RESUMEN
Innate lymphoid cells (ILCs) participate in tissue homeostasis, inflammation, and early immunity against infection. It is unclear how ILCs acquire effector function and whether these mechanisms differ between organs. Through multiplexed single-cell mRNA sequencing, we identified cKit+CD127hiTCF-1hi early differentiation stages of T-bet+ ILC1s. These cells were present across different organs and had the potential to mature toward CD127intTCF-1int and CD127-TCF-1- ILC1s. Paralleling a gradual loss of TCF-1, differentiating ILC1s forfeited their expansion potential while increasing expression of effector molecules, reminiscent of T cell differentiation in secondary lymphoid organs. The transcription factor Hobit was induced in TCF-1hi ILC1s and was required for their effector differentiation. These findings reveal sequential mechanisms of ILC1 lineage commitment and effector differentiation that are conserved across tissues. Our analyses suggest that ILC1s emerge as TCF-1hi cells in the periphery and acquire a spectrum of organ-specific effector phenotypes through a uniform Hobit-dependent differentiation pathway driven by local cues.
Asunto(s)
Diferenciación Celular/inmunología , Inmunidad Innata/inmunología , Linfocitos/inmunología , Factores de Transcripción/inmunología , Animales , Femenino , Inflamación/inmunología , Células Asesinas Naturales/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , ARN Mensajero/inmunología , Linfocitos T/inmunologíaRESUMEN
Tissue-resident memory CD8+ T cells (TRM cells) are crucial in protecting against reinvading pathogens, but the impact of reinfection on their tissue confinement and contribution to recall responses is unclear. We developed a unique lineage tracer mouse model exploiting the TRM-defining transcription factor homolog of Blimp-1 in T cells (Hobit) to fate map the TRM progeny in secondary responses. After reinfection, a sizeable fraction of secondary memory T cells in the circulation developed downstream of TRM cells. These tissue-experienced ex-TRM cells shared phenotypic properties with the effector memory T cell population but were transcriptionally and functionally distinct from other secondary effector memory T cell cells. Adoptive transfer experiments of TRM cells corroborated their potential to form circulating effector and memory cells during recall responses. Moreover, specific ablation of primary TRM cell populations substantially impaired the secondary T cell response, both locally and systemically. Thus, TRM cells retain developmental plasticity and shape both local and systemic T cell responses on reinfection.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Memoria Inmunológica/inmunología , Factor 1 de Unión al Dominio 1 de Regulación Positiva/metabolismo , Traslado Adoptivo , Animales , Diferenciación Celular , Linaje de la Célula , Plasticidad de la Célula , Células Cultivadas , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Factor 1 de Unión al Dominio 1 de Regulación Positiva/genéticaRESUMEN
Resident memory T (TRM) cells have been recently established as an important subset of memory T cells that provide early and essential protection against reinfection in the absence of circulating memory T cells. Recent findings showing that TRM expand in vivo after repeated antigenic stimulation indicate that these memory T cells are not terminally differentiated. This suggests an opportunity for in vitro TRM expansion to apply in an immunotherapy setting. However, it has also been shown that TRM may not maintain their identity and form circulating memory T cells after in vivo restimulation. Therefore, we set out to determine how TRM respond to antigenic activation in culture. Using Listeria monocytogenes and LCMV infection models, we found that TRM from the intraepithelial compartment of the small intestine expand in vitro after antigenic stimulation and subsequent resting in homeostatic cytokines. A large fraction of the expanded TRM retained their phenotype, including the expression of key TRM markers CD69 and CD103 (ITGAE). The optimal culture of TRM required low O2 pressure to maintain the expression of these and other TRM-associated molecules. Expanded TRM retained their effector capacity to produce cytokines after restimulation, but did not acquire a highly glycolytic profile indicative of effector T cells. The proteomic analysis confirmed TRM profile retention, including expression of TRM-related transcription factors, tissue retention factors, adhesion molecules, and enzymes involved in fatty acid metabolism. Collectively, our data indicate that limiting oxygen conditions supports in vitro expansion of TRM cells that maintain their TRM phenotype, at least in part, suggesting an opportunity for therapeutic strategies that require in vitro expansion of TRM.
