Follicular CD4 Research Articles

Follicular regulatory T cells eliminate HIV-1-infected follicular helper T cells in an IL-2 concentration dependent manner.

Follicular helper CD4+ T cells (TFH) are highly permissive to HIV and major foci of virus expression in both untreated and treated infection. Follicular regulatory CD4+ T cells (TFR) limit TFH numbers and function in vitro and in vivo. We evaluated the hypothesis that TFR suppress HIV replication in TFH using a well-established model of ex vivo HIV infection that employs tonsil cells from HIV uninfected individuals spinoculated with CXCR4- and CCR5-tropic HIV-GFP reporter viruses. Both CXCR4 and CCR5-tropic HIV replication were reduced in TFH cultured with TFR as compared to controls. Blocking antibodies to CD39, CTLA-4, IL-10, and TGF-beta failed to reverse suppression of HIV replication by TFR, and there were no sex differences in TFR suppressive activity. TFR reduced viability of TFH and even more so reduced HIV infected TFH as assessed by total and integrated HIV DNA. Exogenous IL-2 enhanced TFH viability and particularly numbers of GFP+ TFH in a concentration dependent manner. TFR reduced productively infected TFH at low and moderate IL-2 concentrations, and this was associated with decreases in extracellular IL-2. Both IL-2 expressing cells and larger numbers of FoxP3+CD4+ cells were detected in follicles and germinal centers of lymph nodes of people living with HIV. TFR may deplete TFH in vivo through restriction of IL-2 and thereby contribute to decay of HIV expressing cells in B cell follicles during HIV infection.

Aging induces severe SIV infection accompanied by an increase in follicular CD8+ T cells with overactive STAT3 signaling.

The number of elderly people living with HIV is increasing globally, and the condition of this population is relatively complicated due to the dual effects of aging and HIV infection. However, the impact of HIV infection combined with aging on the immune homeostasis of secondary lymphoid organs remains unclear. Here, we used the simian immunodeficiency virus mac239 (SIVmac239) strain to infect six young and six old Chinese rhesus macaques (ChRMs) and compared the infection characteristics of the two groups in the chronic stage through multiplex immunofluorescence staining of lymph nodes. The results showed that the SIV production and CD4/CD8 ratio inversion in old ChRMs were more severe than those in young ChRMs in both the peripheral blood and the lymph nodes, especially when a large number of CD8+ T cells infiltrated the follicles and germinal centers. STAT3 in these follicular CXCR5+CD8+ T cells was highly activated, with high expression of granzyme B, which might be caused by the severe inflammatory milieu in the follicles of old ChRMs. This study indicates that aging may be a cofactor involved in SIV-induced immune disorders in secondary lymphoid tissues, affecting the effective antiviral activity of highly enriched follicular CXCR5+CD8+ cells.

Abstract 1361: Crosstalk between peripherally expanded T cells and Tfh-like cells in shaping effector functions of CD8 T cells in ovarian cancer

