T cell dysfunction is a characteristic feature of chronic viral infection and cancer. Recent studies in chronic lymphocytic choriomeningitis virus (LCMV) infection have defined a PD-1+ Tcf-1+ CD8+ ...T cell subset capable of self-renewal and differentiation into more terminally differentiated cells that downregulate Tcf-1 and express additional inhibitory molecules such as Tim3. Here, we demonstrated that expression of the glycoprotein CD101 divides this terminally differentiated population into two subsets. Stem-like Tcf-1+ CD8+ T cells initially differentiated into a transitory population of CD101−Tim3+ cells that later converted into CD101+ Tim3+ cells. Recently generated CD101−Tim3+ cells proliferated in vivo, contributed to viral control, and were marked by an effector-like transcriptional signature including expression of the chemokine receptor CX3CR1, pro-inflammatory cytokines, and granzyme B. PD-1 pathway blockade increased the numbers of CD101−Tim3+ CD8+ T cells, suggesting that these newly generated transitional cells play a critical role in PD-1-based immunotherapy.
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•CX3CR1+ CD8+ T cells are recent progeny of stem-like cells in chronic infection•CX3CR1+ cells differentiate to a dysfunctional state marked by CD101 expression•Transitory CX3CR1+ cells express effector molecules and contribute to viral control•PD-1 pathway blockade increases the number of antigen-specific transitory cells
Chronic viral infection induces exhaustion of antigen-specific T cells. Hudson and colleagues define a transitory, effector-like population of CD8+ T cells that are recently generated from stem-like CD8+ T cells in chronic infection. These transitory cells contribute to viral control and are increased in number following PD-1 pathway blockade.
Tumour-infiltrating lymphocytes are associated with a survival benefit in several tumour types and with the response to immunotherapy
. However, the reason some tumours have high CD8 T cell ...infiltration while others do not remains unclear. Here we investigate the requirements for maintaining a CD8 T cell response against human cancer. We find that CD8 T cells within tumours consist of distinct populations of terminally differentiated and stem-like cells. On proliferation, stem-like CD8 T cells give rise to more terminally differentiated, effector-molecule-expressing daughter cells. For many T cells to infiltrate the tumour, it is critical that this effector differentiation process occur. In addition, we show that these stem-like T cells reside in dense antigen-presenting-cell niches within the tumour, and that tumours that fail to form these structures are not extensively infiltrated by T cells. Patients with progressive disease lack these immune niches, suggesting that niche breakdown may be a key mechanism of immune escape.
Mutation analysis of circulating tumor DNA (ctDNA) has recently been introduced as a noninvasive tumor monitoring method. In this study, we tested the mass spectrometric-based MassARRAY platform for ...multiplexed gene mutation analysis of plasma samples from colorectal cancer (CRC) patients. A total of 160 patients, who underwent curative resection of either primary or metastatic CRC harboring KRAS mutations between 2005 and 2012, were included. Circulating DNA was isolated from plasma was analyzed on the MassARRAY platform with or without selective amplification of mutant DNA fragments. Tumor-specific KRAS mutations were detected in 39.6% (42/106) of patients with distant metastasis, and in 5.6% (3/54) of patients without distant metastasis. Selective amplification of the mutant allele increased sensitivity to 58.5% (62/106) for patients with distant metastasis, and 16.7% (9/54) for patients without distant metastasis. These mutation detection rates were no less than those of droplet digital polymerase chain reaction. Among patients with distant metastasis, detectable plasma KRAS mutations correlated with larger primary tumors and shorter overall survival rate (P = 0.014 and P = 0.003, respectively). In addition, activating PIK3CA mutations were detected together with KRAS mutations in two plasma samples. Taken together, massARRAY platform is a cost-effective, multigene mutation profiling technique for ctDNA with reasonable sensitivity and specificity.
