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1.
Infect Immun ; : e0034524, 2024 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-39324794

RESUMEN

Pro-inflammatory immune responses are rapidly suppressed during blood-stage malaria but the molecular mechanisms driving this regulation are still incompletely understood. In this study, we show that the co-inhibitory receptors TIGIT and PD-1 are upregulated and co-expressed by antigen-specific CD4+ T cells (ovalbumin-specific OT-II cells) during non-lethal Plasmodium yoelii expressing ovalbumin (PyNL-OVA) blood-stage infection. Synergistic blockade of TIGIT and PD-L1, but not individual blockade of each receptor, during the early stages of infection significantly improved parasite control during the peak stages (days 10-15) of infection. Mechanistically, this protection was correlated with significantly increased plasma levels of IFN-γ, TNF, and IL-2, and an increase in the frequencies of IFN-γ-producing antigen-specific T-bet+ CD4+ T cells (OT-II cells), but not antigen-specific CD8+ T cells (OT-I cells), along with expansion of the splenic red pulp and monocyte-derived macrophage populations. Collectively, our study identifies a novel role for TIGIT in combination with the PD1-PD-L1 axis in regulating specific components of the pro-inflammatory immune response and restricting parasite control during the acute stages of blood-stage PyNL infection.

2.
Clin Immunol ; 249: 109287, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36907540

RESUMEN

Sensorineural hearing loss is the most common type of hearing loss in adults and occurs due to damage of the inner ear caused by a range of factors including ageing, excessive noise, toxins, and cancer. Auto-inflammatory disease is also a cause of hearing loss and there is evidence that inflammation could contribute to hearing loss in other conditions. Within the inner ear there are resident macrophage cells that respond to insults and whose activation correlates with damage. The NLRP3 inflammasome is a multi-molecular pro-inflammatory protein complex that forms in activated macrophages and may contribute to hearing loss. The aim of this article is to discuss the evidence for the NLRP3 inflammasome and associated cytokines as potential therapeutic targets for sensorineural hearing loss in conditions ranging from auto-inflammatory disease to tumour-induced hearing loss in vestibular schwannoma.


Asunto(s)
Oído Interno , Pérdida Auditiva Sensorineural , Pérdida Auditiva , Adulto , Humanos , Inflamasomas/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Pérdida Auditiva Sensorineural/etiología , Pérdida Auditiva Sensorineural/metabolismo , Oído Interno/metabolismo , Pérdida Auditiva/complicaciones
3.
Malar J ; 21(1): 206, 2022 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-35768835

RESUMEN

BACKGROUND: Rapid emergence of Plasmodium resistance to anti-malarial drug mainstays has driven a continual effort to discover novel drugs that target different biochemical pathway (s) during infection. Plasma membrane Calcium + 2 ATPase (PMCA4), a novel plasma membrane protein that regulates Calcium levels in various cells, namely red blood cell (RBC), endothelial cell and platelets, represents a new biochemical pathway that may interfere with susceptibility to malaria and/or severe malaria. METHODS: This study identified several pharmacological inhibitors of PMCA4, namely ATA and Resveratrol, and tested for their anti-malarial activities in vitro and in vivo using the Plasmodium falciparum 3D7 strain, the Plasmodium berghei ANKA strain, and Plasmodium yoelii 17XL strain as model. RESULTS: In vitro propagation of P. falciparum 3D7 strain in the presence of a wide concentration range of the inhibitors revealed that the parasite growth was inhibited in a dose-dependent manner, with IC50s at 634 and 0.231 µM, respectively. RESULTS: The results confirmed that both compounds exhibit moderate to potent anti-malarial activities with the strongest parasite growth inhibition shown by resveratrol at 0.231 µM. In vivo models using P. berghei ANKA for experimental cerebral malaria and P. yoelii 17XL for the effect on parasite growth, showed that the highest dose of ATA, 30 mg/kg BW, increased survival of the mice. Likewise, resveratrol inhibited the parasite growth following 4 days intraperitoneal injection at the dose of 100 mg/kg BW. CONCLUSION: The findings indicate that the PMCA4 of the human host may be a potential target for novel anti-malarials, either as single drug or in combination with the currently available effective anti-malarials.


Asunto(s)
Antimaláricos , Malaria Cerebral , Parásitos , Animales , Calcio/farmacología , Ratones , ATPasas Transportadoras de Calcio de la Membrana Plasmática , Plasmodium berghei , Plasmodium falciparum , Resveratrol/farmacología
4.
J Immunol ; 205(6): 1608-1619, 2020 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-32817333

RESUMEN

CD4+ T cell functional inhibition (exhaustion) is a hallmark of malaria and correlates with impaired parasite control and infection chronicity. However, the mechanisms of CD4+ T cell exhaustion are still poorly understood. In this study, we show that Ag-experienced (Ag-exp) CD4+ T cell exhaustion during Plasmodium yoelii nonlethal infection occurs alongside the reduction in mammalian target of rapamycin (mTOR) activity and restriction in CD4+ T cell glycolytic capacity. We demonstrate that the loss of glycolytic metabolism and mTOR activity within the exhausted Ag-expCD4+ T cell population during infection coincides with reduction in T-bet expression. T-bet was found to directly bind to and control the transcription of various mTOR and metabolism-related genes within effector CD4+ T cells. Consistent with this, Ag-expTh1 cells exhibited significantly higher and sustained mTOR activity than effector T-bet- (non-Th1) Ag-expT cells throughout the course of malaria. We identified mTOR to be redundant for sustaining T-bet expression in activated Th1 cells, whereas mTOR was necessary but not sufficient for maintaining IFN-γ production by Th1 cells. Immunotherapy targeting PD-1, CTLA-4, and IL-27 blocked CD4+ T cell exhaustion during malaria infection and was associated with elevated T-bet expression and a concomitant increased CD4+ T cell glycolytic metabolism. Collectively, our data suggest that mTOR activity is linked to T-bet in Ag-expCD4+ T cells but that reduction in mTOR activity may not directly underpin Ag-expTh1 cell loss and exhaustion during malaria infection. These data have implications for therapeutic reactivation of exhausted CD4+ T cells during malaria infection and other chronic conditions.


Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Malaria/inmunología , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Plasmodium yoelii/fisiología , Proteínas de Dominio T Box/metabolismo , Células TH1/inmunología , Animales , Senescencia Celular , Regulación de la Expresión Génica , Glucólisis , Humanos , Tolerancia Inmunológica , Memoria Inmunológica , Interferón gamma/metabolismo , Interleucina-27/metabolismo , Activación de Linfocitos , Malaria/terapia , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas de Dominio T Box/genética
5.
Immunology ; 164(4): 737-753, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34407221

RESUMEN

Experimental cerebral malaria (ECM) is a severe complication of Plasmodium berghei ANKA (PbA) infection in mice, characterized by CD8+ T-cell accumulation within the brain. Whilst the dynamics of CD8+ T-cell activation and migration during extant primary PbA infection have been extensively researched, the fate of the parasite-specific CD8+ T cells upon resolution of ECM is not understood. In this study, we show that memory OT-I cells persist systemically within the spleen, lung and brain following recovery from ECM after primary PbA-OVA infection. Whereas memory OT-I cells within the spleen and lung exhibited canonical central memory (Tcm) and effector memory (Tem) phenotypes, respectively, memory OT-I cells within the brain post-PbA-OVA infection displayed an enriched CD69+ CD103- profile and expressed low levels of T-bet. OT-I cells within the brain were excluded from short-term intravascular antibody labelling but were targeted effectively by longer-term systemically administered antibodies. Thus, the memory OT-I cells were extravascular within the brain post-ECM but were potentially not resident memory cells. Importantly, whilst memory OT-I cells exhibited strong reactivation during secondary PbA-OVA infection, preventing activation of new primary effector T cells, they had dampened reactivation during a fourth PbA-OVA infection. Overall, our results demonstrate that memory CD8+ T cells are systemically distributed but exhibit a unique phenotype within the brain post-ECM, and that their reactivation characteristics are shaped by infection history. Our results raise important questions regarding the role of distinct memory CD8+ T-cell populations within the brain and other tissues during repeat Plasmodium infections.


Asunto(s)
Linfocitos T CD8-positivos/inmunología , Interacciones Huésped-Parásitos/inmunología , Malaria/inmunología , Malaria/parasitología , Plasmodium berghei/fisiología , Animales , Biomarcadores , Linfocitos T CD8-positivos/metabolismo , Linfocitos T CD8-positivos/patología , Quimiotaxis de Leucocito/inmunología , Susceptibilidad a Enfermedades , Epítopos de Linfocito T/inmunología , Eritrocitos/inmunología , Eritrocitos/parasitología , Matriz Extracelular , Memoria Inmunológica , Inmunofenotipificación , Estadios del Ciclo de Vida , Activación de Linfocitos/inmunología , Malaria/metabolismo , Malaria/patología , Malaria Cerebral/inmunología , Malaria Cerebral/metabolismo , Malaria Cerebral/parasitología , Ratones , Ratones Transgénicos , Especificidad de Órganos/inmunología
6.
Malar J ; 20(1): 297, 2021 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-34215257

RESUMEN

BACKGROUND: Recent genome wide analysis studies have identified a strong association between single nucleotide variations within the human ATP2B4 gene and susceptibility to severe malaria. The ATP2B4 gene encodes the plasma membrane calcium ATPase 4 (PMCA4), which is responsible for controlling the physiological level of intracellular calcium in many cell types, including red blood cells (RBCs). It is, therefore, postulated that genetic differences in the activity or expression level of PMCA4 alters intracellular Ca2+ levels and affects RBC hydration, modulating the invasion and growth of the Plasmodium parasite within its target host cell. METHODS: In this study the course of three different Plasmodium spp. infections were examined in mice with systemic knockout of Pmca4 expression. RESULTS: Ablation of PMCA4 reduced the size of RBCs and their haemoglobin content but did not affect RBC maturation and reticulocyte count. Surprisingly, knockout of PMCA4 did not significantly alter peripheral parasite burdens or the dynamics of blood stage Plasmodium chabaudi infection or reticulocyte-restricted Plasmodium yoelii infection. Interestingly, although ablation of PMCA4 did not affect peripheral parasite levels during Plasmodium berghei infection, it did promote slight protection against experimental cerebral malaria, associated with a minor reduction in antigen-experienced T cell accumulation in the brain. CONCLUSIONS: The finding suggests that PMCA4 may play a minor role in the development of severe malarial complications, but that this appears independent of direct effects on parasite invasion, growth or survival within RBCs.


