumor-infiltrating lymphocytes (TILs) co-expressing the exhaustion markers PD-1 and TIM-3 from large-volume melanoma tumors. We additionally performed immunologic phenotyping and functional validation, including at the single-cell level, to identify potential mechanisms that underlie their dysfunctional phenotype.

Results

We identified novel dysregulated pathways in CD8+PD-1+TIM-3+ cells that have not been well studied in TILs; these include bile acid and peroxisome pathway-related metabolism and mammalian target of rapamycin (mTOR) signaling pathways, which are highly correlated with immune checkpoint receptor expression.

Discussion

Based on bioinformatic integration of immunophenotypic data and network analysis, we propose unexpected targets for therapies to rescue the immune response to tumors in melanoma.

Chemerin triggers migration of a CD8 T cell subset with natural killer cell functions

The recruitment of cells with effector functions into the tumor microenvironment holds potential for delaying cancer progression. We show that subsets of human CD28-effector CD8 T cells, CCR7- CD45RO+ effector memory, and CCR7- CD45RO- effector memory RA phenotypes, express the chemerin receptor CMKLR1 and bind chemerin via the receptor. CMKLR1-expressing human CD8 effector memory T cells present gene, protein, and cytotoxic features of NK cells. Active chemerin promotes chemotaxis of CMKLR1-expressing CD8 effector memory cells and triggers activation of the α4β1 integrin. In an experimental prostate tumor mouse model, chemerin expression is downregulated in the tumor microenvironment, which is associated with few tumor-infiltrating CD8+ T cells, while forced overexpression of chemerin by mouse prostate cancer cells leads to an accumulation of intra-tumor CD8+ T cells. Furthermore, α4 integrin blockade abrogated the chemerin-dependent recruitment of CD8+ T effector memory cells into implanted prostate tumors in vivo. The results identify a role for chemerin:CMKLR1 in defining a specialized NK-like CD8 T cell, and suggest the use of chemerin-dependent modalities to target effector CMKLR1-expressing T cells to the tumor microenvironment for immunotherapeutic purposes.

Antigen-specific decidual CD8+ T cells include distinct effector memory and tissue-resident memory cells

Maternal decidual CD8+ T cells must integrate the antithetical demands of providing immunity to infection while maintaining immune tolerance for fetal and placental antigens. Human decidual CD8+ T cells were shown to be highly differentiated memory T cells with mixed signatures of dysfunction, activation, and effector function. However, no information is present on how specificity for microbial or fetal antigens relates to their function or dysfunction. In addition, a key question, whether decidual CD8+ T cells include unique tissue-resident memory T cells (Trm) or also effector memory T cell (Tem) types shared with peripheral blood populations, is unknown. Here, high-dimensional flow cytometry of decidual and blood CD8+ T cells identified 2 Tem populations shared in blood and decidua and 9 functionally distinct Trm clusters uniquely found in decidua. Interestingly, fetus- and virus-specific decidual CD8+ Trm cells had similar features of inhibition and cytotoxicity, with no significant differences in their expression of activation, inhibitory, and cytotoxic molecules, suggesting that not all fetus-specific CD8+ T cell responses are suppressed at the maternal-fetal interface. Understanding how decidual CD8+ T cell specificity relates to their function and tissue residency is crucial in advancing understanding of their contribution to placental inflammation and control of congenital infections.

The pathogenetic significance of exhausted T cells in a mouse model of mature B cell neoplasms

Dysfunctional anti-tumor immunity has been implicated in the pathogenesis of mature B cell neoplasms, such as multiple myeloma and B cell lymphoma; however, the impact of exhausted T cells on disease development remains unclear. Therefore, the present study investigated the features and pathogenetic significance of exhausted T cells using a mouse model of de novo mature B cell neoplasms, which is likely to show immune escape similar to human patients. The results revealed a significant increase in PD-1+ Tim-3- and PD-1+ Tim-3+ T cells in sick mice. Furthermore, PD-1+ Tim-3+ T cells exhibited direct cytotoxicity with a short lifespan, showing transcriptional similarities to terminally exhausted T cells. On the other hand, PD-1+ Tim-3- T cells not only exhibited immunological responsiveness but also retained stem-like transcriptional features, suggesting that they play a role in the long-term maintenance of anti-tumor immunity. In PD-1+ Tim-3- and PD-1+ Tim-3+ T cells, the transcription factors Tox and Nr4a2, which reportedly contribute to the progression of T cell exhaustion, were up-regulated in vivo. These transcription factors were down-regulated by IMiDs in our in vitro T cell exhaustion analyses. The prevention of excessive T cell exhaustion may maintain effective anti-tumor immunity to cure mature B cell neoplasms.

The role of the CD8+ T cell compartment in ageing and neurodegenerative disorders

CD8+ lymphocytes are adaptive immunity cells with the particular function to directly kill the target cell following antigen recognition in the context of MHC class I. In addition, CD8+ T cells may release pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), and a plethora of other cytokines and chemoattractants modulating immune and inflammatory responses. A role for CD8+ T cells has been suggested in aging and several diseases of the central nervous system (CNS), including Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis, limbic encephalitis-induced temporal lobe epilepsy and Susac syndrome. Here we discuss the phenotypic and functional alterations of CD8+ T cell compartment during these conditions, highlighting similarities and differences between CNS disorders. Particularly, we describe the pathological changes in CD8+ T cell memory phenotypes emphasizing the role of senescence and exhaustion in promoting neuroinflammation and neurodegeneration. We also discuss the relevance of trafficking molecules such as selectins, mucins and integrins controlling the extravasation of CD8+ T cells into the CNS and promoting disease development. Finally, we discuss how CD8+ T cells may induce CNS tissue damage leading to neurodegeneration and suggest that targeting detrimental CD8+ T cells functions may have therapeutic effect in CNS disorders.