BackgroundT cell responses are regulated by co-stimulatory and inhibitory receptors along with T cell receptor- and cytokine-mediated signals. CD51, also known as alpha v integrin (ITGAV), is a ...transmembrane glycoprotein of the integrin family involved in cell adhesion, migration, tumorigenesis, and other cellular functions.1–7 However, the expression and function of CD51 in CD8 T cells during activation have not been previously examined. Therefore, this study aimed to investigate the expression and role of CD51 specifically in CD8 T cells.MethodsAnalysis of RNA-sequencing data from exhausted CD8 T cells in mice with chronic lymphocytic choriomeningitis virus (LCMV) or B16F10 tumor models revealed high expression of Itgav (encoding CD51) in exhausted CD8 T cells from both mouse models. Itgav expression increased as CD8 T cells underwent terminal differentiation, similar to the expression pattern of Pdcd1. To assess CD51 expression during T cell activation, we stimulated total splenocytes with anti-CD3 antibodies. Additionally, we examined CD51 expression in exhausted CD8 T cells using four murine models: chronic LCMV infection, B16F10 melanoma, CT26 colon carcinoma, and acute graft-versus-host disease (GvHD). To investigate the role of CD51 in CD8 T cell activation, we employed CD51-blocking antibodies in in vitro activation and utilized CRISPR-mediated knockdown (KD) of CD51 in P14 CD8 T cells in vivo.Results in vitro T cell activation revealed delayed but subsequent upregulation of CD51 expression during CD8 T cell division. Moreover, high CD51 expression was observed in exhausted CD8 T cells from cases of chronic LCMV infection, B16F10 melanoma, CT26 colon carcinoma, and acute GvHD. Furthermore, CD51 expression increased as the cells became more differentiated. CRISPR-mediated knockdown of CD51 resulted in decreased numbers of virus-specific CD8 T cells during LCMV infection, while maintaining granzyme B expression and cytokine production. Blockade of CD51 using antibodies significantly restrained T cell proliferation while preserving CD8 T cell activity.ConclusionsOur study demonstrates the upregulation of CD51 and its impact on CD8 T cell proliferation. Moreover, we identified that CD51-blocking antibodies effectively inhibit T cell activation. These findings highlight CD51 as a newly identified immunomodulatory protein with potential for enhancing the effectiveness of anticancer treatments in tumor models and mitigating immunopathological damage in autoimmune disorders and graft-versus-host diseases.AcknowledgementsThis study was supported by a National Research Foundation of Korea (NRF) grant (S.J.I.) funded by the Korean government (MSIT) (RS-2023–00211426) and by a National Cancer Center Grant (NCC203186) (S.J.I.). This research was also supported by Korea Basic Science Institute (National Research Facilities and Equipment Center) grant funded by the Ministry of Education (2020R1A6C101A191).ReferencesL Seguin, JS Desgrosellier, SM Weis, DA Cheresh. Integrins and cancer: regulators of cancer stemness, metastasis, and drug resistance, Trends Cell Biol. 2015;25:234–240.H Wang, H Chen, Z Jiang, Y Lin, X Wang, J Xiang, J Peng. Integrin subunit alpha V promotes growth, migration, and invasion of gastric cancer cells. Pathol. Res. Pract. 2019;215:152531.J Waisberg, L De Souza Viana, RJ Affonso Junior, SR Silva, MV Denadai, FB Margeotto, CS De Souza, D Matos. Overexpression of the ITGAV gene is associated with progression and spread of colorectal cancer. Anticancer Res. 2014;34:5599–5607.MA Sims, SD Field, MR Barnes, N Shaikh, K Ellington, KE Murphy, N Spurr, DA Campbell. Cloning and characterisation of ITGAV, the genomic sequence for human cell adhesion protein (vitronectin) receptor alpha subunit, CD51, Cytogenet. Cell Genet. 2000;89:268–271.D Bouvard, C Brakebusch, E Gustafsson, A Aszodi, T Bengtsson, A Berna, R Fassler. Functional consequences of integrin gene mutations in mice, Circ. Res. 2001;89:211–223.JA Nemeth, MT Nakada, M Trikha, Z Lang, MS Gordon, GC Jayson, R Corringham, U Prabhakar, HM Davis, RA Beckman. Alpha-v integrins as therapeutic targets in oncology, Cancer Invest. 2007;25:632–646.K Horioka, K Ohuchida, M Sada, B Zheng, T Moriyama, H Fujita, T Manabe, T Ohtsuka, M Shimamoto, T Miyazaki, K Mizumoto, Y Oda, M Nakamura. Suppression of CD51 in pancreatic stellate cells inhibits tumor growth by reducing stroma and altering tumor-stromal interaction in pancreatic cancer. Int. J. Oncol. 2016;48:1499–1508.Ethics ApprovalAll experiments were conducted in accordance with the Institutional Animal Care and Use Committee guidelines of Sungkyunkwan University School of Medicine.
