RESUMEN
T cells producing IFN-γ have long been considered a stalwart for immune protection against Mycobacterium tuberculosis (Mtb), but their relative importance to pulmonary immunity has been challenged by murine studies that achieved protection by adoptively transferred Mtb-specific IFN-γ-/- T cells. Using IFN-γ-/- T cell chimeric mice and adoptive transfer of IFN-γ-/- T cells into TCRß-/-δ-/- mice, we demonstrate that control of lung Mtb burden is in fact dependent on T cell-derived IFN-γ, and, furthermore, mice selectively deficient in T cell-derived IFN-γ develop exacerbated disease compared with T cell-deficient control animals, despite equivalent lung bacterial burdens. Deficiency in T cell-derived IFN-γ skews infected and bystander monocyte-derived macrophages to an alternative M2 phenotype and promotes neutrophil and eosinophil influx. Our studies support an important role for T cell-derived IFN-γ in pulmonary immunity against tuberculosis.
Asunto(s)
Interferón gamma , Pulmón , Ratones Noqueados , Mycobacterium tuberculosis , Tuberculosis Pulmonar , Animales , Ratones , Traslado Adoptivo , Interferón gamma/inmunología , Pulmón/inmunología , Pulmón/microbiología , Macrófagos/inmunología , Ratones Endogámicos C57BL , Mycobacterium tuberculosis/inmunología , Neutrófilos/inmunología , Linfocitos T/inmunología , Tuberculosis Pulmonar/inmunologíaRESUMEN
Despite widespread immunization with Bacille-Calmette-Guérin (BCG), the only currently licensed tuberculosis (TB) vaccine, TB remains a leading cause of mortality globally. There are many TB vaccine candidates in the developmental pipeline, but the lack of a robust animal model to assess vaccine efficacy has hindered our ability to prioritize candidates for human clinical trials. Here we use a murine ultra-low dose (ULD) Mycobacterium tuberculosis (Mtb) challenge model to assess protection conferred by BCG vaccination. We show that BCG confers a reduction in lung bacterial burdens that is more durable than that observed after conventional dose challenge, curbs Mtb dissemination to the contralateral lung, and, in a small percentage of mice, prevents detectable infection. These findings are consistent with the ability of human BCG vaccination to mediate protection, particularly against disseminated disease, in specific human populations and clinical settings. Overall, our findings demonstrate that the ultra-low dose Mtb infection model can measure distinct parameters of immune protection that cannot be assessed in conventional dose murine infection models and could provide an improved platform for TB vaccine testing.
Asunto(s)
Mycobacterium bovis , Mycobacterium tuberculosis , Vacunas contra la Tuberculosis , Animales , Ratones , Humanos , Vacuna BCG , Modelos Animales de Enfermedad , VacunaciónRESUMEN
Bacille Calmette-Guerin (BCG), an attenuated whole cell vaccine based on Mycobacterium bovis, is the only licensed vaccine against Mycobacterium tuberculosis (Mtb), but its efficacy is suboptimal and it fails to protect against pulmonary tuberculosis. We previously reported that Mtb lacking the virulence genes lprG and rv1410c (ΔLprG) was highly attenuated in immune deficient mice. In this study, we show that attenuated ΔLprG Mtb protects C57BL/6J, Balb/cJ, and C3HeB/FeJ mice against Mtb challenge and is as attenuated as BCG in SCID mice. In C3HeB/FeJ mice, ΔLprG vaccination resulted in innate peripheral cytokine production and induced high polyclonal PPD-specific cytokine-secreting CD4+ T lymphocytes in peripheral blood. The ΔLprG vaccine afforded protective efficacy in the lungs of C3H/FeJ mice following both H37Rv and Erdman aerosolized Mtb challenges. Vaccine efficacy correlated with antigen-specific PD-1-negative CD4+ T lymphocytes as well as with serum IL-17 levels after vaccination. We hypothesize that induction of Th17 cells in lung is critical for vaccine protection, and we show a serum cytokine biomarker for IL-17 shortly after vaccination may predict protective efficacy.
