RESUMEN
T cells respond to threats in an antigen-specific manner using T cell receptors (TCRs) that recognize short peptide antigens presented on major histocompatibility complex (MHC) proteins. The TCR-peptide-MHC interaction mediated between a T cell and its target cell dictates its function and thereby influences its role in disease. A lack of approaches for antigen discovery has limited the fundamental understanding of the antigenic landscape of the overall T cell response. Recent advances in high-throughput sequencing, mass cytometry, microfluidics and computational biology have led to a surge in approaches to address the challenge of T cell antigen discovery. Here, we summarize the scope of this challenge, discuss in depth the recent exciting work and highlight the outstanding questions and remaining technical hurdles in this field.
Asunto(s)
Antígenos/inmunología , Complejo Mayor de Histocompatibilidad/inmunología , Receptores de Antígenos de Linfocitos T/inmunología , Linfocitos T/inmunología , Animales , HumanosRESUMEN
CD8+ T cells recognize and eliminate tumors in an antigen-specific manner. Despite progress in characterizing the antitumor T cell repertoire and function, the identification of target antigens remains a challenge. Here we describe the use of chimeric receptors called signaling and antigen-presenting bifunctional receptors (SABRs) in a cell-based platform for T cell receptor (TCR) antigen discovery. SABRs present an extracellular complex comprising a peptide and major histocompatibility complex (MHC), and induce intracellular signaling via a TCR-like signal after binding with a cognate TCR. We devised a strategy for antigen discovery using SABR libraries to screen thousands of antigenic epitopes. We validated this platform by identifying the targets recognized by public TCRs of known specificities. Moreover, we extended this approach for personalized neoantigen discovery.
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Presentación de Antígeno , Receptores de Antígenos de Linfocitos T/metabolismo , Transducción de Señal , Células Presentadoras de Antígenos/citología , Antígenos/química , Antígenos CD/metabolismo , Antígenos de Diferenciación de Linfocitos T/metabolismo , Linfocitos T CD8-positivos/citología , Clonación Molecular , Técnicas de Cocultivo , Epítopos/química , Reacciones Falso Positivas , Biblioteca de Genes , Proteínas Fluorescentes Verdes/metabolismo , Células HEK293 , Humanos , Inmunoterapia/métodos , Células Jurkat , Células K562 , Lectinas Tipo C/metabolismo , Complejo Mayor de Histocompatibilidad , Oligonucleótidos/genética , Péptidos/químicaRESUMEN
T cell receptor (TCR) ligand discovery is essential for understanding and manipulating immune responses to tumors. We developed a cell-based selection platform for TCR ligand discovery that exploits a membrane transfer phenomenon called trogocytosis. We discovered that T cell membrane proteins are transferred specifically to target cells that present cognate peptide-major histocompatibility complex (MHC) molecules. Co-incubation of T cells expressing an orphan TCR with target cells collectively presenting a library of peptide-MHCs led to specific labeling of cognate target cells, enabling isolation of these target cells and sequencing of the cognate TCR ligand. We validated this method for two clinically employed TCRs and further used the platform to identify the cognate neoepitope for a subject-derived neoantigen-specific TCR. Thus, target cell trogocytosis is a robust tool for TCR ligand discovery that will be useful for studying basic tumor immunology and identifying new targets for immunotherapy.
Asunto(s)
Antígenos/química , Técnicas Genéticas , Receptores de Antígenos de Linfocitos T/química , Linfocitos T/citología , Inmunidad Adaptativa , Animales , Biotinilación , ADN/análisis , Epítopos/química , Biblioteca de Genes , Células HEK293 , Humanos , Inmunoterapia , Células Jurkat , Células K562 , Ligandos , Ratones , Péptidos/química , Fagocitosis , Linfocitos T/inmunologíaRESUMEN
At the heart of an innate immune response lies a tightly regulated gene expression program. This precise regulation is crucial because small changes can shift the balance from protective to destructive immunity. Here we identify a frequently used alternative splice site in the gene oligoadenylate synthetase 1g (Oas1g), a key component of the 2-5A antiviral system. Usage of this splice site leads to the generation of a transcript subject to decay, and removal of the site leads to increased expression of Oas1g and an improved antiviral response. However, removal of the splice site also leads to an increase in apoptotic cell death, suggesting this splicing event exists as a compromise between the pathogen protective benefits and collateral damage associated with OAS1g activity. Across the innate immune response, we show that a multitude of alternative splicing events predicted to lead to decay exist, and thus have the potential to play a significant role in the regulation of gene expression in innate immunity.