Asunto(s)
Memoria Inmunológica , Listeria monocytogenes , Células T de Memoria , Animales , Células T de Memoria/inmunología , Memoria Inmunológica/inmunología , Ratones , Listeria monocytogenes/inmunología , Antígenos CD/metabolismo , Antígenos CD/inmunología , Cadenas alfa de Integrinas/metabolismo , Ratones Endogámicos C57BL , Listeriosis/inmunología , Lectinas Tipo C/metabolismo , Lectinas Tipo C/inmunología , Antígenos de Diferenciación de Linfocitos T/inmunología , Antígenos de Diferenciación de Linfocitos T/metabolismo , Citocinas/metabolismo , Citocinas/inmunología , Activación de Linfocitos/inmunología , Virus de la Coriomeningitis Linfocítica/inmunología , Mucosa Intestinal/inmunología , Linfocitos T CD8-positivos/inmunología , Intestino Delgado/inmunología , Células CultivadasRESUMEN
Memory CD8+ T cells are indispensable for maintaining long-term immunity against intracellular pathogens and tumors. Despite their presence at oxygen-deprived infected tissue sites or in tumors, the impact of local oxygen pressure on memory CD8+ T cells remains largely unclear. We sought to elucidate how oxygen pressure impacts memory CD8+ T cells arising after infection with Listeria monocytogenes-OVA. Our data revealed that reduced oxygen pressure during in vitro culture switched CD8+ T cell metabolism from oxidative phosphorylation to a glycolytic phenotype. Quantitative proteomic analysis showed that limiting oxygen conditions increased the expression of glucose transporters and components of the glycolytic pathway, while decreasing TCA cycle and mitochondrial respiratory chain proteins. The altered CD8+ T cell metabolism did not affect the expansion potential, but enhanced the granzyme B and IFN-γ production capacity. In vivo, memory CD8+ T cells cultured under low oxygen pressure provided protection against bacterial rechallenge. Taken together, our study indicates that strategies of cellular immune therapy may benefit from reducing oxygen during culture to develop memory CD8+ T cells with superior effector functions.
Asunto(s)
Listeria monocytogenes , Listeriosis , Neoplasias , Animales , Ratones , Linfocitos T CD8-positivos , Proteómica , Neoplasias/patología , Oxígeno/metabolismo , Glucólisis , Memoria Inmunológica , Ratones Endogámicos C57BLRESUMEN
The transcriptional repressor Blimp-1 mediates the terminal differentiation of many cell types, including T cells. Here we identified Hobit (Znf683) as a previously unrecognized homolog of Blimp-1 that was specifically expressed in mouse natural killer T cells (NKT cells). Through studies of Hobit-deficient mice, we found that Hobit was essential for the formation of mature thymic NKT cells. In the periphery, Hobit repressed the accumulation of interferon-γ (IFN-γ)-producing NK1.1(lo) NKT cells at steady state. After antigenic stimulation, Hobit repressed IFN-γ expression, whereas after innate stimulation, Hobit induced granzyme B expression. Thus, reminiscent of the function of Blimp-1 in other lymphocytes, Hobit controlled the maintenance of quiescent, fully differentiated NKT cells and regulated their immediate effector functions.
Asunto(s)
Diferenciación Celular/genética , Células T Asesinas Naturales/citología , Células T Asesinas Naturales/inmunología , Secuencia de Aminoácidos , Animales , Diferenciación Celular/inmunología , Citometría de Flujo , Ratones , Ratones Noqueados , Datos de Secuencia Molecular , Filogenia , Factor 1 de Unión al Dominio 1 de Regulación Positiva , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Transcripción/genéticaRESUMEN
Tissue-resident memory T cells (Trm) are retained in peripheral tissues after infection for enhanced protection against secondary encounter with the same pathogen. We have previously shown that the transcription factor Hobit and its homolog Blimp-1 drive Trm development after viral infection, but how and when these transcription factors mediate Trm formation remains poorly understood. In particular, the major impact of Blimp-1 in regulating several aspects of effector T-cell differentiation impairs study of its specific role in Trm development. Here, we used the restricted expression of Hobit in the Trm lineage to develop mice with a conditional deletion of Blimp-1 in Trm, allowing us to specifically investigate the role of both transcription factors in Trm differentiation. We found that Hobit and Blimp-1 were required for the upregulation of CD69 and suppression of CCR7 and S1PR1 on virus-specific Trm precursors after LCMV infection, underlining a role in their retention within tissues. The early impact of Hobit and Blimp-1 favored Trm formation and prevented the development of circulating memory T cells. Thus, our findings highlight a role of Hobit and Blimp-1 at the branching point of circulating and resident memory lineages by suppressing tissue egress of Trm precursors early during infection.