Abstract Background: Immune checkpoint blockade (ICB) of PD-1 and/or CTLA-4 can induce long-lasting clinical responses in several neoplasias. However, despite the successful response in some cancer, it is still ineffective for other malignant lesions such as ovarian cancer. Studies on T cell dynamics demonstrated that antitumor immune response from ICB is mediated by clonal replacement of CD8 T cells. Moreover, the presence of clones expanded in both tumor and peripheral tissue, also called dual-expanded, can predict response to ICB. To understand T cell dynamics in ovarian cancer, we characterized intratumoral and peripheral immune cells by single-cell transcriptome and TCR-sequencing. Methods and results: Using the 5’ Chromium assay (10X Genomics) on CD45+ cells isolated from 5 naïve-treatment patients undergoing cytoreductive surgery, we identified T cell states and classified clones by location (blood or tumor) and expansion pattern. In addition, the data revealed that clones expanded within the tumor were terminally exhausted (upregulation of PDCD1, HAVCR2, CTLA4, ENTPD1, and CXCL13 genes), while dual-expanded clones (expanded in blood and tumor) upregulated genes associated with the cytotoxic function of CD8 T cells, such as granzymes (GZMA and GZMB) and perforin (PRF1). Considering the importance of dual-expanded clones in antitumor immune response, we interrogated the cellular interactions they encountered in the tumor microenvironment. Using the tool NicheNet we identified IL21 as one of the top ligands mediating the interaction between dual-expanded clones and T follicular helper-like CD4+ cells (Tfh-like cells). Interestingly, the gene signature of Tfh-like cells showed that besides dual-expanded clones, these cells might attract other immune cells through CXCL13 and oxysterol metabolites. We identified B cells and plasmacytoid dendritic cells (pDCs) as the major cell types recruited by the CXCL13-CXCR5 axis and oxysterol-GPR183, respectively. Additionally, memory-like CD8 T cells were found to express GPR183, suggesting that a gradient of oxysterol might recruit them to a region defined by Tfh-like cells. Conclusions: Taken together, our study provides insights into additional functions of Tfh-like cells in the recruitment of immune cells through oxysterol gradient. A better understanding of the T cell dynamics and antitumor immune response can provide potential development of novel immunotherapy for the treatment of ovarian cancer. Citation Format: Mayra Carneiro, Cheng Zhao, Paméla Thébault, Yacine Bareche, Kurosh Rahimi, Jean-François Cailhier, Anne-Marie Mes-Masson, John Stagg, Sophie Petropoulos, Réjean Lapointe. Crosstalk between peripherally expanded T cells and Tfh-like cells in shaping effector functions of CD8 T cells in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1361.

Altered levels of circulating CD8+CXCR5+PD-1+T follicular cytotoxic cells in primary Sjögren's syndrome.

Circulating CD8+ T-cells expressing the C-X-C chemokine receptor type 5 (CXCR5) (CD8+CXCR5+T), a recently identified follicular cytotoxic T cell subset, are involved in antiviral immunity and autoimmunity, but their abundance and role in the pathogenesis of primary Sjögren syndrome (pSS) are unknown. Circulating CD8+CXCR5+T cell and CD8+ regulatory T cells (CD8+Treg) were evaluated in 49 pSS patients (19 patients with pulmonary involvement) and 24 age- and sex-matched healthy controls (HCs) by flow cytometry. Orthogonal partial least squares discriminant analysis (OPLS-DA) was performed, and receiver operating characteristic curves (ROC) were generated to identify characteristic cell subsets. Spearman's correlation analysis was conducted to examine the relationships between CD8+ T cell subsets and clinical features. The proportions and numbers of CD8+CXCR5+, CD8 + CXCR5+ programmed death 1-positive (PD-1+), and CD8+CXCR5-PD-1+T cells were significantly higher, whereas those of CD8+Treg were markedly lower, in pSS patients than HCs. The CD8+CXCR5+PD-1+T cell to CD8+Treg ratio had the greatest discriminatory power for pSS and HCs according to OPLS-DA and ROC analyses. The increased numbers of CD8+CXCR5+T cells and CD8+CXCR5+PD-1+T cells were strongly associated with those of CD4+CXCR5+T and B cells. The proportions and numbers of CD8+CXCR5+PD-1+T cells were increased in pSS patients with lung involvement. We identified a new CD8+CXCR5+PD-1+T subset, which was increased in abundance in pSS patients, particularly those with lung involvement, compared with HCs. Also, the CD8+CXCR5+PD-1+T to CD8+Treg ratio may be useful for identifying pSS. Our findings suggest that targeting follicular CD8+T cell subsets has therapeutic potential for pSS. Key Points • CD8+CXCR5+ T cells were expanded in the circulation of patients with pSS. • Reduced numbers CD8+Treg cells in pSS patients. • Increased CD8+CXCR5+PD-1+T cells in pSS patients with pulmonary involvement.

