RESUMO
Clinical trials have identified ARID1A mutations as enriched among patients who respond favorably to immune checkpoint blockade (ICB) in several solid tumor types independent of microsatellite instability. We show that ARID1A loss in murine models is sufficient to induce anti-tumor immune phenotypes observed in ARID1A mutant human cancers, including increased CD8+ T cell infiltration and cytolytic activity. ARID1A-deficient cancers upregulated an interferon (IFN) gene expression signature, the ARID1A-IFN signature, associated with increased R-loops and cytosolic single-stranded DNA (ssDNA). Overexpression of the R-loop resolving enzyme, RNASEH2B, or cytosolic DNase, TREX1, in ARID1A-deficient cells prevented cytosolic ssDNA accumulation and ARID1A-IFN gene upregulation. Further, the ARID1A-IFN signature and anti-tumor immunity were driven by STING-dependent type I IFN signaling, which was required for improved responsiveness of ARID1A mutant tumors to ICB treatment. These findings define a molecular mechanism underlying anti-tumor immunity in ARID1A mutant cancers.
Assuntos
Linfócitos T CD8-Positivos , Proteínas de Ligação a DNA , Interferon Tipo I , Proteínas de Membrana , Neoplasias , Transdução de Sinais , Fatores de Transcrição , Animais , Humanos , Camundongos , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/metabolismo , Exodesoxirribonucleases/metabolismo , Inibidores de Checkpoint Imunológico/farmacologia , Inibidores de Checkpoint Imunológico/uso terapêutico , Interferon Tipo I/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Camundongos Endogâmicos C57BL , Mutação , Neoplasias/imunologia , Neoplasias/genética , Proteínas Nucleares/metabolismo , Fosfoproteínas/metabolismo , Fatores de Transcrição/metabolismo , Masculino , Quimiocinas/genética , Quimiocinas/metabolismoRESUMO
In the tumor microenvironment, immune cells and tumor cells interact in a process called cancer immunoediting, giving rise to changes in gene expression, metabolism, mutational burden, and cellularity in the tumor. This SnapShot compares endogenous versus therapy-induced cancer immunoediting and outlines the molecular and cellular characteristics of interactions that result in complete tumor regression versus tumor escape and progression. To view this SnapShot, open or download the PDF.
Assuntos
Neoplasias/imunologia , Microambiente Tumoral , Humanos , Mutação , Neoplasias/genética , Neoplasias/terapia , Evasão TumoralRESUMO
Immunotherapy has revolutionized cancer treatment, yet most patients do not respond. Here, we investigated mechanisms of response by profiling the proteome of clinical samples from advanced stage melanoma patients undergoing either tumor infiltrating lymphocyte (TIL)-based or anti- programmed death 1 (PD1) immunotherapy. Using high-resolution mass spectrometry, we quantified over 10,300 proteins in total and â¼4,500 proteins across most samples in each dataset. Statistical analyses revealed higher oxidative phosphorylation and lipid metabolism in responders than in non-responders in both treatments. To elucidate the effects of the metabolic state on the immune response, we examined melanoma cells upon metabolic perturbations or CRISPR-Cas9 knockouts. These experiments indicated lipid metabolism as a regulatory mechanism that increases melanoma immunogenicity by elevating antigen presentation, thereby increasing sensitivity to T cell mediated killing both in vitro and in vivo. Altogether, our proteomic analyses revealed association between the melanoma metabolic state and the response to immunotherapy, which can be the basis for future improvement of therapeutic response.