Asunto(s)
Linfocitos T CD8-positivos , Memoria Inmunológica , Coriomeningitis Linfocítica , Virus de la Coriomeningitis Linfocítica , Factor 1 de Unión al Dominio 1 de Regulación Positiva , Factores de Transcripción , Animales , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Linfocitos T CD8-positivos/patología , Coriomeningitis Linfocítica/inmunología , Coriomeningitis Linfocítica/patología , Virus de la Coriomeningitis Linfocítica/inmunología , Ratones , Factor 1 de Unión al Dominio 1 de Regulación Positiva/inmunología , Factores de Transcripción/genética , Factores de Transcripción/inmunología , Factores de Transcripción/metabolismoRESUMEN
Tissue-resident memory CD8+ T cells (TRM ) localize to barrier tissues and mediate local protection against reinvading pathogens. Circulating central memory (TCM ) and effector memory CD8+ T cells (TEM ) also contribute to tissue recall responses, but their potential to form mucosal TRM remains unclear. Here, we employed adoptive transfer and lymphocytic choriomeningitis virus reinfection models to specifically assess secondary responses of TCM and TEM at mucosal sites. Donor TCM and TEM exhibited robust systemic recall responses, but only limited accumulation in the small intestine, consistent with reduced expression of tissue-homing and -retention molecules. Murine and human circulating memory T cells also exhibited limited CD103 upregulation following TGF-ß stimulation. Upon pathogen clearance, TCM and TEM readily gave rise to secondary TEM . TCM also formed secondary central memory in lymphoid tissues and TRM in internal tissues, for example, the liver. Both TCM and TEM failed to substantially contribute to resident mucosal memory in the small intestine, while activated intestinal TRM , but not liver TRM , efficiently reformed CD103+ TRM . Our findings demonstrate that circulating TCM and TEM are limited in generating mucosal TRM upon reinfection. This may pose important implications on cell therapy and vaccination strategies employing memory CD8+ T cells for protection at mucosal sites.
Asunto(s)
Antígenos CD/inmunología , Linfocitos T CD8-positivos/inmunología , Inmunidad Mucosa , Memoria Inmunológica , Cadenas alfa de Integrinas/inmunología , Inmunidad Adaptativa , Traslado Adoptivo , Animales , Antígenos CD/metabolismo , Linfocitos T CD8-positivos/clasificación , Linfocitos T CD8-positivos/citología , Diferenciación Celular/inmunología , Femenino , Humanos , Cadenas alfa de Integrinas/metabolismo , Mucosa Intestinal/citología , Mucosa Intestinal/inmunología , Intestino Delgado/citología , Intestino Delgado/inmunología , Activación de Linfocitos , Virus de la Coriomeningitis Linfocítica/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Membrana Mucosa/citología , Membrana Mucosa/inmunología , Factor de Crecimiento Transformador beta/inmunologíaRESUMEN
Invariant natural killer T cells (iNKT) constitute up to 50% of liver lymphocytes and contribute to immunosurveillance as well as pathogenesis of the liver. Systemic activation of iNKT cells induces acute immune-mediated liver injury. However, how tissue damage events regulate iNKT cell function and homeostasis remains unclear. We found that specifically tissue-resident iNKT cells in liver and spleen express the tissue-damage receptor P2RX7 and the P2RX7-activating ectoenzyme ARTC2. P2RX7 expression restricted formation of iNKT cells in the liver suggesting that liver iNKT cells are actively restrained under homeostatic conditions. Deliberate activation of P2RX7 in vivo by exogenous NAD resulted in a nearly complete iNKT cell ablation in liver and spleen in a P2RX7-dependent manner. Tissue damage generated by acetaminophen-induced liver injury reduced the number of iNKT cells in the liver. The tissue-damage-induced iNKT cell depletion was driven by P2RX7 and localized to the site of injury, as iNKT cells in the spleen remained intact. The depleted liver iNKT cells reconstituted only slowly compared to other lymphocytes such as regulatory T cells. These findings suggest that tissue-damage-mediated depletion of iNKT cells acts as a feedback mechanism to limit iNKT cell-induced pathology resulting in the establishment of a tolerogenic environment.