Asunto(s)
Resistencia a la Enfermedad/genética , Malaria/genética , ATPasas Transportadoras de Calcio de la Membrana Plasmática/genética , Plasmodium/fisiología , Animales , Membrana Celular , Malaria/sangre , Malaria/parasitología , Malaria Cerebral/genética , Malaria Cerebral/parasitología , Ratones , Ratones Noqueados , ATPasas Transportadoras de Calcio de la Membrana Plasmática/metabolismo , Plasmodium berghei/fisiología , Plasmodium chabaudi/fisiología , Plasmodium yoelii/fisiología
7.
Proc Natl Acad Sci U S A ; 115(28): 7404-7409, 2018 07 10.
Artículo en Inglés | MEDLINE | ID: mdl-29954866

RESUMEN

Cerebral malaria (CM) is a serious neurological complication caused by Plasmodium falciparum infection. Currently, the only treatment for CM is the provision of antimalarial drugs; however, such treatment by itself often fails to prevent death or development of neurological sequelae. To identify potential improved treatments for CM, we performed a nonbiased whole-brain transcriptomic time-course analysis of antimalarial drug chemotherapy of murine experimental CM (ECM). Bioinformatics analyses revealed IL33 as a critical regulator of neuroinflammation and cerebral pathology that is down-regulated in the brain during fatal ECM and in the acute period following treatment of ECM. Consistent with this, administration of IL33 alongside antimalarial drugs significantly improved the treatment success of established ECM. Mechanistically, IL33 treatment reduced inflammasome activation and IL1ß production in microglia and intracerebral monocytes in the acute recovery period following treatment of ECM. Moreover, treatment with the NLRP3-inflammasome inhibitor MCC950 alongside antimalarial drugs phenocopied the protective effect of IL33 therapy in improving the recovery from established ECM. We further showed that IL1ß release from macrophages was stimulated by hemozoin and antimalarial drugs and that this was inhibited by MCC950. Our results therefore demonstrate that manipulation of the IL33-NLRP3 axis may be an effective therapy to suppress neuroinflammation and improve the efficacy of antimalarial drug treatment of CM.


Asunto(s)
Antimaláricos/farmacología , Encéfalo/parasitología , Sistemas de Liberación de Medicamentos/métodos , Interleucina-33/metabolismo , Malaria Cerebral/tratamiento farmacológico , Malaria Falciparum/tratamiento farmacológico , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Plasmodium falciparum/metabolismo , Animales , Encéfalo/metabolismo , Encéfalo/patología , Modelos Animales de Enfermedad , Femenino , Perfilación de la Expresión Génica , Hemoproteínas/metabolismo , Interleucina-1beta/biosíntesis , Interleucina-33/antagonistas & inhibidores , Macrófagos/metabolismo , Macrófagos/patología , Malaria Cerebral/metabolismo , Malaria Cerebral/patología , Malaria Falciparum/metabolismo , Malaria Falciparum/patología , Masculino , Ratones , Proteína con Dominio Pirina 3 de la Familia NLR/antagonistas & inhibidores , Transcriptoma/efectos de los fármacos
8.
Parasite Immunol ; 42(9): e12723, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32306409

RESUMEN

AIMS: Co-inhibitory receptors play a major role in controlling the Th1 response during blood-stage malaria. Whilst PD-1 is viewed as the dominant co-inhibitory receptor restricting T cell responses, the roles of other such receptors in coordinating Th1 cell activity during malaria are poorly understood. METHODS AND RESULTS: Here, we show that the co-inhibitory receptor Tim-3 is expressed on splenic antigen-specific T-bet+ (Th1) OT-II cells transiently during the early stage of infection with transgenic Plasmodium yoelii NL parasites expressing ovalbumin (P yoelii NL-OVA). We reveal that co-blockade of Tim-3 and PD-L1 during the acute phase of P yoelii NL infection did not improve the Th1 cell response but instead led to a specific reduction in the numbers of splenic Th1 OT-II cells. Combined blockade of Tim-3 and PD-L1 did elevate anti-parasite IgG antibody responses. Nevertheless, co-blockade of Tim-3 and PD-L1 did not affect IFN-γ production by OT-II cells and did not influence parasite control during P yoelii NL-OVA infection. CONCLUSION: Thus, our results show that Tim-3 plays an unexpected combinatorial role with PD-1 in promoting and/ or sustaining a Th1 cell response during the early phase of blood-stage P. yoelii NL infection but combined blockade does not dramatically influence anti-parasite immunity.


Asunto(s)
Receptor 2 Celular del Virus de la Hepatitis A/inmunología , Malaria/inmunología , Receptor de Muerte Celular Programada 1/inmunología , Células TH1/inmunología , Animales , Antígeno B7-H1 , Línea Celular , Epítopos/inmunología , Malaria/parasitología , Masculino , Ratones Endogámicos C57BL , Bazo/inmunología
9.
PLoS Pathog ; 13(3): e1006267, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-28273147