Asunto(s)
Vacunas contra la Tuberculosis/genética , Vacunas contra la Tuberculosis/inmunología , Vacunas Atenuadas/genética , Vacunas Atenuadas/inmunología , Factores de Virulencia/genética , Animales , Genes Bacterianos/genética , Interleucina-17/inmunología , Ratones , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/inmunología , Células Th17/inmunología , Tuberculosis Pulmonar/inmunología , Tuberculosis Pulmonar/prevención & controlRESUMEN
Progress in tuberculosis vaccine development is hampered by an incomplete understanding of the immune mechanisms that protect against infection with Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis. Although the M72/ASOE1 trial yielded encouraging results (54% efficacy in subjects with prior exposure to Mtb), a highly effective vaccine against adult tuberculosis remains elusive. We show that in a mouse model, establishment of a contained and persistent yet non-pathogenic infection with Mtb ("contained Mtb infection", CMTB) rapidly and durably reduces tuberculosis disease burden after re-exposure through aerosol challenge. Protection is associated with elevated activation of alveolar macrophages, the first cells that respond to inhaled Mtb, and accelerated recruitment of Mtb-specific T cells to the lung parenchyma. Systems approaches, as well as ex vivo functional assays and in vivo infection experiments, demonstrate that CMTB reconfigures tissue resident alveolar macrophages via low grade interferon-γ exposure. These studies demonstrate that under certain circumstances, the continuous interaction of the immune system with Mtb is beneficial to the host by maintaining elevated innate immune responses.
Asunto(s)
Modelos Animales de Enfermedad , Mycobacterium tuberculosis/inmunología , Vacunas contra la Tuberculosis/inmunología , Tuberculosis/inmunología , Tuberculosis/virología , Animales , Macrófagos Alveolares/inmunología , RatonesRESUMEN
Many studies have examined pathways controlling effector T cell differentiation, but less is known about the fate of individual CD8+ T cells during infection. Here, we examine the antiviral and antibacterial responses of single CD8+ T cells from the polyclonal repertoire. The progeny of naive clonal CD8+ T cells displayed unique profiles of differentiation based on extrinsic pathogen-induced environmental cues, with some clones demonstrating extreme bias toward a single developmental pathway. Moreover, even within the same animal, a single naive CD8+ T cell exhibited distinct fates that were controlled by tissue-specific events. However, memory CD8+ T cells relied on intrinsic factors to control differentiation upon challenge. Our results demonstrate that stochastic and instructive events differentially contribute to shaping the primary and secondary CD8+ T cell response and provide insight into the underlying forces that drive effector differentiation and protective memory formation.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Listeriosis/inmunología , Estomatitis Vesicular/inmunología , Animales , Diferenciación Celular , Femenino , Memoria Inmunológica , Listeria monocytogenes/inmunología , Activación de Linfocitos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Virus de la Estomatitis Vesicular Indiana/inmunologíaRESUMEN
Growing evidence suggests the outcome of Mycobacterium tuberculosis infection is established rapidly after exposure, but how the current tuberculosis vaccine, bacillus Calmette-Guérin (BCG), impacts early immunity is poorly understood. In this study, we found that murine BCG immunization promotes a dramatic shift in infected cell types. Although alveolar macrophages are the major infected cell for the first 2 weeks in unimmunized animals, BCG promotes the accelerated recruitment and infection of lung-infiltrating phagocytes. Interestingly, this shift is dependent on CD4 T cells, yet does not require intrinsic recognition of Ag presented by infected alveolar macrophages. M. tuberculosis-specific T cells are first activated in lung regions devoid of infected cells, and these events precede vaccine-induced reduction of the bacterial burden, which occurs only after the colocalization of T cells and infected cells. Understanding how BCG alters early immune responses to M. tuberculosis provides new avenues to improve upon the immunity it confers.
