Search

In esophageal squamous cell carcinoma (ESCC), lymph node (LN) metastasis is associated with poor survival. Emerging evidence has demonstrated elevated CD8+ T‐cell levels in metastatic LNs following immunotherapy and increased chemoresistance. However, the underlying regulatory mechanisms of CD8+ T cells in chemoresistant/metastatic patients have not been elucidated. Given that metastasis is linked to aberrant splicing patterns, transcripts with alternative splicing forms also play a critical role. With spatial transcriptomics (ST), spatial isoform transcriptomics (SiT), single‐cell RNA sequencing (scRNA‐seq), and T‐cell receptor (TCR) sequencing, the spatial isoforms are analyzed quantitatively in human solid tumors and LNs. These isoforms are classified according to expression and spatial distribution patterns and proposed that the temporal heterogeneity in isoforms is attributed to isoform biogenesis dynamics. C1QC+ tumor‐associated macrophages (TAMs) contribute to the formation of metastases in the context of both immunotherapy and chemotherapy. Additionally, CD74 isoforms can be targeted by mRNA drugs, such as antisense oligonucleotides (ASOs) and RNA interference (RNAi), to prevent chemoresistance and metastasis. Overall, this work suggests that C1QC+ TAMs interact with CD8+CXCL13+ Tex cells via enrichment with the CD74 isoform in the ESCC 's metastatic lymph node. [ABSTRACT FROM AUTHOR]

T cells are essential tumor suppressors in cancer immunology, but their dysfunction induced by cancer cells can result in T cell exhaustion. Exhausted T cells (Tex) significantly influence the tumor immune environment, and thus, there is a need for their thorough investigation across different types of cancer. Here, we address the role of Tex cells in pan-cancer, focusing on the expression, mutations, methylation, immune infiltration, and drug sensitivity of a molecular signature comprising of the genes HAVCR2, CXCL13, LAG3, LAYN, TIGIT, and PDCD1across multiple cancer types, using bioinformatics analysis of TCGA data. Our analysis revealed that the Tex signature genes are differentially expressed across 14 cancer types, being correlated with patient survival outcomes, with distinct survival trends. Pathway analysis indicated that the Tex genes influence key cancer-related pathways, such as apoptosis, EMT, and DNA damage pathways. Immune infiltration analysis highlighted a positive correlation between Tex gene expression and immune cell infiltration in bladder cancer, while mutations in these genes were associated with specific immune cell enrichments in UCEC and SKCM. CNVs in Tex genes were widespread across cancers. We also highlight high LAYN methylation in most tumors and a negative correlation between methylation levels and immune cell infiltration in various cancers. Drug sensitivity analysis identified numerous correlations, with CXCL13 and HAVCR2 expressions influencing sensitivity to several drugs, including Apitolisib, Belinostat, and Docetaxel. Overall, these findings highlight the importance of reviving exhausted T cells to enhance the treatment efficacy to significantly boost anti-tumor immunity and achieve better clinical outcomes. [ABSTRACT FROM AUTHOR]

Physiological changes during pregnancy make the individuals more susceptible to severe respiratory diseases. Hence, pregnant women with coronavirus disease 2019 (COVID-19) are likely at a higher risk. We investigated the effects of COVID-19 on T cell response and serum cytokine profile in pregnant patients. Peripheral blood mononuclear cells (PBMCs) of women with COVID-19 were collected during the first trimester of pregnancy, and the percentage of total lymphocytes, as well as CD4 + and CD8 + T cells, was assessed using flow cytometry. The expression of the programmed death-1 (PD-1) marker for exhausted T cells was evaluated. Additionally, the serum samples were provided to evaluate the levels of antiviral and proinflammatory cytokines, as well as laboratory serological tests. Pregnant women with COVID-19 presented lymphopenia with diminished CD4 + and CD8 + T cells. Besides, high expression levels of the PD-1 gene and protein were observed on PBMCs and T cells, respectively, when compared with normal pregnant individuals. Moreover, serum levels of TNF-α, IL-6, IL-1β, and IL-2 receptor were notably enhanced, while IFN-I α/β values were significantly decreased in the patients when compared with controls. Furthermore, hyperlipidemia, hyperglycemia, and hypertension were directly correlated with the disease although serum albumin and vitamin D3 levels adversely affected the viral infection. Our study showed extreme lymphopenia and poor T cell response while elevated values of serum inflammatory cytokines in infected pregnant women. Moreover, a hypertension background or metabolic changes, including hyperlipidemia, hyperglycemia, and vitamin D3 or albumin deficiency, might be promising prognostic factors in pregnant women with COVID-19. [ABSTRACT FROM AUTHOR]

Isolation of tumor-specific T cells and their antigen receptors (TCRs) from malignant pleural effusions (MPE) may facilitate the development of TCR-transduced adoptive cellular immunotherapy products for advanced lung cancer patients. However, the characteristics and markers of tumor-specific T-cells in MPE are largely undefined. To this end, to establish the phenotypes and antigen specificities of CD8+ T cells, we performed single-cell RNA and TCR sequencing of samples from three advanced lung cancer patients. Dimensionality reduction on a total of 4,983 CD8+ T cells revealed 10 clusters including naïve, memory, and exhausted phenotypes. We focused particularly on exhausted T cell clusters and tested their TCR reactivity against neoantigens predicted from autologous cancer cell lines. Four different TCRs specific for the same neoantigen and one orphan TCR specific for the autologous cell line were identified from one of the patients. Differential gene expression analysis in tumor-specific T cells relative to the other T cells identified CXCL13, as a candidate gene expressed by tumor-specific T cells. In addition to expressing CXCL13, tumor-specific T cells were present in a higher proportion of T cells co-expressing PDCD1(PD-1)/TNFRSF9(4-1BB). Furthermore, flow cytometric analyses in advanced lung cancer patients with MPE documented that those with high PD-1/4-1BB expression have a better prognosis in the subset of 57 adenocarcinoma patients (p = .039). These data suggest that PD-1/4-1BB co-expression might identify tumor-specific CD8+ T cells in MPE, which are associated with patients’ prognosis. (233 words)

Objective To compare and analyze the differences in CD8+ naive, effector, memory, exhausted and regulatory T cells in order to investigate the impact of gender on the differentiation fate of CD8+ T cells in the context of type 1 diabetes (T1D) based on female and male non-obese diabetic (NOD) mice and healthy Institute for Cancer Research (ICR) mice. Methods The frequencies and phenotypes of CD8+ T cell differentiation subsets including naive T cells (TN), central memory T cells (TCM), effector T cells (TEFF), effector precursor T cells (TEP), exhausted T cells (TEX), precursor exhausted T cells (TPEX) and regulatory T cells (Tregs) in the spleen, pancreatic draining lymph nodes (pLN) and pancreas infiltrating lymphocytes (PIL) of male and female NOD mice were detected by flow cytometry. Results The frequencies of IFN-γ+, CD107a+ and CCL5+ CD8+ TEFF in pLN and PIL of female NOD mice were significantly higher than those of male NOD mice. However, the frequencies of CD8+ TN, CD8+ TCM, CD8+ TEX, CD8+ TPEX and CD122+CD8+ Tregs subsets in the spleen were significantly decreased. While there were no significant differences in the above CD8+ T cell subsets except CD8+ Tregs between female and male ICR mice. Conclusion Androgen may inhibit the differentiation of memory T cells into effector T cells and promote the exhaustion of effector T cells, leading to the difference in morbidity between the male and female mice.