Hypermethylation at the CXCR5 gene locus limits trafficking potential of CD8+ T cells into B-cell follicles during HIV-1 infection

AbstractCD8+ T cells play an important role in HIV control. However, in human lymph nodes (LNs), only a small subset of CD8+ T cells express CXCR5, the chemokine receptor required for cell migration into B-cell follicles, which are major sanctuaries for HIV persistence in individuals on therapy. Here, we investigate the impact of HIV infection on follicular CD8+ T cell (fCD8) frequencies, trafficking patterns, and CXCR5 regulation. We show that, although HIV infection results in a marginal increase in fCD8s in LNs, the majority of HIV-specific CD8+ T cells are CXCR5− (non-fCD8s) (P < .003). Mechanistic investigations using Assay for Transposase-Accessible Chromatin using sequencing showed that non-fCD8s have closed chromatin at the CXCR5 transcriptional start site (TSS). DNA bisulfite sequencing identified DNA hypermethylation at the CXCR5 TSS as the most probable cause of closed chromatin. Transcriptional factor footprint analysis revealed enrichment of transforming growth factors (TGFs) at the TSS of fCD8s. In vitro stimulation of non-fCD8s with recombinant TGF-β resulted in a significant increase in CXCR5 expression (fCD8s). Thus, this study identifies TGF-β signaling as a viable strategy for increasing fCD8 frequencies in follicular areas of the LN where they are needed to eliminate HIV-infected cells, with implications for HIV cure strategies.

CTLA4 Protects Against Maladaptive Cytotoxicity During Terminal Differentiation of Effector and Follicular CD4+&amp;nbsp;T Cells

CTLA4 Protects Against Maladaptive Cytotoxicity During Terminal Differentiation of Effector and Follicular CD4+&amp;nbsp;T Cells

The diagnostic role of PD‐1+ CXCR5+ follicular helper CD8+ T cell in renal allograft dysfunction

BackgroundThe roles of PD‐1+CXCR5+ follicular helper CD8+ T cell were reported in different disease conditions, but their roles in transplantation are unclear. In this study, the association between PD‐1+CXCR5+ follicular helper CD8+ T cell and renal allograft dysfunction in kidney transplant recipients (KTRs) was investigated.Methods82 KTRs were enrolled in this study. 45 KTRs were included in the chronic allograft dysfunction (CAD) group, and 37 KTRs were included in the stable recipients group. Among the CAD group, 12 cases of antibody‐mediated rejection (ABMR) and 4 cases of T cell–mediated rejection (TCMR) were diagnosed by biopsy. The percentage of CXCR5+CD8+ T cells and the co‐expression of signal transducers and activators of transcription 4 (STAT4), STAT5, and PD‐1 in peripheral blood were determined by flow cytometry.ResultsThe expression of CXCR5 on CD3+CD8+ T cells and the percentage of STAT5+CXCR5+ cells in the CD3+CD8+ T‐cell population were significantly lower in the CAD group (p < 0.05), while the expression of PD‐1+CXCR5+CD8+ T cells was significantly higher (p < 0.05). Through logistic regression analysis, we concluded that the percentage of PD‐1+CXCR5+CD8+ T cells was an independent risk factor for renal dysfunction. Grouping by pathological type, PD‐1+CXCR5+CD8+ T cells showed relatively good diagnostic efficacy for ABMR by ROC analysis.ConclusionsOur results suggested that PD‐1+CXCR5+CD8+ T cells were a promising biomarker for distinguishing renal allograft dysfunction and different allograft pathological types. Also, our findings may provide new ways of identifying and treating allograft rejection.

Machine learning based deconvolution of microarray atrial samples from atrial fibrillation patients reveals increased fractions of follicular CD4+ T lymphocytes and gamma-delta T cells.