Asunto(s)
Vacuna BCG/inmunología , Linfocitos T CD4-Positivos/inmunología , Macrófagos Alveolares/inmunología , Tuberculosis Pulmonar/inmunología , Animales , Activación de Linfocitos/inmunología , Macrófagos/inmunología , Macrófagos/microbiología , Macrófagos Alveolares/microbiología , Ratones , Ratones Endogámicos C57BL , Tuberculosis Pulmonar/prevención & controlRESUMEN
IFNs, which transduce pivotal signals through Stat1 and Stat2, effectively suppress the replication of Legionella pneumophila in primary murine macrophages. Although the ability of IFN-γ to impede L. pneumophila growth is fully dependent on Stat1, IFN-αß unexpectedly suppresses L. pneumophila growth in both Stat1- and Stat2-deficient macrophages. New studies demonstrating that the robust response to IFN-αß is lost in Stat1-Stat2 double-knockout macrophages suggest that Stat1 and Stat2 are functionally redundant in their ability to direct an innate response toward L. pneumophila. Because the ability of IFN-αß to signal through Stat1-dependent complexes (i.e., Stat1-Stat1 and Stat1-Stat2 dimers) has been well characterized, the current studies focus on how Stat2 is able to direct a potent response to IFN-αß in the absence of Stat1. These studies reveal that IFN-αß is able to drive the formation of a Stat2 and IFN regulatory factor 9 complex that drives the expression of a subset of IFN-stimulated genes, but with substantially delayed kinetics. These observations raise the possibility that this pathway evolved in response to microbes that have devised strategies to subvert Stat1-dependent responses.
Asunto(s)
Subunidad gamma del Factor 3 de Genes Estimulados por el Interferón/inmunología , Legionelosis/inmunología , Macrófagos/inmunología , Receptor de Interferón alfa y beta/inmunología , Factor de Transcripción STAT1/inmunología , Factor de Transcripción STAT2/inmunología , Animales , Células de la Médula Ósea/inmunología , Células de la Médula Ósea/microbiología , Células de la Médula Ósea/patología , Regulación de la Expresión Génica , Interacciones Huésped-Patógeno , Subunidad gamma del Factor 3 de Genes Estimulados por el Interferón/genética , Interferón gamma/genética , Interferón gamma/inmunología , Legionella pneumophila/inmunología , Legionelosis/genética , Legionelosis/microbiología , Legionelosis/patología , Macrófagos/microbiología , Macrófagos/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Cultivo Primario de Células , Multimerización de Proteína , Receptor de Interferón alfa y beta/genética , Factor de Transcripción STAT1/deficiencia , Factor de Transcripción STAT1/genética , Factor de Transcripción STAT2/deficiencia , Factor de Transcripción STAT2/genética , Transducción de Señal , Factores de TiempoRESUMEN
IL-15 plays a multifaceted role in immune homeostasis, but the unreliability of IL-15 detection has stymied exploration of IL-15 regulation in vivo. To visualize IL-15 expression, we created a transgenic mouse expressing emerald-GFP (EmGFP) under IL-15 promoter control. EmGFP/IL-15 was prevalent in innate cells including dendritic cells (DCs), macrophages, and monocytes. However, DC subsets expressed varying levels of EmGFP/IL-15 with CD8(+) DCs constitutively expressing EmGFP/IL-15 and CD8(-) DCs expressing low EmGFP/IL-15 levels. Virus infection resulted in IL-15 upregulation in both subsets. By crossing the transgenic mice to mice deficient in specific elements of innate signaling, we found a cell-intrinsic dependency of DCs and Ly6C(+) monocytes on IFN-α receptor expression for EmGFP/IL-15 upregulation after vesicular stomatitis virus infection. In contrast, myeloid cells did not require the expression of MyD88 to upregulate EmGFP/IL-15 expression. These findings provide evidence of previously unappreciated regulation of IL-15 expression in myeloid lineages during homeostasis and following infection.
Asunto(s)
Células Dendríticas/metabolismo , Interleucina-15/biosíntesis , Transducción de Señal/inmunología , Animales , Separación Celular , Células Dendríticas/inmunología , Citometría de Flujo , Interleucina-15/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Microscopía Confocal , Factor 88 de Diferenciación Mieloide/inmunología , Factor 88 de Diferenciación Mieloide/metabolismo , Receptor de Interferón alfa y beta/inmunología , Receptor de Interferón alfa y beta/metabolismo , Estomatitis Vesicular/inmunologíaRESUMEN
Pulmonary Mycobacterium tuberculosis (Mtb) infection results in highly heterogeneous lesions ranging from granulomas with central necrosis to those primarily comprised of alveolitis. While alveolitis has been associated with prior immunity in human post-mortem studies, the drivers of these distinct pathologic outcomes are poorly understood. Here, we show that these divergent lesion structures can be modeled in C3HeB/FeJ mice and are regulated by prior immunity. Using quantitative imaging, scRNAseq, and flow cytometry, we demonstrate that Mtb infection in the absence of prior immunity elicits dysregulated neutrophil recruitment and necrotic granulomas. In contrast, prior immunity induces rapid recruitment and activation of T cells, local macrophage activation, and diminished late neutrophil responses. Depletion studies at distinct infection stages demonstrated that neutrophils are required for early necrosis initiation and necrosis propagation at chronic stages, whereas early CD4 T cell responses prevent neutrophil feedforward circuits and necrosis. Together, these studies reveal fundamental determinants of tuberculosis lesion structure and pathogenesis, which have important implications for new strategies to prevent or treat tuberculosis.