Asunto(s)
Acetaminofén/efectos adversos , Enfermedad Hepática Inducida por Sustancias y Drogas/inmunología , Hígado/patología , Células T Asesinas Naturales/fisiología , Receptores Purinérgicos P2X7/metabolismo , Acetaminofén/administración & dosificación , Animales , Células Cultivadas , Modelos Animales de Enfermedad , Humanos , Tolerancia Inmunológica , Activación de Linfocitos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores Purinérgicos P2X7/genéticaRESUMEN
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the current coronavirus disease 2019 (COVID-19) pandemic. Understanding the immune response that provides specific immunity but may also lead to immunopathology is crucial for the design of potential preventive and therapeutic strategies. Here, we characterized and quantified SARS-CoV-2-specific immune responses in patients with different clinical courses. Compared to individuals with a mild clinical presentation, CD4+ T-cell responses were qualitatively impaired in critically ill patients. Strikingly, however, in these patients the specific IgG antibody response was remarkably strong. Furthermore, in these critically ill patients, a massive influx of circulating T cells into the lungs was observed, overwhelming the local T-cell compartment, and indicative of vascular leakage. The observed disparate T- and B-cell responses could be indicative of a deregulated immune response in critically ill COVID-19 patients.
Asunto(s)
Anticuerpos Antivirales/inmunología , Linfocitos B/inmunología , Linfocitos T CD4-Positivos/inmunología , COVID-19/inmunología , Inmunoglobulina G/inmunología , SARS-CoV-2/inmunología , Adulto , Anciano , Linfocitos B/patología , Linfocitos T CD4-Positivos/patología , COVID-19/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Índice de Severidad de la EnfermedadRESUMEN
CD70 and CD27 are costimulatory molecules that provide essential signals for the expansion and differentiation of CD8(+) T cells. Here, we show that CD27-driven costimulation lowered the threshold of T cell receptor activation on CD8(+) T cells and enabled responses against low-affinity antigens. Using influenza infection to study in vivo consequences, we found that CD27-driven costimulation promoted a CD8(+) T cell response of overall low affinity. These qualitative effects of CD27 on T cell responses were maintained into the memory phase. On a clonal level, CD27-driven costimulation established a higher degree of variety in memory CD8(+) T cells. The benefit became apparent when mice were reinfected, given that CD27 improved CD8(+) T cell responses against reinfection with viral variants, but not with identical virus. We propose that CD27-driven costimulation is a strategy to generate memory clones that have potential reactivity to a wide array of mutable pathogens.