Acute viral infection or vaccination generates highly functional memory CD8 T cells following the Ag resolution. In contrast, persistent antigenic stimulation in chronic viral infection and cancer ...leads to a state of T-cell dysfunction termed T-cell exhaustion. We and other have recently identified a novel subset of exhausted CD8 T cells that act as stem cells for maintaining virus-specific CD8 T cells in a mouse model of chronic lymphocytic choriomeningitis virus infection. This stem cell-like CD8 T-cell subset has been also observed in both mouse and human tumor models. Most importantly, in both chronic viral infection and tumor models, the proliferative burst of Ag-specific CD8 T cells driven by PD-1-directed immunotherapy comes exclusively from this stem cell-like CD8 T-cell subset. Therefore, a better understanding of the mechanisms how CD8 T-cell subsets are regulated during chronic viral infection and cancer is required to improve the current immunotherapies that restore the function of exhausted CD8 T cells. In this review, we discuss the differentiation of virus-specific CD8 T cells during chronic viral infection, the characteristics and function of CD8 T-cell subsets, and the therapeutic intervention of PD-1-directed immunotherapy in cancer.
BackgroundRadiotherapy (RT) has been shown to stimulate an antitumor immune response in irradiated tumors as well as unirradiated distant sites (abscopal effect). Previous studies have demonstrated a ...role for the tumor-draining lymph node (LN) in mediating an anti-programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) stimulated antitumor immune response. Here, we investigated whether the LN is also important in mediating a RT alone stimulated abscopal response.MethodsWe used a subcutaneous modified B16F10 flank tumor model injected bilaterally. Our B16F10 cell line has an inserted viral glycoprotein which facilitated identification of tumor-specific T-cells. RT was directed at one flank tumor alone or one flank tumor and the tumor-draining LN. We evaluated response by tumor growth measurements and flow cytometry of both tumor-infiltrating and LN T-cells.ResultsWe show that local tumor irradiation improves distant tumor control (abscopal effect). Depletion of CD8+ T-cells significantly reduced this abscopal response. We have previously shown, in a chronic lymphocytic choriomeningitis virus (LCMV) infection, that the T-cell proliferative burst following blockade of PD-1/L1 is provided by a ‘stem-like’ CD8+ T-cell subset which then differentiate into terminally differentiated effectors. These terminally differentiated effectors have the potential to kill virally infected or tumor cells following PD-1/L1 blockade. In the chronic LCMV infection, stem-like CD8+ T-cells were found exclusively in secondary lymphoid organs. Similarly, here we found these cells at high frequencies in the tumor-draining LN, but at low frequencies within the tumor. The effect of RT on this T-cell subset in unknown. Interestingly, tumor irradiation stimulated total CD8+ and stem-like CD8+ T-cell proliferation in the LN. When the LN and the tumor were then targeted with RT, the abscopal effect was reduced, and we found a concomitant reduction in the number of total tumor-specific CD8+ T-cells and stem-like CD8+ T-cells in both the irradiated and unirradiated tumor.ConclusionsThese correlative results suggest the tumor-draining LN may be an important mediator of the abscopal effect by serving as a stem-like CD8+ T-cell reservoir, a site for stem-like T-cell expansion, and a site from which they can populate the tumor.
Highlights • miR-373 identified as a target of epigenetic aberration in NSCLC. • miR-373 acts as a tumor suppressor. • miR-33 is a negative regulator of the EMT in lung cancer. • miR-373 regulates ...EMT phenotype through IRAK2 and LAMP1.