RESUMEN
A polymorphism causing deficiencies in Toll-interacting protein (TOLLIP), an inhibitory adaptor protein affecting endosomal trafficking, is associated with increased tuberculosis (TB) risk. It is, however, unclear how TOLLIP affects TB pathogenesis. Here we show that TB severity is increased in Tollip-/- mice, characterized by macrophage- and T cell-driven inflammation, foam cell formation and lipid accumulation. Tollip-/- alveolar macrophages (AM) specifically accumulated lipid and underwent necrosis. Transcriptional and protein analyses of Mycobacterium tuberculosis (Mtb)-infected, Tollip-/- AM revealed increased EIF2 signalling and downstream upregulation of the integrated stress response (ISR). These phenotypes were linked, as incubation of the Mtb lipid mycolic acid with Mtb-infected Tollip-/- AM activated the ISR and increased Mtb replication. Correspondingly, the ISR inhibitor, ISRIB, reduced Mtb numbers in AM and improved Mtb control, overcoming the inflammatory phenotype. In conclusion, targeting the ISR offers a promising target for host-directed anti-TB therapy towards improved Mtb control and reduced immunopathology.
Asunto(s)
Mycobacterium tuberculosis , Tuberculosis , Animales , Ratones , Macrófagos Alveolares/microbiología , Tuberculosis/microbiología , Mycobacterium tuberculosis/fisiología , Macrófagos/microbiología , Lípidos , Péptidos y Proteínas de Señalización Intracelular/metabolismoRESUMEN
To investigate how host and pathogen diversity govern immunity against Mycobacterium tuberculosis (Mtb), we performed a large-scale screen of vaccine-mediated protection against aerosol Mtb infection using three inbred mouse strains [C57BL/6 (B6), C3HeB/FeJ (C3H), Balb/c x 129/SvJ (C129F1)] and three Mtb strains (H37Rv, CDC1551, SA161) representing two lineages and distinct virulence properties. We compared three protective modalities, all of which involve inoculation with live mycobacteria: Bacillus Calmette-Guérin (BCG), the only approved TB vaccine, delivered either subcutaneously or intravenously, and concomitant Mtb infection (CoMtb), a model of pre-existing immunity in which a low-level Mtb infection is established in the cervical lymph node following intradermal inoculation. We examined lung bacterial burdens at early (Day 28) and late (Day 98) time points after aerosol Mtb challenge and histopathology at Day 98. We observed substantial heterogeneity in the reduction of bacterial load afforded by these modalities at Day 28 across the combinations and noted a strong positive correlation between bacterial burden in unvaccinated mice and the degree of protection afforded by vaccination. Although we observed variation in the degree of reduction in bacterial burdens across the nine mouse/bacterium strain combinations, virtually all protective modalities performed similarly for a given strain-strain combination. We also noted dramatic variation in histopathology changes driven by both host and bacterial genetic backgrounds. Vaccination improved pathology scores for all infections except CDC1551. However, the most dramatic impact of vaccination on lesion development occurred for the C3H-SA161 combination, where vaccination entirely abrogated the development of the large necrotic lesions that arise in unvaccinated mice. In conclusion, we find that substantial TB heterogeneity can be recapitulated by introducing variability in both host and bacterial genetics, resulting in changes in vaccine-mediated protection as measured both by bacterial burden as well as histopathology. These differences can be harnessed in future studies to identify immune correlates of vaccine efficacy.