A potential relationship between T cell immunity and development of atrial fibrillation (AF) has been proposed. Historically in AF patients it has been reported that peripheral blood had elevated CD4+ T cells. However few studies have explored whether there is a direct increase of CD4+ T cells in atrial tissues with AF. In this study, public domain micro-array dataset of cardiac surgery patients with atrial tissue biopsies in AF and non-AF patients have been used to explore immune cell subsets. Machine learning based deconvolution of permanent atrial fibrillation microarray atrial samples was applied using Cibersort to enumerate the relative fractions of twenty-two different leukocyte sub-populations. Cibersort enumerated significantly increased fractions of follicular CD4+ T lymphocytes and gamma-delta T cells in the atria of permanent AF subjects. Gene expression analysis of permanent AF microarray tissue samples with elevated follicular CD4+ T cell fractions with gene pathways associated with myocardial substrate remodelling. That is both integrin and non-integrin mediated gene interactions between inflammatory cells and the extra cellular matrix, including infiltrating follicular CD4+ T cells that trafficked to the atria by virtue of the repertoire of cell surfaced expressed adhesion molecules. Additionally, IL-17 and other interleukin inflammatory gene heat maps were associated with enhanced CD4+ follicular T cell expression in our profiled atrial tissues with AF. These observations suggest that atrial structural remodelling was associated with the presence of pathogenic T cell mediated inflammation, present in AF atria but not in non-AF atria.

Single-Cell Transcriptomic Analysis of Ecosystems in Papillary Thyroid Carcinoma Progression.

BackgroundDespite extensive research, the papillary thyroid carcinoma (PTC) ecosystem is poorly characterized and, in particular, locoregional progression. Available evidence supports that single-cell transcriptome sequencing (Sc-RNA seq) can dissect tumor ecosystems.MethodsTissue samples from one PTC patient, including matched primary tumor (Ca), lymph node (LN) metastasis, and paracancerous tissue (PCa), were subjected to Sc-RNA seq with 10×Genomics. Dual-label immunofluorescence and immunohistochemistry were used to confirm the existence of cell subtypes in a separate cohort.Results11,805 cell transcriptomes were profiled, cell landscapes of PTC were composed of malignant follicular epithelial cells (MFECs), CD8+ and CD4+ T cells, B cells, vascular endothelial cells, fibroblasts and cancer-associated fibroblasts (CAFs). Between Ca and LN ecosystems, the proportions of MFEC and interstitial cells were similar, less than 1/25(229/6,694, 361/3,895), while the proportion of normal follicular epithelial cells (NFECs) and interstitial cells was > 2 in PCa (455/171). NFECs in PCa formed a separate cluster, while MFECs in Ca and LN exhibited a profound transcriptional overlap, and the interstitial cells among these samples had an overall concordance in their identity and representation, albeit with some distinctions in terms of the cell percentage per subset. A fraction of the B cell subpopulation in Ca expressed inhibitory receptors, while their respective ligand genes were clearly transcribed in T cell and malignant epithelial cell clusters, while some CD8+ T cells in both Ca and LN produced high levels of inhibitory receptors whose respective ligands were overexpressed in some CD4+ T cells. Three CAF subtypes in Ca and LN were identified, which may be due to mutual transitions.ConclusionsOur data provide new insights into the PTC ecosystem and highlight the differences in ecosystems in PTC progression, which updates our understanding of PTC biology and will improve individualized patient treatment.

Follicular Helper CD4+ T Cells, Follicular Regulatory CD4+ T Cells, and Inducible Costimulator and Their Roles in Multiple Sclerosis and Experimental Autoimmune Encephalomyelitis.