Liver metastasis (LM) is an important factor leading to colorectal cancer (CRC) mortality. However, the effect of T‐cell exhaustion on LM in CRC is unclear. Single‐cell sequencing data derived from the Gene Expression Omnibus database. Data were normalized using the Seurat package and subsequently clustered and annotated into different cell clusters. The differentiation trajectories of epithelial cells and T cells were characterized based on pseudo‐time analysis. Single‐sample gene set enrichment analysis (ssGSEA) was used to calculate enrichment scores for different cell clusters and to identify enriched biological pathways. Finally, cell communication analysis was performed. Nine cell subpopulations were identified from CRC samples with LM. The proportion of T cells increased in LM. T cells can be subdivided into NK/T cells, regulatory T cells (Treg) and exhausted T cells (Tex). In LM, cell adhesion and proliferation activity of Tex were promoted. Epithelial cells can be categorized into six subpopulations. The transformation of primary CRC into LM involved two evolutionary branches of Tex cells. Epithelial cells two were at the beginning of the trajectory in CRC but at the end of the trajectory in CRC with LM. The receptor ligands CEACAM5 and ADGRE5‐CD55 played critical roles in the interactions between Tex and Treg cell‐epithelial cell, which may promote the epithelial‐mesenchymal transition process in CRC. Tex cells are able to promote the process of LM in CRC, which in turn promotes tumour development. This provides a new perspective on the treatment and diagnosis of CRC. [ABSTRACT FROM AUTHOR]

Background: T cells and regulatory T cells (Tregs) play a critical role in viral infectious immunity. Exhaustion of T cells during infection and decreased Tregs both contribute to the exacerbation of the disease. In the present study, we assessed T cells and regulatory T cells of COVID-19 patients and a control group according to the expression of the PD-1 molecule. Methods: Forty-two COVID-19 patients and 40 controls were enrolled in the study. In COVID-19 patients, blood samples were collected on the first day of their hospitalization. Regulatory T cells (CD4+, CD25+, FOXP3+), CD4+PD-1+, and PD-1+ regulatory T cells were assessed by flow cytometry. Results: The percentage of CD4+PD-1 + T cells in COVID-19 patients was significantly higher compared to the control group (P < 0.0001). The percentage of PD-1+ regulatory T cells was significantly increased in the patient group compared to the control group (P < 0.0001). However, the Treg percentage was significantly decreased in the patient group compared to the control group (P < 0.0001). The frequency of CD4+PD-1 + T cells, Tregs, and PD-1+ Tregs had acceptable sensitivity and specificity for assisting in the diagnosis of severe/critical COVID-19. The declined Tregs and enhanced CD4+CD25+, CD4+PD-1+, and PD-1 + T cells were associated with disease severity. Conclusion: The decrease in Tregs and the increase in exhaustion of these cells and T cells play an important role in COVID-19 pathogenesis. These immune parameters could be used as meaningful indicators for assisting in the diagnosis of severe/critical COVID-19.

Chimeric antigen receptor T (CAR-T) cell therapy targeting T cell tumors still faces many challenges, one of which is its fratricide due to the target gene expressed on CAR-T cells. Despite this, these CAR-T cells can be expanded in vitro by extending the culture time and effectively eliminating malignant T cells. However, the mechanisms underlying CAR-T cell survival in cell subpopulations, the molecules involved, and their regulation are still unknown. We performed single-cell transcriptome profiling to investigate the fratricidal CAR-T products (CD26 CAR-Ts and CD44v6 CAR-Ts) targeting T cells, taking CD19 CAR-Ts targeting B cells from the same donor as a control. Compared with CD19 CAR-Ts, fratricidal CAR-T cells exhibit no unique cell subpopulation, but have more exhausted T cells, fewer cytotoxic T cells, and more T cell receptor (TCR) clonal amplification. Furthermore, we observed that fratricidal CAR-T cell survival was accompanied by target gene expression. Gene expression results suggest that fratricidal CAR-T cells may downregulate their human leukocyte antigen (HLA) molecules to evade T cell recognition. Single-cell regulatory network analysis and suppression experiments revealed that exhaustion mediated by critical regulatory factors may contribute to fratricidal CAR-T cell survival. Together, these data provide valuable and first-time insights into the survival of fratricidal CAR-T cells.

Summary: Background: While mutation-derived neoantigens are well recognized in generating anti-tumour T cell response, increasing evidences highlight the complex association between tumour mutation burden (TMB) and tumour infiltrating lymphocytes (TILs). The exploration of non-TMB determinants of active immune response could improve the prognosis prediction and provide guidance for current immunotherapy. Methods: The transcriptomic and whole exome sequence data in The Cancer Genome Atlas were used to examine the relationship between TMB and exhausted CD8+ T cells (Tex), as an indicator of tumour antigen-specific T cells across nine major cancer types. Computational clustering analysis was performed on 4510 tumours to identify different immune profiles. NanoString gene expression analysis and single cell RNA-seq analysis using fresh human breast cancer were performed for finding validation. Findings: TMB was found to be poorly correlated with active immune response in various cancer types. Patient clustering analysis revealed a group of tumours with abundant Tex but low TMB. In those tumours, we observed significantly higher expression of the stimulator of interferon genes (STING) signalling. Dendritic cells, particularly those of BATF3+ lineage, were also found to be essential for accumulation of Tex within tumours. Mechanistically, loss of genomic and cellular integrity, marked by decreased DNA damage repair, defective replication stress response, and increased apoptosis were shown to drive STING activation. Interpretation: These results highlight that TMB alone does not fully predict tumour immune profiles, with STING signalling compensating for low TMB in non-hypermutated tumours to enhance anti-tumour immunity. Translating these results, STING agonists may benefit patients with non-hypermutated tumours. STING activation may serve as an additional biomarker to predict response to immune checkpoint blockades alongside TMB. Our research also unravelled the interplay between genomic instability and STING activation, informing potential combined chemotherapy targeting the axis of genomic integrity and immunotherapy. Funding: City of Hope Christopher Family Endowed Innovation Fund for Alzheimer’s Disease and Breast Cancer Research in honor of Vineta Christopher; Breast Cancer Alliance Early Career Investigator Award; National Cancer Institute of the National Institutes of Health under award number R01CA256989 and R01CA240392.

Purpose of reviewRecent developments in immunotherapy have transformed the landscape of melanoma therapy. Here, we review markers for response to immunotherapy.Recent findingsCurrent immunotherapies disable immune checkpoints on T cells and other immune cells and allow immune rejection of tumor. This process depends crucially on a preexisting response to the development of the melanoma. Here we describe the complexity of the anti-tumor immune response and the links to the development of markers that are currently used or under investigation in the clinic. We describe immune response biomarkers along with new developments that could translate into advances.