3D reconstruction of skin and spatial mapping of immune cell density, vascular distance and effects of sun exposure and aging

Mapping the human body at single cell resolution in three dimensions (3D) is important for understanding cellular interactions in context of tissue and organ organization. 2D spatial cell analysis in a single tissue section may be limited by cell numbers and histology. Here we show a workflow for 3D reconstruction of multiplexed sequential tissue sections: MATRICS-A (Multiplexed Image Three-D Reconstruction and Integrated Cell Spatial - Analysis). We demonstrate MATRICS-A in 26 serial sections of fixed skin (stained with 18 biomarkers) from 12 donors aged between 32-72 years. Comparing the 3D reconstructed cellular data with the 2D data, we show significantly shorter distances between immune cells and vascular endothelial cells (56 µm in 3D vs 108 µm in 2D). We also show 10-70% more T cells (total) within 30 µm of a neighboring T helper cell in 3D vs 2D. Distances of p53, DDB2 and Ki67 positive cells to the skin surface were consistent across all ages/sun exposure and largely localized to the lower stratum basale layer of the epidermis. MATRICS-A provides a framework for analysis of 3D spatial cell relationships in healthy and aging organs and could be further extended to diseased organs.

The Relationship Between Decreased CD-8 T-Cells and Mortality in Patients with COVID-19 Pneumonia in the Intensive Care Unit, A Retrospective Study

Objective

CD-8 T-cells are responsible for the clearance of virally infected cells. In patients with Coronavirus disease-2019 (COVID-19) pneumonia, there are quantitative reductions and functional impairments in T-cells. Low CD-8 T-cell levels cause worse clinical situations. In this study, the relationship between decreased CD-8 T-cells and mortality in patients with COVID-19 pneumonia in the intensive care unit (ICU) was investigated.

Methods

In this multicenter retrospective study, 277 patients were analyzed. Demographic data, ICU admission scores, blood gas levels, laboratory samples, and outcomes were recorded. Statistical Package for the Social Sciences version 28 was used for statistical analysis.

Results

Two hundred forty of 277 patients were included in the study. The mortality rate was 43.3%. In non-survivors, median values of age, Charlson comorbidity index, Acute Physiology and Chronic Health Evaluation II (APACHE-II), procalcitonin, leukocyte count, neutrophil count, neutrophil-lymphocyte count ratio, and duration of invasive mechanical ventilation were significantly higher, whereas median values of PaO₂-FiO₂ ratio, lymphocyte count, CD-4, and CD-8 T-cells were significantly lower than those in survivors. In the multivariate Cox regression model, the risk of mortality increased 1.04-fold (1.02-1.06) and 1.05-fold (1.01-10.8) by every one unit increase in age and APACHE-II, respectively, whereas it decreased 0.71-fold (0.58-0.87) by every hundred increase in CD-8 T-cells P < 0.001, P=0.007 and P=0.001 respectively.

Conclusion

According to our findings, age, APACHE-II, and CD-8 T-cell levels seem to be independent risk factors for mortality in patients with COVID-19 pneumonia in the ICU.

Characterization of antigen-specific CD8+ memory T cell subsets in peripheral blood of patients with multiple sclerosis

Background

Increasing evidence indicates the importance of CD8⁺ T cells in autoimmune attack against CNS myelin and axon in multiple sclerosis (MS). Previous research has also discovered that myelin-reactive T cells have memory phenotype functions in MS patients. However, limited evidence is available regarding the role of CD8⁺ memory T cell subsets in MS. This study aimed to explore potential antigen-specific memory T cell-related biomarkers and their association with disease activity.

Methods

The myelin oligodendrocyte glycoprotein (MOG)-specific CD8⁺ memory T cell subsets and their related cytokines (perforin, granzyme B, interferon (IFN)-γ) and negative co-stimulatory molecules (programmed cell death protein 1 (PD-1), T- cell Ig and mucin domain 3 (Tim-3)) were analyzed by flow cytometry and real-time PCR in peripheral blood of patients with relapsing-remitting MS.

Results

We found that MS patients had elevated frequency of MOG-specific CD8⁺ T cells, MOG-specific central memory T cells (T_CM), MOG-specific CD8⁺ effector memory T cells (T_EM), and MOG-specific CD8⁺ terminally differentiated cells (T_EMRA); elevated granzyme B expression on MOG-specific CD8⁺ T_CM; and, on MOG-specific CD8⁺ T_EM, elevated granzyme B and reduced PD-1 expression. The Expanded Disability Status Scale score (EDSS) in MS patients was correlated with the frequency of MOG-specific CD8⁺ T_CM, granzyme B expression in CD8⁺ T_CM, and granzyme B and perforin expression on CD8⁺ T_EM, but with reduced PD-1 expression on CD8⁺ T_EM.

Conclusion

The dysregulation of antigen-specific CD8⁺ memory T cell subsets, along with the abnormal expression of their related cytokines and negative co-stimulatory molecules, may reflect an excessive or persistent inflammatory response induced during early stages of the illness. Our findings strongly suggest positive regulatory roles for memory T cell populations in MS pathogenesis, probably via molecular mimicry to trigger or promote abnormal peripheral immune responses. Furthermore, downregulated PD-1 expression may stimulate a positive feedback effect, promoting MS-related inflammatory responses via the interaction of PD-1 ligands. Therefore, these parameters are potential serological biomarkers for predicting disease development in MS.

Genes associated with cellular senescence favor melanoma prognosis by stimulating immune responses in tumor microenvironment

PURPOSE

Skin cutaneous melanoma (SKCM), a malignant tumor from melanocytes, is the fifth most prevalent tumor. Immune checkpoint inhibitor (ICI) immunotherapy improves prognosis of SKCM, but immune response varies for different populations. Cellular senescence in the tumor microenvironment (TME) promotes antitumor immunity, mediated by dendritic cells (DC) and CD8+ T cells. Therefore, we sought to explore the role of cellular senescence in the TME of SKCM through bioinformatics and machine learning.

METHODS

First, we obtained 93 cellular senescence-prognosis genes (CSPGs) by univariate survival analysis. Thereafter, 23 optimal CSPGs were obtained by least absolute shrinkage and selection operator (lasso) analysis. Based on the riskscore obtained by lasso analysis and clinical information from multivariate cox, we obtained the nomogram of SKCM, which was validated in the validation cohort. Based on the riskscore, the patients were split into low- and high-risk groups. Functional differences between the two groups were analyzed using Metascape and GSEA, and immune infiltration differences were achieved by multiple algorithms. We obtained a risk prediction nomogram for the validated SKCM based on the lasso model by univariate and multivariate cox regression analysis.