Follicular helper CD4+ T (TFH) cells are a specialized subset of effector T cells that play a central role in orchestrating adaptive immunity. TFH cells mainly promote germinal center (GC) formation, provide help to B cells for immunoglobulin affinity maturation and class-switch recombination of B cells, and facilitate production of long-lived plasma cells and memory B cells. TFH cells express the nuclear transcriptional repressor B cell lymphoma 6 (Bcl-6), the chemokine (C-X-C motif) receptor 5 (CXCR5), the CD28 family members programmed cell death protein-1 (PD-1) and inducible costimulator (ICOS) and are also responsible for the secretion of interleukin-21 (IL-21) and IL-4. Follicular regulatory CD4+ T (TFR) cells, as a regulatory counterpart of TFH cells, participate in the regulation of GC reactions. TFR cells not only express markers of TFH cells but also express markers of regulatory T (Treg) cells containing FOXP3, glucocorticoid-induced tumor necrosis factor receptor (GITR), cytotoxic T lymphocyte antigen 4 (CTLA-4), and IL-10, hence owing to the dual characteristic of TFH cells and Treg cells. ICOS, expressed on activated CD4+ effector T cells, participates in T cell activation, differentiation, and effector process. The expression of ICOS is highest on TFH and TFR cells, indicating it as a key regulator of humoral immunity. Multiple sclerosis (MS) is a severe autoimmune disease that affects the central nervous system and results in disability, mediated by autoreactive T cells with evolving evidence of a remarkable contribution from humoral responses. This review summarizes recent advances regarding TFH cells, TFR cells, and ICOS, as well as their functional characteristics in relation to MS.

Influence of Tumor Immune Infiltration on Immune Checkpoint Inhibitor Therapeutic Efficacy: A Computational Retrospective Study

The tumor immune microenvironment (TIME) is likely an important determinant of sensitivity to immune checkpoint inhibitor (ICI) treatment. However, a comprehensive analysis covering the complexity and diversity of the TIME and its influence on ICI therapeutic efficacy is still lacking. Data from 782 samples from 10 ICI clinical trials were collected. To infer the infiltration of 22 subsets of immune cells, CIBERSORTx was applied to the bulk tumor transcriptomes. The associations between each cell fraction and the response to ICI treatment, progression-free survival (PFS) and overall survival (OS) were evaluated, modeling cellular proportions as quartiles. Activity of the interferon-γ pathway, the cytolytic activity score and the MHC score were associated with good prognosis in melanoma. Of the immune cells investigated, M1 macrophages, activated memory CD4+ T cells, T follicular helper (Tfh) cells and CD8+ T cells correlated with response and prolonged PFS and OS, while resting memory CD4+ T cells was associated with unfavorable prognosis in melanoma and urothelial cancer. Consensus clustering revealed four immune subgroups with distinct responses to ICI therapy and survival patterns. The cluster with high proportions of infiltrated CD8+ T cells, activated memory CD4+ T cells, and Tfh cells and low levels of resting memory CD4+ T cells exhibited a higher tumor mutation burden and neoantigen load in melanoma and conferred a higher probability of response and improved survival. Local systemic immune cellular differences were associated with outcomes after ICI therapy. Further investigations of the tumor-infiltrating cellular immune response will lay the foundation for achieving durable efficacy.

The tumor immune microenvironment and immune-related signature predict the chemotherapy response in patients with osteosarcoma

BackgroundGenome-wide expression profiles have been shown to predict the response to chemotherapy. The purpose of this study was to develop a novel predictive signature for chemotherapy in patients with osteosarcoma.MethodsWe analysed the relevance of immune cell infiltration and gene expression profiles of the tumor samples of good responders with those of poor responders from the TARGET and GEO databases. Immune cell infiltration was evaluated using a single-sample gene set enrichment analysis (ssGSEA) and the CIBERSORT algorithm between good and poor chemotherapy responders. Differentially expressed genes were identified based on the chemotherapy response. LASSO regression and binary logistic regression analyses were applied to select the differentially expressed immune-related genes (IRGs) and developed a predictive signature in the training cohort. A receiver operating characteristic (ROC) curve analysis was employed to assess and validate the predictive accuracy of the predictive signature in the validation cohort.ResultsThe analysis of immune infiltration showed a positive relationship between high-level immune infiltration and good responders, and T follicular helper cells and CD8 T cells were significantly more abundant in good responders with osteosarcoma. Two hundred eighteen differentially expressed genes were detected between good and poor responders, and a five IRGs panel comprising TNFRSF9, CD70, EGFR, PDGFD and S100A6 was determined to show predictive power for the chemotherapy response. A chemotherapy-associated predictive signature was developed based on these five IRGs. The accuracy of the predictive signature was 0.832 for the training cohort and 0.720 for the validation cohort according to ROC analysis.ConclusionsThe novel predictive signature constructed with five IRGs can be effectively utilized to predict chemotherapy responsiveness and help improve the efficacy of chemotherapy in patients with osteosarcoma.