Asunto(s)
Mycobacterium tuberculosis , Animales , Mycobacterium tuberculosis/inmunología , Mycobacterium tuberculosis/genética , Ratones , Variación Genética , Femenino , Tuberculosis/prevención & control , Tuberculosis/inmunología , Tuberculosis/microbiología , Vacunas contra la Tuberculosis/inmunología , Ratones Endogámicos C57BL , Ratones Endogámicos BALB C , Interacciones Huésped-Patógeno/inmunología , Vacuna BCG/inmunología , Pulmón/microbiología , Pulmón/patología , Pulmón/inmunología , Modelos Animales de Enfermedad , Carga Bacteriana , VacunaciónRESUMEN
Bacillus Calmette-Guérin (BCG) remains the only approved tuberculosis (TB) vaccine despite limited efficacy. Preclinical studies of next-generation TB vaccines typically use a murine aerosol model with a supraphysiologic challenge dose. Here, we show that the protective efficacy of a live attenuated Mycobacterium tuberculosis (Mtb) vaccine ΔLprG markedly exceeds that of BCG in a low-dose murine aerosol challenge model. BCG reduced bacterial loads but did not prevent establishment or dissemination of infection in this model. In contrast, ΔLprG prevented detectable infection in 61% of mice and resulted in anatomic containment of 100% breakthrough infections to a single lung. Protection was partially abrogated in a repeated low-dose challenge model, which showed serum IL-17A, IL-6, CXCL2, CCL2, IFN-γ, and CXCL1 as correlates of protection. These data demonstrate that ΔLprG provides increased protection compared to BCG, including reduced detectable infection and anatomic containment, in a low-dose murine challenge model.
RESUMEN
Dendritic cells (DCs) must achieve a critical balance between activation and tolerance, a process influenced by cytokines and growth factors. IL-10, which transduces signals through Stat3, has emerged as one important negative regulator of DC activation. To directly examine the role Stat3 plays in regulating DC activity, the Stat3 gene was targeted for deletion with a CD11c-cre transgene. Stat3 CKO mice developed cervical lymphadenopathy as well as a mild ileocolitis that persisted throughout life and was associated with impaired weight gain. Consistent with this, Stat3-deficient DCs demonstrated enhanced immune activity, including increased cytokine production, Ag-dependent T-cell activation and resistance to IL-10-mediated suppression. These results reveal a cell-intrinsic negative regulatory role of Stat3 in DCs and link increased DC activation with perturbed immune homeostasis and chronic mucosal inflammation.
Asunto(s)
Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Factor de Transcripción STAT3/metabolismo , Animales , Antígeno CD11c/genética , Antígeno CD11c/metabolismo , Células Cultivadas , Enfermedad de Crohn/genética , Enfermedad de Crohn/metabolismo , Enfermedad de Crohn/patología , Citocinas/sangre , Citocinas/metabolismo , Células Dendríticas/efectos de los fármacos , Ensayo de Inmunoadsorción Enzimática , Femenino , Citometría de Flujo , Interferón gamma/sangre , Interferón gamma/metabolismo , Interleucina-10/farmacología , Enfermedades Linfáticas/genética , Enfermedades Linfáticas/metabolismo , Enfermedades Linfáticas/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos , Ratones Noqueados , Ratones Transgénicos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factor de Transcripción STAT3/genética , Factor de Necrosis Tumoral alfa/sangre , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Whether antibiotic treatment during gestation impacts T cell immunity to vaccination in offspring is unexplored. Dams treated with polymyxin B (PMB) during gestation (Mg) displayed altered microbial communities prior to delivery compared to control dams (Mc). Differences in microbiota were also evident in pups born to polymyxin B-treated dams (Pg) compared to control pups (Pc). When pups were immunized with Bacille Calmette-Guerin (BCG), we observed no difference in TB10.4-specific T cells between Pc and Pg 4 weeks postimmunization. Significantly fewer splenic CD4 T cells from BCG-vaccinated Pg produced interleukin-2 (IL-2) upon stimulation, suggesting a possible functional deficiency. There was no difference in purified protein derivative (PPD)-specific IgG between Pc and Pg at this time point. However, when infected with Mycobacterium tuberculosis, Pg displayed significantly higher bacterial burden in the lung than Pc. Our results show that maternal PMB treatment during gestation may not impact splenic antigen-specific T cell responses following BCG vaccination but alters susceptibility to M. tuberculosis in offspring. IMPORTANCE The composition of the pioneer microbiota that colonize the infant gut are determined by the mother. Polymyxin B-induced changes in the maternal microbiota during pregnancy impact the offspring gut microbiota but not vaccine-specific CD4 T cell response. However, when infected with Mycobacterium tuberculosis, offspring born to mothers with an altered gut microbiota are susceptible to infection compared to those born to mothers not exposed to antibiotics.