Primary cutaneous squamous cell carcinoma (cSCC) is the second most common human cancer with a rising incidence of about 1.8 million in the United States annually. Primary cSCC is usually curable by surgery; however, in some cases, cSCC eventuates in nodal metastasis and death from disease specific death. cSCC results in up to 15,000 deaths each year in the United States. Until recently, nonsurgical options for treatment of locally advanced or metastatic cSCC were largely ineffective. With the advent of checkpoint inhibitor immunotherapy, including cemiplimab and pembrolizumab, response rates climbed to 50%, representing a vast improvement over chemotherapeutic agents used previously. Herein, we discuss the phenotype and function of SCC associated Langerhans cells, dendritic cells, macrophages, myeloid derived suppressor cells and T cells as well as SCCassociated lymphatics and blood vessels. Possible role(s) of SCC-associated cytokines in progression and invasion are reviewed. We also discuss the SCC immune microenvironment in the context of currently available and pipeline therapeutics. [ABSTRACT FROM AUTHOR]

[Display omitted] Chimeric antigen receptor (CAR)-T therapy has demonstrated sustained clinical remission in numerous hematologic malignancies and has expanded to encompass solid tumors and autoimmune diseases. While progress is being made in establishing optimal culture conditions for CAR-T cells, the identification of the most effective cytokine for promoting their persistence in vitro remains elusive. Here, we employed scRNA-seq (single-cell RNA sequencing) analysis to investigate the potential alterations in biological processes within CAR-T cells following exposure to cytokines (IL-2, IL-12, and IL-21) and antigens. Transcriptomic changes in diverse CAR-T groups were compared following various treatments, with a focus on epigenetic modifications, metabolic shifts, cellular senescence, and exhaustion. Our study reveals that CAR-T cells treated with antigen, IL-2, and IL-12 exhibit signs of exhaustion and senescence, whereas those treated with IL-21 do not display these characteristics. The activities of glycolysis and epigenetic changes were significantly increased by treatments with antigens, IL-2, and IL-12, while IL-21 treatment maintained the oxidative phosphorylation (OXPHOS) of CAR-T cells. Our findings suggest that IL-21 may play a role in preventing senescence and could be utilized in combination with other strategies, such as IL-2 and IL-12, for CAR-T culture. [ABSTRACT FROM AUTHOR]

Primary cutaneous squamous cell carcinoma (cSCC) is the second most common human cancer with a rising incidence of about 1.8 million in the United States annually. Primary cSCC is usually curable by surgery; however, in some cases, cSCC eventuates in nodal metastasis and death from disease specific death. cSCC results in up to 15,000 deaths each year in the United States. Until recently, non-surgical options for treatment of locally advanced or metastatic cSCC were largely ineffective. With the advent of checkpoint inhibitor immunotherapy, including cemiplimab and pembrolizumab, response rates climbed to 50%, representing a vast improvement over chemotherapeutic agents used previously. Herein, we discuss the phenotype and function of SCC associated Langerhans cells, dendritic cells, macrophages, myeloid derived suppressor cells and T cells as well as SCC-associated lymphatics and blood vessels. Possible role(s) of SCC-associated cytokines in progression and invasion are reviewed. We also discuss the SCC immune microenvironment in the context of currently available and pipeline therapeutics.

Lung cancer and mainly non-small cell lung cancer (NSCLC) still remain a prevalent malignancy worldwide despite sustained screening approaches. Furthermore, a significant proportion of the cases are diagnosed at advanced stages when conservative therapy is often unsuccessful. Cell senescence is an endogenous antitumor weapon but when it is upregulated exerts opposite activities favoring tumor metastasizing and poor response to therapy. However, little is known about this dangerous relationship between cell senescence and NSCLC outcome or on potential approaches to mitigate its unfavorable consequences. We discuss cell senescence focusing on immune senescence, its cell and humoral effectors (namely immune senescence associated secretory phenotype-iSASP), its impact on NSCLC outcome, and its biomarkers. Senotherapeutics as mitigating approaches are also considered based on the availability of experimental data pertinent to NSCLC. Characterization of NSCLC subsets in which immune senescence is a risk factor for poor prognosis and poor therapeutic response might be very helpful in supporting the addition of senotherapeutics to conventional cancer therapy. This approach has the potential to improve disease outcome but more studies in this area are necessary. [ABSTRACT FROM AUTHOR]

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease and is emerging as the leading cause of cirrhosis, liver transplantation and hepatocellular carcinoma (HCC). NAFLD is a metabolic disease that is considered the hepatic manifestation of the metabolic syndrome; however, during the evolution of NAFLD from steatosis to non-alcoholic steatohepatitis (NASH), to more advanced stages of NASH with liver fibrosis, the immune system plays an integral role. Triggers for inflammation are rooted in hepatic (lipid overload, lipotoxicity, oxidative stress) and extrahepatic (gut-liver axis, adipose tissue, skeletal muscle) systems, resulting in unique immune-mediated pathomechanisms in NAFLD. In recent years, the implementation of single-cell RNA-sequencing and high dimensional multi-omics (proteogenomics, lipidomics) and spatial transcriptomics have tremendously advanced our understanding of the complex heterogeneity of various liver immune cell subsets in health and disease. In NAFLD, several emerging inflammatory mechanisms have been uncovered, including profound macrophage heterogeneity, auto-aggressive T cells, the role of unconventional T cells and platelet-immune cell interactions, potentially yielding novel therapeutics. In this review, we will highlight the recent discoveries related to inflammation in NAFLD, discuss the role of immune cell subsets during the different stages of the disease (including disease regression) and integrate the multiple systems driving inflammation. We propose a refined concept by which the immune system contributes to all stages of NAFLD and discuss open scientific questions arising from this paradigm shift that need to be unravelled in the coming years. Finally, we discuss novel therapeutic approaches to target the multiple triggers of inflammation, including combination therapy via nuclear receptors (FXR agonists, PPAR agonists). [ABSTRACT FROM AUTHOR]

T-cell factor 1 (TCF1)+Programmed cell death-1 (PD-1)+ tumour-infiltrating lymphocytes (TILs) are a recently defined subset of exhausted T-cells (Texh-cells) that exhibit a progenitor phenotype. They have been associated with a response to immune checkpoint inhibitor (ICI) therapy in murine tumour models and in patients with malignant melanoma. We investigated the significance of TCF1+PD-1+ TILs as a predictive biomarker for ICI therapy response in non-small-cell lung cancer (NSCLC). Two different cohorts of NSCLC patients treated with ICI targeting the PD-1/PD-L1 pathway were included. RNA-seq was performed using NSCLC tissues obtained from 234 patients prior to immunotherapy (RNA-seq cohort). Double immunostaining of TCF1 and PD-1 and single immunostaining of other immunologic markers were performed in resected tumour tissues from another 116 patients (immunohistochemistry cohort). In the RNA-seq cohort, both Texh-cell and progenitor Texh-cell gene sets were enriched in responders compared with non-responders. Larger Texh-cell fractions and increased progenitor Texh-cell gene sets were significantly associated with better progression-free survival (PFS). In the immunohistochemistry cohort, the TCF1+PD-1+ TIL number and PD-L1 tumour proportion score were significantly higher in responders than in non-responders. A high number of TCF1+PD-1+ TILs was significantly associated with both PFS and overall survival (OS) after ICI therapy, and it independently predicted a better PFS and OS according to multivariate analysis. TCF1+PD-1+ TILs, representing progenitor Texh-cells, predict both better response and survival in NSCLC patients after ICI therapy. Thus, they may be a useful predictive biomarker for ICI therapy in NSCLC. • Progenitor exhausted T-cell signature is related to a better response to ICI in NSCLC. • TCF1+PD-1+ tumour-infiltrating lymphocytes represent progenitor exhausted T cells. • High TCF1+PD-1+ TIL levels predict responsiveness to ICI and better survival in NSCLC. • TCF1+PD-1+ TIL is a useful predictive biomarker for ICI therapy in NSCLC patients. [ABSTRACT FROM AUTHOR]

