RESUMEN
During chronic infection, virus-specific CD8+ cytotoxic T lymphocytes (CTLs) progressively lose their ability to mount effective antiviral responses. This "exhaustion" is coupled to persistent upregulation of inhibitory receptor programmed death-1 (PD-1) (Pdcd1)-key in suppressing antiviral CTL responses. Here, we investigate allelic Pdcd1 subnuclear localization and transcription during acute and chronic lymphocytic choriomeningitis virus (LCMV) infection in mice. Pdcd1 alleles dissociate from transcriptionally repressive chromatin domains (lamin B) in virus-specific exhausted CTLs but not in naive or effector CTLs. Relative to naive CTLs, nuclear positioning and Pdcd1-lamina dissociation in exhausted CTLs reflect loss of Pdcd1 promoter methylation and greater PD-1 upregulation, although a direct correlation is not observed in effector cells, 8 days post-infection. Genetic deletion of B lymphocyte-induced maturation protein 1 (Blimp-1) enhances Pdcd1-lamina dissociation in effector CTLs, suggesting that Blimp-1 contributes to maintaining Pdcd1 localization to repressive lamina. Our results identify mechanisms governing Pdcd1 subnuclear localization and the broader role of chromatin dynamics in T cell exhaustion.
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Chronological aging correlates with epigenetic modifications at specific loci, calibrated to species lifespan. Such 'epigenetic clocks' appear conserved among mammals, but whether they are cell autonomous and restricted by maximal organismal lifespan remains unknown. We used a multilifetime murine model of repeat vaccination and memory T cell transplantation to test whether epigenetic aging tracks with cellular replication and if such clocks continue 'counting' beyond species lifespan. Here we found that memory T cell epigenetic clocks tick independently of host age and continue through four lifetimes. Instead of recording chronological time, T cells recorded proliferative experience through modification of cell cycle regulatory genes. Applying this epigenetic profile across a range of human T cell contexts, we found that naive T cells appeared 'young' regardless of organism age, while in pediatric patients, T cell acute lymphoblastic leukemia appeared to have epigenetically aged for up to 200 years. Thus, T cell epigenetic clocks measure replicative history and can continue to accumulate well-beyond organismal lifespan.
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The durability of an antitumor immune response is mediated in part by the persistence of progenitor exhausted CD8+ T cells (Tpex). Tpex serve as a resource for replenishing effector T cells and preserve their quantity through self-renewal. However, it is unknown how T cell receptor (TCR) engagement affects the self-renewal capacity of Tpex in settings of continued antigen exposure. Here we use a Lewis lung carcinoma model that elicits either optimal or attenuated TCR signaling in CD8+ T cells to show that formation of Tpex in tumor-draining lymph nodes and their intratumoral persistence is dependent on optimal TCR engagement. Notably, attenuated TCR stimulation accelerates the terminal differentiation of optimally primed Tpex. This TCR-reinforced Tpex development and self-renewal is coupled to proximal positioning to dendritic cells and epigenetic imprinting involving increased chromatin accessibility at Egr2 and Tcf1 target loci. Collectively, this study highlights the critical function of TCR engagement in sustaining Tpex during tumor progression.
