RESUMEN
The differentiation of CD4(+) helper T cell subsets with diverse effector functions is accompanied by changes in metabolism required to meet their bioenergetic demands. We find that follicular B helper T (Tfh) cells exhibited less proliferation, glycolysis, and mitochondrial respiration, accompanied by reduced mTOR kinase activity compared to T helper 1 (Th1) cells in response to acute viral infection. IL-2-mediated activation of the Akt kinase and mTORc1 signaling was both necessary and sufficient to shift differentiation away from Tfh cells, instead promoting that of Th1 cells. These findings were not the result of generalized signaling attenuation in Tfh cells, because they retained the ability to flux calcium and activate NFAT-transcription-factor-dependent cytokine production. These data identify the interleukin-2 (IL-2)-mTORc1 axis as a critical orchestrator of the reciprocal balance between Tfh and Th1 cell fates and their respective metabolic activities after acute viral infection.
Asunto(s)
Interleucina-2/fisiología , Complejos Multiproteicos/fisiología , Proteínas Proto-Oncogénicas c-akt/fisiología , Transducción de Señal/fisiología , Subgrupos de Linfocitos T/metabolismo , Linfocitos T Colaboradores-Inductores/metabolismo , Serina-Treonina Quinasas TOR/fisiología , Animales , Apoptosis , Señalización del Calcio , Ciclo Celular , División Celular , Activación Enzimática , Glucosa/metabolismo , Glucólisis , Subunidad alfa del Receptor de Interleucina-2/fisiología , Virus de la Coriomeningitis Linfocítica/inmunología , Diana Mecanicista del Complejo 1 de la Rapamicina , Ratones Endogámicos C57BL , Factores de Transcripción NFATC/fisiología , Consumo de Oxígeno , Factor 1 de Unión al Dominio 1 de Regulación Positiva , Organismos Libres de Patógenos Específicos , Subgrupos de Linfocitos T/citología , Subgrupos de Linfocitos T/inmunología , Linfocitos T Colaboradores-Inductores/citología , Linfocitos T Colaboradores-Inductores/inmunología , Linfocitos T Colaboradores-Inductores/virología , Células TH1/citología , Células TH1/inmunología , Células TH1/metabolismo , Factores de Transcripción/biosíntesis , Factores de Transcripción/genéticaRESUMEN
Follicular helper T (Tfh) cells are required for the establishment of T-dependent B cell memory and high affinity antibody-secreting cells. We have revealed herein opposing roles for signal transducer and activator of transcription 3 (STAT3) and type I interferon (IFN) signaling in the differentiation of Tfh cells following viral infection. STAT3-deficient CD4(+) T cells had a profound defect in Tfh cell differentiation, accompanied by decreased germinal center (GC) B cells and antigen-specific antibody production during acute infection with lymphocytic choriomeningitis virus. STAT3-deficient Tfh cells had strikingly increased expression of a number of IFN-inducible genes, in addition to enhanced T-bet synthesis, thus adopting a T helper 1 (Th1) cell-like effector phenotype. Conversely, IFN-αß receptor blockade restored Tfh and GC B cell phenotypes in mice containing STAT3-deficient CD4(+) T cells. These data suggest mutually repressive roles for STAT3 and type I IFN signaling pathways in the differentiation of Tfh cells following viral infection.