RESULTS

In the low-risk group, immune responses were in an active state. NK, CD8+ T, DC, macrophages, and neutrophils were significantly upregulated, and ICI-relevant genes were notably upregulated. With the differentially expressed genes (DEGs) and optimal CSPGs, we obtained the hub genes: NOX4, NTN4, PROX1, and TRPM8. The hub genes were mainly expressed by cancer-associated fibroblasts (CAFs) and endothelial cells by single cell analysis, which were mainly associated with angiogenesis.

CONCLUSION

Genes associated with cellular senescence favor SKCM prognosis by stimulating immune responses in TME. Patients with high expression of cellular senescence associated genes in the TME might have better benefit from ICI immunotherapy. Cellular senescence functions as a pro-tumor agent in mesenchymal cells and needs further study.

Progress in nanoparticle-based regulation of immune cells

Immune cells are indispensable defenders of the human body, clearing exogenous pathogens and toxicities or endogenous malignant and aging cells. Immune cell dysfunction can cause an inability to recognize, react, and remove these hazards, resulting in cancers, inflammatory diseases, autoimmune diseases, and infections. Immune cells regulation has shown great promise in treating disease, and immune agonists are usually used to treat cancers and infections caused by immune suppression. In contrast, immunosuppressants are used to treat inflammatory and autoimmune diseases. However, the key to maintaining health is to restore balance to the immune system, as excessive activation or inhibition of immune cells is a common complication of immunotherapy. Nanoparticles are efficient drug delivery systems widely used to deliver small molecule inhibitors, nucleic acid, and proteins. Using nanoparticles for the targeted delivery of drugs to immune cells provides opportunities to regulate immune cell function. In this review, we summarize the current progress of nanoparticle-based strategies for regulating immune function and discuss the prospects of future nanoparticle design to improve immunotherapy.

A novel Toxoplasma gondii TGGT1_316290 mRNA-LNP vaccine elicits protective immune response against toxoplasmosis in mice

Toxoplasma gondii (T. gondii) can infect almost all warm-blooded animals and is a major threat to global public health. Currently, there is no effective drug or vaccine for T. gondii. In this study, bioinformatics analysis on B and T cell epitopes revealed that TGGT1_316290 (TG290) had superior effects compared with the surface antigen 1 (SAG1). TG290 mRNA-LNP was constructed through the Lipid Nanoparticle (LNP) technology and intramuscularly injected into the BALB/c mice, and its immunogenicity and efficacy were explored. Analysis of antibodies, cytokines (IFN-γ, IL-12, IL-4, and IL-10), lymphocytes proliferation, cytotoxic T lymphocyte activity, dendritic cell (DC) maturation, as well as CD4⁺ and CD8⁺ T lymphocytes revealed that TG290 mRNA-LNP induced humoral and cellular immune responses in vaccinated mice. Furthermore, T-Box 21 (T-bet), nuclear factor kappa B (NF-kB) p65, and interferon regulatory factor 8 (IRF8) subunit were over-expressed in the TG290 mRNA-LNP-immunized group. The survival time of mice injected with TG290 mRNA-LNP was significantly longer (18.7 ± 3 days) compared with the survival of mice of the control groups (p < 0.0001). In addition, adoptive immunization using 300 μl serum and lymphocytes (5*10⁷) of mice immunized with TG290 mRNA-LNP significantly prolonged the survival time of these mice. This study demonstrates that TG290 mRNA-LNP induces specific immune response against T. gondii and may be a potential toxoplasmosis vaccine candidate for this infection.

CD8+ T cell exhaustion in anti-tumour immunity: The new insights for cancer immunotherapy

CD8⁺ T cells play a crucial role in anti-tumour immunity, but they often undergo exhaustion, which affects the anti-tumour activity of CD8⁺ T cells. The effect and mechanism of exhausted CD8⁺ T cells have become the focus of anti-tumour immunity research. Recently, a large number of studies have confirmed that long-term antigen exposure can induce exhaustion. Cytokines previously have identified their effects (such as IL-2 and IL-10) may play a dual role in the exhaustion process of CD8⁺ T cells, suggesting a new mechanism of inducing exhaustion. This review just focuses our current understanding of the biology of exhausted CD8⁺ T cells, including differentiation pathways, cellular characteristics and signalling pathways involved in inducing exhaustion, and summarizes how these can be applied to tumour immunotherapy.

Actin depolymerizing factor-based nanomaterials: A novel strategy to enhance E. mitis-specific immunity

The epidemic of avian coccidiosis seriously threatens the animals' welfare and the economic gains of the poultry industry. Widespread in avian coccidiosis, Eimeria mitis (E. mitis) could obviously impair the production performance of the infected chickens. So far, few effective vaccines targeting E. mitis have been reported, and the nanovaccines composed of nanospheres captured our particular attention. At the present study, we construct two kinds of nanospheres carrying the recombinant E. mitis actin depolymerizing factor (rEmADF), then the characterization was then analyzed. After safety evaluation, the protective efficacy of rEmADF along with its nanospheres were investigated in chickens. The promoted secretions of antibodies and cytokines, as well as the enhanced percentages of CD4⁺ and CD8⁺ T cells were evaluated by the ELISA and flow cytometry assay. In addition, the absolute quantitative real-time PCR (qPCR) assay implied that vaccinations with rEmADF-entrapped nanospheres could significantly reduce the replications of E. mitis in feces. Compared with the rEmADF-loaded chitosan (EmADF-CS) nanospheres, the PLGA nanospheres carrying rEmADF (EmADF-PLGA nanosphers) were more effective in up-regulating weight efficiency of animals and generated equally ability in controlling E. mitis burdens in feces, suggesting the PLGA and CS nanospheres loaded with rEmADF were the satisfactory nanovaccines for E. mitis defense. Collectively, nanomaterials may be an effective antigen delivery system that could help recombinant E. mitis actin depolymerizing factor to enhance immunoprotections in chicken against the infections of E. mitis.