Asunto(s)
Linfocitos T CD8-positivos , Carcinoma Pulmonar de Lewis , Factor Nuclear 1-alfa del Hepatocito , Ratones Endogámicos C57BL , Receptores de Antígenos de Linfocitos T , Animales , Linfocitos T CD8-positivos/inmunología , Receptores de Antígenos de Linfocitos T/metabolismo , Receptores de Antígenos de Linfocitos T/inmunología , Ratones , Carcinoma Pulmonar de Lewis/inmunología , Carcinoma Pulmonar de Lewis/patología , Carcinoma Pulmonar de Lewis/metabolismo , Factor Nuclear 1-alfa del Hepatocito/metabolismo , Diferenciación Celular/inmunología , Células Dendríticas/inmunología , Transducción de Señal/inmunología , Ratones Noqueados , Activación de Linfocitos/inmunología , Autorrenovación de las Células , Ratones Transgénicos , Proteína 2 de la Respuesta de Crecimiento PrecozRESUMEN
Thirty years of foundational research investigating molecular and cellular mechanisms promoting T cell exhaustion are now enabling rational design of T cell-based therapies for the treatment of chronic infections and cancer. Once described as a static cell fate, it is now well appreciated that the developmental path toward exhaustion is composed of a heterogeneous pool of cells with varying degrees of effector potential that ultimately converge on a terminally differentiated state. Recent description of the developmental stages along the differentiation trajectory of T cell exhaustion has provided insight into past immunotherapeutic success and future opportunities. Here, we discuss the hallmarks of distinct developmental stages occurring along the path to T cell dysfunction and the impact of these discrete CD8+ T cell fates on cancer immunotherapy.
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Linfocitos T CD8-positivos , Agotamiento de Células T , Diferenciación Celular , InmunoterapiaRESUMEN
Functional persistence of chimeric antigen receptor (CAR) T cells is required for sustaining an antitumor response. Recently, Jain et al. revealed that disruption of TET2 in CAR T cells resulted in antigen-independent CAR T cell hyperproliferation that enhanced tumor control in mice, highlighting the potential of epigenetic strategies to improve T cell-based cancer immunotherapy.
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Dioxigenasas , Neoplasias , Animales , Ratones , Linfocitos T , Inmunoterapia Adoptiva/métodos , Receptores de Antígenos de Linfocitos T/genética , Neoplasias/terapia , Inmunoterapia/métodos , Proteínas de Unión al ADN/genéticaRESUMEN
Disrupting cell cycle regulators can overcome anticancer T cell dysfunction.
Asunto(s)
Ciclo Celular , Inmunoterapia Adoptiva , Complejo Mediador , Neoplasias , Linfocitos T , Ciclo Celular/genética , Ciclo Celular/inmunología , Neoplasias/inmunología , Neoplasias/terapia , Linfocitos T/inmunología , HumanosRESUMEN
The functional decline in T cells during their chronic stimulation, commonly referred to as T cell exhaustion, is a major limitation for current immunotherapy approaches. As modern medicine embraces therapeutic approaches that exploit the immuno-oncology interface, a primary question is how is T cell function maintained over time in scenarios of prolonged tumor burden. Deciphering the molecular mechanisms of T cell exhaustion is now enabling the field to begin using cardinal features of T cell differentiation to develop biomarkers that can delineate responders from nonresponders prior to treatment with T cell-based therapeutics. Furthermore, applying principles of basic T cell immunity toward the development of cancer treatments is laying a foundation for rational approaches to improve immunotherapy by redirecting T cells away from a dysfunctional developmental trajectory.
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Neoplasias , Linfocitos T , Humanos , Inmunoterapia , Activación de Linfocitos , Neoplasias/terapiaRESUMEN
The immune system undergoes a progressive functional remodeling with age. Understanding how age bias shapes antitumor immunity is essential in designing effective immunotherapies, especially for pediatric patients. Here, we explore antitumor CD8+ T cell responses generated in young (prepubescent) and adult (presenescent) mice. Using an MHCI-deficient tumor model, we observed that tumor-reactive CD8+ T cells expanded in young tumor-bearing (TB) mice acquired a terminally differentiated phenotype characterized by overexpression of inhibitory receptors and the transcription factor Tox1. Furthermore, tumor-infiltrating CD8+ T cells from young tumors yielded a poor cytokine response compared with CD8+ T cells infiltrating adult tumors. Young migratory dendritic cells (migDCs) from the draining lymph nodes (dLNs), and mononuclear phagocytic cells (MPCs) infiltrating young tumors, were more competent in capturing and cross-presenting tumor antigen, leading to enhanced priming of CD8+ T cells in dLNs and their subsequent terminal differentiation in the tumors. Single-cell transcriptional profiling of tumor-infiltrating MPCs demonstrated that young MPCs are polarized toward an inflammatory, effector phenotype. Consistent with our observations in young versus adult TB mice, analysis of immune infiltrates from pediatric solid tumors showed a correlation between tumor-infiltrating CD8+ T cells with an exhaustion phenotype and the frequency of PD-L1-expressing monocytes/macrophages. Collectively, these data indicate that a young tissue microenvironment contributes to the generation of an immune response skewed toward a less pliable terminal effector state, thus narrowing the window for immunotherapeutic interventions.