Asunto(s)
Diferenciación Celular , Interferón Tipo I/metabolismo , Factor de Transcripción STAT3/metabolismo , Linfocitos T Colaboradores-Inductores/citología , Linfocitos T Colaboradores-Inductores/metabolismo , Animales , Anticuerpos Antivirales/inmunología , Especificidad de Anticuerpos/inmunología , Linfocitos B/efectos de los fármacos , Linfocitos B/inmunología , Linfocitos B/metabolismo , Antígenos CD4/genética , Linfocitos T CD4-Positivos/citología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Diferenciación Celular/genética , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Centro Germinal/inmunología , Centro Germinal/metabolismo , Cambio de Clase de Inmunoglobulina/genética , Interferón Tipo I/genética , Coriomeningitis Linfocítica/genética , Coriomeningitis Linfocítica/inmunología , Coriomeningitis Linfocítica/metabolismo , Virus de la Coriomeningitis Linfocítica/inmunología , Ratones , Ratones Noqueados , Factor de Transcripción STAT1/metabolismo , Factor de Transcripción STAT3/deficiencia , Factor de Transcripción STAT3/genética , Transducción de Señal , Linfocitos T Colaboradores-Inductores/inmunología , TranscriptomaRESUMEN
Tissue-resident memory T (Trm) cells provide enhanced protection against infection at mucosal sites. Here we found that CD4(+) T cells are important for the formation of functional lung-resident CD8(+) T cells after influenza virus infection. In the absence of CD4(+) T cells, CD8(+) T cells displayed reduced expression of CD103 (Itgae), were mislocalized away from airway epithelia, and demonstrated an impaired ability to recruit CD8(+) T cells to the lung airways upon heterosubtypic challenge. CD4(+) T cell-derived interferon-γ was necessary for generating lung-resident CD103(+) CD8(+) Trm cells. Furthermore, expression of the transcription factor T-bet was increased in "unhelped" lung Trm cells, and a reduction in T-bet rescued CD103 expression in the absence of CD4(+) T cell help. Thus, CD4(+) T cell-dependent signals are important to limit expression of T-bet and allow for the development of CD103(+) CD8(+) Trm cells in the lung airways following respiratory infection.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Memoria Inmunológica , Subtipo H3N2 del Virus de la Influenza A/inmunología , Pulmón/inmunología , Infecciones por Orthomyxoviridae/inmunología , Proteínas de Dominio T Box/biosíntesis , Animales , Antígenos CD/inmunología , Cadenas alfa de Integrinas/inmunología , Interferón gamma/inmunología , Pulmón/citología , Activación de Linfocitos/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Membrana Mucosa/citología , Membrana Mucosa/inmunologíaRESUMEN
Protein kinase B (also known as AKT) and the mechanistic target of rapamycin (mTOR) are central regulators of T cell differentiation, proliferation, metabolism, and survival. Here, we show that during chronic murine lymphocytic choriomeningitis virus infection, activation of AKT and mTOR are impaired in antiviral cytotoxic T lymphocytes (CTLs), resulting in enhanced activity of the transcription factor FoxO1. Blockade of inhibitory receptor programmed cell death protein 1 (PD-1) in vivo increased mTOR activity in virus-specific CTLs, and its therapeutic effects were abrogated by the mTOR inhibitor rapamycin. FoxO1 functioned as a transcriptional activator of PD-1 that promoted the differentiation of terminally exhausted CTLs. Importantly, FoxO1-null CTLs failed to persist and control chronic viral infection. Collectively, this study shows that CTLs adapt to persistent infection through a positive feedback pathway (PD-1?FoxO1?PD-1) that functions to both desensitize virus-specific CTLs to antigen and support their survival during chronic viral infection.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Factores de Transcripción Forkhead/inmunología , Coriomeningitis Linfocítica/inmunología , Virus de la Coriomeningitis Linfocítica/inmunología , Receptor de Muerte Celular Programada 1/biosíntesis , Linfocitos T Citotóxicos/inmunología , Animales , Anticuerpos Bloqueadores/farmacología , Anticuerpos Monoclonales/farmacología , Antígenos CD28/inmunología , Diferenciación Celular/inmunología , Línea Celular Tumoral , Enfermedad Crónica , Proteína Forkhead Box O1 , Factores de Transcripción Forkhead/biosíntesis , Factores de Transcripción Forkhead/genética , Granzimas/biosíntesis , Humanos , Interferón gamma/biosíntesis , Células Jurkat , Activación de Linfocitos/inmunología , Coriomeningitis Linfocítica/virología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Receptor de Muerte Celular Programada 1/inmunología , Proteínas Proto-Oncogénicas c-akt/biosíntesis , Receptores de Antígenos de Linfocitos T/inmunología , Sirolimus/farmacología , Linfocitos T Citotóxicos/citología , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Serina-Treonina Quinasas TOR/biosíntesisRESUMEN
Pathogen-induced inflammation modulates CD8 T cell effector and memory differentiation. In this issue of Immunity, Plumlee et al. (2013) demonstrate that clonally distinct CD8 T cells have the ability to generate numerous types of effector cell fates based on extrinsic pathogen-induced environmental cues.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Listeriosis/inmunología , Estomatitis Vesicular/inmunología , Animales , FemeninoRESUMEN
CD4(+) T cells differentiate into multiple effector types, but it is unclear how they form memory T cells during infection in vivo. Profiling virus-specific CD4(+) T cells revealed that effector cells with T helper 1 (Th1) or T follicular helper (Tfh) cell characteristics differentiated into memory cells, although expression of Tfh cell markers declined over time. In contrast to virus-specific effector CD8(+) T cells, increased IL-7R expression was not a reliable marker of CD4(+) memory precursor cells. However, decreased Ly6C and T-bet (Tbx21) expression distinguished a subset of Th1 cells that displayed greater longevity and proliferative responses to secondary infection. Moreover, the gene expression profile of Ly6C(lo)T-bet(int) Th1 effector cells was virtually identical to mature memory CD4(+) T cells, indicating early maturation of memory CD4(+) T cell features in this subset during acute viral infection. This study provides a framework for memory CD4(+) T cell development after acute viral infection.