Abstract Background The immunosuppressive tumour microenvironment is a critical factor in the initiation and progression of glioblastoma (GBM), which is characterized by an abundance of tumour-associated macrophages (TAMs) but a paucity of infiltrating T cells. In this research, we studied whether epithelial membrane protein 3 (EMP3) plays a crucial role in immune modulation in GBM. Methods TCGA and CGGA transcriptomic profiles of wild-type IDH1 GBM were used for bioinformatic analysis. The role of EMP3 in GBM was validated through in vivo and in vitro experiments. Human GBM specimens were collected and evaluated using immunofluorescence analysis. Results EMP3 was associated with immunosuppression in GBM. Elevated EMP3 in GBM areas was accompanied by high expression of PD-L1 and abundant M2 TAM recruitment but a lake of T cell infiltration. We found that EMP3 was a potent protein in M2 TAM polarization and recruitment that impaired the ability of GBM cells to secrete CCL2 and TGF-β1. Furthermore, EMP3 suppressed T cell infiltration into GBM tumours by inhibiting the secretion of CXCL9 and CXCL10 by macrophages and led to an effective response to anti-PD1 therapy. Conclusions EMP3 is thus a critical immunosuppressive factor for recruiting TAMs in GBM and suppressing intratumoural T cell infiltration to facilitate tumour progression and is a potential therapeutic target.

Z-DNA binding protein (ZBP1) very much represents the nuclear option. By initiating inflammatory cell death (ICD), ZBP1 activates host defenses to destroy infectious threats. ZBP1 is also able to induce noninflammatory regulated cell death via apoptosis (RCD). ZBP1 senses the presence of left-handed Z-DNA and Z-RNA (ZNA), including that formed by expression of endogenous retroelements. Viruses such as the Epstein–Barr "kissing virus" inhibit ICD, RCD and other cell death signaling pathways to produce persistent infection. EBV undergoes lytic replication in plasma cells, which maintain detectable levels of basal ZBP1 expression, leading us to suggest a new role for ZBP1 in maintaining EBV latency, one of benefit for both host and virus. We provide an overview of the pathways that are involved in establishing latent infection, including those regulated by MYC and NF-κB. We describe and provide a synthesis of the evidence supporting a role for ZNA in these pathways, highlighting the positive and negative selection of ZNA forming sequences in the EBV genome that underscores the coadaptation of host and virus. Instead of a fight to the death, a state of détente now exists where persistent infection by the virus is tolerated by the host, while disease outcomes such as death, autoimmunity and cancer are minimized. Based on these new insights, we propose actionable therapeutic approaches to unhost EBV. [ABSTRACT FROM AUTHOR]

The infiltration of tumor-reactive T cells in the tumor site is associated with better survival and immunotherapy response. However, tumor-reactive T cells were often represented by the infiltration of total CD8+ T cells, which was confounded by the presence of bystander T cells. To identify tumor-reactive T cells at the cancer lesion, we performed integration analyses of three scRNA-seq data sets of T cells in melanoma. Extensive heterogeneous functional states of T cells were revealed in the tumor microenvironment. Among these states, we identified a subset of tumor-reactive T cells which specifically expressed tumor-reactive markers and T cell activation signature, and were strongly enriched for larger T cell receptor (TCR) clones. We further identified and validated a tumor-reactive T cell signature (TRS) to evaluate the tumor reactivity of T cells in tumor patients. Patients with high TRS scores have strong immune activity and high mutation burden in the TCGA-SKCM cohort. We also demonstrated a significant association of the TRS with the clinical outcomes of melanoma patients, with higher TRS scores representing better survival, which was validated in four external independent cohorts. Furthermore, the TRS scores exhibited greater performance on prognosis prediction than infiltration levels of CD8+ T cells and previously published prognosis-related signatures. Finally, we observed the capability of TRS to predict immunotherapy response in melanoma. Together, based on integrated analysis of single-cell RNA-sequencing, we developed and validated a tumor-reactive-related signature that demonstrated significant association with clinical outcomes and response to immunotherapy. [ABSTRACT FROM AUTHOR]

The infiltration of tumor-reactive T cells in the tumor site is associated with better survival and immunotherapy response. However, tumor-reactive T cells were often represented by the infiltration of total CD8+ T cells, which was confounded by the presence of bystander T cells. To identify tumor-reactive T cells at the cancer lesion, we performed integration analyses of three scRNA-seq data sets of T cells in melanoma. Extensive heterogeneous functional states of T cells were revealed in the tumor microenvironment. Among these states, we identified a subset of tumor-reactive T cells which specifically expressed tumor-reactive markers and T cell activation signature, and were strongly enriched for larger T cell receptor (TCR) clones. We further identified and validated a tumor-reactive T cell signature (TRS) to evaluate the tumor reactivity of T cells in tumor patients. Patients with high TRS scores have strong immune activity and high mutation burden in the TCGA-SKCM cohort. We also demonstrated a significant association of the TRS with the clinical outcomes of melanoma patients, with higher TRS scores representing better survival, which was validated in four external independent cohorts. Furthermore, the TRS scores exhibited greater performance on prognosis prediction than infiltration levels of CD8+ T cells and previously published prognosis-related signatures. Finally, we observed the capability of TRS to predict immunotherapy response in melanoma. Together, based on integrated analysis of single-cell RNA-sequencing, we developed and validated a tumor-reactive-related signature that demonstrated significant association with clinical outcomes and response to immunotherapy.

In persistent high-risk HPV infection, viral gene expression can trigger some important early changes to immune capabilities which act to protect the lesion from immune attack and subsequently promote its growth and ability for sustained immune escape. This includes immune checkpoint-inhibitor ligand expression (e.g. PD-L1) by tumour or associated immune cells that can block any anti-tumour T-cell effectors. While there are encouraging signs of efficacy for cancer immunotherapies including with immune checkpoint inhibitors, therapeutic vaccines and adoptive cell therapies, overall response and survival rates remain relatively low. HPV oncogene vaccination has shown some useful efficacy in treatment of patients with high-grade lesions but was unable to control later stage cancers. To maximally exploit anti-tumour immune responses, the suppressive factors associated with HPV carcinogenesis must be countered. Importantly, a combination of chemotherapy, reducing immunosuppressive myeloid cells, with therapeutic HPV vaccination significantly improves impact on cancer treatment. Many clinical trials are investigating checkpoint inhibitor treatments in HPV associated cancers but response rates are limited; combination with vaccination is being tested. Further investigation of how chemo- and/or radio-therapy can influence the recovery of effective anti-tumour immunity is warranted. Understanding how to optimally deploy and sequence conventional and immunotherapies is the challenge.