The Pathogenic Role of CD4+ Tissue-Resident Memory T Cells Bearing T Follicular Helper-Like Phenotype in Pemphigus Lesions

In skin lesions caused by pemphigus, a group of life-threatening autoimmune bullous diseases, an over-representation of CD4+ tissue-resident memory T (TRM) cells was found. We sought to investigate the contributions of CD4+ TRM cells to the severity and refractoriness of pemphigus and their role in local immunological pathogenesis. Our data showed that CD4+ TRM cells accumulated significantly in pemphigus skin lesions. These CD4+ TRM cells expressed a specific set of T follicular helper cell‒related costimulatory molecules. We also found that CD4+ TRM cells remaining in the lesions produced IL-17A and IL-21. Invitro, CD4+ TRM cells exhibited strong support and assistance to autoantibody production. Through transcriptomic sequencing and bioinformatics analysis, we identified that the transcription factor IRF4 was responsible for IL-21 overexpression and autoantibody production. Our results showed that T follicular helper-like CD4+ TRM cells in pemphigus lesions promoted local autoantibody production, resulting in the formation and recurrence of lesions, which supports targeting this cell subset in pemphigus treatment. IRF4 might serve as a potential therapeutic target.

The Tumour Immune Infiltrations in Immune Checkpoint Inhibitor Therapeutic Efficacy: A Computational Retrospective Study

Background: Tumour immune microenvironment (TIME) are likely to be important determinants in sensitive to immune checkpoint inhibitors (ICI) treatment. However, a comprehensive analysis covers the complexity and diversity of the TIME and its influence on ICI therapeutic efficacy is still lacking. Methods: Data of 782 samples from 10 ICI clinical trials were collected. To infer 22 subsets of immune cells, CIBERSORTx was applied to bulk tumour transcriptomes. The associations between each cell fraction and response to ICI treatment, progression-free survival (PFS) and overall survival (OS) were evaluated, modelling cellular proportions as quartiles. Findings: Activity of interferon-γ pathway, cytolytic activity score and MHC score were associated with well prognosis in melanoma. Of the immune cells investigated, M1 macrophages, activated memory CD4+ T cells, T follicular helper (Tfh) cells and CD8+ T cells correlated with response, prolonged PFS and OS, while resting memory CD4+ T cells and resting masts cells associated with unfavourable prognosis within pan cancer and melanoma. Consensus clustering revealed four immune subgroups with distinct response to ICI therapy and survival patterns. A cluster with high proportions of infiltrated CD8+ T cells, activated memory CD4+ T cells, Tfh cells and low level of resting memory CD4+ T cells, exhibited higher tumour mutation burden and neoantigen load within melanoma, was conferred higher ratio of response and improved survival. Interpretation: The local systemic immune cellular difference associated with outcomes after ICI therapy. Further investigations of the tumour-infiltrating cellular immune response lay the foundation for achieving durable efficacy. Funding: This study was supported by the National Scientific Foundation of China (No. 31801121) and National Natural Science Foundation of Hunan (No. 2020JJ5879). Declaration of Interest: None to declare. Ethical Approval: This study has been approved by the Institute of Clinical Pharmacology, Central South University.