Asunto(s)
Linfocitos T CD8-positivos/metabolismo , Virus de la Influenza A/inmunología , Infecciones por Orthomyxoviridae/inmunología , Especificidad del Receptor de Antígeno de Linfocitos T , Miembro 7 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/metabolismo , Animales , Variación Antigénica , Antígenos Virales/inmunología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/patología , Linfocitos T CD8-positivos/virología , Células Clonales , Humanos , Memoria Inmunológica , Virus de la Influenza A/patogenicidad , Activación de Linfocitos/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Especificidad del Receptor de Antígeno de Linfocitos T/genética , Miembro 7 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/genética , Miembro 7 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/inmunologíaRESUMEN
CD8 T cells acquire cytotoxic molecules including granzyme B during effector differentiation. Both tissue-resident memory CD8 T cells (Trm) and circulating CD45RA+ effector-type T cells (Temra) cells have the ability to retain granzyme B protein expression into the memory phase, but it is unclear how this persistence of cytolytic activity is regulated during steady state. Previously, we have described that the transcriptional regulators Hobit and Blimp-1 have overlapping target genes that include granzyme B, but their impact on the regulation of cytotoxicity in Trm and Temra cells during homeostasis has remained unclear. We examined the expression regulation of Hobit and Blimp-1 in murine and human CD8 T-cells to determine their timeframe of activity. While Blimp-1 mRNA was expressed throughout effector and memory T cells, Blimp-1 protein, was only transiently expressed during the effector stage. In contrast, Hobit mRNA and protein expression was stably maintained during quiescence, but downregulated after activation. Notably, Blimp-1 was required for expression of granzyme B in murine effector T cells and Trm, while Hobit specifically regulated granzyme B in murine Trm during the memory phase. These findings suggest that Blimp-1 initiates cytotoxic effector function and that Hobit maintains cytotoxicity in a deployment-ready modus in Trm.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Memoria Inmunológica , Factor 1 de Unión al Dominio 1 de Regulación Positiva/genética , Factores de Transcripción/genética , Animales , Células Cultivadas , Regulación de la Expresión Génica/inmunología , Granzimas/genética , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Células T Asesinas Naturales/inmunología , Factor 1 de Unión al Dominio 1 de Regulación Positiva/inmunología , Factores de Transcripción/inmunología , Factores de Transcripción/metabolismoRESUMEN
Human cytomegalovirus (CMV) induces the formation of effector CD8(+) T cells that are maintained for decades during the latent stage of infection. Effector CD8(+) T cells appear quiescent, but maintain constitutive cytolytic capacity and can immediately produce inflammatory cytokines such as IFN-γ after stimulation. It is unclear how effector CD8(+) T cells can be constitutively maintained in a terminal stage of effector differentiation in the absence of overt viral replication. We have recently described the zinc finger protein Homolog of Blimp-1 in T cells (Hobit) in murine NKT cells. Here, we show that human Hobit was uniformly expressed in effector-type CD8(+) T cells, but not in naive or in most memory CD8(+) T cells. Human CMV-specific but not influenza-specific CD8(+) T cells expressed high levels of Hobit. Consistent with the high homology between the DNA-binding Zinc Finger domains of Hobit and Blimp-1, Hobit displayed transcriptional activity at Blimp-1 target sites. Expression of Hobit strongly correlated with T-bet and IFN-γ expression within the CD8(+) T-cell population. Furthermore, Hobit was both necessary and sufficient for the production of IFN-γ. These data implicate Hobit as a novel transcriptional regulator in quiescent human effector-type CD8(+) T cells that regulates their immediate effector functions.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Citomegalovirus/inmunología , Interferón gamma/inmunología , Proteínas Represoras/inmunología , Animales , Línea Celular , Humanos , Virus de la Influenza A/inmunología , Interferón gamma/genética , Ratones , Células T Asesinas Naturales/inmunología , Factor 1 de Unión al Dominio 1 de Regulación Positiva , Proteínas Represoras/genética , Factores de Transcripción/genética , Factores de Transcripción/inmunologíaRESUMEN
Apoptosis plays an essential role in the removal of activated CD8 T cells that are no longer required during or postinfection. The Bim-dependent intrinsic pathway of apoptosis removes effector CD8 T cells upon clearance of viral infection, which is driven by withdrawal of growth factors. Binding of Fas ligand to Fas mediates activation-induced T cell death in vitro and cooperates with Bim to eliminate CD8 T cells during chronic infection in vivo, but it is less clear how this pathway of apoptosis is initiated. In this study, we show that the costimulatory TNFR CD27 provides a dual trigger that can enhance survival of CD8 T cells, but also removal of activated CD8 T cells through Fas-driven apoptosis. Using in vitro stimulation assays of murine T cells with cognate peptide, we show that CD27 increases T cell survival after stimulation with low doses of Ag, whereas CD27 induces Fas-driven T cell apoptosis after stimulation with high doses of Ag. In vivo, the impact of constitutive CD70-driven stimulation on the accumulation of memory and effector CD8 T cells is limited by Fas-driven apoptosis. Furthermore, introduction of CD70 signaling during acute infection with influenza virus induces Fas-dependent elimination of influenza-specific CD8 T cells. These findings suggest that CD27 suppresses its costimulatory effects on T cell survival through activation of Fas-driven T cell apoptosis to maintain T cell homeostasis during infection.