Asunto(s)
2',5'-Oligoadenilato Sintetasa/metabolismo , Empalme Alternativo , Antivirales/metabolismo , Regulación de la Expresión Génica/genética , Inmunidad Innata/genética , Sitios de Empalme de ARN , 2',5'-Oligoadenilato Sintetasa/genética , Animales , Apoptosis , Células HEK293 , Humanos , Ratones , Degradación de ARNm Mediada por Codón sin Sentido , Células RAW 264.7RESUMEN
Immunotherapy treatments harnessing the patient's immune system herald a new era of personalized medicine, offering hope for curative responses in patients with serious illnesses. Cell-mediated immunity can eliminate cancer cells and provide durable remissions. This often relies on repurposing cytotoxic T cell activity through modified T cell receptors or chimeric antigen receptors. Furthermore, synthetic biology has expanded the cell engineering toolkit to provide immune cells with more functionality, including disease targeting, potency, and safety. We focus on T cell-based immunotherapy, highlighting discoveries of genetic engineering and therapeutic use. We also examine emerging paths that could be undertaken to improve this novel class of drugs, and discuss the challenges of toxicities as well as other limitations of cellular immunotherapy.
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Inmunoterapia , Neoplasias/terapia , Medicina de Precisión , Animales , Humanos , Neoplasias/inmunologíaRESUMEN
T cell receptor (TCR) ligand discovery is crucial to monitoring T cell responses to antigen and to identifying antigens reactive against orphan TCRs of interest. In a recent article, Elledge and colleagues describe a functional T cell ligand screening platform for unbiased TCR ligand discovery.
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Epítopos de Linfocito T , Receptores de Antígenos de Linfocitos T , Ligandos , Linfocitos T/inmunologíaRESUMEN
Deregulation of several microRNAs (miRs) can influence critical developmental checkpoints during hematopoiesis as well as cell functions, eventually leading to the development of autoimmune disease or cancer. We found that miR-125b is expressed in bone marrow multipotent progenitors and myeloid cells but shut down in the B-cell lineage, and the gene encoding miR-125b lacked transcriptional activation markers in B cells. To understand the biological importance of the physiological silencing of miR-125b expression in B cells, we drove its expression in the B-cell lineage and found that dysregulated miR-125b expression impaired egress of immature B cells from the bone marrow to peripheral blood. Such impairment appeared to be mediated primarily by inhibited expression of the sphingosine-1-phosphate receptor 1 (S1PR1). Enforced expression of S1PR1 or clustered regularly interspaced short palindromic repeats/Cas9-mediated genome editing of the miR-125b targeting site in the S1PR1 3' untranslated region rescued the miR-125b-mediated defect in B-cell egress. In addition to impaired B-cell egress, miR-125b dysregulation initially reduced pre-B-cell output but later induced pre-B-cell lymphoma/leukemia in mice. Genetic deletion of IRF4 was found in miR-125b-induced B-cell cancer, but its role in oncogenic miR-125b-induced B-cell transformation is still unknown. Here, we further demonstrated an interaction of the effects of miR-125b and IRF4 in cancer induction by showing that miR125b-induced B-cell leukemia was greatly accelerated in IRF4 homozygous mutant mice. Thus, we conclude that physiological silencing of miR-125b is required for normal B-cell development and also acts as a mechanism of cancer suppression.
Asunto(s)
Linfocitos B/metabolismo , Represión Epigenética , Regulación Leucémica de la Expresión Génica , Silenciador del Gen , MicroARNs/biosíntesis , Leucemia-Linfoma Linfoblástico de Células Precursoras B/metabolismo , ARN Neoplásico/biosíntesis , Animales , Linfocitos B/patología , Células HEK293 , Humanos , Ratones , MicroARNs/genética , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patología , ARN Neoplásico/genéticaRESUMEN
Epigenetic marks, such as DNA methylation, histone post-translational modifications and miRNAs, are induced in B cells by the same stimuli that drive the antibody response. They play major roles in regulating somatic hypermutation (SHM), class switch DNA recombination (CSR), and differentiation to plasma cells or long-lived memory B cells. Histone modifications target the CSR and, possibly, SHM machinery to the immunoglobulin locus; they together with DNA methylation and miRNAs modulate the expression of critical elements of that machinery, such as activation-induced cytidine deaminase (AID), as well as factors central to plasma cell differentiation, such as B lymphocyte-induced maturation protein-1 (Blimp-1). These inducible B cell-intrinsic epigenetic marks instruct the maturation of antibody responses. Their dysregulation plays an important role in aberrant antibody responses to foreign antigens, such as those of microbial pathogens, and self-antigens, such as those targeted in autoimmunity, and B cell neoplasia.