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Presentación de Antígeno/inmunología , Antígenos de Neoplasias/inmunología , Linfocitos T CD8-positivos/inmunología , Animales , Diferenciación Celular/inmunología , Línea Celular Tumoral , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones TransgénicosRESUMEN
CD19-CAR T cell therapy has evolved into the standard of care for relapsed/refractory B cell acute lymphoblastic leukemia (ALL); however, limited persistence of the CAR T cells enables tumor relapse for many patients. To gain a deeper understanding of the molecular characteristics associated with CAR T cell differentiation, we performed longitudinal genome-wide DNA methylation profiling of CD8+ CD19-CAR T cells post-infusion in ALL patients. We report that CAR T cells undergo a rapid and broad erasure of repressive DNA methylation reprograms at effector-associated genes. The CAR T cell post-infusion changes are further characterized by repression of genes (e.g., TCF7 and LEF1) associated with memory potential and a DNA methylation signature (e.g., demethylation at CX3CR1, BATF, and TOX) demarcating a transition toward exhaustion-progenitor T cells. Thus, CD19-CAR T cells undergo exhaustion-associated DNA methylation programming, indicating that efforts to prevent this process may be an attractive approach to improve CAR T cell efficacy.
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Antígenos CD19/inmunología , Linfocitos T CD8-positivos/inmunología , Metilación de ADN , Regulación Neoplásica de la Expresión Génica , Inmunoterapia Adoptiva/métodos , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Receptores de Antígenos de Linfocitos T/inmunología , Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/inmunología , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Adulto JovenRESUMEN
Chimeric antigen receptor (CAR) T cell therapy is revolutionizing cancer immunotherapy for patients with B cell malignancies and is now being developed for solid tumors and chronic viral infections. Although clinical trials have demonstrated the curative potential of CAR T cell therapy, a substantial and well-established limitation is the heightened contraction and transient persistence of CAR T cells during prolonged antigen exposure. The underlying mechanism(s) for this dysfunctional state, often termed CAR T cell exhaustion, remains poorly defined. Here, we report that exhaustion of human CAR T cells occurs through an epigenetic repression of the T cell's multipotent developmental potential. Deletion of the de novo DNA methyltransferase 3 alpha (DNMT3A) in T cells expressing first- or second-generation CARs universally preserved the cells' ability to proliferate and mount an antitumor response during prolonged tumor exposure. The increased functionality of the exhaustion-resistant DNMT3A knockout CAR T cells was coupled to an up-regulation of interleukin-10, and genome-wide DNA methylation profiling defined an atlas of genes targeted for epigenetic silencing. This atlas provides a molecular definition of CAR T cell exhaustion, which includes many transcriptional regulators that limit the "stemness" of immune cells, including CD28, CCR7, TCF7, and LEF1. Last, we demonstrate that this epigenetically regulated multipotency program is firmly coupled to the clinical outcome of prior CAR T cell therapies. These data document the critical role epigenetic mechanisms play in limiting the fate potential of human T cells and provide a road map for leveraging this information for improving CAR T cell efficacy.