Asunto(s)
Antígenos/inmunología , Apoptosis/inmunología , Ligando CD27/inmunología , Linfocitos T CD8-positivos/inmunología , Transducción de Señal , Receptor fas/inmunología , Animales , Antígenos/genética , Antígenos/metabolismo , Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/inmunología , Proteínas Reguladoras de la Apoptosis/metabolismo , Proteína 11 Similar a Bcl2 , Ligando CD27/genética , Ligando CD27/metabolismo , Linfocitos T CD8-positivos/metabolismo , Supervivencia Celular/genética , Supervivencia Celular/inmunología , Enfermedad Crónica , Memoria Inmunológica/genética , Infecciones/genética , Infecciones/inmunología , Infecciones/metabolismo , Proteínas de la Membrana/genética , Proteínas de la Membrana/inmunología , Proteínas de la Membrana/metabolismo , Ratones , Ratones Noqueados , Péptidos/genética , Péptidos/inmunología , Péptidos/metabolismo , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/inmunología , Proteínas Proto-Oncogénicas/metabolismo , Miembro 7 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/genética , Miembro 7 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/inmunología , Miembro 7 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/metabolismo , Receptor fas/genética , Receptor fas/metabolismoAsunto(s)
Células de la Médula Ósea/citología , Células de la Médula Ósea/metabolismo , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Comunicación Celular , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/metabolismo , Memoria Inmunológica , Animales , Autorrenovación de las Células , Microambiente Celular , Interacciones Huésped-Patógeno , Activación de Linfocitos/inmunología , Ratones , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismoRESUMEN
CD161(++)IL-18Rα(+)CD8(+) human T cells have recently been identified as a new subset of memory cells but their exact role remains unclear. CD161(++)IL-18Rα(+)CD8(+), mucosal-associated invariant T cells express a semi-invariant TCR Vα7.2-Jα33, which recognizes the MHC-related protein 1. On the basis of properties including the expression of the ABC-B1 transporter, cKit expression and survival after chemotherapy, CD161(++)IL-18Rα(+)CD8(+) T cells have been designated as 'stem' cells. Here we analyse location and functional properties of CD161(++)IL-18Rα(+) CD8(+) T cells and question whether they have other traits that would mark them as genuine 'stem' cells. CD161(++)IL-18Rα(+)CD8(+) T cells were found in peripheral blood, spleen and bone marrow but interestingly hardly at all in lymph nodes (LNs), which may possibly be explained by the finding that these cells express a specific set of chemokine receptors that allows migration to inflamed tissue rather than to LNs. In addition to TCR ligation and co-stimulation, CD161(++)IL-18Rα(+) CD8(+) T cells require cytokines for proliferation. The CD161(++)IL-18Rα(+) CD8(+) pool contains cells reactive towards peptides, derived from both persisting and cleared viruses. Although CD161(++)IL-18Rα(+) CD8(+) T cells express the ABC-B1 transporter, they have shorter telomeres and less telomerase activity and do not express aldehyde dehydrogenase. Finally, CD161(++)IL-18Rα(+) CD8(+) T cells show similarities to terminally differentiated T cells, expressing IFNγ, KLRG1 and the transcription factor Blimp-1. In conclusion, CD161(++)IL-18Rα(+) CD8(+) T cells lack many features of typical 'stem' cells, but appear rather to be a subset of effector-type cells.