RESUMEN

The murine model of experimental cerebral malaria (ECM) has been utilised extensively in recent years to study the pathogenesis of human cerebral malaria (HCM). However, it has been proposed that the aetiologies of ECM and HCM are distinct, and, consequently, no useful mechanistic insights into the pathogenesis of HCM can be obtained from studying the ECM model. Therefore, in order to determine the similarities and differences in the pathology of ECM and HCM, we have performed the first spatial and quantitative histopathological assessment of the ECM syndrome. We demonstrate that the accumulation of parasitised red blood cells (pRBCs) in brain capillaries is a specific feature of ECM that is not observed during mild murine malaria infections. Critically, we show that individual pRBCs appear to occlude murine brain capillaries during ECM. As pRBC-mediated congestion of brain microvessels is a hallmark of HCM, this suggests that the impact of parasite accumulation on cerebral blood flow may ultimately be similar in mice and humans during ECM and HCM, respectively. Additionally, we demonstrate that cerebrovascular CD8+ T-cells appear to co-localise with accumulated pRBCs, an event that corresponds with development of widespread vascular leakage. As in HCM, we show that vascular leakage is not dependent on extensive vascular destruction. Instead, we show that vascular leakage is associated with alterations in transcellular and paracellular transport mechanisms. Finally, as in HCM, we observed axonal injury and demyelination in ECM adjacent to diverse vasculopathies. Collectively, our data therefore shows that, despite very different presentation, and apparently distinct mechanisms, of parasite accumulation, there appear to be a number of comparable features of cerebral pathology in mice and in humans during ECM and HCM, respectively. Thus, when used appropriately, the ECM model may be useful for studying specific pathological features of HCM.


Asunto(s)
Encéfalo/patología , Encéfalo/parasitología , Modelos Animales de Enfermedad , Malaria Cerebral/patología , Malaria Cerebral/parasitología , Animales , Eritrocitos/parasitología , Femenino , Técnica del Anticuerpo Fluorescente , Humanos , Procesamiento de Imagen Asistido por Computador , Inmunohistoquímica , Masculino , Ratones , Ratones Endogámicos C57BL , Microscopía Electrónica de Transmisión , Plasmodium berghei
10.
J Immunol ; 197(8): 3152-3164, 2016 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-27630165

RESUMEN

CD4+ T cells that produce IFN-γ are the source of host-protective IL-10 during primary infection with a number of different pathogens, including Plasmodium spp. The fate of these CD4+IFN-γ+IL-10+ T cells following clearance of primary infection and their subsequent influence on the course of repeated infections is, however, presently unknown. In this study, utilizing IFN-γ-yellow fluorescent protein (YFP) and IL-10-GFP dual reporter mice, we show that primary malaria infection-induced CD4+YFP+GFP+ T cells have limited memory potential, do not stably express IL-10, and are disproportionately lost from the Ag-experienced CD4+ T cell memory population during the maintenance phase postinfection. CD4+YFP+GFP+ T cells generally exhibited a short-lived effector rather than effector memory T cell phenotype postinfection and expressed high levels of PD-1, Lag-3, and TIGIT, indicative of cellular exhaustion. Consistently, the surviving CD4+YFP+GFP+ T cell-derived cells were unresponsive and failed to proliferate during the early phase of secondary infection. In contrast, CD4+YFP+GFP- T cell-derived cells expanded rapidly and upregulated IL-10 expression during secondary infection. Correspondingly, CD4+ T cells were the major producers within an accelerated and amplified IL-10 response during the early stage of secondary malaria infection. Notably, IL-10 exerted quantitatively stronger regulatory effects on innate and CD4+ T cell responses during primary and secondary infections, respectively. The results in this study significantly improve our understanding of the durability of IL-10-producing CD4+ T cells postinfection and provide information on how IL-10 may contribute to optimized parasite control and prevention of immune-mediated pathology during repeated malaria infections.


Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Memoria Inmunológica , Interleucina-10/metabolismo , Malaria/inmunología , Plasmodium/inmunología , Animales , Linfocitos T CD4-Positivos/parasitología , Linfocitos T CD4-Positivos/trasplante , Supervivencia Celular , Células Cultivadas , Humanos , Inmunosenescencia , Interferón gamma/genética , Interferón gamma/metabolismo , Interleucina-10/genética , Activación de Linfocitos , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos
11.
Infect Immun ; 85(11)2017 11.
Artículo en Inglés | MEDLINE | ID: mdl-28874445

RESUMEN

Experimental cerebral malaria (ECM) is a gamma interferon (IFN-γ)-dependent syndrome. However, whether IFN-γ promotes ECM through direct and synergistic targeting of multiple cell populations or by acting primarily on a specific responsive cell type is currently unknown. Here, using a panel of cell- and compartment-specific IFN-γ receptor 2 (IFN-γR2)-deficient mice, we show that IFN-γ causes ECM by signaling within both the hematopoietic and nonhematopoietic compartments. Mechanistically, hematopoietic and nonhematopoietic compartment-specific IFN-γR signaling exerts additive effects in orchestrating intracerebral inflammation, leading to the development of ECM. Surprisingly, mice with specific deletion of IFN-γR2 expression on myeloid cells, T cells, or neurons were completely susceptible to terminal ECM. Utilizing a reductionist in vitro system, we show that synergistic IFN-γ and tumor necrosis factor (TNF) stimulation promotes strong activation of brain blood vessel endothelial cells. Combined, our data show that within the hematopoietic compartment, IFN-γ causes ECM by acting redundantly or by targeting non-T cell or non-myeloid cell populations. Within the nonhematopoietic compartment, brain endothelial cells, but not neurons, may be the major target of IFN-γ leading to ECM development. Collectively, our data provide information on how IFN-γ mediates the development of cerebral pathology during malaria infection.