Asunto(s)
Mycobacterium bovis , Mycobacterium tuberculosis , Femenino , Embarazo , Antibacterianos/farmacología , Antibacterianos/metabolismo , Vacuna BCG , Linfocitos T CD4-Positivos , Polimixina B/farmacología , Vacunación , AnimalesRESUMEN
CD4 T cell effector function is required for optimal containment of Mycobacterium tuberculosis (Mtb) infection. IFNÉ£ produced by CD4 T cells is a key cytokine that contributes to protection. However, lung-infiltrating CD4 T cells have a limited ability to produce IFNÉ£, and IFNÉ£ plays a lesser protective role within the lung than at sites of Mtb dissemination. In a murine infection model, we observed that IFNÉ£ production by Mtb-specific CD4 T cells is rapidly extinguished within the granuloma but not within unaffected lung regions, suggesting localized immunosuppression. We identified a signature of TGFß signaling within granuloma-infiltrating T cells in both mice and rhesus macaques. Selective blockade of TGFß signaling in T cells resulted in an accumulation of terminally differentiated effector CD4 T cells, improved IFNÉ£ production within granulomas, and reduced bacterial burdens. These findings uncover a spatially localized immunosuppressive mechanism associated with Mtb infection and provide potential targets for host-directed therapy.
Asunto(s)
Granuloma/inmunología , Linfocitos T/inmunología , Factor de Crecimiento Transformador beta/metabolismo , Tuberculosis/inmunología , Inmunidad Adaptativa , Animales , Linfocitos T CD4-Positivos , Muerte Celular , Citocinas , Modelos Animales de Enfermedad , Femenino , Granuloma/microbiología , Inflamación , Interferón gamma , Pulmón/microbiología , Macaca mulatta , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Mycobacterium tuberculosis , Células TH1RESUMEN
Tuberculosis (TB) is a heterogeneous disease manifesting in a subset of individuals infected with aerosolized Mycobacterium tuberculosis (Mtb). Unlike human TB, murine infection results in uniformly high lung bacterial burdens and poorly organized granulomas. To develop a TB model that more closely resembles human disease, we infected mice with an ultra-low dose (ULD) of between 1-3 founding bacteria, reflecting a physiologic inoculum. ULD-infected mice exhibited highly heterogeneous bacterial burdens, well-circumscribed granulomas that shared features with human granulomas, and prolonged Mtb containment with unilateral pulmonary infection in some mice. We identified blood RNA signatures in mice infected with an ULD or a conventional Mtb dose (50-100 CFU) that correlated with lung bacterial burdens and predicted Mtb infection outcomes across species, including risk of progression to active TB in humans. Overall, these findings highlight the potential of the murine TB model and show that ULD infection recapitulates key features of human TB.
Asunto(s)
Modelos Animales de Enfermedad , Mycobacterium tuberculosis/patogenicidad , Tuberculosis Pulmonar , Animales , Carga Bacteriana , Biomarcadores/sangre , Progresión de la Enfermedad , Femenino , Granuloma/patología , Humanos , Pulmón/microbiología , Macaca mulatta , Ratones , Ratones Endogámicos C57BL , Mycobacterium tuberculosis/crecimiento & desarrollo , RNA-Seq , Tuberculosis Pulmonar/sangre , Tuberculosis Pulmonar/microbiología , Tuberculosis Pulmonar/patologíaRESUMEN
Legionella pneumophila remains an important opportunistic pathogen of human macrophages. Its more limited ability to replicate in murine macrophages has been attributed to redundant innate sensor systems that detect and effectively respond to this infection. The current studies evaluate the role of one of these innate response systems, the type I interferon (IFN-I) autocrine loop. The ability of L. pneumophila to induce IFN-I expression was found to be dependent on IRF-3, but not NF-kappaB. Secreted IFN-Is then in turn suppress the intracellular replication of L. pneumophila. Surprisingly, this suppression is mediated by a pathway that is independent of Stat1, Stat2, Stat3, but correlates with the polarization of macrophages toward the M1 or classically activated phenotype.