Asunto(s)
Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/inmunología , Memoria Inmunológica , Subunidad alfa del Receptor de Interleucina-18/metabolismo , Subfamilia B de Receptores Similares a Lectina de Células NK/metabolismo , Células Madre/citología , Linfocitos T CD8-positivos/metabolismo , Linfocitos T CD8-positivos/ultraestructura , Humanos , Microscopía Electrónica de Transmisión de Rastreo , Células Madre/inmunología , Células Madre/metabolismo , Células Madre/ultraestructura , Telomerasa/metabolismo , Telómero/ultraestructura , Homeostasis del TelómeroRESUMEN
CD70 provides costimulation that enhances effector T cell differentiation upon binding of its receptor, CD27. During chronic immune activation, CD70 is constitutively expressed on activated immune cells, and this induces T cell-driven disruption of neutralizing Ab responses via an unknown mechanism. We used CD70-transgenic mice to investigate the effect of constitutive expression of CD70 on T cell-dependent B cell responses. CD70 induced up-regulation of the B cell follicle homing chemokine receptor CXCR5 on T cells, enabling not only CD4 but also CD8 T cells to infiltrate the B cell follicles. CD70-transgenic mice failed to develop productive germinal center formation and displayed impaired IgG Ab responses. Defective germinal center B cell differentiation was critically dependent on CD70-mediated CD27 signaling in T cells, and involved Fas-dependent impairment of germinal center B cell differentiation. Thus, CD70-driven costimulation enables T cells to terminate B cell responses, thereby compromising durable Ab production. Our findings imply that the CD70- and CD27-driven costimulatory axis may be involved in shutdown of B cell responses before clearance of Ag. Because CD70 is expressed constitutively in chronic viral infections such as HIV-1 infection, this mechanism may also contribute to defects in humoral immunity associated with this disease.
Asunto(s)
Linfocitos B/inmunología , Ligando CD27/inmunología , Centro Germinal/inmunología , Subgrupos de Linfocitos T/inmunología , Miembro 7 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/inmunología , Traslado Adoptivo , Animales , Anticuerpos Antivirales/inmunología , Anticuerpos Antivirales/metabolismo , Linfocitos B/metabolismo , Linfocitos B/virología , Ligando CD27/metabolismo , Diferenciación Celular/inmunología , Proteína Ligando Fas/inmunología , Proteína Ligando Fas/metabolismo , Haptenos , Hemocianinas/inmunología , Inmunoglobulina G/inmunología , Ratones , Ratones Transgénicos , Receptores CXCR5/inmunología , Receptores CXCR5/metabolismo , Transducción de Señal/inmunología , Bazo/inmunología , Bazo/patología , Subgrupos de Linfocitos T/metabolismo , Subgrupos de Linfocitos T/virología , Miembro 7 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/genética , Miembro 7 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/metabolismo , Regulación hacia Arriba/inmunología , Receptor fas/inmunología , Receptor fas/metabolismoRESUMEN
Tissue-resident memory T (TRM) cells with potent antiviral and antibacterial functions protect the epithelial and mucosal surfaces of our bodies against infection with pathogens. The strong proinflammatory activities of TRM cells suggest requirement for expression of inhibitory molecules to restrain these memory T cells under steady state conditions. We previously identified the adhesion G protein-coupled receptor GPR56 as an inhibitory receptor of human cytotoxic lymphocytes that regulates their cytotoxic effector functions. Here, we explored the expression pattern, expression regulation, and function of GPR56 on pathogen-specific CD8+ T cells using two infection models. We observed that GPR56 is expressed on TRM cells during acute infection and is upregulated by the TRM cell-inducing cytokine TGF-ß and the TRM cell-associated transcription factor Hobit. However, GPR56 appeared dispensable for CD8+ T-cell differentiation and function upon acute infection with LCMV as well as Listeria monocytogenes. Thus, TRM cells specifically acquire the inhibitory receptor GPR56, but the impact of this receptor on TRM cells after acute infection does not appear essential to regulate effector functions of TRM cells.