Assuntos
Imunoterapia/métodos , Melanoma/metabolismo , Melanoma/terapia , Mitocôndrias/metabolismo , Proteômica/métodos , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/terapia , Transferência Adotiva/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Linhagem Celular Tumoral , Estudos de Coortes , Feminino , Humanos , Metabolismo dos Lipídeos/imunologia , Linfócitos do Interstício Tumoral/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Linfócitos T/imunologia , Resultado do Tratamento , Adulto JovemRESUMO
CD8+ T cells are end effectors of cancer immunity. Most forms of effective cancer immunotherapy involve CD8+ T cell effector function. Here, we review the current understanding of T cell function in cancer, focusing on key CD8+ T cell subtypes and states. We discuss factors that influence CD8+ T cell differentiation and function in cancer through a framework that incorporates the classic three-signal model and a fourth signal-metabolism-and also consider the impact of the tumor microenvironment from a T cell perspective. We argue for the notion of immunotherapies as "pro-drugs" that act to augment or modulate T cells, which ultimately serve as the drug in vivo, and for the importance of overall immune health in cancer treatment and prevention. The progress in understanding T cell function in cancer has and will continue to improve harnessing of the immune system across broader tumor types to benefit more patients.
Assuntos
Linfócitos T CD8-Positivos , Neoplasias , Humanos , Imunoterapia , Ativação Linfocitária , Microambiente TumoralRESUMO
CD8+ T cells provide host protection against pathogens by differentiating into distinct effector and memory cell subsets, but how chromatin is site-specifically remodeled during their differentiation is unclear. Due to its critical role in regulating chromatin and enhancer accessibility through its nucleosome remodeling activities, we investigated the role of the canonical BAF (cBAF) chromatin remodeling complex in antiviral CD8+ T cells during infection. ARID1A, a subunit of cBAF, was recruited early after activation and established de novo open chromatin regions (OCRs) at enhancers. Arid1a deficiency impaired the opening of thousands of activation-induced enhancers, leading to loss of TF binding, dysregulated proliferation and gene expression, and failure to undergo terminal effector differentiation. Although Arid1a was dispensable for circulating memory cell formation, tissue-resident memory (Trm) formation was strongly impaired. Thus, cBAF governs the enhancer landscape of activated CD8+ T cells that orchestrates TF recruitment and activity and the acquisition of specific effector and memory differentiation states.
Assuntos
Linfócitos T CD8-Positivos , Sequências Reguladoras de Ácido Nucleico , Cromatina , Nucleossomos , AntiviraisRESUMO
The limited efficacy of immunotherapies against glioblastoma underscores the urgency of better understanding immunity in the central nervous system. We found that treatment with αCTLA-4, but not αPD-1, prolonged survival in a mouse model of mesenchymal-like glioblastoma. This effect was lost upon the depletion of CD4+ T cells but not CD8+ T cells. αCTLA-4 treatment increased frequencies of intratumoral IFNγ-producing CD4+ T cells, and IFNγ blockade negated the therapeutic impact of αCTLA-4. The anti-tumor activity of CD4+ T cells did not require tumor-intrinsic MHC-II expression but rather required conventional dendritic cells as well as MHC-II expression on microglia. CD4+ T cells interacted directly with microglia, promoting IFNγ-dependent microglia activation and phagocytosis via the AXL/MER tyrosine kinase receptors, which were necessary for tumor suppression. Thus, αCTLA-4 blockade in mesenchymal-like glioblastoma promotes a CD4+ T cell-microglia circuit wherein IFNγ triggers microglia activation and phagocytosis and microglia in turn act as antigen-presenting cells fueling the CD4+ T cell response.
Assuntos
Glioblastoma , Camundongos , Animais , Glioblastoma/tratamento farmacológico , Glioblastoma/metabolismo , Antígeno CTLA-4 , Células Th1 , Microglia , Linfócitos T CD8-Positivos , Fagocitose , Células Dendríticas , Linfócitos T CD4-PositivosRESUMO
Choices have consequences. Immune cells survey and migrate throughout the body and sometimes take residence in niche environments with distinct communities of cells, extracellular matrix, and nutrients that may differ from those in which they matured. Imbedded in immune cell physiology are metabolic pathways and metabolites that not only provide energy and substrates for growth and survival, but also instruct effector functions, differentiation, and gene expression. This review of immunometabolism will reference the most recent literature to cover the choices that environments impose on the metabolism and function of immune cells and highlight their consequences during homeostasis and disease.