Abstract
Graft-versus-host disease (GvHD) is a severe complication of hematopoietic stem cell transplantation driven by activated allogeneic T cells. Here, we identify a distinct subset of T cell ...factor-1 (TCF1)
+
CD8
+
T cells in mouse allogeneic and xenogeneic transplant models of acute GvHD. These TCF1
+
cells exhibit distinct characteristics compared to TCF1
-
cells, including lower expression of inhibitory receptors and higher expression of costimulatory molecules. Notably, the TCF1
+
subset displays exclusive proliferative potential and could differentiate into TCF1
-
effector cells upon antigenic stimulation. Pathway analyses support the role of TCF1
+
and TCF1
-
subsets as resource cells and effector cells, respectively. Furthermore, the TCF1
+
CD8
+
T cell subset is primarily present in the spleen and exhibits a resident phenotype. These findings provide insight into the differentiation of allogeneic and xenogeneic CD8
+
T cells and have implications for the development of immunotherapeutic strategies targeting acute GvHD.
Brown adipose tissue (BAT) plays a pivotal role in maintaining body temperature and energy homeostasis. BAT dysfunction is associated with impaired metabolic health. Here, we show that Ssu72 ...phosphatase is essential for mRNA translation of genes required for thermogenesis in BAT. Ssu72 is found to be highly expressed in BAT among adipose tissue depots, and the expression level of Ssu72 is increased upon acute cold exposure. Mice lacking adipocyte Ssu72 exhibit cold intolerance during acute cold exposure. Mechanistically, Ssu72 deficiency alters cytosolic mRNA translation program through hyperphosphorylation of eIF2α and reduces translation of mitochondrial oxidative phosphorylation (OXPHOS) subunits, resulting in mitochondrial dysfunction and defective thermogenesis in BAT. In addition, metabolic dysfunction in Ssu72-deficient BAT returns to almost normal after restoring Ssu72 expression. In summary, our findings demonstrate that cold-responsive Ssu72 phosphatase is involved in cytosolic translation of key thermogenic effectors via dephosphorylation of eIF2α in brown adipocytes, providing insights into metabolic benefits of Ssu72.
In chronic infections and cancer, exhausted CD8 T cells exhibit heterogeneous subpopulations. TCF1+PD-1+ progenitor exhausted CD8 T cells (Tpex) can self-renew and give rise to Tim-3+PD-1+ terminally ...differentiated CD8 T cells that retain their effector functions. Tpex cells are thus essential to maintaining a pool of antigen-specific CD8 T cells during persistent antigenic stimulation, and only they respond to PD-1-targeted therapy. Despite their potential as a crucial therapeutic target for immune interventions, the mechanisms controlling the maintenance of virus-specific Tpex cells remain to be determined. We observed approximately 10-fold fewer Tpex cells in the spleens of mice chronically infected with lymphocytic choriomeningitis virus (LCMV) one-year post-infection (p.i.) than at three months p.i. Similar to memory CD8 T cells, Tpex cells have been found to undergo self-renewal in the lymphoid organs, prominently the bone marrow, during chronic LCMV infection. Furthermore,
treatment with IL-15 preferentially induced the proliferation of Tpex cells rather than the terminally differentiated subsets. Interestingly, single-cell RNA sequencing analysis of LCMV-specific exhausted CD8 T cells after
IL-15 treatment compared with those before treatment revealed increased expression of ribosome-related genes and decreased expression of genes associated with the TCR signaling pathway and apoptosis in both Tpex and Ttex subsets. The exogenous administration of IL-15 to chronically LCMV-infected mice also significantly increased self-renewal of Tpex cells in the spleen and bone marrow. In addition, we assessed the responsiveness of CD8 tumor-infiltrating lymphocytes (TILs) from renal cell carcinoma patients to IL-15. Similar to the data we obtained from chronic viral infection in mice, the expansion of the Tpex subset of PD-1+ CD8 TILs upon
IL-15 treatment was significantly higher than that of the terminally differentiated subset. These results show that IL-15 could promote self-renewal of Tpex cells, which has important therapeutic implications.
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