Asunto(s)
Diferenciación Celular/inmunología , Memoria Inmunológica , Receptores Acoplados a Proteínas G/metabolismo , Linfocitos T/inmunología , Animales , Linfocitos T CD8-positivos/inmunología , Citocinas/biosíntesis , Citotoxicidad Inmunológica , Regulación de la Expresión Génica , Listeria/fisiología , Virus de la Coriomeningitis Linfocítica/fisiología , Ratones , Receptores Acoplados a Proteínas G/genética , Regulación hacia ArribaRESUMEN
Tissue-resident memory CD8+ T cells (TRM) constitute a noncirculating memory T cell subset that provides early protection against reinfection. However, how TRM arise from antigen-triggered T cells has remained unclear. Exploiting the TRM-restricted expression of Hobit, we used TRM reporter/deleter mice to study TRM differentiation. We found that Hobit was up-regulated in a subset of LCMV-specific CD8+ T cells located within peripheral tissues during the effector phase of the immune response. These Hobit+ effector T cells were identified as TRM precursors, given that their depletion substantially decreased TRM development but not the formation of circulating memory T cells. Adoptive transfer experiments of Hobit+ effector T cells corroborated their biased contribution to the TRM lineage. Transcriptional profiling of Hobit+ effector T cells underlined the early establishment of TRM properties including down-regulation of tissue exit receptors and up-regulation of TRM-associated molecules. We identified Eomes as a key factor instructing the early bifurcation of circulating and resident lineages. These findings establish that commitment of TRM occurs early in antigen-driven T cell differentiation and reveal the molecular mechanisms underlying this differentiation pathway.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Células T de Memoria/inmunología , Proteínas de Dominio T Box/inmunología , Animales , Diferenciación Celular , Ratones , Ratones Endogámicos C57BL , Ratones TransgénicosRESUMEN
Tissue-resident memory CD8+ T (TRM) cells that develop in the epithelia at portals of pathogen entry are important for improved protection against re-infection. CD8+ TRM cells within the skin and the small intestine are long-lived and maintained independently of circulating memory CD8+ T cells. In contrast to CD8+ TRM cells at these sites, CD8+ TRM cells that arise after influenza virus infection within the lungs display high turnover and require constant recruitment from the circulating memory pool for long-term persistence. The distinct characteristics of CD8+ TRM cell maintenance within the lungs may suggest a unique program of transcriptional regulation of influenza-specific CD8+ TRM cells. We have previously demonstrated that the transcription factors Hobit and Blimp-1 are essential for the formation of CD8+ TRM cells across several tissues, including skin, liver, kidneys, and the small intestine. Here, we addressed the roles of Hobit and Blimp-1 in CD8+ TRM cell differentiation in the lungs after influenza infection using mice deficient for these transcription factors. Hobit was not required for the formation of influenza-specific CD8+ TRM cells in the lungs. In contrast, Blimp-1 was essential for the differentiation of lung CD8+ TRM cells and inhibited the differentiation of central memory CD8+ T (TCM) cells. We conclude that Blimp-1 rather than Hobit mediates the formation of CD8+ TRM cells in the lungs, potentially through control of the lineage choice between TCM and TRM cells during the differentiation of influenza-specific CD8+ T cells.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Memoria Inmunológica/inmunología , Pulmón/inmunología , Factor 1 de Unión al Dominio 1 de Regulación Positiva/inmunología , Factores de Transcripción/inmunología , Animales , Diferenciación Celular/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Infecciones por Orthomyxoviridae/inmunologíaRESUMEN
Tissue-resident memory T cells (TRM) are noncirculating immune cells that contribute to the first line of local defense against reinfections. Their location at hotspots of pathogen encounter frequently exposes TRM to tissue damage. This history of danger-signal exposure is an important aspect of TRM-mediated immunity that has been overlooked so far. RNA profiling revealed that TRM from liver and small intestine express P2RX7, a damage/danger-associated molecular pattern (DAMP) receptor that is triggered by extracellular nucleotides (ATP, NAD+). We confirmed that P2RX7 protein was expressed in CD8+ TRM but not in circulating T cells (TCIRC) across different infection models. Tissue damage induced during routine isolation of liver lymphocytes led to P2RX7 activation and resulted in selective cell death of TRM P2RX7 activation in vivo by exogenous NAD+ led to a specific depletion of TRM while retaining TCIRC The effect was absent in P2RX7-deficient mice and after P2RX7 blockade. TCR triggering down-regulated P2RX7 expression and made TRM resistant to NAD-induced cell death. Physiological triggering of P2RX7 by sterile tissue damage during acetaminophen-induced liver injury led to a loss of previously acquired pathogen-specific local TRM in wild-type but not in P2RX7 KO T cells. Our results highlight P2RX7-mediated signaling as a critical pathway for the regulation of TRM maintenance. Extracellular nucleotides released during infection and tissue damage could deplete TRM locally and free niches for new and infection-relevant specificities. This suggests that the recognition of tissue damage promotes persistence of antigen-specific over bystander TRM in the tissue niche.