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Inmunoterapia Adoptiva , Neoplasias , Antígenos CD28 , Epigénesis Genética , Humanos , Neoplasias/terapia , Linfocitos T , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
To gain insight into the signaling determinants of effector-associated DNA methylation programming among CD8 T cells, we explore the role of interleukin (IL)-12 in the imprinting of IFNg expression during CD8 T cell priming. We observe that anti-CD3/CD28-mediated stimulation of human naive CD8 T cells is not sufficient to induce substantial demethylation of the IFNg promoter. However, anti-CD3/CD28 stimulation in the presence of the inflammatory cytokine, IL-12, results in stable demethylation of the IFNg locus that is commensurate with IFNg expression. IL-12-associated demethylation of the IFNg locus is coupled to cell division through TET2-dependent demethylation in an ex vivo human chimeric antigen receptor T cell model system and an in vivo immunologically competent murine system. Collectively, these data illustrate that IL-12 signaling promotes TET2-mediated effector DNA demethylation programming in CD8 T cells and serve as proof of concept that cytokines can guide induction of epigenetically regulated traits for T cell-based immunotherapies.
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Linfocitos T CD8-positivos/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Metilación de ADN/efectos de los fármacos , Proteínas de Unión al ADN/metabolismo , Dioxigenasas/metabolismo , Interferón gamma/metabolismo , Interleucina-12/farmacología , Coriomeningitis Linfocítica/enzimología , Células T de Memoria/efectos de los fármacos , Animales , Linfocitos T CD8-positivos/enzimología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/virología , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Proteínas de Unión al ADN/genética , Dioxigenasas/genética , Modelos Animales de Enfermedad , Humanos , Memoria Inmunológica/efectos de los fármacos , Interferón gamma/genética , Coriomeningitis Linfocítica/genética , Coriomeningitis Linfocítica/inmunología , Virus de la Coriomeningitis Linfocítica/inmunología , Virus de la Coriomeningitis Linfocítica/patogenicidad , Células T de Memoria/enzimología , Células T de Memoria/inmunología , Células T de Memoria/virología , Ratones Endogámicos C57BL , Ratones Noqueados , Prueba de Estudio Conceptual , Transducción de SeñalRESUMEN
Prolonged TCR-driven stimulation can induce a dysfunctional T cell state, broadly described as T cell exhaustion, limiting the clinical potential of chimeric antigen receptor (CAR) T cells. Recent findings in Science indicate that early cessation of CAR T cell tonic signaling can prevent stabilization of exhaustion-associated epigenetic programs, enabling a prolonged anti-tumor response.
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Neoplasias , Receptores Quiméricos de Antígenos , Humanos , Activación de Linfocitos , Neoplasias/genética , Neoplasias/terapia , Receptores Quiméricos de Antígenos/genética , Transducción de Señal , Linfocitos T/inmunologíaRESUMEN
The conceptualization of adaptive immunity, founded on the observation of immunological memory, has served as the basis for modern vaccination and immunotherapy approaches. This fundamental concept has allowed immunologists to explore mechanisms that enable humoral and cellular lymphocytes to tailor immune response functions to a wide array of environmental insults and remain poised for future pathogenic encounters. Until recently, for T cells it has remained unclear how memory differentiation acquires and sustains a gene expression program that grants a cell with a capacity for a heightened recall response. Recent investigations into this critical question have identified epigenetic programs as a causal molecular mechanism governing T cell subset specification and immunological memory. Here, we outline the studies that have illustrated this concept and posit on how insights into T cell adaptive immunity can be applied to improve upon existing immunotherapies.