Spermidine Promotes Nb CAR-T Mediated Cytotoxicity to Lymphoma Cells Through Elevating Proliferation and Memory

Purpose

Due to the natural advantages of spermidine in immunity, we investigated the effects of spermidine pretreatment on nanobody-based CAR-T cells (Nb CAR-T) mediated cytotoxicity and potential mechanism.

Patients and Methods

The optimal concentration of spermidine was determined by detecting its impact on viability and proliferation of T cells. The phenotypic characteristic of CAR-T cells, which were treated with spermidine for 4 days, was examined by flow cytometry. The expansion ability of CAR-T cells was monitored in being cocultured with tumor cells. Additionally, CAR-T cells were stimulated by lymphoma cells to test its cytotoxicity in vitro, and the supernatant in co-culture models were collected to test the cytokine production. Furthermore, xenograft models were constructed to detect the anti-tumor activity of CAR-T cells in vivo.

Results

The optimal concentration of spermidine acting on T cells was 5μM. The antigen-dependent proliferation of spermidine pretreatment CD19 CAR-T cells or Nb CAR-T cells was increased compared to control. Central memory T cells(TCM) dominated the CAR-T cell population in the presence of spermidine. When spermidine pretreatment CAR-T cells were stimulated with Daudi cells, the secretion of IL-2 and IFN-γ has been significantly enhanced. The ability of CAR-T cells to lysis Daudi cells was enhanced with the help of spermidine, even at higher tumor loads. Pre-treated Nb CAR-T cells with spermidine were able to control tumor cells in vivo, and therefore prolong mice survival.

Conclusion

Our results revealed that spermidine could promote Nb CAR-T mediated cytotoxicity to lymphomas cells through enhancing memory and proliferation, and provided a meaningful approach to strengthen the anti-tumor effect of CAR-T cells.

Expression of inhibitory receptors PD-1, CTLA-4, and Tim-3 by peripheral T cells during pregnancy

Background. Inhibitory receptors and their ligands (also called checkpoint molecules) are important feedback regulators of the immune response. However, their role in immunological adaptation during pregnancy remains poorly understood.

The aim of the study was to evaluate the level of checkpoint molecule (PD-1, CTLA-4, Tim-3) expression in peripheral T cells in pregnant women compared with fertile non-pregnant women.

Materials and methods. The study included 36 women in the second half of pregnancy without pregnancy complications, 12 of whom had extragenital pathology. The control group consisted of 28 age-matched fertile non-pregnant women. The proportion of CD8+PD-1+, CD8+TIM-3+, CD8+PD-1+TIM-3+, CD4+PD-1+, CD4+TIM-3+, and CD4+PD-1+TIM-3+ was evaluated by flow cytometry using the corresponding monoclonal antibodies (BD Biosciences, USA).

Results. The proportion of CD4+Tim-3+ and CD8+PD-1+ Т cells and CD4+ and CD8+ Т lymphocytes co-expressing PD-1 and Tim-3 in the peripheral blood of pregnant women was statistically significantly higher than in non-pregnant women. An increase in CD4+Tim-3+ and CD8+PD-1+ T cells was observed both in pregnant women with and without extragenital pathology. However, pregnant women with extragenital pathology were characterized by a higher CD8+PD-1+ count and a smaller number of CD8+Tim-3+ cells, as well as by a lack of an increase in PD-1+Tim-3+ T cells typical of pregnant women. The number of comorbidities was directly correlated with the proportion of CD8+PD-1+ lymphocytes and inversely correlated with the proportion of CD8+Tim-3+ and CD4+ PD-1+Tim-3+ cells. In addition, the expression of checkpoint molecules was associated with gestational age (a direct correlation was found with the proportion of CD8+Tim-3+, CD4+PD-1+Tim-3+, and CD8+PD-1+Tim-3+ cells) and to a lesser extent – with the age of pregnant women (an inverse relationship was found with the proportion of CD8+Tim-3+ cells).

Conclusion. Pregnant women in the second half of pregnancy are characterized by increased expression of PD-1 and Tim-3 molecules in peripheral T cells. At the same time, concomitant extragenital pathology affects the expression of these molecules.

CXCR5+CD8 T cells: Potential immunotherapy targets or drivers of immune-mediated adverse events?

CXCR5⁺CD8 T cells have attracted significant interest within multiple areas of immunology, cancer, and infection. This is in part due to their apparent dual functionality. These cells perform as cytotoxic cells in a variety of infection states including LCMV, HBV, HIV and SIV. However, CXCR5⁺CD8 T cells also associate with B cells in peripheral organs and function to stimulate B cell proliferation, antibody/B cell receptor class-switch, and antibody production. CXCR5⁺CD8 T cells are similar to CXCR5⁺CD4 T follicular helpers in their genetic make-up, B cell interactions, and functionality despite possessing elevated programmed cell death 1 and cytotoxic proteins. Within cancer CXCR5⁺CD8 T cells have risen as potential prognostic markers for overall survival and are functionally cytotoxic within tumor microenvironments. In inflammatory disease and autoimmunity, CXCR5⁺CD8 T cells are implicated in disease progression. During viral infection and cancer, CXCR5 expression on CD8 T cells generally is indicative of progenitor memory stem-like exhausted cells, which are more responsive to immune checkpoint blockade therapy. The use of immune checkpoint inhibitors to overcome immune exhaustion in cancer, and subsequent consequence of immune adverse events, highlights the dual nature of the cellular immune response. This review will detail the functionality of CXCR5⁺CD8 T cells in cancer and autoimmunity with potential repercussions during immune checkpoint blockade therapy discussed.

miR-150 promotes progressive T cell differentiation via inhibiting FOXP1 and RC3H1

