RESUMO
Dengue is a mosquito-borne disease caused by one of four serotypes of Dengue virus (DENV-1-4). Severe dengue infection in humans is characterized by thrombocytopenia, increased vascular permeability, hemorrhage and shock. However, there is little information about host response to DENV infection. Here, mechanisms accounting for IFN-γ production and effector function during dengue disease were investigated in a murine model of DENV-2 infection. IFN-γ expression was greatly increased after infection of mice and its production was preceded by increase in IL-12 and IL-18 levels. In IFN-γ(-/-) mice, DENV-2-associated lethality, viral loads, thrombocytopenia, hemoconcentration, and liver injury were enhanced, when compared with wild type-infected mice. IL-12p40(-/-) and IL-18(-/-) infected-mice showed decreased IFN-γ production, which was accompanied by increased disease severity, higher viral loads and enhanced lethality. Blockade of IL-18 in infected IL-12p40(-/-) mice resulted in complete inhibition of IFN-γ production, greater DENV-2 replication, and enhanced disease manifestation, resembling the response seen in DENV-2-infected IFN-γ(-/-) mice. Reduced IFN-γ production was associated with diminished Nitric Oxide-synthase 2 (NOS2) expression and NOS2(-/-) mice had elevated lethality, more severe disease evolution and increased viral load after DENV-2 infection. Therefore, IL-12/IL-18-induced IFN-γ production and consequent NOS2 induction are of major importance to host resistance against DENV infection.
Assuntos
Vírus da Dengue/imunologia , Dengue/imunologia , Interferon gama/imunologia , Interleucina-12/imunologia , Interleucina-18/imunologia , Óxido Nítrico/metabolismo , Animais , Dengue/patologia , Modelos Animais de Doenças , Interferon gama/deficiência , Interferon gama/metabolismo , Interleucina-12/deficiência , Interleucina-12/metabolismo , Interleucina-18/deficiência , Interleucina-18/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Índice de Gravidade de Doença , Análise de SobrevidaRESUMO
Helminths and their products have a profound immunomodulatory effect upon the inductive and effector phases of inflammatory responses, including allergy. We have demonstrated that PAS-1, a protein isolated from Ascaris suum worms, has an inhibitory effect on lung allergic inflammation due to its ability to down-regulate eosinophilic inflammation, Th2 cytokine release and IgE antibody production. Here, we investigated the role of IL-12, IFN-gamma and IL-10 in the PAS-1-induced inhibitory mechanism using a murine model of asthma. Wild type C57BL/6, IL-12(-/-), IFN-gamma(-/-) and IL-10(-/-) mice were immunized with PAS-1 and/or OVA and challenged with the same antigens intranasally. The suppressive effect of PAS-1 was demonstrated on the cellular influx into airways, with reduction of eosinophil number and eosinophil peroxidase activity in OVA+PAS-1-immunized wild type mice. This effect well correlated with a significant reduction in the levels of IL-4, IL-5, IL-13 and eotaxin in BAL fluid. Levels of IgE and IgG1 antibodies were also impaired in serum from these mice. The inhibitory activity of PAS-1 was also observed in IL-12(-/-) mice, but not in IFN-gamma(-/-) and IL-10(-/-) animals. These data show that IFN-gamma and IL-10, but not IL-12, play an important role in the PAS-1 modulatory effect.
Assuntos
Ascaris suum/imunologia , Hiper-Reatividade Brônquica/imunologia , Proteínas de Helminto/metabolismo , Interferon gama/imunologia , Interleucina-10/imunologia , Animais , Formação de Anticorpos/imunologia , Hiper-Reatividade Brônquica/genética , Hiper-Reatividade Brônquica/metabolismo , Movimento Celular/imunologia , Imunoglobulina G/imunologia , Interferon gama/deficiência , Interferon gama/genética , Interferon gama/metabolismo , Interleucina-10/deficiência , Interleucina-10/genética , Interleucina-10/metabolismo , Interleucina-12/deficiência , Interleucina-12/genética , Interleucina-12/imunologia , Interleucina-12/metabolismo , Leucócitos/citologia , Leucócitos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
BACKGROUND: Epidemiological and experimental data suggest that bacterial lipopolysaccharides (LPS) can either protect from or exacerbate allergic asthma. Lipopolysaccharides trigger immune responses through toll-like receptor 4 (TLR4) that in turn activates two major signalling pathways via either MyD88 or TRIF adaptor proteins. The LPS is a pro-Type 1 T helper cells (Th1) adjuvant while aluminium hydroxide (alum) is a strong Type 2 T helper cells (Th2) adjuvant, but the effect of the mixing of both adjuvants on the development of lung allergy has not been investigated. OBJECTIVE: We determined whether natural (LPS) or synthetic (ER-803022) TLR4 agonists adsorbed onto alum adjuvant affect allergen sensitization and development of airway allergic disease. To dissect LPS-induced molecular pathways, we used TLR4-, MyD88-, TRIF-, or IL-12/IFN-gamma-deficient mice. METHODS: Mice were sensitized with subcutaneous injections of ovalbumin (OVA) with or without TLR4 agonists co-adsorbed onto alum and challenged with intranasally with OVA. The development of allergic lung disease was evaluated 24 h after last OVA challenge. RESULTS: Sensitization with OVA plus LPS co-adsorbed onto alum impaired in dose-dependent manner OVA-induced Th2-mediated allergic responses such as airway eosinophilia, type-2 cytokines secretion, airway hyper-reactivity, mucus hyper production and serum levels of IgE or IgG1 anaphylactic antibodies. Although the levels of IgG2a, Th1-affiliated isotype increased, investigation into the lung-specific effects revealed that LPS did not induce a Th1 pattern of inflammation. Lipopolysaccharides impaired the development of Th2 immunity, signaling via TLR4 and MyD88 molecules and via the IL-12/IFN-gamma axis, but not through TRIF pathway. Moreover, the synthetic TLR4 agonists that proved to have a less systemic inflammatory response than LPS also protected against allergic asthma development. CONCLUSION: Toll-like receptor 4 agonists co-adsorbed with allergen onto alum down-modulate allergic lung disease and prevent the development of polarized T cell-mediated airway inflammation.