Assuntos
Leucócitos/citologia , Leucócitos/imunologia , Animais , Trato Gastrointestinal/citologia , Trato Gastrointestinal/imunologia , Humanos , Leucócitos/metabolismo , Linfócitos T/imunologia , Microambiente TumoralRESUMO
T cell dysfunction in cancer comes in many forms, with two new varieties reported in this issue. Daley et al. find that T cells expressing γδ T cell receptors (TCR) promote pancreatic tumor growth by inhibiting activation of T cells with conventional TCRs. Singer et al. characterize dysfunctional tumor infiltrating lymphocytes to reveal a role for zinc homeostasis in anti-tumor immunity.
Assuntos
Neoplasias/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Humanos , Linfócitos do Interstício Tumoral/imunologia , Linfócitos T/imunologiaRESUMO
A common metabolic alteration in the tumor microenvironment (TME) is lipid accumulation, a feature associated with immune dysfunction. Here, we examined how CD8+ tumor infiltrating lymphocytes (TILs) respond to lipids within the TME. We found elevated concentrations of several classes of lipids in the TME and accumulation of these in CD8+ TILs. Lipid accumulation was associated with increased expression of CD36, a scavenger receptor for oxidized lipids, on CD8+ TILs, which also correlated with progressive T cell dysfunction. Cd36-/- T cells retained effector functions in the TME, as compared to WT counterparts. Mechanistically, CD36 promoted uptake of oxidized low-density lipoproteins (OxLDL) into T cells, and this induced lipid peroxidation and downstream activation of p38 kinase. Inhibition of p38 restored effector T cell functions in vitro, and resolution of lipid peroxidation by overexpression of glutathione peroxidase 4 restored functionalities in CD8+ TILs in vivo. Thus, an oxidized lipid-CD36 axis promotes intratumoral CD8+ T cell dysfunction and serves as a therapeutic avenue for immunotherapies.
Assuntos
Antígenos CD36/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Peroxidação de Lipídeos/fisiologia , Lipoproteínas LDL/metabolismo , Neoplasias/metabolismo , Receptores Depuradores/metabolismo , Animais , Transporte Biológico/fisiologia , Linhagem Celular Tumoral , Células HEK293 , Humanos , Leucócitos Mononucleares/metabolismo , Linfócitos do Interstício Tumoral/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microambiente Tumoral/fisiologiaRESUMO
Memory T cells are critical for long-term immunity against reinfection and require interleukin-7 (IL-7), but the mechanisms by which IL-7 controls memory T cell survival, particularly metabolic fitness, remain elusive. We discover that IL-7 induces expression of the glycerol channel aquaporin 9 (AQP9) in virus-specific memory CD8+ T cells, but not naive cells, and that AQP9 is vitally required for their long-term survival. AQP9 deficiency impairs glycerol import into memory CD8+ T cells for fatty acid esterification and triglyceride (TAG) synthesis and storage. These defects can be rescued by ectopic expression of TAG synthases, which restores lipid stores and memory T cell survival. Finally, we find that TAG synthesis is a central component of IL-7-mediated survival of human and mouse memory CD8+T cells. This study uncovers the metabolic mechanisms by which IL-7 tailors the metabolism of memory T cells to promote their longevity and fast response to rechallenge.
Assuntos
Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Sobrevivência Celular , Memória Imunológica , Triglicerídeos/metabolismo , Animais , Aquaporinas/metabolismo , Infecções por Arenaviridae/imunologia , Linfócitos T CD8-Positivos/metabolismo , Glicerol/metabolismo , Humanos , Interleucina-7/metabolismo , Vírus da Coriomeningite Linfocítica/fisiologia , Camundongos , Transdução de SinaisRESUMO
Impaired insulin-mediated suppression of hepatic glucose production (HGP) plays a major role in the pathogenesis of type 2 diabetes (T2D), yet the molecular mechanism by which this occurs remains unknown. Using a novel in vivo metabolomics approach, we show that the major mechanism by which insulin suppresses HGP is through reductions in hepatic acetyl CoA by suppression of lipolysis in white adipose tissue (WAT) leading to reductions in pyruvate carboxylase flux. This mechanism was confirmed in mice and rats with genetic ablation of insulin signaling and mice lacking adipose triglyceride lipase. Insulin's ability to suppress hepatic acetyl CoA, PC activity, and lipolysis was lost in high-fat-fed rats, a phenomenon reversible by IL-6 neutralization and inducible by IL-6 infusion. Taken together, these data identify WAT-derived hepatic acetyl CoA as the main regulator of HGP by insulin and link it to inflammation-induced hepatic insulin resistance associated with obesity and T2D.