Asunto(s)
Encéfalo/inmunología , Células Endoteliales/inmunología , Interferón gamma/genética , Malaria Cerebral/genética , Plasmodium berghei/patogenicidad , Receptores de Interferón/genética , Animales , Encéfalo/irrigación sanguínea , Encéfalo/parasitología , Encéfalo/patología , Moléculas de Adhesión Celular/genética , Moléculas de Adhesión Celular/inmunología , Quimiocinas CXC/genética , Quimiocinas CXC/inmunología , Modelos Animales de Enfermedad , Células Endoteliales/parasitología , Regulación de la Expresión Génica , Interferón gamma/inmunología , Interleucinas/genética , Interleucinas/inmunología , Malaria Cerebral/inmunología , Malaria Cerebral/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Células Mieloides/inmunología , Células Mieloides/parasitología , Neuronas/inmunología , Neuronas/parasitología , Plasmodium berghei/inmunología , Receptores de Interferón/deficiencia , Receptores de Interferón/inmunología , Transducción de Señal , Linfocitos T/inmunología , Linfocitos T/parasitología
12.
PLoS Pathog ; 11(2): e1004607, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25659095

RESUMEN

Cerebral malaria (CM) is a complex parasitic disease caused by Plasmodium sp. Failure to establish an appropriate balance between pro- and anti-inflammatory immune responses is believed to contribute to the development of cerebral pathology. Using the blood-stage PbA (Plasmodium berghei ANKA) model of infection, we show here that administration of the pro-Th2 cytokine, IL-33, prevents the development of experimental cerebral malaria (ECM) in C57BL/6 mice and reduces the production of inflammatory mediators IFN-γ, IL-12 and TNF-α. IL-33 drives the expansion of type-2 innate lymphoid cells (ILC2) that produce Type-2 cytokines (IL-4, IL-5 and IL-13), leading to the polarization of the anti-inflammatory M2 macrophages, which in turn expand Foxp3 regulatory T cells (Tregs). PbA-infected mice adoptively transferred with ILC2 have elevated frequency of M2 and Tregs and are protected from ECM. Importantly, IL-33-treated mice deleted of Tregs (DEREG mice) are no longer able to resist ECM. Our data therefore provide evidence that IL-33 can prevent the development of ECM by orchestrating a protective immune response via ILC2, M2 macrophages and Tregs.


Asunto(s)
Interleucina-33/inmunología , Macrófagos/inmunología , Malaria Cerebral/inmunología , Linfocitos T Reguladores/inmunología , Células Th2/inmunología , Traslado Adoptivo , Animales , Técnicas de Cocultivo , Modelos Animales de Enfermedad , Ensayo de Inmunoadsorción Enzimática , Femenino , Citometría de Flujo , Inmunidad Innata , Ratones , Ratones Endogámicos C57BL , Plasmodium berghei/inmunología , Reacción en Cadena en Tiempo Real de la Polimerasa
13.
PLoS Pathog ; 11(11): e1005210, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26562533

RESUMEN

There is significant evidence that brain-infiltrating CD8+ T cells play a central role in the development of experimental cerebral malaria (ECM) during Plasmodium berghei ANKA infection of C57BL/6 mice. However, the mechanisms through which they mediate their pathogenic activity during malaria infection remain poorly understood. Utilizing intravital two-photon microscopy combined with detailed ex vivo flow cytometric analysis, we show that brain-infiltrating T cells accumulate within the perivascular spaces of brains of mice infected with both ECM-inducing (P. berghei ANKA) and non-inducing (P. berghei NK65) infections. However, perivascular T cells displayed an arrested behavior specifically during P. berghei ANKA infection, despite the brain-accumulating CD8+ T cells exhibiting comparable activation phenotypes during both infections. We observed T cells forming long-term cognate interactions with CX3CR1-bearing antigen presenting cells within the brains during P. berghei ANKA infection, but abrogation of this interaction by targeted depletion of the APC cells failed to prevent ECM development. Pathogenic CD8+ T cells were found to colocalize with rare apoptotic cells expressing CD31, a marker of endothelial cells, within the brain during ECM. However, cellular apoptosis was a rare event and did not result in loss of cerebral vasculature or correspond with the extensive disruption to its integrity observed during ECM. In summary, our data show that the arrest of T cells in the perivascular compartments of the brain is a unique signature of ECM-inducing malaria infection and implies an important role for this event in the development of the ECM-syndrome.


Asunto(s)
Linfocitos T CD8-positivos/inmunología , Malaria Cerebral/inmunología , Malaria Falciparum/microbiología , Parasitemia/inmunología , Plasmodium berghei/inmunología , Animales , Linfocitos T CD8-positivos/parasitología , Modelos Animales de Enfermedad , Malaria Cerebral/parasitología , Malaria Cerebral/patología , Ratones Endogámicos C57BL
14.
Infect Immun ; 84(1): 34-46, 2016 01.
Artículo en Inglés | MEDLINE | ID: mdl-26459508