Summary: Little data are available for the expression of immune checkpoint (IC) molecules within myelodysplastic syndrome (MDS). Here, we report increased PD‐L1+CD34+CD38− and PD‐L1+CD34+CD38+ stem cell frequencies within MDS patients compared to stem cell recipients in remission. Additionally, we observed exceedingly similar PD1+ and Tim‐3+ T‐cell frequencies between acute myeloid leukaemia (AML) and MDS samples that were elevated compared to patients in remission. Furthermore, we found highly dynamic Tim‐3+ and PD1+ T‐cell frequencies within serial samples of relapsing MDS with excess blasts (MDS‐EB II) patients, correlating with further disease markers. These findings support the idea of a potential successful implementation of IC inhibitor treatment in suitable MDS patients. [ABSTRACT FROM AUTHOR]

Background: The immunosuppressive tumour microenvironment is a critical factor in the initiation and progression of glioblastoma (GBM), which is characterized by an abundance of tumour-associated macrophages (TAMs) but a paucity of infiltrating T cells. In this research, we studied whether epithelial membrane protein 3 (EMP3) plays a crucial role in immune modulation in GBM. Methods: TCGA and CGGA transcriptomic profiles of wild-type IDH1 GBM were used for bioinformatic analysis. The role of EMP3 in GBM was validated through in vivo and in vitro experiments. Human GBM specimens were collected and evaluated using immunofluorescence analysis. Results: EMP3 was associated with immunosuppression in GBM. Elevated EMP3 in GBM areas was accompanied by high expression of PD-L1 and abundant M2 TAM recruitment but a lake of T cell infiltration. We found that EMP3 was a potent protein in M2 TAM polarization and recruitment that impaired the ability of GBM cells to secrete CCL2 and TGF-β1. Furthermore, EMP3 suppressed T cell infiltration into GBM tumours by inhibiting the secretion of CXCL9 and CXCL10 by macrophages and led to an effective response to anti-PD1 therapy. Conclusions: EMP3 is thus a critical immunosuppressive factor for recruiting TAMs in GBM and suppressing intratumoural T cell infiltration to facilitate tumour progression and is a potential therapeutic target. [ABSTRACT FROM AUTHOR]

Purpose of Review: This review will focus on the most common co-inhibitory molecules, emphasizing the importance of these in relation to rheumatic disease. Recent Findings: Checkpoint molecules are pivotal in determining the outcome of antigen activation. Checkpoint molecules consist of co-stimulatory and co-inhibitory molecules, where the first activates and the latter inhibits the antigen presentation process. Studies show that increased activity of co-inhibitory molecules is associated with a good prognosis in rheumatic diseases. Opposite, when cancer patients are treated with antibodies blocking the inhibitory pathways, autoimmune diseases, including arthritis, develop as immune-related adverse events (IrAE). This emphasizes the importance of these pathways in autoimmune disease. Summary: Co-inhibitory molecules are becoming increasingly interesting as future treatment targets in rheumatic conditions. Treatments with antibodies blocking these pathways result in IrAE, often manifesting as autoimmune rheumatic diseases. Therefore, a need to get acquainted with these molecules is growing so we can cope with future challenges in rheumatic diseases. [ABSTRACT FROM AUTHOR]

Background: Targeting exhausted T (Tex) cells is a promising strategy for anti-tumour treatment. Previously, we demonstrated that Hirsutella sinensis fungus (HSF) could significantly increase T cell infiltration and the effector T cell ratio in the tumor microenvironment, activating systemic immune responses. However, we do not know how HSF regulates Tex cells in the tumor microenvironment. Here, we explored the mechanism underlying HSF inhibition of Tex cells and tumor growth and metastasis in breast cancer.Methods: We examined the effects of HSF on various tumor mouse models using in vivo imaging technology. Lung metastasis was detected by H&E staining and the T cell subsets in the tumor microenvironment were assayed with flow cytometry. The in vitro proliferation, function and apoptosis of CD8+ T cells were measured, as well as the T-bet and PD-1 mRNA expressions.Results: HSF inhibited tumor growth and lung metastasis in the mice, and had significantly higher CD44LowCD62LHi and CD44HiCD62LLowpopulations in the tumour-infiltrating CD8+ T cells. However, HSF significantly reduced levels of inhibitory receptors, such as PD-1, TIGIT, CTLA-4, and regulatory T cells. In vitro, HSF inhibited the CD8+ T cell apoptosis rate, and promoted CD8+ T cell proliferation and secretion of interferon (IFN)-γ and granzyme B. Furthermore, HSF treatment both in vivo and in vitro significantly increased Eomes expression, while decreasing T-bet expression.Conclusion: HSF exerted anti-tumour effects mainly through the immune system, by promoting effector/memory T cells and reducing Tex cell production in the tumor microenvironment. The specific mechanisms involved inhibiting T-bet and promoting Eomes to decrease the expression of immune inhibitor receptors and enhance the T cell function, respectively.

Isolation of tumor-specific T cells and their antigen receptors (TCRs) from malignant pleural effusions (MPE) may facilitate the development of TCR-transduced adoptive cellular immunotherapy products for advanced lung cancer patients. However, the characteristics and markers of tumor-specific T-cells in MPE are largely undefined. To this end, to establish the phenotypes and antigen specificities of CD8 + T cells, we performed single-cell RNA and TCR sequencing of samples from three advanced lung cancer patients. Dimensionality reduction on a total of 4,983 CD8 + T cells revealed 10 clusters including naïve, memory, and exhausted phenotypes. We focused particularly on exhausted T cell clusters and tested their TCR reactivity against neoantigens predicted from autologous cancer cell lines. Four different TCRs specific for the same neoantigen and one orphan TCR specific for the autologous cell line were identified from one of the patients. Differential gene expression analysis in tumor-specific T cells relative to the other T cells identified CXCL13 , as a candidate gene expressed by tumor-specific T cells. In addition to expressing CXCL13 , tumor-specific T cells were present in a higher proportion of T cells co-expressing PDCD1 (PD-1)/ TNFRSF9 (4-1BB). Furthermore, flow cytometric analyses in advanced lung cancer patients with MPE documented that those with high PD-1/4-1BB expression have a better prognosis in the subset of 57 adenocarcinoma patients ( p  = .039). These data suggest that PD-1/4-1BB co-expression might identify tumor-specific CD8 + T cells in MPE, which are associated with patients' prognosis. (233 words)., Competing Interests: This study was partly funded by NEC Corporation., (© 2024 The Author(s). Published with license by Taylor & Francis Group, LLC.)