Asunto(s)
Antígenos Ly/inmunología , Memoria Inmunológica , Proteínas de Dominio T Box/inmunología , Células TH1/inmunología , Animales , Antígenos Ly/genética , Proliferación Celular , Regulación de la Expresión Génica , Virus de la Coriomeningitis Linfocítica , Ratones , Ratones Endogámicos C57BL , Proteínas de Dominio T Box/genética , Células TH1/citología , Células TH1/virologíaRESUMEN
Regulatory T cells are crucial for preventing autoimmunity, but how their function is restrained to allow optimal effector T cells responses in appropriate contexts is unclear. In a recent paper in the Journal of Experimental Medicine, Campbell and colleagues demonstrate that virus-induced type I interferon acts directly on Treg cells to allow for functional antiviral T cell responses.
Asunto(s)
Interferón Tipo I/inmunología , Subgrupos de Linfocitos T/inmunología , Linfocitos T Reguladores/inmunología , Virosis/inmunología , Animales , Citotoxicidad Inmunológica , Humanos , Tolerancia Inmunológica , Memoria Inmunológica , Ratones , Ratones Noqueados , Factores de Transcripción STAT/metabolismo , Subgrupos de Linfocitos T/virología , Linfocitos T Reguladores/virologíaRESUMEN
Vaccine-induced memory is necessary for protective immunity to pathogens, but many viruses induce a state of transient immune suppression that might contribute to the inability of a vaccine to elicit immunity. We evaluated here the fate of bystander T cells activated by third party cognate antigens during acute viral infections in vivo, using distinct models to track and specifically activate HY and P14 transgenic bystander CD8 T cells in vivo during acute arenavirus infections of mice. Viral infections acted as stimulatory adjuvants when bystander T cells were exposed to an inflammatory milieu and cognate antigens at the beginning of infections, but bystander CD8 T cell proliferation in response to cognate antigen was inhibited 3 to 9 days after virus infection. Reduced proliferation was not dependent on Fas-FasL- or tumor necrosis factor (TNF)-induced activation-induced cell death or on deficiencies of antigen presentation. Instead, reduced proliferation was associated with a delayed onset of division that was an intrinsic defect of T cells. Inhibition of proliferation could be simulated by exposure of T cells to the Toll-like receptor agonist and type I interferon (IFN) inducer poly(I · C). T cells lacking IFN-α/ß receptors resisted both the suppressive effects of preexposure to poly(I · C) and the stimulatory effects of type I IFN, indicating that the timing of exposure to IFN can have negative or positive effects on T cell proliferation. Inhibition of T cell receptor-stimulated bystander CD8 T cell proliferation during acute viral infections may reflect the reduced ability of vaccines to elicit protective immunity when administered during an acute illness.
Asunto(s)
Infecciones por Arenaviridae/inmunología , Terapia de Inmunosupresión , Interferón Tipo I/inmunología , Activación de Linfocitos/inmunología , Virus de la Coriomeningitis Linfocítica/inmunología , Virus Pichinde/inmunología , Animales , Infecciones por Arenaviridae/virología , Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/inmunología , Línea Celular , Cricetinae , Femenino , Interferón Tipo I/farmacología , Activación de Linfocitos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos C3H , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones TransgénicosRESUMEN
Nonvirus-specific bystander CD8 T cells bathe in an inflammatory environment during viral infections. To determine whether bystander CD8 T cells are affected by these environments, we examined P14, HY, and OT-I TCR transgenic CD8 T cells sensitized in vivo by IFN-alphabeta-inducing viral infections or by polyinosinic:polycytidylic acid. These sensitized cells rapidly exerted effector functions, such as IFN-gamma production and degranulation, on contact with their high-affinity cognate Ag. Sensitization required self-MHC I and indirect effects of IFN-alphabeta, which together upregulated the T-box transcription factor Eomesodermin, potentially enabling the T cells to rapidly transcribe CTL effector genes and behave like memory cells rather than naive T cells. IL-12, IL-15, IL-18, and IFN-gamma were not individually required for sensitization to produce IFN-gamma, but IL-15 was required for upregulation of granzyme B. These experiments indicate that naive CD8 T cells receive signals from self-MHC and IFN-alphabeta and that, by this process, CD8 T cell responses to viral infection can undergo distinct differentiation pathways, depending on the timing of Ag encounter during the virus-induced IFN response.