Assuntos
Acetilcoenzima A/metabolismo , Resistência à Insulina , Fígado/metabolismo , Paniculite/metabolismo , Tecido Adiposo Branco/química , Adolescente , Animais , Diabetes Mellitus Tipo 2 , Dieta Hiperlipídica , Glucose/metabolismo , Humanos , Hiperglicemia , Interleucina-6/análise , Lipólise , Masculino , Camundongos , Obesidade/metabolismo , Ratos Sprague-DawleyRESUMO
Activated T cells engage aerobic glycolysis and anabolic metabolism for growth, proliferation, and effector functions. We propose that a glucose-poor tumor microenvironment limits aerobic glycolysis in tumor-infiltrating T cells, which suppresses tumoricidal effector functions. We discovered a new role for the glycolytic metabolite phosphoenolpyruvate (PEP) in sustaining T cell receptor-mediated Ca(2+)-NFAT signaling and effector functions by repressing sarco/ER Ca(2+)-ATPase (SERCA) activity. Tumor-specific CD4 and CD8 T cells could be metabolically reprogrammed by increasing PEP production through overexpression of phosphoenolpyruvate carboxykinase 1 (PCK1), which bolstered effector functions. Moreover, PCK1-overexpressing T cells restricted tumor growth and prolonged the survival of melanoma-bearing mice. This study uncovers new metabolic checkpoints for T cell activity and demonstrates that metabolic reprogramming of tumor-reactive T cells can enhance anti-tumor T cell responses, illuminating new forms of immunotherapy.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos do Interstício Tumoral/imunologia , Melanoma/imunologia , Melanoma/terapia , Monitorização Imunológica , Fosfoenolpiruvato/metabolismo , Microambiente Tumoral , Animais , Cálcio/metabolismo , Retículo Endoplasmático/metabolismo , Glicólise , Hexoquinase/metabolismo , Imunoterapia , Camundongos , Fatores de Transcrição NFATC/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Transdução de Sinais , Fator de Crescimento Transformador beta/imunologiaRESUMO
CD8+ T cells are essential components of the immune response against viral infections and tumours, and are capable of eliminating infected and cancerous cells. However, when the antigen cannot be cleared, T cells enter a state known as exhaustion1. Although it is clear that chronic antigen contributes to CD8+ T cell exhaustion, less is known about how stress responses in tissues regulate T cell function. Here we show a new link between the stress-associated catecholamines and the progression of T cell exhaustion through the ß1-adrenergic receptor ADRB1. We identify that exhausted CD8+ T cells increase ADRB1 expression and that exposure of ADRB1+ T cells to catecholamines suppresses their cytokine production and proliferation. Exhausted CD8+ T cells cluster around sympathetic nerves in an ADRB1-dependent manner. Ablation of ß1-adrenergic signalling limits the progression of T cells towards the exhausted state in chronic infection and improves effector functions when combined with immune checkpoint blockade (ICB) in melanoma. In a pancreatic cancer model resistant to ICB, ß-blockers and ICB synergize to boost CD8+ T cell responses and induce the development of tissue-resident memory-like T cells. Malignant disease is associated with increased catecholamine levels in patients2,3, and our results establish a connection between the sympathetic stress response, tissue innervation and T cell exhaustion. Here, we uncover a new mechanism by which blocking ß-adrenergic signalling in CD8+ T cells rejuvenates anti-tumour functions.