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Epigénesis Genética , Memoria Inmunológica , Inmunidad Adaptativa/genética , Diferenciación Celular , Subgrupos de Linfocitos TRESUMEN
Chimeric antigen receptor (CAR)-T-cell therapeutic efficacy is associated with long-term T-cell persistence and acquisition of memory. Memory-subset formation requires T-cell factor 1 (TCF-1), a master transcription factor for which few regulators have been identified. Here, we demonstrate using an immune-competent mouse model of B-cell acute lymphoblastic leukemia (ALL; B-ALL) that Regnase-1 deficiency promotes TCF-1 expression to enhance CAR-T-cell expansion and memory-like cell formation. This leads to improved CAR-T-mediated tumor clearance, sustained remissions, and protection against secondary tumor challenge. Phenotypic, transcriptional, and epigenetic profiling identified increased tumor-dependent programming of Regnase-1-deficient CAR-T cells into TCF-1+ precursor exhausted T cells (TPEX) characterized by upregulation of both memory and exhaustion markers. Regnase-1 directly targets Tcf7 messenger RNA (mRNA); its deficiency augments TCF-1 expression leading to the formation of TPEX that support long-term CAR-T-cell persistence and function. Regnase-1 deficiency also reduces exhaustion and enhances the activity of TCF-1- CAR-T cells. We further validate these findings in human CAR-T cells, where Regnase-1 deficiency mediates enhanced tumor clearance in a xenograft B-ALL model. This is associated with increased persistence and expansion of a TCF-1+ CAR-T-cell population. Our findings demonstrate the pivotal roles of TPEX, Regnase-1, and TCF-1 in mediating CAR-T-cell persistence and recall responses, and identify Regnase-1 as a modulator of human CAR-T-cell longevity and potency that may be manipulated for improved therapeutic efficacy.
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Inmunoterapia Adoptiva , Leucemia-Linfoma Linfoblástico de Células Precursoras/inmunología , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Ribonucleasas/metabolismo , Factor 1 de Transcripción de Linfocitos T/metabolismo , Linfocitos T/inmunología , Animales , Antígenos CD19/metabolismo , Línea Celular Tumoral , Reprogramación Celular , Modelos Animales de Enfermedad , Epigénesis Genética , Humanos , Inmunocompetencia/inmunología , Memoria Inmunológica , Ratones Endogámicos C57BL , Ratones Transgénicos , Fenotipo , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologíaRESUMEN
Stringent nonpharmaceutical interventions (NPIs) such as lockdowns and border closures are not currently recommended for pandemic influenza control. New Zealand used these NPIs to eliminate coronavirus disease 2019 during its first wave. Using multiple surveillance systems, we observed a parallel and unprecedented reduction of influenza and other respiratory viral infections in 2020. This finding supports the use of these NPIs for controlling pandemic influenza and other severe respiratory viral threats.
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COVID-19/epidemiología , Gripe Humana/epidemiología , Infecciones del Sistema Respiratorio/epidemiología , COVID-19/prevención & control , COVID-19/virología , Control de Enfermedades Transmisibles , Monitoreo Epidemiológico , Hospitalización/estadística & datos numéricos , Humanos , Gripe Humana/prevención & control , Gripe Humana/virología , Nueva Zelanda/epidemiología , Pandemias , Salud Pública , Infecciones del Sistema Respiratorio/prevención & control , Infecciones del Sistema Respiratorio/virología , SARS-CoV-2/aislamiento & purificaciónRESUMEN
Stringent nonpharmaceutical interventions (NPIs) such as lockdowns and border closures are not currently recommended for pandemic influenza control. New Zealand used these NPIs to eliminate coronavirus disease 2019 during its first wave. Using multiple surveillance systems, we observed a parallel and unprecedented reduction of influenza and other respiratory viral infections in 2020. This finding supports the use of these NPIs for controlling pandemic influenza and other severe respiratory viral threats.
RESUMEN
The full potential of T cell-based immunotherapies remains limited by a variety of T cell extrinsic and intrinsic immunosuppressive mechanisms that can become imprinted to stably reduce the antitumor ability of T cells. Here, we discuss recent insights into memory CD8+ T cell differentiation and exhaustion and the association of these differentiation states with clinical outcomes during immune checkpoint blockade and chimeric antigen receptor (CAR) T cell therapeutic modalities. We consider the barriers limiting immunotherapy with a focus on epigenetic regulation impeding efficacy of adoptively transferred T cells and other approaches that augment T cell responses such as immune checkpoint blockade. Furthermore, we outline conceptual and technical breakthroughs that can be applied to existing therapeutic approaches and to the development of novel cutting-edge strategies.