Chimeric antigen receptor T (CAR-T) cell therapy targeting T cell tumors still faces many challenges, one of which is its fratricide due to the target gene expressed on CAR-T cells. Despite this, these CAR-T cells can be expanded in vitro by extending the culture time and effectively eliminating malignant T cells. However, the mechanisms underlying CAR-T cell survival in cell subpopulations, the molecules involved, and their regulation are still unknown. We performed single-cell transcriptome profiling to investigate the fratricidal CAR-T products (CD26 CAR-Ts and CD44v6 CAR-Ts) targeting T cells, taking CD19 CAR-Ts targeting B cells from the same donor as a control. Compared with CD19 CAR-Ts, fratricidal CAR-T cells exhibit no unique cell subpopulation, but have more exhausted T cells, fewer cytotoxic T cells, and more T cell receptor (TCR) clonal amplification. Furthermore, we observed that fratricidal CAR-T cell survival was accompanied by target gene expression. Gene expression results suggest that fratricidal CAR-T cells may downregulate their human leukocyte antigen (HLA) molecules to evade T cell recognition. Single-cell regulatory network analysis and suppression experiments revealed that exhaustion mediated by critical regulatory factors may contribute to fratricidal CAR-T cell survival. Together, these data provide valuable and first-time insights into the survival of fratricidal CAR-T cells., Competing Interests: The authors declare no potential competing interests., (© 2024 The Authors.)

Background: The treatment and prognosis of patients with advanced hepatocellular carcinoma (HCC) have been a major medical challenge. Unraveling the landscape of tumor immune infiltrating cells (TIICs) in the immune microenvironment of HCC is of great significance to probe the molecular mechanisms., Methods: Based on single-cell data of HCC, the cell landscape was revealed from the perspective of TIICs. Special cell subpopulations were determined by the expression levels of marker genes. Differential expression analysis was conducted. The activity of each subpopulation was determined based on the highly expressed genes. CTLA4+ T-cell subpopulations affecting the prognosis of HCC were determined based on survival analysis. A single-cell regulatory network inference and clustering analysis was also performed to determine the transcription factor regulatory networks in the CTLA4+ T cell subpopulations., Results: 10 cell types were identified and NK cells and T cells showed high abundance in tumor tissues. Two NK cells subpopulations were present, FGFBP2+ NK cells, B3GNT7+ NK cells. Four T cells subpopulations were present, LAG3+ T cells, CTLA4+ T cells, RCAN3+ T cells, and HPGDS+ Th2 cells. FGFBP2+ NK cells, and CTLA4+ T cells were the exhaustive subpopulation. High CTLA4+ T cells contributed to poor prognostic outcomes and promoted tumor progression. Finally, a network of transcription factors regulated by NR3C1, STAT1, and STAT3, which were activated, was present in CTLA4+ T cells., Conclusion: CTLA4+ T cell subsets in HCC exhibited functional exhaustion characteristics that probably inhibited T cell function through a transcription factor network dominated by NR3C1, STAT1, and STAT3.

T cells are crucial for the success of immune‐based cancer therapy. Reinvigorating antitumor T cell activity by blocking checkpoint inhibitory receptors has provided clinical benefits for many cancer patients. However, the efficacy of these treatments varies in cancer patients and the mechanisms underlying these diverse responses remain elusive. The density and status of tumor‐infiltrating T cells have been shown to positively correlate with patient response to checkpoint blockades. Therefore, further understanding of the heterogeneity, clonal expansion, migration, and effector functions of tumor‐infiltrating T cells will provide fundamental insights into antitumor immune responses. To this end, recent advances in single‐cell RNA sequencing technology have enabled profound and extensive characterization of intratumoral immune cells and have improved our understanding of their dynamic relationships. Here, we summarize recent progress in single‐cell RNA sequencing technology and current strategies to uncover heterogeneous tumor‐infiltrating T cell subsets. In particular, we discuss how the coupling of deep transcriptome information with T cell receptor (TCR)‐based lineage tracing has furthered our understanding of intratumoral T cell populations. We also discuss the functional implications of various T cell subsets in tumors and highlight the identification of novel T cell markers with therapeutic or prognostic potential. [ABSTRACT FROM AUTHOR]

Exhausted and dysfunctional T cells triggered by infection and cancer render the immune system unable to eliminate these pathogens. Pharmacologic blockade of the surface receptors that inhibit T‐cell function has shown remarkable success in patients with various malignancies. In this Review, we discuss the emerging evidence of inhibiting checkpoint pathways as a potential role in controlling or clearing infectious diseases. Though interesting tendencies, much work is still needed in order to develop safe strategies that can be translated into clinically relevant outcomes in patients with infections. [ABSTRACT FROM AUTHOR]

Background: While mutation-derived neoantigens are well recognized in generating anti-tumour T cell response, increasing evidences highlight the complex association between tumour mutation burden (TMB) and tumour infiltrating lymphocytes (TILs). The exploration of non-TMB determinants of active immune response could improve the prognosis prediction and provide guidance for current immunotherapy., Methods: The transcriptomic and whole exome sequence data in The Cancer Genome Atlas were used to examine the relationship between TMB and exhausted CD8+ T cells (Tex), as an indicator of tumour antigen-specific T cells across nine major cancer types. Computational clustering analysis was performed on 4510 tumours to identify different immune profiles. NanoString gene expression analysis and single cell RNA-seq analysis using fresh human breast cancer were performed for finding validation., Findings: TMB was found to be poorly correlated with active immune response in various cancer types. Patient clustering analysis revealed a group of tumours with abundant Tex but low TMB. In those tumours, we observed significantly higher expression of the stimulator of interferon genes (STING) signalling. Dendritic cells, particularly those of BATF3+ lineage, were also found to be essential for accumulation of Tex within tumours. Mechanistically, loss of genomic and cellular integrity, marked by decreased DNA damage repair, defective replication stress response, and increased apoptosis were shown to drive STING activation., Interpretation: These results highlight that TMB alone does not fully predict tumour immune profiles, with STING signalling compensating for low TMB in non-hypermutated tumours to enhance anti-tumour immunity. Translating these results, STING agonists may benefit patients with non-hypermutated tumours. STING activation may serve as an additional biomarker to predict response to immune checkpoint blockades alongside TMB. Our research also unravelled the interplay between genomic instability and STING activation, informing potential combined chemotherapy targeting the axis of genomic integrity and immunotherapy., Funding: City of Hope Christopher Family Endowed Innovation Fund for Alzheimer's Disease and Breast Cancer Research in honor of Vineta Christopher; Breast Cancer Alliance Early Career Investigator Award; National Cancer Institute of the National Institutes of Health under award number R01CA256989 and R01CA240392., Competing Interests: Declaration of interests All authors declare no conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Graphical abstract Highlights • SFI administration was sufficient to alleviate the depressive-like behaviors of tumor-bearing mice. • SFI might inhibit pro-inflammatory cytokines produced by peripheral immune cells. • SFI might relieve fatigue symptoms by restraining the dysfunction of exhausted T cells. • SFI might improve the immunity of tumor-bearing mice through the targets of PDL1, TIM3 and FOXP3. Abstract Cancer-related fatigue (CRF) not only has a negative impact on work, daily activities and social relationships, but also be a predictor of cancer patients' survival. And it has no FDA-approved therapy. ShenQi FuZheng Injection (SFI) is clinically used for adjuvant treatment of lung cancer and gastric cancer. And we found that SFI can improve the incidence of CRF in patients with gastric cancer. However, its efficacy against CRF remains to be elucidated. In the present study we established a tumor-bearing mouse fatigue model, conducted the forced swim test (FST) and grip strength measurements to evaluate the therapeutic effect of SFI. Additionally, we detected inflammation and immune indicators. The result showed that SFI administration could reduce depressive-like behaviors in tumor-bearing mice and inhibit tumor growth. In addition, SFI might improve fatigue symptoms by inhibiting pro-inflammatory cytokines produced by peripheral immune cells, restrain the dysfunction of exhausted T cells and improve the anti-tumor immunity through the targets of PDL1, TIM3 and FOXP3. These data suggested that SFI might be useful in alleviating CRF and provide further support to confirm SFI as a potential therapy for CRF in humans. [ABSTRACT FROM AUTHOR]