Immune Infiltration Landscape in Clear Cell Renal Cell Carcinoma Implications.

The malignant phenotypes of cancer are defined not only by its intrinsic tumor cells but also by the tumor infiltrating immune cells (TIICs) recruited to the cancer microenvironment. Clear cell renal cell carcinoma (ccRCC) immune microenvironment plays an important role in the tumorigenesis. This research investigated the characteristics of immune cell invasion of renal cell carcinoma and provided clues for future clinical implementation. Retrospectively, ccRCC gene expression was analyzed with appropriate clinicopathological data from the Cancer Genome Atlas (TCGA) and GEO database up to December 2019. The CIBERSORT algorithm, meta-analysis, principal component analysis (PCA), Single-Sample Gene Set Enrichment Analysis (ssGSEA) and hierarchical agglomerative clustering were used to measure and evaluate the respective proportions of 22 cell types of immune infiltration using normalized gene expression data. We also focused on evaluating the association with TIICs subpopulations and clinical features and molecular subtypes. TIICs subpopulation, especially Macrophages subgroup, T follicular helper (Tfh) cells and CD8 T cells, all contribute to tumorigenesis. Unsupervised clustering analysis revealed that there existed two distinct TIICs subgroups with different survival patterns. TIICs are extensively involved in the pathogenesis and development of the ccRCC. Characterizing the composition of TIICs influences the metabolism of tumors, activity, level, stage, and survival of patients. Collectively, the TIIC analysis has the potential to assist in the assessment and selection of ccRCC prognosis and treatment.

Conversations that count: Cellular interactions that drive T cell fate.

The relationship between the extrinsic environment and the internal transcriptional network is circular. Naive T cells first engage with antigen‐presenting cells to set transcriptional differentiation networks in motion. In turn, this regulates specific chemokine receptors that direct migration into distinct lymph node niches. Movement into these regions brings newly activated T cells into contact with accessory cells and cytokines that reinforce the differentiation programming to specify T cell function. We and others have observed similarities in the transcriptional networks that specify both CD4+ T follicular helper (TFH) cells and CD8+ central memory stem‐like (TSCM) cells. Here, we compare and contrast the current knowledge for these shared differentiation programs, compared to their effector counterparts, CD4+ T‐helper 1 (TH1) and CD8+ short‐lived effector (TSLEC) cells. Understanding the interplay between cellular interactions and transcriptional programming is essential to harness T cell differentiation that is fit for purpose; to stimulate potent T cell effector function for the elimination of chronic infection and cancer; or to amplify the formation of humoral immunity and longevity of cellular memory to prevent infectious diseases.

CD8+ T cells located in tertiary lymphoid structures are associated with improved prognosis in patients with gastric cancer.

The presence of tumor infiltrating lymphocytes (TILs) and tertiary lymphoid structures (TLSs) in tumor tissues are of great prognostic significance in several types of human cancer. The present study investigated the density of TILs and TLSs in gastric cancer (GC) tissues and their association with pathological parameters. Moreover, the clinical significance of follicular CD8+ cytotoxic T cells present within the germinal centers of the tumor-associated TLSs was investigated. Immunohistochemistry and H&E staining were used to examine the infiltration and distribution patterns of TILs, TLSs and germinal center (gc) CD8+ TILs in tumor tissues obtained from 63 patients with GC. The number of TILs, TLSs, combination of TILs and TLSs (TILs-TLSs) and gcCD8+ TILs were used to define tumoral immune parameters, and the prognostic value of these parameters was assessed. The analysis revealed that patients with GC with increased levels of TILs, TLSs, or gcCD8+ TILs exhibited improved overall survival. In addition, gcCD8+ TILs levels were significantly associated with patient age, histological grade and pTN stage. Increased levels of TILs-TLSs were positively associated with nerve invasion, tumor thrombus, nodal metastasis and histological grade. Multivariate Cox regression analysis revealed that TILs-TLSs and gcCD8+ TILs were independent prognostic factors. The data obtained in the present study demonstrated that high levels of tumoral immune parameters are important independent prognostic predictors for human GC. The results also suggested a possible role of gcCD8+ TILs in tumor immune surveillance.