Asunto(s)
Formación de Anticuerpos/genética , Autoinmunidad/genética , Epigénesis Genética/genética , Animales , Linfocitos B/citología , Linfocitos B/inmunología , Diferenciación Celular/genética , Diferenciación Celular/inmunología , Humanos , Cambio de Clase de Inmunoglobulina/genética , Cambio de Clase de Inmunoglobulina/inmunologíaRESUMEN
Class-switch DNA recombination (CSR) and somatic hypermutation (SHM), which require activation-induced cytidine deaminase (AID), and plasma cell differentiation, which requires B lymphocyte-induced maturation protein-1 (Blimp-1), are critical for the generation of class-switched and hypermutated (mature) Ab and autoantibody responses. We show that histone deacetylase inhibitors valproic acid and butyrate dampened AICDA/Aicda (AID) and PRDM1/Prdm1 (Blimp-1) mRNAs by upregulating miR-155, miR-181b, and miR-361 to silence AICDA/Aicda, and miR-23b, miR-30a, and miR-125b to silence PRDM1/Prdm1, in human and mouse B cells. This led to downregulation of AID, Blimp-1, and X-box binding protein 1, thereby inhibiting CSR, SHM, and plasma cell differentiation without altering B cell viability or proliferation. The selectivity of histone deacetylase inhibitor-mediated silencing of AICDA/Aicda and PRDM1/Prdm1 was emphasized by unchanged expression of HoxC4 and Irf4 (important inducers/modulators of AICDA/Aicda), Rev1 and Ung (central elements for CSR/SHM), and Bcl6, Bach2, or Pax5 (repressors of PRDM1/Prdm1 expression), as well as unchanged expression of miR-19a/b, miR-20a, and miR-25, which are not known to regulate AICDA/Aicda or PRDM1/Prdm1. Through these B cell-intrinsic epigenetic mechanisms, valproic acid blunted class-switched and hypermutated T-dependent and T-independent Ab responses in C57BL/6 mice. In addition, it decreased class-switched and hypermutated autoantibodies, ameliorated disease, and extended survival in lupus MRL/Fas(lpr/lpr) mice. Our findings outline epigenetic mechanisms that modulate expression of an enzyme (AID) and transcription factors (Blimp-1 and X-box binding protein 1) that are critical to the B cell differentiation processes that underpin Ab and autoantibody responses. They also provide therapeutic proof-of-principle in autoantibody-mediated autoimmunity.
Asunto(s)
Formación de Anticuerpos , Linfocitos B/efectos de los fármacos , Linfocitos B/fisiología , Citidina Desaminasa/genética , Epigénesis Genética , Silenciador del Gen , Inhibidores de Histona Desacetilasas/farmacología , MicroARNs/genética , Proteínas Represoras/genética , Animales , Anticuerpos/inmunología , Anticuerpos/metabolismo , Autoanticuerpos/biosíntesis , Autoanticuerpos/inmunología , Linfocitos B/citología , Diferenciación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/genética , Metilación de ADN/efectos de los fármacos , Proteínas de Unión al ADN/genética , Relación Dosis-Respuesta a Droga , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Técnicas de Inactivación de Genes , Humanos , Cambio de Clase de Inmunoglobulina/efectos de los fármacos , Activación de Linfocitos/efectos de los fármacos , Activación de Linfocitos/inmunología , Ratones , Ratones Endogámicos MRL lpr , Células Plasmáticas/citología , Células Plasmáticas/efectos de los fármacos , Células Plasmáticas/inmunología , Células Plasmáticas/metabolismo , Factor 1 de Unión al Dominio 1 de Regulación Positiva , Factores de Transcripción del Factor Regulador X , Hipermutación Somática de Inmunoglobulina/efectos de los fármacos , Factores de Transcripción/genéticaRESUMEN
Despite extensive studies on the antitumor properties of berberine, a small molecule derived from Coptidis rhizoma (Huanglian in Chinese) and many other plants, the underlying mechanism remains poorly understood. Here, we found that berberine-induced cell apoptosis in human gastric cancer cells with the increase of the expression level of cleaved poly ADP-ribose polymerase and caspase-3, and the impairment of mitochondrial membrane potential (Δψm) in berberine-treated gastric cancer cells. In our further studies, the results demonstrated that Akt-related mitochondrial pathway may partly involve in the berberine-induced apoptosis in human gastric cancer cells. Moreover, berberine inhibited the Akt/mTOR/p70S6/S6 pathway in berberine-treated BGC-823 cells. Meanwhile, berberine significantly inhibited the activation of Akt and suppressed tumor growth in xenograft nude mice injected with human gastric cancer cells. Thus, our findings reveal that the underlying mechanism that Akt signaling may contribute to berberine-induced cell apoptosis in gastric cancer cells and might represent an important molecular basis for berberine to act as an anticancer agent.