T cell immunoglobulin mucin-3 (TIM-3) is an immune checkpoint identified as one of the key players in regulating T-cell responses. Studies have shown that TIM-3 is upregulated in the tumor microenvironment (TME). However, the precise role of TIM-3 in colorectal cancer (CRC) TME is yet to be elucidated. We performed phenotypic and molecular characterization of TIM-3+ T cells in the TME and circulation of CRC patients by analyzing tumor tissues (TT, TILs), normal tissues (NT, NILs), and peripheral blood mononuclear cells (PBMC). TIM-3 was upregulated on both CD4+ and CD3+CD4− (CD8+) TILs. CD4+TIM-3+ TILs expressed higher levels of T regulatory cell (Tregs)-signature genes, including FoxP3 and Helios, compared with their TIM-3− counterparts. Transcriptomic and ingenuity pathway analyses showed that TIM-3 potentially activates inflammatory and tumor metastatic pathways. Moreover, NF-κB-mediated transcription factors were upregulated in CD4+TIM-3+ TILs, which could favor proliferation/invasion and induce inflammatory and T-cell exhaustion pathways. In addition, we found that CD4+TIM-3+ TILs potentially support tumor invasion and metastasis, compared with conventional CD4+CD25+ Tregs in the CRC TME. However, functional studies are warranted to support these findings. In conclusion, this study discloses some of the functional pathways of TIM-3+ TILs, which could improve their targeting in more specific therapeutic approaches in CRC patients.

The IL-17 family contributes to host defense against many intracellular pathogens by mechanisms that are not fully understood. CD8+ T lymphocytes are key elements against intracellular microbes, and their survival and ability to mount cytotoxic responses are orchestrated by several cytokines. Here, we demonstrated that IL-17RA-signaling cytokines sustain pathogen-specific CD8+ T cell immunity. The absence of IL-17RA and IL-17A/F during Trypanosoma cruzi infection resulted in increased tissue parasitism and reduced frequency of parasite-specific CD8+ T cells. Impaired IL-17RA-signaling in vivo increased apoptosis of parasite-specific CD8+ T cells, while in vitro recombinant IL-17 down-regulated the pro-apoptotic protein BAD and promoted the survival of activated CD8+ T cells. Phenotypic, functional, and transcriptomic profiling showed that T. cruzi-specific CD8+ T cells derived from IL-17RA-deficient mice presented features of cell dysfunction. PD-L1 blockade partially restored the magnitude of CD8+ T cell responses and parasite control in these mice. Adoptive transfer experiments established that IL-17RA-signaling is intrinsically required for the proper maintenance of functional effector CD8+ T cells. Altogether, our results identify IL-17RA and IL-17A as critical factors for sustaining CD8+ T cell immunity to T. cruzi.

The IL-17 family contributes to host defense against many intracellular pathogens by mechanisms that are not fully understood. CD8+ T lymphocytes are key elements against intracellular microbes, and their survival and ability to mount cytotoxic responses are orchestrated by several cytokines. Here, we demonstrated that IL-17RA-signaling cytokines sustain pathogen-specific CD8+ T cell immunity. The absence of IL-17RA and IL-17A/F during Trypanosoma cruzi infection resulted in increased tissue parasitism and reduced frequency of parasite-specific CD8+ T cells. Impaired IL-17RA-signaling in vivo increased apoptosis of parasite-specific CD8+ T cells, while in vitro recombinant IL-17 down-regulated the pro-apoptotic protein BAD and promoted the survival of activated CD8+ T cells. Phenotypic, functional, and transcriptomic profiling showed that T. cruzi -specific CD8+ T cells derived from IL-17RA-deficient mice presented features of cell dysfunction. PD-L1 blockade partially restored the magnitude of CD8+ T cell responses and parasite control in these mice. Adoptive transfer experiments established that IL-17RA-signaling is intrinsically required for the proper maintenance of functional effector CD8+ T cells. Altogether, our results identify IL-17RA and IL-17A as critical factors for sustaining CD8+ T cell immunity to T. cruzi. [ABSTRACT FROM AUTHOR]

Worldwide, 71 million individuals are chronically infected with Hepatitis C Virus (HCV). Chronic HCV infection can lead to potentially fatal outcomes including liver cirrhosis and hepatocellular carcinoma. HCV-specific immune responses play a major role in viral control and may explain why approximately 20% of infections are spontaneously cleared before the establishment of chronicity. Chronic infection, associated with prolonged antigen exposure, leads to immune exhaustion of HCV-specific T cells. These exhausted T cells are unable to control the viral infection. Before the introduction of direct acting antivirals (DAAs), interferon (IFN)-based therapies demonstrated successful clearance of viral infection in approximately 50% of treated patients. New effective and well-tolerated DAAs lead to a sustained virological response (SVR) in more than 95% of patients regardless of viral genotype. Researchers have investigated whether treatment, and the subsequent elimination of HCV antigen, can reverse this HCV-induced exhausted phenotype. Here we review literature exploring the restoration of HCV-specific immune responses following antiviral therapy, both IFN and DAA-based regimens. IFN treatment during acute HCV infection results in greater immune restoration than IFN treatment of chronically infected patients. Immune restoration data following DAA treatment in chronically HCV infected patients shows varied results but suggests that DAA treatment may lead to partial restoration that could be improved with earlier administration. Future research should investigate immune restoration following DAA therapies administered during acute HCV infection.

Objectives The phenotypic and functional properties of Tim-3+/ PD-1+/ CD8+ cells as exhausted T cells were investigated in chronic lymphocytic leukemia ( CLL). Methods Frequency of CD8+/Tim-3+/ PD-1+ exhausted cells was determined by flow cytometry. For functional analysis, magnetic beads-isolated CD8+ T cells were stimulated with PHA and PMA/ionocymin to assess their proliferative responses and cytokine production by MTT and ELISA, respectively. Cytotoxic activity of isolated CD8+ T cells was determined using CD107a degranulation assay. Results The proportion of exhausted CD8+ T cells was significantly higher in CLL compared to controls. Isolated CD8+ T cells from CLL showed functional defects in proliferation, degranulation, and cytokines production. While IL-2, TNF-α, and IFN-γ were significantly lower in CLL patients, IL-10 was higher in the patients group. Patients with progressive clinical stages showed higher frequency and dysfunction of exhausted CD8+ T cells. Conclusion Targeting immune inhibitory receptors to restore the function of tumor surrounding T cells could be helpful for immunotherapy of CLL. [ABSTRACT FROM AUTHOR]