T cells used in immune cell therapy, represented by T cell receptor therapy (TCR-T), are usually activated and proliferated in vitro and are induced to a terminally differentiated phenotype, with limited viability after transfusion back into the body. T cells exhibited a robust proliferative potential and in vivo viability in the early stages of progressive differentiation. In this study, we identified microRNAs that regulate T cell differentiation. After microRNA sequencing of the four subsets: Naïve T cells (T_N), stem cell-like memory T cells (T_SCM), central memory T cells (T_CM）, and effector memory T cells (T_EM), miR-150 was identified as the most highly expressed miRNA among the four subsets and was lowly expressed in the T_SCM cells. We predicted the target genes of miR-150 miRNA and performed Gene Ontology and Kyoto Encyclopaedia of Genes and Genomes analyses. We observed that the target genes of miR-150 were enriched in pathways associated with T-cell differentiation. FOXP1 and RC3H1 were identified as key target genes of miR-150 in the regulation of T-cell function. We examined the effects of miR-150 on the differentiation and function of healthy donor T-cells. We observed that miR-150 overexpression promoted T-cell differentiation to effector T-cells and effector memory T-cells, enhanced apoptosis, inhibited cell proliferation and increased secretion of pro-inflammatory cytokines such as IFN-γ and TNF-α. In addition, the expressions of early differentiation-related genes (ACTN1, CERS6, BCL2, and EOMES), advanced differentiation-related genes (KLRG1), and effector-function-related genes (PRF1 and GZMB) were significantly decreased after overexpression of miR-150. Collectively, our results suggested that miR-150 can promote progressive differentiation of T cells and the downmodulation of miR-150 expression while performing adoptive immunotherapy may inhibit T-cell differentiation and increase the proliferative potential of T cells.

PTPRO-related CD8+ T-cell signatures predict prognosis and immunotherapy response in patients with breast cancer

BACKGROUND

Poor immunogenicity and extensive immunosuppressive T-cell infiltration in the tumor immune microenvironment (TIME) have been identified as potential barriers to immunotherapy success in "immune-cold" breast cancers. Thus, it is crucial to identify biomarkers that can predict immunotherapy efficacy. Protein tyrosine phosphatase receptor type O (PTPRO) regulates multiple kinases and pathways and has been implied to play a regulatory role in immune cell infiltration in various cancers.

METHODS

ESTIMATE and single-sample gene set enrichment analysis (ssGSEA) were performed to uncover the TIME landscape. The correlation analysis of PTPRO and immune infiltration was performed to characterize the immune features of PTPRO. Univariate and multivariate Cox analyses were applied to determine the prognostic value of various variables and construct the PTPRO-related CD8⁺ T-cell signatures (PTSs). The Kaplan-Meier curve and the receiver operating characteristic (ROC) curve were used to estimate the performance of PTS in assessing prognosis and immunotherapy response in multiple validation datasets.

RESULTS

High PTPRO expression was related to high infiltration levels of CD8⁺ T cells, as well as macrophages, activated dendritic cells (aDCs), tumor-infiltrating lymphocytes (TILs), and Th1 cells. Given the critical role of CD8⁺ T cells in the TIME, we focused on the impact of PTPRO expression on CD8⁺ T-cell infiltration. The prognostic PTS was then constructed using the TCGA training dataset. Further analysis showed that the PTS exhibited favorable prognostic performance in multiple validation datasets. Of note, the PTS could accurately predict the response to immune checkpoint inhibitors (ICIs).

CONCLUSION

PTPRO significantly impacts CD8⁺ T-cell infiltration in breast cancer, suggesting a potential role of immunomodulation. PTPRO-based PTS provides a new immune cell paradigm for prognosis, which is valuable for immunotherapy decisions in cancer patients.

A Predictive Model Based on Pyroptosis-Related Gene Features Can Effectively Predict Clear Cell Renal Cell Carcinoma Prognosis and May Be an Underlying Target for Immunotherapy

Methods

The clinical information and RNA-seq data of ccRCC patients were collected from the TCGA dataset to first explore differential pyroptosis-related genes (PRGs). Univariate Cox regression and consensus clustering were applied to identify ccRCC subtypes. The prognostic PRGs were subjected to LASSO regression analysis to establish a prognostic model and to investigate its value and function. Finally, the relationship of the model immunity checkpoints and immunity infiltration was assessed.

Results

The receiver operating characteristic (ROC) showed that the 1-year, 3-year, and 5-year prediction rates of the prognostic model were 0.715, 0.693, and 0.732, respectively. The high-risk group had lower overall survival and higher stage than the low-risk group. Functional enrichment analysis showed that PRGs were significantly enriched mainly in the PPAR pathway, inflammatory pathway, and immune activity. ccRCC patient prognosis correlates with immune components in the microenvironment, and immune checkpoint molecules are significantly expressed in the high-risk group. Immunotherapy may be effective in the high-risk group.

Conclusion

Pyroptosis-related gene has an important impact on the progression of ccRCC and can be used as an independent predictor of patient prognosis. In addition, immune checkpoint molecules are significantly upregulated in high-risk populations, which may be a potential target for immunotherapy.

PLGA Nanospheres as Delivery Platforms for Eimeria mitis 1a Protein: A Novel Strategy to Improve Specific Immunity

The infections of chicken coccidiosis impact the welfare of chickens and the economical production of poultry. Eimeria mitis is ubiquitous in chicken coccidiosis, and E. mitis infection can significantly affect the productivity of birds. Up to now, few efficient vaccines against E. mitis have been reported, whereas the recombinant subunit vaccines delivered by nanomaterials may elicit an encouraging outcome. Thus, in this study, we chose E. mitis 1a (Em1a) protein as the candidate antigen to generate Em1a preparations. The recombinant Em1a (rEm1a) protein was encapsulated with poly lactic-co-glycolic acid (PLGA) and chitosan (CS) nanospheres. The physical characterization of the rEm1a-PLGA and rEm1a-CS nanospheres was investigated, and the resulting nanospheres were proven to be nontoxic. The protective efficacy of rEm1a-PLGA and rEm1a-CS preparations was evaluated in E. mitis-challenged birds in comparison with two preparations containing rEm1a antigen emulsified in commercially available adjuvants. ELISA assay, flow cytometry analysis, and quantitative real-time PCR (qPCR) analysis indicated that vaccination with rEm1a-loaded nanospheres significantly upregulated the secretions of antibodies and cytokines and proportions of CD4⁺ and CD8⁺ T lymphocytes. Compared with the other three preparations, rEm1a-PLGA nanosphere was more effective in improving growth performance and inhibiting oocyst output in feces, indicating that the PLGA nanosphere was associated with optimal protection against E. mitis. Collectively, our results highlighted the advantages of nanovaccine in eliciting protective immunity and may provide a new perspective for developing effective vaccines against chicken coccidiosis.