Assuntos
Linfócitos T CD8-Positivos , Catecolaminas , Receptores Adrenérgicos beta 1 , Sistema Nervoso Simpático , Exaustão das Células T , Humanos , Antígenos/imunologia , Antígenos/metabolismo , Catecolaminas/metabolismo , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Proliferação de Células , Inibidores de Checkpoint Imunológico/uso terapêutico , Melanoma/imunologia , Melanoma/metabolismo , Melanoma/terapia , Células T de Memória/citologia , Células T de Memória/imunologia , Neoplasias Pancreáticas/imunologia , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/terapia , Receptores Adrenérgicos beta 1/metabolismo , Sistema Nervoso Simpático/imunologia , Sistema Nervoso Simpático/fisiologia , Estresse FisiológicoRESUMO
T cell responses are guided by cytokines that induce transcriptional regulators, which ultimately control differentiation of effector and memory T cells. However, it is unknown how the activities of these molecular regulators are coordinated and integrated during the differentiation process. Using genetic approaches and transcriptional profiling of antigen-specific CD8(+) T cells, we reveal a common program of effector differentiation that is regulated by IL-2 and IL-12 signaling and the combined activities of the transcriptional regulators Blimp-1 and T-bet. The loss of both T-bet and Blimp-1 leads to abrogated cytotoxic function and ectopic IL-17 production in CD8(+) T cells. Overall, our data reveal two major overlapping pathways of effector differentiation governed by the availability of Blimp-1 and T-bet and suggest a model for cytokine-induced transcriptional changes that combine, quantitatively and qualitatively, to promote robust effector CD8(+) T cell differentiation.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Diferenciação Celular/imunologia , Interleucina-12/imunologia , Interleucina-2/imunologia , Proteínas com Domínio T/imunologia , Fatores de Transcrição/imunologia , Animais , Infecções por Arenaviridae/imunologia , Imunoprecipitação da Cromatina , Citocinas/imunologia , Citometria de Fluxo , Perfilação da Expressão Gênica , Vírus da Influenza A Subtipo H1N1 , Interleucina-17/imunologia , Vírus da Coriomeningite Linfocítica , Camundongos , Infecções por Orthomyxoviridae/imunologia , Fator 1 de Ligação ao Domínio I Regulador Positivo , Reação em Cadeia da Polimerase em Tempo Real , Fator de Transcrição STAT4/imunologia , Fator de Transcrição STAT5/imunologia , Análise de Sequência de RNA , Transdução de SinaisRESUMO
Our knowledge of T cell metabolism relies primarily on studies performed in vitro that may not fully recapitulate physiological conditions in vivo. In this issue of Immunity, Ma et al. find that the in vivo environment dictates the metabolic phenotype of effector CD8+ T cells-particularly their glucose utilization.
Assuntos
Linfócitos T CD8-Positivos , Glucose , Isótopos , Metabolômica , FenótipoRESUMO
Memory CD8(+) T cells are critical for host defense upon reexposure to intracellular pathogens. We found that interleukin 10 (IL-10) derived from CD4(+) regulatory T cells (Treg cells) was necessary for the maturation of memory CD8(+) T cells following acute infection with lymphocytic choriomeningitis virus (LCMV). Treg cell-derived IL-10 was most important during the resolution phase, calming inflammation and the activation state of dendritic cells. Adoptive transfer of IL-10-sufficient Treg cells during the resolution phase 'restored' the maturation of memory CD8(+) T cells in IL-10-deficient mice. Our data indicate that Treg cell-derived IL-10 is needed to insulate CD8(+) T cells from inflammatory signals, and reveal that the resolution phase of infection is a critical period that influences the quality and function of developing memory CD8(+) T cells.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Interleucina-10/imunologia , Coriomeningite Linfocítica/imunologia , Vírus da Coriomeningite Linfocítica/imunologia , Linfócitos T Reguladores/imunologia , Transferência Adotiva , Animais , Linfócitos T CD8-Positivos/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Citometria de Fluxo , Perfilação da Expressão Gênica , Interações Hospedeiro-Patógeno/imunologia , Memória Imunológica/imunologia , Inflamação/genética , Inflamação/imunologia , Inflamação/metabolismo , Interleucina-10/genética , Interleucina-10/metabolismo , Coriomeningite Linfocítica/genética , Coriomeningite Linfocítica/virologia , Vírus da Coriomeningite Linfocítica/fisiologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Linfócitos T Reguladores/metabolismo , Linfócitos T Reguladores/transplanteRESUMO
Protective immunity against pathogens depends on the efficient generation of functionally diverse effector and memory T lymphocytes. However, whether plasticity during effector-to-memory CD8+ T cell differentiation affects memory lineage specification and functional versatility remains unclear. Using genetic fate mapping analysis of highly cytotoxic KLRG1+ effector CD8+ T cells, we demonstrated that KLRG1+ cells receiving intermediate amounts of activating and inflammatory signals downregulated KLRG1 during the contraction phase in a Bach2-dependent manner and differentiated into all memory T cell linages, including CX3CR1int peripheral memory cells and tissue-resident memory cells. "ExKLRG1" memory cells retained high cytotoxic and proliferative capacity distinct from other populations, which contributed to effective anti-influenza and anti-tumor immunity. Our work demonstrates that developmental plasticity of KLRG1+ effector CD8+ T cells is important in promoting functionally versatile memory cells and long-term protective immunity.