T cell exhaustion is defined by poor effector function, sustained expression of inhibitory receptors and decrease of cytokine. It is a state of T cell dysfunction that arises during cancer. T cell exhaustion is associated with negative immunoregulatory pathways which can be grouped into three main categories: cell surface inhibitory receptors, cytokine and immunoregulatory cell types. It can induce immune escape in tumor. But exhausted T cells is not irreversible. Blocking the appropriate pathways with monoclonal antibody may reverse the dysfunction of exhausted T cells, improve the anti-tumor immunity and tumor control probability. It is a new immunotherapy to treat cancer by reversing the exhausted T cells in cancer patients. [ABSTRACT FROM AUTHOR]

Immunotherapy plays an increasingly important role in the treatment of most malignant tumors, and CD8+ T cells are the most important antitumor effector cells in the process of immunotherapy, and their number and functional status largely determine the antitumor effect. However, under continuous antigen exposure and the stimulation of inflammatory factors, CD8+ T cells gradually show a weakened proliferation and effector function, accompanied by the expression of a variety of inhibitory receptors. This state is known as CD8+ T cell "exhaustion" and often leads to the loss of control and progression of tumors. Recent studies provided us a better understanding of the mechanisms of T cell exhaustion, this review provides an overview of the activation, exhaustion mechanisms and exhaustion characteristics of CD8+ T cells. Although immunotherapy can reverse the exhaustion of CD8+ T cells and significantly improve the antitumor effects, single immunotherapy often has limitations, and it is difficult to achieve satisfactory antitumor effects, therefore, this review also summarizes up-to-date information related to cancer immunotherapy, and these emerging insights provide promising clues to the future management of malignant tumors. • CD8+ T cell exhaustion is one of the main factors that limit the efficacy of cancer immunotherapy. • T cell exhaustion represents a distinct state of T cell differentiation, and exhausted CD8+ T cells possess an obviously different transcriptome from memory and effector CD8+ T cells. • Single immunotherapy has limitations and is difficult to achieve satisfactory antitumor effects, combination immunotherapy has greatly improved the antitumor efficacy. • Novel immunotherapeutic agents, more effective combination immunotherapy, and accurate biomarkers may be the future directions of immunotherapy research. [ABSTRACT FROM AUTHOR]

Paired single-cell RNA and T cell receptor sequencing (scRNA/TCR-seq) has allowed for enhanced resolution of clonal T cell dynamics in cancer. Here, we report a scRNA/TCR-seq analysis of 187,650 T cells from 31 tissue regions, including tumor, adjacent normal tissues, and lymph nodes (LN), from three patients with non-small cell lung cancer after immune checkpoint blockade (ICB). Regions with viable cancer cells are enriched for exhausted CD8+ T cells, regulatory CD4+ T cells (Treg), and follicular helper CD4+ T cells (TFH). Tracking T cell clonotypes across tissues, combined with neoantigen specificity assays, reveals that TFH and tumor-specific exhausted CD8+ T cells are clonally linked to TCF7 + SELL + progenitors in tumor draining LNs, and progressive exhaustion trajectories of CD8+ T, Treg, and TFH cells with proximity to the tumor microenvironment. Finally, longitudinal tracking of tumor-specific CD8+ and CD4+ T cell clones reveals persistence in the peripheral blood for years after ICB therapy. [Display omitted] • Single-cell RNA/TCR-seq with deep intra-patient, regional resolution in NSCLC • TFH, Treg, and CD8+ T cell subsets undergo progressive exhaustion with tumor proximity • LN TCF7 + progenitor exhausted T cells are clonally linked to tumor exhausted T cells • Tumor-specific T cells in aggregate persist after ICB Pai et al. report a single T cell lung cancer dataset allowing for the lineage tracing of T cells across tumor regions, lymph nodes, and peripheral blood. This resource reveals clonal linkage of antigen-specific TCF7 + SELL + progenitor exhausted cells in the lymph node and their exhausted counterparts in the tumor, and long-term peripheral persistence of these cells after checkpoint blockade. [ABSTRACT FROM AUTHOR]

Tuberculosis, a contagious bacterial infection caused by Mycobacterium tuberculosis, is a substantial global health problem, impacting millions of lives annually. Exhausted T-cell signatures are critical for predicting clinical responses to tuberculosis infection. To obtain a panoramic transcriptional profile of T cells, we performed single-cell RNA-sequencing analysis of CD4 + T and CD8 + T cells isolated from peripheral blood mononuclear cells of healthy individuals and patients with tuberculosis. We identified seven subsets in CD8 + T cells and eight subsets in CD4 + T cells and elucidated the transcriptomic landscape changes and characteristics of each subset. We further investigated the cell-to-cell relationship of each subgroup of the two cell types. Different signature genes and pathways of exhausted CD4 + and CD8 + T cells were examined. We identified 12 genes with potential associations of T-cell exhaustion after tuberculosis infection. We also identified five genes as potential exhaustion marker genes. The CD8-EX3 subcluster in CD8 + T-exhausted cells was identified as an exhaustion-specific subcluster. The identified gene module further clarified the key factors influencing CD8 + T cell exhaustion. These data provide new insights into T-cell signatures in tuberculosis-exhausted populations. IMPORTANCE Identifying the changes in immune cells in response to infection can provide a better understanding of the effects of Mycobacterium tuberculosis on the host immune system. We performed single-cell RNA-sequencing analysis of CD4 + T and CD8 + T cells isolated from peripheral blood mononuclear cells of healthy individuals and patients with tuberculosis to reveal the cellular characteristics. Different signature genes and pathways of exhausted CD4 + and CD8 + T cells were examined. These will facilitate a more comprehensive understanding of the onset and underlying mechanism of T-cell exhaustion during active Mtb infection.

T-cell exhaustion has become an important issue in chronic infection because exhausted antigen-specific T cells show impaired abilities to eradicate persistently infected pathogens and produce effector cytokines, such as IFN-γ and TNF-α. Thus, strategies to either restore endogenous exhausted T cell responses or provide functional T cells are needed for therapeutics of chronic infection. Despite promising developments using antibodies and cell immunotherapy, there have been no reported attempts to restore exhausted T cells using treatment with materials derived from natural resources. Here, using a mouse model of chronic infection with lymphocytic choriomeningitis virus (LCMV), we found that vinegar-processed flowers (flos) of Daphne genkwa (vp-genkwa), which was composed mainly of four index components, restored exhausted CD4 + and CD8 + T cells significantly, as corroborated by evidence that vp-genkwa treatment enhanced functional LCMV-specific CD4 + and CD8 + T cells, both quantitatively and qualitatively. Furthermore, pretreatment with vp-genkwa prevented the generation of exhausted LCMV-specific CD8 + T cells. Such restorations of exhausted LCMV-specific CD4 + and CD8 + T cells by vp-genkwa were closely associated with reduced viral burden in sera and tissues. More interestingly, vp-genkwa treatment induced down-regulation of negative molecules, such as PD-1 and Tim-3, in exhausted CD4 + and CD8 + T cells with more apparent down-regulation of Tim-3, suggesting that Tim-3 molecule may be a major target in restoring exhausted T cell responses. Collectively, these results provide valuable new insights into the use of vp-genkwa to develop a therapeutic strategy for chronic human diseases, such as hepatitis B and C virus, human immunodeficiency virus, and cancers. [ABSTRACT FROM AUTHOR]