Tri-functional T-cell engagers target immune checkpoint inhibitors PD-1 and TIGIT to enhance CD8 effector T-cell functions in chronically SHIV-infected rhesus macaques

Abstract Checkpoint inhibitors, such as PD-1 and TIGIT, are crucial dysregulators of CD8 T cell function during chronic HIV/SIV infections. Importantly, these checkpoint inhibitors are highly expressed on the surface of CD4 T cells that harbor latent HIV. We have previously demonstrated that an anti-HIV/anti-CD3 bispecific T-cell engager (BiTE) can be used to redirect follicular CD8 (fCD8) T cells to kill HIV infected cells in vitro. Here, we hypothesize that adding an extra specificity to target PD-1 or TIGIT to the BiTE will further enhance the functional activities of CD8 T cells and simultaneously lower the threshold for reactivation of HIV latently infected cells. By using HIV-infected cell lines and primary CD4 T cells isolated from chronically SHIV-infected lymph nodes (LN) as target cells in in vitro and ex vivo killing assays, we found that trifunctional anti-HIV/anti-CD3-anti-TIGIT or anti-HIV/anti-CD3-anti-PD1 increased (1) T-cell specific activation, (2) antigen-specific CD107a degranulation, levels of granzyme B, cytokine/chemokine release by CD8 T cells, and (3) the killing capability of functionally compromised CD8 T cells when compared to the BiTE. When administered at 100 mcg/kg subcutaneously to chronically SHIV-infected animals, we demonstrated that anti-HIV/anti-CD3-anti-TIGIT could safely be used to augment activation and expansion of CD8 effector T cells that further resulted in a better elimination of the SHIV-infected cells as shown by the reduction in cell-associated SHIV gag DNA and RNA. Together, our results indicate that trifunctional T cell engagers targeting checkpoint inhibitors may serve as novel immunotherapeutic strategies to eliminate infected cells in HIV infected individuals.

Exhausted phenotype of follicular CD8 T cells in CVID

Exhausted phenotype of follicular CD8 T cells in CVID

Follicular cytotoxic CD8 T cells present high cytokine expression, and are more susceptible to Breg-mediated suppression in non-small cell lung cancer.

Tumor-infiltrating CD8 T cells are instrumental to antitumor immunity. In this study, we found that a subset of CXCR5-expressing CD8 T cells, termed follicular cytotoxic T (Tfc) cells, potently infiltrated the untreated tumors from non-small cell lung cancer (NSCLC) patients. On average, Tfc cells represented 14% of total tumor-infiltrating CD8 T cells and 6.6% of total tumor-infiltrating lymphocytes. Upon antigenic stimulation, Tfc cells presented significantly higher degranulation and stronger release of proinflammatory cytokines, including IFNg, IL2, and TNF, and the pleiotropic cytokine IL10 than non-Tfc cells. However, the expression of granzyme B and perforin was significantly lower in Tfc cells than in non-Tfc CD8 T cells. B regulatory (Breg) cells could significantly suppress proinflammatory cytokine production in both Tfc cells and non-Tfc CD8 T cells, but in Tfc cells, a lower concentration was required. Moreover, Breg cells could significantly elevate IL10 expression by Tfc cells but could not affect IL-10 expression by non-Tfc CD8 T cells. The neutralization of IL10 significantly reduced the extent of Breg-mediated regulation. Together, this study demonstrated that Tfc cells represented a significant proportion of tumor-infiltrating CD8 T cells in lung carcinoma. These Tfc cells were different from non-Tfc CD8 T cells in terms of cytokine expression and granzyme and perforin release and were more susceptible to Breg-mediated suppression in an IL-10-dependent manner.