Nano vaccines for T. gondii Ribosomal P2 Protein With Nanomaterials as a Promising DNA Vaccine Against Toxoplasmosis

Caused by Toxoplasma gondii, toxoplasmosis has aroused great threats to public health around the world. So far, no effective vaccine or drug is commercially available, and the demands for a safe and effective therapeutic strategy have become more and more urgent. In the current study, we constructed a DNA vaccine encoding T. gondii ribosomal P2 protein (TgP2) and denoted as TgP2-pVAX1 plasmid. To improve the immunoprotection, nanomaterial poly-lactic-co-glycolic acid (PLGA) and chitosan were used as the delivery vehicle to construct TgP2-pVAX1/PLGA and TgP2-pVAX1/CS nanospheres. Before vaccinations in BALB/c mice, TgP2-pVAX1 plasmids were transiently transfected into Human Embryonic Kidney (HEK) 293-T cells, and the expression of the eukaryotic plasmids was detected by laser confocal microscopy and Western blotting. Then the immunoprotection of naked DNA plasmids and their two nano-encapsulations were evaluated in the laboratory animal model. According to the investigations of antibody, cytokine, dendritic cell (DC) maturation, molecule expression, splenocyte proliferation, and T lymphocyte proportion, TgP2-pVAX1 plasmid delivered by two types of nanospheres could elicit a mixed Th1/Th2 immune response and Th1 immunity as the dominant. In addition, TgP2-pVAX1/PLGA and TgP2-pVAX1/CS nanospheres have great advantages in enhancing immunity against a lethal dose of T. gondii RH strain challenge. All these results suggested that TgP2-pVAX1 plasmids delivered by PLGA or chitosan nanomaterial could be promising vaccines in resisting toxoplasmosis and deserve further investigations and applications.

PD-1-induced proliferating T cells exhibit a distinct transcriptional signature

Ligation of the inhibitory receptor PD-1 on T cells results in the inhibition of numerous cellular functions. Despite the overtly inhibitory outcome of PD-1 signalling, there are additionally a collection of functions that are activated. We have observed that CD4+ T cells stimulated through the T-cell receptor and PD-1 primarily do not proliferate; however, there is a population of cells that proliferates more than T-cell receptor stimulation alone. These highly proliferating cells could potentially be associated with PD-1-blockade unresponsiveness in patients. In this study, we have performed RNA sequencing and found that following PD-1 ligation proliferating and non-proliferating T cells have distinct transcriptional signatures. Remarkably, the proliferating cells showed an enrichment of genes associated with an activated state despite PD-1 signalling. Additionally, circulating follicular helper T cells were significantly more prevalent in the non-proliferating population, demonstrated by enrichment of the associated genes CXCR5, CCR7, TCF7, BCL6 and PRDM1 and validated at the protein level. Translationally, we also show that there are more follicular helper T cells in patients that respond favourably to PD-1 blockade. Overall, the presence of transcriptionally and functionally distinct T cell populations responsive to PD-1 ligation may provide insights into the clinical differences observed following therapeutic PD-1 blockade.

Immunotherapeutic Potential of T Memory Stem Cells

Memory T cells include T memory stem cells (T_SCM) and central memory T cells (T_CM). Compared with effector memory T cells (T_EM) and effector T cells (T_EFF), they have better durability and anti-tumor immunity. Recent studies have shown that although T_SCM has excellent self-renewal ability and versatility, if it is often exposed to antigens and inflammatory signals, T_SCM will behave as a variety of inhibitory receptors such as PD-1, TIM-3 and LAG-3 expression, and metabolic changes from oxidative phosphorylation to glycolysis. These changes can lead to the exhaustion of T cells. Cumulative evidence in animal experiments shows that it is the least differentiated cell in the memory T lymphocyte system and is a central participant in many physiological and pathological processes in humans. It has a good clinical application prospect, so it is more and more important to study the factors affecting the formation of T_SCM. This article summarizes and prospects the phenotypic and functional characteristics of T_SCM, the regulation mechanism of formation, and its application in treatment of clinical diseases.

Prognostic Gene Expression Signature in Patients With Distinct Glioma Grades

Background

Glioma is the most common type of primary brain tumor in adults. Patients with the most malignant form have an overall survival time of <16 months. Although considerable progress has been made in defining the adapted therapeutic strategies, measures to counteract tumor escape have not kept pace, due to the developed resistance of malignant glioma. In fact, identifying the nature and role of distinct tumor-infiltrating immune cells in glioma patients would decipher potential mechanisms behind therapy failure.

Methods

We integrated into our study glioma transcriptomic datasets from the Cancer Genome Atlas (TCGA) cohort (154 GBM and 516 LGG patients). LM22 immune signature was built using CIBERSORT. Hierarchical clustering and UMAP dimensional reduction algorithms were applied to identify clusters among glioma patients either in an unsupervised or supervised way. Furthermore, differential gene expression (DGE) has been performed to unravel the top expressed genes among the identified clusters. Besides, we used the least absolute shrinkage and selection operator (LASSO) and Cox regression algorithm to set up the most valuable prognostic factor.

Results

Our study revealed, following gene enrichment analysis, the presence of two distinct groups of patients. The first group, defined as cluster 1, was characterized by the presence of immune cells known to exert efficient antitumoral immune response and was associated with better patient survival, whereas the second group, cluster 2, which exhibited a poor survival, was enriched with cells and molecules, known to set an immunosuppressive pro-tumoral microenvironment. Interestingly, we revealed that gene expression signatures were also consistent with each immune cluster function. A strong presence of activated NK cells was revealed in cluster 1. In contrast, potent immunosuppressive components such as regulatory T cells, neutrophils, and M0/M1/M2 macrophages were detected in cluster 2, where, in addition, inhibitory immune checkpoints, such as PD-1, CTLA-4, and TIM-3, were also significantly upregulated. Finally, Cox regression analysis further corroborated that tumor-infiltrating cells from cluster 2 exerted a significant impact on patient prognosis.