RESUMEN

Immune-mediated pathology in interleukin-10 (IL-10)-deficient mice during blood-stage malaria infection typically manifests in nonlymphoid organs, such as the liver and lung. Thus, it is critical to define the cellular sources of IL-10 in these sensitive nonlymphoid compartments during infection. Moreover, it is important to determine if IL-10 production is controlled through conserved or disparate molecular programs in distinct anatomical locations during malaria infection, as this may enable spatiotemporal tuning of the regulatory immune response. In this study, using dual gamma interferon (IFN-γ)-yellow fluorescent protein (YFP) and IL-10-green fluorescent protein (GFP) reporter mice, we show that CD4(+) YFP(+) T cells are the major source of IL-10 in both lymphoid and nonlymphoid compartments throughout the course of blood-stage Plasmodium yoelii infection. Mature splenic CD4(+) YFP(+) GFP(+) T cells, which preferentially expressed high levels of CCR5, were capable of migrating to and seeding the nonlymphoid tissues, indicating that the systemically distributed host-protective cells have a common developmental history. Despite exhibiting comparable phenotypes, CD4(+) YFP(+) GFP(+) T cells from the liver and lung produced significantly larger quantities of IL-10 than their splenic counterparts, showing that the CD4(+) YFP(+) GFP(+) T cells exert graded functions in distinct tissue locations during infection. Unexpectedly, given the unique environmental conditions within discrete nonlymphoid and lymphoid organs, we show that IL-10 production by CD4(+) YFP(+) T cells is controlled systemically during malaria infection through IL-27 receptor signaling that is supported after CD4(+) T cell priming by ICOS signaling. The results in this study substantially improve our understanding of the systemic IL-10 response to malaria infection, particularly within sensitive nonlymphoid organs.


Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Proteína Coestimuladora de Linfocitos T Inducibles/inmunología , Interleucina-10/inmunología , Interleucinas/inmunología , Malaria/inmunología , Traslado Adoptivo , Animales , Proteínas Bacterianas/genética , Linfocitos T CD4-Positivos/trasplante , Proteínas Fluorescentes Verdes/genética , Interferón gamma/genética , Interferón gamma/inmunología , Interleucina-10/genética , Hígado/inmunología , Proteínas Luminiscentes/genética , Pulmón/inmunología , Malaria/parasitología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Plasmodium yoelii/inmunología , Bazo/inmunología
15.
PLoS Pathog ; 9(4): e1003293, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23593003

RESUMEN

The IL-27R, WSX-1, is required to limit IFN-γ production by effector CD4⁺ T cells in a number of different inflammatory conditions but the molecular basis of WSX-1-mediated regulation of Th1 responses in vivo during infection has not been investigated in detail. In this study we demonstrate that WSX-1 signalling suppresses the development of pathogenic, terminally differentiated (KLRG-1⁺) Th1 cells during malaria infection and establishes a restrictive threshold to constrain the emergent Th1 response. Importantly, we show that WSX-1 regulates cell-intrinsic responsiveness to IL-12 and IL-2, but the fate of the effector CD4⁺ T cell pool during malaria infection is controlled primarily through IL-12 dependent signals. Finally, we show that WSX-1 regulates Th1 cell terminal differentiation during malaria infection through IL-10 and Foxp3 independent mechanisms; the kinetics and magnitude of the Th1 response, and the degree of Th1 cell terminal differentiation, were comparable in WT, IL-10R1⁻/⁻ and IL-10⁻/⁻ mice and the numbers and phenotype of Foxp3⁺ cells were largely unaltered in WSX-1⁻/⁻ mice during infection. As expected, depletion of Foxp3⁺ cells did not enhance Th1 cell polarisation or terminal differentiation during malaria infection. Our results significantly expand our understanding of how IL-27 regulates Th1 responses in vivo during inflammatory conditions and establishes WSX-1 as a critical and non-redundant regulator of the emergent Th1 effector response during malaria infection.


Asunto(s)
Interferón gamma/biosíntesis , Interleucina-12/metabolismo , Malaria Falciparum/inmunología , Receptores de Citocinas/metabolismo , Células TH1/inmunología , Animales , Apoptosis , Diferenciación Celular , Proliferación Celular , Supervivencia Celular , Factores de Transcripción Forkhead/metabolismo , Interleucina-1/metabolismo , Interleucina-10/genética , Subunidad alfa del Receptor de Interleucina-10/genética , Interleucina-2/metabolismo , Interleucina-27/metabolismo , Lectinas Tipo C , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Plasmodium falciparum/inmunología , Receptores de Citocinas/genética , Receptores Inmunológicos/metabolismo , Receptores de Interleucina , Transducción de Señal , Proteínas de Dominio T Box/biosíntesis
16.
J Immunol ; 190(9): 4553-61, 2013 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-23536628

RESUMEN

IL-27 exerts pleiotropic suppressive effects on naive and effector T cell populations during infection and inflammation. Surprisingly, however, the role of IL-27 in restricting or shaping effector CD4(+) T cell chemotactic responses, as a mechanism to reduce T cell-dependent tissue inflammation, is unknown. In this study, using Plasmodium berghei NK65 as a model of a systemic, proinflammatory infection, we demonstrate that IL-27R signaling represses chemotaxis of infection-derived splenic CD4(+) T cells in response to the CCR5 ligands, CCL4 and CCL5. Consistent with these observations, CCR5 was expressed on significantly higher frequencies of splenic CD4(+) T cells from malaria-infected, IL-27R-deficient (WSX-1(-/-)) mice than from infected wild-type mice. We find that IL-27 signaling suppresses splenic CD4(+) T cell CCR5-dependent chemotactic responses during infection by restricting CCR5 expression on CD4(+) T cell subtypes, including Th1 cells, and also by controlling the overall composition of the CD4(+) T cell compartment. Diminution of the Th1 response in infected WSX-1(-/-) mice in vivo by neutralization of IL-12p40 attenuated CCR5 expression by infection-derived CD4(+) T cells and also reduced splenic CD4(+) T cell chemotaxis toward CCL4 and CCL5. These data reveal a previously unappreciated role for IL-27 in modulating CD4(+) T cell chemotactic pathways during infection, which is related to its capacity to repress Th1 effector cell development. Thus, IL-27 appears to be a key cytokine that limits the CCR5-CCL4/CCL5 axis during inflammatory settings.


Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Malaria/inmunología , Receptores de Citocinas/inmunología , Transducción de Señal/inmunología , Animales , Linfocitos T CD4-Positivos/metabolismo , Quimiocina CCL4/inmunología , Quimiocina CCL4/metabolismo , Quimiocina CCL5/inmunología , Quimiocina CCL5/metabolismo , Inflamación/inmunología , Subunidad p40 de la Interleucina-12/inmunología , Subunidad p40 de la Interleucina-12/metabolismo , Interleucina-2/inmunología , Interleucina-2/metabolismo , Interleucinas/inmunología , Interleucinas/metabolismo , Malaria/metabolismo , Ratones , Ratones Endogámicos C57BL , Plasmodium berghei/inmunología , Receptores CCR5/inmunología , Receptores CCR5/metabolismo , Receptores de Citocinas/metabolismo , Receptores de Interleucina , Receptores de Interleucina-10/inmunología , Receptores de Interleucina-10/metabolismo , Células TH1/inmunología , Células TH1/metabolismo
17.
Infect Immun ; 82(1): 10-20, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24101691

RESUMEN

Interleukin-27 (IL-27) is known to control primary CD4(+) T cell responses during a variety of different infections, but its role in regulating memory CD4(+) T responses has not been investigated in any model. In this study, we have examined the functional importance of IL-27 receptor (IL-27R) signaling in regulating the formation and maintenance of memory CD4(+) T cells following malaria infection and in controlling their subsequent reactivation during secondary parasite challenge. We demonstrate that although the primary effector/memory CD4(+) T cell response was greater in IL-27R-deficient (WSX-1(-/-)) mice following Plasmodium berghei NK65 infection than in wild-type (WT) mice, there were no significant differences in the size of the maintained memory CD4(+) T population(s) at 20 weeks postinfection in the spleen, liver, or bone marrow of WSX-1(-/-) mice compared with WT mice. However, the composition of the memory CD4(+) T cell pool was slightly altered in WSX-1(-/-) mice following clearance of primary malaria infection, with elevated numbers of late effector memory CD4(+) T cells in the spleen and liver and increased production of IL-2 in the spleen. Crucially, WSX-1(-/-) mice displayed significantly enhanced parasite control compared with WT mice following rechallenge with homologous malaria parasites. Improved parasite control in WSX-1(-/-) mice during secondary infection was associated with elevated systemic production of multiple inflammatory innate and adaptive cytokines and extremely rapid proliferation of antigen-experienced T cells in the liver. These data are the first to demonstrate that IL-27R signaling plays a role in regulating the magnitude and quality of secondary immune responses during rechallenge infections.


Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Inflamación/inmunología , Interleucinas/inmunología , Malaria/inmunología , Receptores de Interleucina/inmunología , Animales , Recuento de Células , Citocinas/sangre , Modelos Animales de Enfermedad , Inmunidad Celular , Interleucinas/fisiología , Hígado/inmunología , Malaria/sangre , Malaria/parasitología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Parasitemia/inmunología , Plasmodium berghei , Transducción de Señal/inmunología , Bazo/inmunología
18.
Infect Immun ; 82(11): 4654-65, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25156724

RESUMEN

Model antigens are frequently introduced into pathogens to study determinants that influence T-cell responses to infections. To address whether an antigen's subcellular location influences the nature and magnitude of antigen-specific T-cell responses, we generated Plasmodium berghei parasites expressing the model antigen ovalbumin (OVA) either in the parasite cytoplasm or on the parasitophorous vacuole membrane (PVM). For cytosolic expression, OVA alone or conjugated to mCherry was expressed from a strong constitutive promoter (OVAhsp70 or OVA::mCherryhsp70); for PVM expression, OVA was fused to HEP17/EXP1 (OVA::Hep17hep17). Unexpectedly, OVA expression in OVAhsp70 parasites was very low, but when OVA was fused to mCherry (OVA::mCherryhsp70), it was highly expressed. OVA expression in OVA::Hep17hep17 parasites was strong but significantly less than that in OVA::mCherryhsp70 parasites. These transgenic parasites were used to examine the effects of antigen subcellular location and expression level on the development of T-cell responses during blood-stage infections. While all OVA-expressing parasites induced activation and proliferation of OVA-specific CD8(+) T cells (OT-I) and CD4(+) T cells (OT-II), the level of activation varied: OVA::Hep17hep17 parasites induced significantly stronger splenic and intracerebral OT-I and OT-II responses than those of OVA::mCherryhsp70 parasites, but OVA::mCherryhsp70 parasites promoted stronger OT-I and OT-II responses than those of OVAhsp70 parasites. Despite lower OVA expression levels, OVA::Hep17hep17 parasites induced stronger T-cell responses than those of OVA::mCherryhsp70 parasites. These results indicate that unconjugated cytosolic OVA is not stably expressed in Plasmodium parasites and, importantly, that its cellular location and expression level influence both the induction and magnitude of parasite-specific T-cell responses. These parasites represent useful tools for studying the development and function of antigen-specific T-cell responses during malaria infection.