Asunto(s)
Autoantígenos/fisiología , Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/inmunología , Diferenciación Celular/inmunología , Antígenos de Histocompatibilidad Clase I/fisiología , Interferón-alfa/fisiología , Interferón beta/fisiología , Transducción de Señal/inmunología , Animales , Infecciones por Arenaviridae/inmunología , Efecto Espectador/inmunología , Linfocitos T CD8-positivos/virología , Femenino , Antígeno H-Y/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Virus Pichinde/inmunología , Fase de Descanso del Ciclo Celular/inmunología , Regulación hacia Arriba/inmunologíaRESUMEN
T follicular helper cells (Tfh) are crucial for the initiation and maintenance of germinal center (GC) reactions and high affinity, isotype-switched antibody responses. In this study, we demonstrate that direct TGF-ß signaling to CD4 T cells is important for the formation of influenza-specific Tfh cells, GC reactions, and development of isotype-switched, flu-specific antibody responses. Early during infection, TGF-ß signaling suppressed the expression of the high affinity IL-2 receptor α chain (CD25) on virus-specific CD4 T cells, which tempered IL-2 signaling and STAT5 and mammalian target of rapamycin (mTOR) activation in Tfh precursor CD4 T cells. Inhibition of mTOR allowed for the differentiation of Tfh cells in the absence of TGF-ßR signaling, suggesting that TGF-ß insulates Tfh progenitor cells from IL-2-delivered mTOR signals, thereby promoting Tfh differentiation during acute viral infection. These findings identify a new pathway critical for the generation of Tfh cells and humoral responses during respiratory viral infections.
Asunto(s)
Formación de Anticuerpos/inmunología , Cambio de Clase de Inmunoglobulina/inmunología , Pulmón/inmunología , Membrana Mucosa/inmunología , Transducción de Señal , Linfocitos T Colaboradores-Inductores/inmunología , Factor de Crecimiento Transformador beta/metabolismo , Animales , Linfocitos B/inmunología , Diferenciación Celular/inmunología , Perfilación de la Expresión Génica , Centro Germinal/inmunología , Pulmón/patología , Pulmón/virología , Ratones , Membrana Mucosa/patología , Membrana Mucosa/virología , Orthomyxoviridae/fisiología , Infecciones por Orthomyxoviridae/inmunología , Infecciones por Orthomyxoviridae/patología , Especificidad de la Especie , Serina-Treonina Quinasas TOR/metabolismoRESUMEN
The transcription factor T-bet is critical for cytotoxic T lymphocyte (CTL) differentiation, but it is unclear how it operates in a graded manner in the formation of both terminal effector and memory precursor cells during viral infection. We find that, at high concentrations, T-bet induced expression of Zeb2 mRNA, which then triggered CTLs to adopt terminally differentiated states. ZEB2 and T-bet cooperate to switch on a terminal CTL differentiation program, while simultaneously repressing genes necessary for central memory CTL development. Chromatin immunoprecipitation sequencing showed that a large proportion of these genes were bound by T-bet, and this binding was altered by ZEB2 deficiency. Furthermore, T-bet overexpression could not fully bypass ZEB2 function. Thus, the coordinated actions of T-bet and ZEB2 outline a novel genetic pathway that forces commitment of CTLs to terminal differentiation, thereby restricting their memory cell potential.