Conclusion

Our work brings to light the tight implication of immune components on glioma patient prognosis. This would contribute to potentially developing better immune-based therapeutic approaches.

IL-21 Prevents Expansion of CD8+CD28- T Cells Stimulated by IL-15 and Changes Their Subset Distribution

BACKGROUND

To examine the effect of interleukin (IL)-21 on the proliferation, subsets, and immunological characteristics of CD8⁺CD28^- T cells stimulated by IL-15 in vitro.

METHODS

Purified CD8⁺ T cells stimulated with allogeneic CD2^- cells obtained from the peripheral blood mononuclear cells of healthy volunteers were cocultured in the presence of IL-15 alone or IL-21 and IL-15 combined. The dynamic changes in the proliferation, subsets, and phenotypic characteristics of CD8⁺CD28^- T cells were detected. Our work, involving human participants, complied with the Declaration of Helsinki and the Declaration of Istanbul.

RESULTS

IL-21 prevented the expansion of CD8⁺CD28^- T cells stimulated by IL-15 by sustaining CD28 expression at the mRNA level. IL-15 altered the expanded CD8⁺CD28^- T cell memory subsets over the coculture duration, but the addition of IL-21 could change the subset distribution. In the presence of IL-15, the in vitro-expanded CD8⁺CD28^- T cells were mainly intermediately differentiated cells, but they were mainly late differentiated cells in the presence of IL-21 plus IL-15. Moreover, IL-21 upregulated the expression of toxic molecules in the IL-15-expanded CD8⁺CD28^- T cells.

CONCLUSIONS

IL-21 prevents IL-15-induced CD8⁺CD28^- T cell amplification by downregulating CD28 at the transcriptional level. IL-21 can alter the subpopulation distribution and phenotypic characteristics of CD8⁺CD28^- T cells stimulated by IL-15.

Identification and Targeting of Mutant Peptide Neoantigens in Cancer Immunotherapy

In recent decades, adoptive cell transfer and checkpoint blockade therapies have revolutionized immunotherapeutic approaches to cancer treatment. Advances in whole exome/genome sequencing and bioinformatic detection of tumour-specific genetic variations and the amino acid sequence alterations they induce have revealed that T cell mediated anti-tumour immunity is substantially directed at mutated peptide sequences, and the identification and therapeutic targeting of patient-specific mutated peptide antigens now represents an exciting and rapidly progressing frontier of personalized medicine in the treatment of cancer. This review outlines the historical identification and validation of mutated peptide neoantigens as a target of the immune system, and the technical development of bioinformatic and experimental strategies for detecting, confirming and prioritizing both patient-specific or "private" and frequently occurring, shared "public" neoantigenic targets. Further, we examine the range of therapeutic modalities that have demonstrated preclinical and clinical anti-tumour efficacy through specifically targeting neoantigens, including adoptive T cell transfer, checkpoint blockade and neoantigen vaccination.

"Go", "No Go," or "Where to Go"; does microbiota dictate T cell exhaustion, programming, and HIV persistence?

PURPOSE OF REVIEW

People living with HIV who fail to fully reconstitute CD4+T cells after combination antiretroviral therapy therapy (i.e. immune nonresponders or INRs) have higher frequencies of exhausted T cells are enriched in a small pool of memory T cells where HIV persists and have an abundance of plasma metabolites of bacterial and host origins. Here, we review the current understanding of critical features of T cell exhaustion associated with HIV persistence; we propose to develop novel strategies to reinvigorate the effector function of exhausted T cells with the aim of purging the HIV reservoir.

RECENT FINDINGS

We and others have recently reported the role of microbiota and metabolites in regulating T cell homeostasis, effector function, and senescence. We have observed that bacteria of the Firmicute phyla (specifically members of the genus Lactobacilli), associated metabolites (β-hydroxybutyrate family), and bile acids can promote regulatory T cell differentiation in INRs with a senescent peripheral blood gene expression profile.

SUMMARY

The cross-talk between immune cells and gut microbes at the intestinal mucosa (a major effector site of the mucosal immune response), regulates the priming, proliferation, and differentiation of local and distant immune responses. This cross-talk via the production of major metabolite families (like serum amyloid A, polysaccharide A, and aryl hydrocarbon receptor ligands) plays a key role in maintaining immune homeostasis. HIV infection/persistence leads to gut dysbiosis/microbial translocation, resulting in the local and systemic dissemination of microbes. The ensuing increase in immune cell-microbiome (including pathogens) interaction promotes heightened inflammatory responses and is implicated in regulating innate/adaptive immune effector differentiation cascades that drive HIV persistence. The exact role of the microbiota and associated metabolites in regulating T cell- mediated effector functions that can restrict HIV persistence continue to be the subject of on-going studies and are reviewed here.

PD-L1 Overexpression, SWI/SNF Complex Deregulation, and Profound Transcriptomic Changes Characterize Cancer-Dependent Exhaustion of Persistently Activated CD4+ T Cells

Simple Summary

Growing tumors induce an immune response. For proper immune response, both CD8⁺ and CD4⁺ effector T cells are required. Tumors avoid attacks from tumor-infiltrating lymphocytes (TILs) via induction of several inhibitory signals, such as PD-L1/2, which bind to the PD-1 receptor, consequently leading to T cell dysfunction, exhaustion, and apoptosis. The mechanism of T cell exhaustion has been studied mostly in CD8+ T cells, although some results suggest that CD4⁺ effector T cells also undergo exhaustion. In this study, we analyze global transcript profiling, PD-1 and PD-L1 expression, and chromatin status on the PD-L1 locus. We find that in exhausted CD4⁺ T cells, the levels of PD-L1 are increased at both the transcript and protein levels, while PD-L1 expression depends on SWI/SNF chromatin remodeling and PRC2-repressive complexes. The expression of PD-L1 in exhausted CD4⁺ T cells can be reversible.