Asunto(s)
Apoptosis/efectos de los fármacos , Berberina/farmacología , Proteínas Proto-Oncogénicas c-akt/fisiología , Transducción de Señal/efectos de los fármacos , Neoplasias Gástricas/tratamiento farmacológico , Animales , Línea Celular Tumoral , Femenino , Humanos , Ratones , Ratones Endogámicos BALB C , Mitocondrias/efectos de los fármacos , Proteínas Quinasas S6 Ribosómicas 70-kDa/antagonistas & inhibidores , Proteínas Quinasas S6 Ribosómicas 70-kDa/fisiología , Transducción de Señal/fisiología , Neoplasias Gástricas/patología , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Serina-Treonina Quinasas TOR/fisiología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Class switch DNA recombination (CSR) crucially diversifies Ab biologic effector functions. 14-3-3γ specifically binds to the 5'-AGCT-3' repeats in the IgH locus switch (S) regions. By interacting directly with the C-terminal region of activation-induced cytidine deaminase (AID), 14-3-3γ targets this enzyme to S regions to mediate CSR. In this study, we showed that 14-3-3γ was expressed in germinal center B cells in vivo and induced in B cells by T-dependent and T-independent primary CSR-inducing stimuli in vitro in humans and mice. Induction of 14-3-3γ was rapid, peaking within 3 h of stimulation by LPSs, and sustained over the course of AID and CSR induction. It was dependent on recruitment of NF-κB to the 14-3-3γ gene promoter. The NF-κB recruitment enhanced the occupancy of the CpG island within the 14-3-3γ promoter by CFP1, a component of the COMPASS histone methyltransferase complex, and promoter-specific enrichment of histone 3 lysine 4 trimethylation (H3K4me3), which is indicative of open chromatin state and marks transcription-competent promoters. NF-κB also potentiated the binding of B cell lineage-specific factor E2A to an E-box motif located immediately downstream of the two closely-spaced transcription start sites for sustained 14-3-3γ expression and CSR induction. Thus, 14-3-3γ induction in CSR is enabled by the CFP1-mediated H3K4me3 enrichment in the promoter, dependent on NF-κB and sustained by E2A.
Asunto(s)
Proteínas 14-3-3/biosíntesis , Linfocitos B/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/fisiología , Islas de CpG/genética , Proteínas de Unión al ADN/fisiología , Cambio de Clase de Inmunoglobulina/fisiología , FN-kappa B/fisiología , Regiones Promotoras Genéticas/genética , Transactivadores/fisiología , Proteínas 14-3-3/genética , Regiones no Traducidas 3'/genética , Animales , Linfocitos B/citología , Linfocitos B/inmunología , Secuencia de Bases , Células Cultivadas , Secuencia Conservada , Citidina Desaminasa/metabolismo , Elementos E-Box/genética , Centro Germinal/metabolismo , Células HEK293 , Histona Metiltransferasas , N-Metiltransferasa de Histona-Lisina/metabolismo , Histonas/metabolismo , Humanos , Lipopolisacáridos/inmunología , Lipopolisacáridos/farmacología , Cooperación Linfocítica , Metilación , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Datos de Secuencia Molecular , Procesamiento Proteico-Postraduccional , Alineación de Secuencia , Homología de Secuencia de Ácido Nucleico , Organismos Libres de Patógenos Específicos , Sitio de Iniciación de la Transcripción , Regulación hacia Arriba/genética , Regulación hacia Arriba/inmunologíaRESUMEN
Lactate influences the behavior of various immune cell types. In a recent Nature Immunology study, Ma et al. revealed that lithium carbonate induces monocarboxylate transporter 1 translocation to mitochondria, enhancing cytoplasmic lactate transport into the mitochondria and increasing lactate mitochondrial metabolism, thereby promoting T cell effector function.