Assuntos
Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Memória Imunológica/imunologia , Ativação Linfocitária/imunologia , Receptores Imunológicos/metabolismo , Animais , Fatores de Transcrição de Zíper de Leucina Básica/genética , Diferenciação Celular/imunologia , Linhagem Celular Tumoral , Linhagem da Célula/imunologia , Vírus da Influenza A/imunologia , Subunidade p35 da Interleucina-12/imunologia , Lectinas Tipo C , Listeria monocytogenes/imunologia , Melanoma Experimental , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores Imunológicos/genética , Vírus da Estomatite Vesicular Indiana/imunologiaRESUMO
Activated CD8(+) T cells choose between terminal effector cell (TEC) or memory precursor cell (MPC) fates. We found that the signaling receptor Notch controls this 'choice'. Notch promoted the differentiation of immediately protective TECs and was correspondingly required for the clearance of acute infection with influenza virus. Notch activated a major portion of the TEC-specific gene-expression program and suppressed the MPC-specific program. Expression of Notch was induced on naive CD8(+) T cells by inflammatory mediators and interleukin 2 (IL-2) via pathways dependent on the metabolic checkpoint kinase mTOR and the transcription factor T-bet. These pathways were subsequently amplified downstream of Notch, creating a positive feedback loop. Notch thus functions as a central hub where information from different sources converges to match effector T cell differentiation to the demands of an infection.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Diferenciação Celular/imunologia , Receptores Notch/imunologia , Subpopulações de Linfócitos T/imunologia , Imunidade Adaptativa/imunologia , Transferência Adotiva , Animais , Linfócitos T CD8-Positivos/citologia , Separação Celular , Citometria de Fluxo , Vírus da Influenza A , Ativação Linfocitária/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Infecções por Orthomyxoviridae/imunologia , Reação em Cadeia da Polimerase em Tempo Real , Subpopulações de Linfócitos T/citologia , Transcriptoma , Transdução GenéticaRESUMO
Understanding immunological memory formation depends on elucidating how multipotent memory precursor (MP) cells maintain developmental plasticity and longevity to provide long-term immunity while other effector cells develop into terminally differentiated effector (TE) cells with limited survival. Profiling active (H3K27ac) and repressed (H3K27me3) chromatin in naive, MP, and TE CD8+ T cells during viral infection revealed increased H3K27me3 deposition at numerous pro-memory and pro-survival genes in TE relative to MP cells, indicative of fate restriction, but permissive chromatin at both pro-memory and pro-effector genes in MP cells, indicative of multipotency. Polycomb repressive complex 2 deficiency impaired clonal expansion and TE cell differentiation, but minimally impacted CD8+ memory T cell maturation. Abundant H3K27me3 deposition at pro-memory genes occurred late during TE cell development, probably from diminished transcription factor FOXO1 expression. These results outline a temporal model for loss of memory cell potential through selective epigenetic silencing of pro-memory genes in effector T cells.