Asunto(s)
Regulación de la Expresión Génica/fisiología , Malaria/parasitología , Ovalbúmina/metabolismo , Plasmodium berghei/metabolismo , Transporte de Proteínas/fisiología , Animales , Femenino , Malaria/sangre , Ratones , Organismos Modificados Genéticamente , Ovalbúmina/genética , Plasmodium berghei/genética , Bazo/citología , Linfocitos T/fisiología
19.
PLoS Pathog ; 8(2): e1002504, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22319445

RESUMEN

The balance between pro-inflammatory and regulatory immune responses in determining optimal T cell activation is vital for the successful resolution of microbial infections. This balance is maintained in part by the negative regulators of T cell activation, CTLA-4 and PD-1/PD-L, which dampen effector responses during chronic infections. However, their role in acute infections, such as malaria, remains less clear. In this study, we determined the contribution of CTLA-4 and PD-1/PD-L to the regulation of T cell responses during Plasmodium berghei ANKA (PbA)-induced experimental cerebral malaria (ECM) in susceptible (C57BL/6) and resistant (BALB/c) mice. We found that the expression of CTLA-4 and PD-1 on T cells correlates with the extent of pro-inflammatory responses induced during PbA infection, being higher in C57BL/6 than in BALB/c mice. Thus, ECM develops despite high levels of expression of these inhibitory receptors. However, antibody-mediated blockade of either the CTLA-4 or PD-1/PD-L1, but not the PD-1/PD-L2, pathways during PbA-infection in ECM-resistant BALB/c mice resulted in higher levels of T cell activation, enhanced IFN-γ production, increased intravascular arrest of both parasitised erythrocytes and CD8(+) T cells to the brain, and augmented incidence of ECM. Thus, in ECM-resistant BALB/c mice, CTLA-4 and PD-1/PD-L1 represent essential, independent and non-redundant pathways for maintaining T cell homeostasis during a virulent malaria infection. Moreover, neutralisation of IFN-γ or depletion of CD8(+) T cells during PbA infection was shown to reverse the pathologic effects of regulatory pathway blockade, highlighting that the aetiology of ECM in the BALB/c mice is similar to that in C57BL/6 mice. In summary, our results underscore the differential and complex regulation that governs immune responses to malaria parasites.


Asunto(s)
Antígenos de Diferenciación/inmunología , Antígeno B7-H1/inmunología , Linfocitos T CD8-positivos/inmunología , Antígeno CTLA-4/inmunología , Plasmodium berghei/patogenicidad , Animales , Antígenos de Diferenciación/metabolismo , Antígeno B7-H1/metabolismo , Linfocitos T CD8-positivos/metabolismo , Antígeno CTLA-4/metabolismo , Eritrocitos/parasitología , Interferón gamma/inmunología , Activación de Linfocitos/inmunología , Malaria Cerebral/inmunología , Malaria Cerebral/microbiología , Malaria Cerebral/patología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Plasmodium berghei/inmunología , Receptor de Muerte Celular Programada 1
20.
J Immunol ; 189(2): 968-79, 2012 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-22723523

RESUMEN

It is well established that IFN-γ is required for the development of experimental cerebral malaria (ECM) during Plasmodium berghei ANKA infection of C57BL/6 mice. However, the temporal and tissue-specific cellular sources of IFN-γ during P. berghei ANKA infection have not been investigated, and it is not known whether IFN-γ production by a single cell type in isolation can induce cerebral pathology. In this study, using IFN-γ reporter mice, we show that NK cells dominate the IFN-γ response during the early stages of infection in the brain, but not in the spleen, before being replaced by CD4(+) and CD8(+) T cells. Importantly, we demonstrate that IFN-γ-producing CD4(+) T cells, but not innate or CD8(+) T cells, can promote the development of ECM in normally resistant IFN-γ(-/-) mice infected with P. berghei ANKA. Adoptively transferred wild-type CD4(+) T cells accumulate within the spleen, lung, and brain of IFN-γ(-/-) mice and induce ECM through active IFN-γ secretion, which increases the accumulation of endogenous IFN-γ(-/-) CD8(+) T cells within the brain. Depletion of endogenous IFN-γ(-/-) CD8(+) T cells abrogates the ability of wild-type CD4(+) T cells to promote ECM. Finally, we show that IFN-γ production, specifically by CD4(+) T cells, is sufficient to induce expression of CXCL9 and CXCL10 within the brain, providing a mechanistic basis for the enhanced CD8(+) T cell accumulation. To our knowledge, these observations demonstrate, for the first time, the importance of and pathways by which IFN-γ-producing CD4(+) T cells promote the development of ECM during P. berghei ANKA infection.


Asunto(s)
Encéfalo/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/patología , Linfocitos T CD8-positivos/inmunología , Movimiento Celular/inmunología , Interferón gamma/biosíntesis , Malaria Cerebral/inmunología , Malaria Cerebral/patología , Traslado Adoptivo , Animales , Encéfalo/parasitología , Encéfalo/patología , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD8-positivos/patología , Movimiento Celular/genética , Modelos Animales de Enfermedad , Femenino , Predisposición Genética a la Enfermedad/genética , Inmunidad Innata/genética , Interferón gamma/deficiencia , Interferón gamma/genética , Malaria Cerebral/parasitología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Plasmodium berghei/inmunología
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