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Carbonato de Litio , Neoplasias , Humanos , Carbonato de Litio/farmacología , Linfocitos T , Mitocondrias , Ácido LácticoRESUMEN
ABSTRACT: The efficacy of adaptive immune responses in cancer treatment relies heavily on the state of the T cells. Upon antigen exposure, T cells undergo metabolic reprogramming, leading to the development of functional effectors or memory populations. However, within the tumor microenvironment (TME), metabolic stress impairs CD8 + T cell anti-tumor immunity, resulting in exhausted differentiation. Recent studies suggested that targeting T cell metabolism could offer promising therapeutic opportunities to enhance T cell immunotherapy. In this review, we provide a comprehensive summary of the intrinsic and extrinsic factors necessary for metabolic reprogramming during the development of effector and memory T cells in response to acute and chronic inflammatory conditions. Furthermore, we delved into the different metabolic switches that occur during T cell exhaustion, exploring how prolonged metabolic stress within the TME triggers alterations in cellular metabolism and the epigenetic landscape that contribute to T cell exhaustion, ultimately leading to a persistently exhausted state. Understanding the intricate relationship between T cell metabolism and cancer immunotherapy can lead to the development of novel approaches to improve the efficacy of T cell-based treatments against cancer.
Asunto(s)
Linfocitos T CD8-positivos , Neoplasias , Humanos , Linfocitos T CD8-positivos/metabolismo , Inmunoterapia/métodos , Diferenciación Celular , Neoplasias/terapia , Neoplasias/metabolismo , Microambiente TumoralRESUMEN
One-carbon metabolism (1CM), comprising folate metabolism and methionine metabolism, serves as an important mechanism for cellular energy provision and the production of vital signaling molecules, including single-carbon moieties. Its regulation is instrumental in sustaining the proliferation of cancer cells and facilitating metastasis; in addition, recent research has shed light on its impact on the efficacy of T cell-mediated immunotherapy. In this review, we consolidate current insights into how 1CM affects T cell activation, differentiation, and functionality. Furthermore, we delve into the strategies for modulating 1CM in both T cells and tumor cells to enhance the efficacy of adoptively transferred T cells, overcome metabolic challenges in the tumor microenvironment (TME), and maximize the benefits of T cell-mediated immunotherapy.
RESUMEN
Deciphering cellular interactions is essential to both understand the mechanisms underlying a broad range of human diseases, but also to manipulate therapies targeting these diseases. Here, the formation of cell doublets resulting from specific membrane ligand-receptor interactions is discovered. Based on this phenomenon, the study developed DoubletSeeker, a novel high-throughput method for the reliable identification of ligand-receptor interactions. The study shows that DoubletSeeker can accurately identify T cell receptor (TCR)-antigen interactions with high sensitivity and specificity. Notably, DoubletSeeker effectively captured paired TCR-peptide major histocompatibility complex (pMHC) information during a highly complex library-on-library screening and successfully identified three mutant TCRs that specifically recognize the MART-1 epitope. In turn, DoubletSeeker can act as an antigen discovery platform that allows for the development of novel immunotherapy targets, making it valuable for investigating fundamental tumor immunology.
Asunto(s)
Antígenos , Receptores de Antígenos de Linfocitos T , Humanos , Ligandos , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/metabolismo , Péptidos , Complejo Mayor de HistocompatibilidadRESUMEN
The acidic metabolic byproducts within the tumor microenvironment (TME) hinder T cell effector functions. However, their effects on T cell infiltration remain largely unexplored. Leveraging the comprehensive The Cancer Genome Atlas dataset, we pinpoint 16 genes that correlate with extracellular acidification and establish a metric known as the "tumor acidity (TuAci) score" for individual patients. We consistently observe a negative association between the TuAci score and T lymphocyte score (T score) across various human cancer types. Mechanistically, extracellular acidification significantly impedes T cell motility by suppressing podosome formation. This phenomenon can be attributed to the reduced expression of methyltransferase-like 3 (METTL3) and the modification of RNA N6-methyladenosine (m6A), resulting in a subsequent decrease in the expression of integrin ß1 (ITGB1). Importantly, enforced ITGB1 expression leads to enhanced T cell infiltration and improved antitumor activity. Our study suggests that modulating METTL3 activity or boosting ITGB1 expression could augment T cell infiltration within the acidic TME, thereby improving the efficacy of cell therapy.