Abstract

Growing tumors avoid recognition and destruction by the immune system. During continuous stimulation of tumor-infiltrating lymphocytes (TILs) by tumors, TILs become functionally exhausted; thus, they become unable to kill tumor cells and to produce certain cytokines and lose their ability to proliferate. This collectively results in the immune escape of cancer cells. Here, we show that breast cancer cells expressing PD-L1 can accelerate exhaustion of persistently activated human effector CD4⁺ T cells, manifesting in high PD-1 and PD-L1 expression level son T cell surfaces, decreased glucose metabolism genes, strong downregulation of SWI/SNF chromatin remodeling complex subunits, and p21 cell cycle inhibitor upregulation. This results in inhibition of T cell proliferation and reduction of T cell numbers. The RNAseq analysis on exhausted CD4⁺ T cells indicated strong overexpression of IDO1 and genes encoding pro-inflammatory cytokines and chemokines. Some interleukins were also detected in media from CD4⁺ T cells co-cultured with cancer cells. The PD-L1 overexpression was also observed in CD4⁺ T cells after co-cultivation with other cell lines overexpressing PD-L1, which suggested the existence of a general mechanism of CD4⁺ T cell exhaustion induced by cancer cells. The ChIP analysis on the PD-L1 promoter region indicated that the BRM recruitment in control CD4⁺ T cells was replaced by BRG1 and EZH2 in CD4⁺ T cells strongly exhausted by cancer cells. These findings suggest that epi-drugs such as EZH2 inhibitors may be used as immunomodulators in cancer treatment.

Single-cell profiling of tumor-infiltrating TCF1/TCF7+ T cells reveals a T lymphocyte subset associated with tertiary lymphoid structures/organs and a superior prognosis in oral cancer

OBJECTIVES

Despite substantial advances in treatment, clinical outcomes for oral squamous cell carcinoma (OSCC) remain unsatisfactory. Tumor-infiltrating lymphocytes (TILs) are an important prognostic factor for patients and are heterogeneous. Some studies have suggested that TCF1/TCF7⁺ T cells and tertiary lymphatic structure/organ (TLS) play an important role in tumor immunity. However, how they affect tumor immunity and whether they are related to prognosis in OSCC have not been reported in detail.

MATERIALS AND METHODS

We isolated OSCC cells and performed single-cell RNA sequencing (scRNA-seq). We used immunohistochemistry (IHC) to analyze the relationship between TLSs and prognosis. Multiplex immunohistochemistry (MIHC), flow cytometry (FCM) and spatial analysis were performed to verify the characteristics of TCF1/TCF7⁺ T cells. The prognostic significance and upstream regulatory network of the TCF1/TCF7⁺ T cell subpopulation were determined by multivariate analysis and Scenic software.

RESULTS

We found a strong association between TCF1/TCF7⁺ T cell subsets, TLSs and prognosis. The results suggested that TCF1/TCF7⁺ T cells express high levels of TLS-related genes and low levels of immune checkpoint molecules. Finally, we found that TCF1/TCF7⁺ T cells were significantly associated with favorable outcomes. We also describe the upstream drivers that these cells rely on.

CONCLUSIONS

TCF1/TCF7⁺ T cells could be used as a new therapeutic target to regulate the immune response of OSCC and are expected to be a new prognostic marker.

Novel high-affinity EGFRvIII-specific chimeric antigen receptor T cells effectively eliminate human glioblastoma

Objectives

The increasing success of Chimeric Antigen Receptor (CAR) T cell therapy in haematological malignancies is reinvigorating its application in many other cancer types and with renewed focus on its application to solid tumors. We present a novel CAR against glioblastoma, an aggressive, malignant glioma, with a dismal survival rate for which treatment options have remained unchanged for over a decade.

Methods

We use the human Retained Display (ReD) antibody platform (Myrio Therapeutics) to identify a novel single‐chain variable fragment (scFv) that recognises epidermal growth factor receptor mutant variant III (EGFRvIII), a common and tumor‐specific mutation found in glioblastoma. We use both in vitro functional assays and an in vivo orthotopic xenograft model of glioblastoma to examine the function of our novel CAR, called GCT02, targeted using murine CAR T cells.

Results

Our EGFRvIII‐specific scFv was found to be of much higher affinity than reported comparators reverse‐engineered from monoclonal antibodies. Despite the higher affinity, GCT02 CAR T cells kill equivalently but secrete lower amounts of cytokine. In addition, GCT02‐CAR T cells also mediate rapid and complete tumor elimination in vivo.

Conclusion

We present a novel EGFRvIII‐specific CAR, with effective antitumor functions both in in vitro and in a xenograft model of human glioblastoma.

Common Peripheral Immunity Mechanisms in Multiple Sclerosis and Alzheimer's Disease

Neurodegenerative diseases are closely related to inflammatory and autoimmune events, suggesting that the dysregulation of the immune system is a key pathological factor. Both multiple sclerosis (MS) and Alzheimer's disease (AD) are characterized by infiltrating immune cells, activated microglia, astrocyte proliferation, and neuronal damage. Moreover, MS and AD share a common pro-inflammatory signature, characterized by peripheral leukocyte activation and transmigration to the central nervous system (CNS). MS and AD are both characterized by the accumulation of activated neutrophils in the blood, leading to progressive impairment of the blood–brain barrier. Having migrated to the CNS during the early phases of MS and AD, neutrophils promote local inflammation that contributes to pathogenesis and clinical progression. The role of circulating T cells in MS is well-established, whereas the contribution of adaptive immunity to AD pathogenesis and progression is a more recent discovery. Even so, blocking the transmigration of T cells to the CNS can benefit both MS and AD patients, suggesting that common adaptive immunity mechanisms play a detrimental role in each disease. There is also growing evidence that regulatory T cells are beneficial during the initial stages of MS and AD, supporting the link between the modulatory immune compartments and these neurodegenerative disorders. The number of resting regulatory T cells declines in both diseases, indicating a common pathogenic mechanism involving the dysregulation of these cells, although their precise role in the control of neuroinflammation remains unclear. The modulation of leukocyte functions can benefit MS patients, so more insight into the role of peripheral immune cells may reveal new targets for pharmacological intervention in other neuroinflammatory and neurodegenerative diseases, including AD.