Asunto(s)
Inmunidad Innata , Interferón Tipo I/inmunología , Interferones/inmunología , Enfermedad de los Legionarios/inmunología , Animales , Comunicación Autocrina/inmunología , Células Cultivadas , Legionella pneumophila/fisiología , Activación de Macrófagos , Macrófagos/citología , Macrófagos/inmunología , Ratones , FN-kappa B , Factores de Transcripción STATRESUMEN
Recently developed approaches for highly multiplexed imaging have revealed complex patterns of cellular positioning and cell-cell interactions with important roles in both cellular- and tissue-level physiology. However, tools to quantitatively study cellular patterning and tissue architecture are currently lacking. Here, we develop a spatial analysis toolbox, the histo-cytometric multidimensional analysis pipeline (CytoMAP), which incorporates data clustering, positional correlation, dimensionality reduction, and 2D/3D region reconstruction to identify localized cellular networks and reveal features of tissue organization. We apply CytoMAP to study the microanatomy of innate immune subsets in murine lymph nodes (LNs) and reveal mutually exclusive segregation of migratory dendritic cells (DCs), regionalized compartmentalization of SIRPα- dermal DCs, and preferential association of resident DCs with select LN vasculature. The findings provide insights into the organization of myeloid cells in LNs and demonstrate that CytoMAP is a comprehensive analytics toolbox for revealing features of tissue organization in imaging datasets.
Asunto(s)
Tejido Linfoide/metabolismo , Células Mieloides/metabolismo , Animales , Ratones , Análisis EspacialRESUMEN
Mycobacterium tuberculosis (Mtb) infection is initiated in the distal airways, but the bacteria ultimately disseminate to the lung interstitium. Although various cell types, including alveolar macrophages (AM), neutrophils, and permissive monocytes, are known to be infected with Mtb, the initially infected cells as well as those that mediate dissemination from the alveoli to the lung interstitium are unknown. In this study, using a murine infection model, we reveal that early, productive Mtb infection occurs almost exclusively within airway-resident AM. Thereafter Mtb-infected, but not uninfected, AM localize to the lung interstitium through mechanisms requiring an intact Mtb ESX-1 secretion system. Relocalization of infected AM precedes Mtb uptake by recruited monocyte-derived macrophages and neutrophils. This dissemination process is driven by non-hematopoietic host MyD88/interleukin-1 receptor inflammasome signaling. Thus, interleukin-1-mediated crosstalk between Mtb-infected AM and non-hematopoietic cells promotes pulmonary Mtb infection by enabling infected cells to disseminate from the alveoli to the lung interstitium.
Asunto(s)
Macrófagos Alveolares/inmunología , Mycobacterium tuberculosis/inmunología , Alveolos Pulmonares/inmunología , Alveolos Pulmonares/microbiología , Tuberculosis/inmunología , Tuberculosis/microbiología , Animales , Proteínas Bacterianas/metabolismo , Granuloma/microbiología , Granuloma/patología , Inmunidad Innata/inmunología , Inflamación/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Factor 88 de Diferenciación Mieloide/metabolismo , Receptores de Interleucina-1/metabolismoRESUMEN
CD4 T cells are critical for protective immunity against Mycobacterium tuberculosis (Mtb), the cause of tuberculosis (TB). Yet to date, TB vaccine candidates that boost antigen-specific CD4 T cells have conferred little or no protection. Here we examined CD4 T cell responses to two leading TB vaccine antigens, ESAT-6 and Ag85B, in Mtb-infected mice and in vaccinated humans with and without underlying Mtb infection. In both species, Mtb infection drove ESAT-6-specific T cells to be more differentiated than Ag85B-specific T cells. The ability of each T cell population to control Mtb in the lungs of mice was restricted for opposite reasons: Ag85B-specific T cells were limited by reduced antigen expression during persistent infection, whereas ESAT-6-specific T cells became functionally exhausted due to chronic antigenic stimulation. Our findings suggest that different vaccination strategies will be required to optimize protection mediated by T cells recognizing antigens expressed at distinct stages of Mtb infection.