Asunto(s)
Integrina beta1 , Neoplasias , Humanos , Tratamiento Basado en Trasplante de Células y Tejidos , Concentración de Iones de Hidrógeno , Integrina beta1/genética , Metiltransferasas/genética , Linfocitos T , Microambiente TumoralRESUMEN
Immunoglobulin (Ig) class switch DNA recombination (CSR) and somatic hypermutation (SHM) are critical for the maturation of the antibody response. Activation-induced cytidine deaminase (AID) initiates CSR and SHM by deaminating deoxycytidines (dCs) in switch (S) and V(D)J region DNA, respectively, to generate deoxyuracils (dUs). Processing of dUs by uracil DNA glycosylase (UNG) yields abasic sites, which are excised by apurinic/apyrimidinic endonucleases, eventually generating double strand DNA breaks, the obligatory intermediates of CSR. Here, we found that the bivalent iron ion (Fe(2+), ferrous) suppressed CSR, leading to decreased number of switched B cells, decreased postrecombination Iµ-C(H) transcripts, and reduced titers of secreted class-switched IgG1, IgG3, and IgA antibodies, without alterations in critical CSR factors, such as AID, 14-3-3γ, or PTIP, or in general germline I(H)-S-C(H) transcription. Fe(2+) did not affect B cell proliferation or plasmacytoid differentiation. Rather, it inhibited AID-mediated dC deamination in a dose-dependent fashion. The inhibition of intrinsic AID enzymatic activity by Fe(2+) was specific, as shown by lack of inhibition of AID-mediated dC deamination by other bivalent metal ions, such as Zn(2+), Mn(2+), Mg(2+), or Ni(2+), and the inability of Fe(2+) to inhibit UNG-mediated dU excision. Overall, our findings have outlined a novel role of iron in modulating a B cell differentiation process that is critical to the generation of effective antibody responses to microbial pathogens and tumoral cells. They also suggest a possible role of iron in dampening AID-dependent autoimmunity and neoplastic transformation.
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Citidina Desaminasa/antagonistas & inhibidores , Citidina Desaminasa/metabolismo , Roturas del ADN de Doble Cadena , Cambio de Clase de Inmunoglobulina/fisiología , Hierro/metabolismo , Células Plasmáticas/metabolismo , Recombinación Genética/fisiología , Animales , Diferenciación Celular/fisiología , Citidina Desaminasa/genética , Inmunoglobulina A/genética , Inmunoglobulina A/metabolismo , Inmunoglobulina G/genética , Inmunoglobulina G/metabolismo , Ratones , Células Plasmáticas/citologíaRESUMEN
The accumulation of acidic metabolic waste products within the tumor microenvironment inhibits effector functions of tumor-infiltrating lymphocytes (TILs). However, it remains unclear how an acidic environment affects T cell metabolism and differentiation. Here we show that prolonged exposure to acid reprograms T cell intracellular metabolism and mitochondrial fitness and preserves T cell stemness. Mechanistically, elevated extracellular acidosis impairs methionine uptake and metabolism via downregulation of SLC7A5, therefore altering H3K27me3 deposition at the promoters of key T cell stemness genes. These changes promote the maintenance of a 'stem-like memory' state and improve long-term in vivo persistence and anti-tumor efficacy in mice. Our findings not only reveal an unexpected capacity of extracellular acidosis to maintain the stem-like properties of T cells, but also advance our understanding of how methionine metabolism affects T cell stemness.
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Acidosis , Neoplasias , Animales , Ratones , Neoplasias/metabolismo , Diferenciación Celular , Microambiente Tumoral , Acidosis/metabolismo , CarbonoRESUMEN
The discovery and characterization of antigen-specific CD8+ T cell clonotypes typically involves the labor-intensive synthesis and construction of peptide-MHC tetramers. We adapt single-chain trimer (SCT) technologies into a high throughput platform for pMHC library generation, showing that hundreds can be rapidly prepared across multiple Class I HLA alleles. We use this platform to explore the impact of peptide and SCT template mutations on protein expression yield, thermal stability, and functionality. SCT libraries were an efficient tool for identifying T cells recognizing commonly reported viral epitopes. We then construct SCT libraries to capture SARS-CoV-2 specific CD8+ T cells from COVID-19 participants and healthy donors. The immunogenicity of these epitopes is validated by functional assays of T cells with cloned TCRs captured using SCT libraries. These technologies should enable the rapid analyses of peptide-based T cell responses across several contexts, including autoimmunity, cancer, or infectious disease.