Asunto(s)
Diferenciación Celular/inmunología , Proteínas de Homeodominio/inmunología , Coriomeningitis Linfocítica/inmunología , Proteínas Represoras/inmunología , Proteínas de Dominio T Box/inmunología , Linfocitos T Citotóxicos/inmunología , Animales , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Diferenciación Celular/genética , Análisis por Conglomerados , Citometría de Flujo , Proteínas de Homeodominio/genética , Interacciones Huésped-Patógeno/inmunología , Lectinas Tipo C , Coriomeningitis Linfocítica/genética , Coriomeningitis Linfocítica/virología , Virus de la Coriomeningitis Linfocítica/inmunología , Virus de la Coriomeningitis Linfocítica/fisiología , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Análisis de Secuencia por Matrices de Oligonucleótidos , Unión Proteica/inmunología , Receptores Inmunológicos/inmunología , Receptores Inmunológicos/metabolismo , Proteínas Represoras/deficiencia , Proteínas Represoras/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Proteínas de Dominio T Box/genética , Proteínas de Dominio T Box/metabolismo , Linfocitos T Citotóxicos/metabolismo , Transcriptoma/genética , Transcriptoma/inmunología , Caja Homeótica 2 de Unión a E-Box con Dedos de ZincRESUMEN
During the course of many chronic viral infections, the antiviral T cell response becomes attenuated through a process that is regulated in part by the host. While elevated expression of the immunosuppressive cytokine IL-10 is involved in the suppression of viral-specific T cell responses, the relevant cellular sources of IL-10, as well as the pathways responsible for IL-10 induction, remain unclear. In this study, we traced IL-10 production over the course of chronic lymphocytic choriomeningitis virus (LCMV) infection in an IL-10 reporter mouse line. Using this model, we demonstrated that virus-specific T cells with reduced inflammatory function, particularly Th1 cells, display elevated and sustained IL-10 expression during chronic LCMV infection. Furthermore, ablation of IL-10 from the T cell compartment partially restored T cell function and reduced viral loads in LCMV-infected animals. We found that viral persistence is needed for sustained IL-10 production by Th1 cells and that the transcription factor BLIMP-1 is required for IL-10 expression by Th1 cells. Restimulation of Th1 cells from LCMV-infected mice promoted BLIMP-1 and subsequent IL-10 expression, suggesting that constant antigen exposure likely induces the BLIMP-1/IL-10 pathway during chronic viral infection. Together, these data indicate that effector T cells self-limit their responsiveness during persistent viral infection via an IL-10-dependent negative feedback loop.
Asunto(s)
Interleucina-10/biosíntesis , Coriomeningitis Linfocítica/inmunología , Células TH1/inmunología , Factores de Transcripción/metabolismo , Animales , Enfermedad Crónica , Citocinas/biosíntesis , Mediadores de Inflamación/metabolismo , Interleucina-10/genética , Coriomeningitis Linfocítica/metabolismo , Coriomeningitis Linfocítica/virología , Virus de la Coriomeningitis Linfocítica/inmunología , Virus de la Coriomeningitis Linfocítica/patogenicidad , Sistema de Señalización de MAP Quinasas , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Factor 1 de Unión al Dominio 1 de Regulación Positiva , Receptores de Antígenos de Linfocitos T/metabolismo , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Células TH1/metabolismoRESUMEN
It is well known that infection by the human immunodeficiency virus (HIV) dysregulates cell physiology, but little information is available on the consequences of HIV infection in primary macrophages and microglia. The authors examined the relationship between cell proliferation and HIV infection in primary cultures of microglia and in human central nervous system (CNS). In cultures infected with HIV (ADA and BaL), granulocyte-macrophage colony-stimulating factor (GM-CSF)-mediated cell proliferation was reduced in productively infected (p24+) cells as compared to p24- cells. The reduction was observed with both Ki67 and BrdU labeling, suggesting a G1/S block. The reduction was insignificant when microglia were infected with a Vpr- mutant virus. In human CNS, proliferating (Ki67+) cells were rare but were increased in the HIV+ and HIV encephalitis (HIVE) groups compared to the HIV- group. A positive correlation between GM-CSF immunoreactivity and Ki67 counts, implicating GM-CSF as a growth factor in human CNS was found. The relationship between total macrophage (CD68+) proliferation and infected macrophage (p24+) proliferation was assessed in HIVE by double labeling. Whereas 1.2% of total CD68+ cells were Ki67+, only 0.5% of HIV p24+ cells were Ki67+ (P < .05). Furthermore, staining for CD45RB (as opposed to CD68) facilitated the identification of Ki67+ microglia, indicating that CD68 could underestimate proliferating microglia. The authors conclude that although there is increased expression of GM-CSF and increased cell proliferation in the CNS of HIV-seropositive individuals, cell proliferation in the productively infected population is actually suppressed. These data suggest that there might be a viral gain in the suppressed host cell proliferation.