Assuntos
Adjuvantes Imunológicos/administração & dosagem , Hidróxido de Alumínio/administração & dosagem , Asma/prevenção & controle , Lipopolissacarídeos/administração & dosagem , Receptor 4 Toll-Like/agonistas , Proteínas Adaptadoras de Transporte Vesicular/deficiência , Proteínas Adaptadoras de Transporte Vesicular/imunologia , Alérgenos/imunologia , Animais , Anticorpos/sangue , Asma/imunologia , Líquido da Lavagem Broncoalveolar/imunologia , Células Cultivadas , Citocinas/análise , Citocinas/imunologia , Modelos Animais de Doenças , Feminino , Interferon gama/imunologia , Interleucina-12/deficiência , Interleucina-12/imunologia , Interleucina-12/metabolismo , Pulmão/imunologia , Pulmão/patologia , Camundongos , Camundongos Endogâmicos BALB C , Fator 88 de Diferenciação Mieloide/imunologia , Ovalbumina/imunologia , Fosfolipídeos/farmacologia , Receptor 4 Toll-Like/imunologiaRESUMO
Toxoplasma gondii strains displaying the Type I/III genotype are associated with acquired ocular toxoplasmosis in humans. Here, we used a mice model to characterize some immunological mechanisms involved in host resistance to infection with such strains. We have chosen the Type I/III strains D8, G2 and P-Br, which cause a chronic infection in mice that resembles human toxoplamosis. Mice deficient of molecules MyD88, IFN-gamma, and IL-12 were susceptible to all three parasite strains. This finding indicates the importance of innate mechanisms in controlling infection. On the other hand, MHC haplotype did not influenced resistance/susceptibility; since mice lineages displaying a same genetic background but different MHC haplotypes (H2b or H2d) developed similar mortality and cyst numbers after infection with those strains. In contrast, the C57BL/6 genetic background, and not MHC haplotype, was critical for development of intestinal inflammation caused by any of the studied strains. Finally, regarding effector mechanisms, we observed that B and CD8+ T lymphocytes controlled survival,whereas the inducible nitric oxide synthase influenced cyst numbers in brains of mice infected with Type I/III strains. These findings are relevant to further understanding of the immunologic mechanisms involved in host protection and pathogenesis during infection with T. gondii.
Assuntos
Haplótipos/genética , Complexo Principal de Histocompatibilidade/genética , Camundongos Endogâmicos/imunologia , Toxoplasma/genética , Toxoplasmose Animal/imunologia , Toxoplasmose Cerebral/imunologia , Animais , Modelos Animais de Doenças , Genótipo , Interferon gama/deficiência , Interferon gama/imunologia , Interleucina-12/deficiência , Interleucina-12/imunologia , Complexo Principal de Histocompatibilidade/imunologia , Camundongos , Camundongos Endogâmicos/genética , Fator 88 de Diferenciação Mieloide/deficiência , Fator 88 de Diferenciação Mieloide/imunologia , Fatores de Tempo , Receptores Toll-Like/imunologia , Toxoplasma/patogenicidade , Toxoplasmose Animal/parasitologia , Toxoplasmose Animal/patologia , Toxoplasmose Cerebral/parasitologia , Toxoplasmose Cerebral/patologia , Virulência/genéticaRESUMO
Sepsis is a systemic inflammatory response resulting from local infection due, at least in part, to impaired neutrophil migration. IL-12 and IL-18 play an important role in neutrophil migration. We have investigated the mechanism and relative role of IL-12 and IL-18 in polymicrobial sepsis induced by cecal ligation and puncture (CLP) in mice. Wild-type (WT) and IL-18(-/-) mice were resistant to sublethal CLP (SL-CLP) sepsis. In contrast, IL-12(-/-) mice were susceptible to SL-CLP sepsis with high bacteria load in peritoneal cavity and systemic inflammation (serum TNF-alpha and lung neutrophil infiltration). The magnitude of these events was similar to those observed in WT mice with lethal CLP sepsis. The inability of IL-12(-/-) mice to restrict the infection was not due to impairment of neutrophil migration, but correlated with decrease of phagocytosis, NO production, and microbicidal activities of their neutrophils, and with reduction of systemic IFN-gamma synthesis. Consistent with this observation, IFN-gamma(-/-) mice were as susceptible to SL-CLP as IL-12(-/-) mice. Moreover, addition of IFN-gamma to cultures of neutrophils from IL-12(-/-) mice restored their phagocytic, microbicidal activities and NO production. Mortality of IL-12(-/-) mice to SL-CLP was prevented by treatment with IFN-gamma. Thus we show that IL-12, but not IL-18, is critical to an efficient host defense in polymicrobial sepsis. IL-12 acts through induction of IFN-gamma and stimulation of phagocytic and microbicidal activities of neutrophils, rather than neutrophil migration per se. Our data therefore provide further insight into the defense mechanism against this critical area of infectious disease.
Assuntos
Ceco/imunologia , Ceco/metabolismo , Interleucina-12/metabolismo , Ativação de Neutrófilo/imunologia , Subunidades Proteicas/metabolismo , Punções , Sepse/imunologia , Sepse/metabolismo , Animais , Ceco/microbiologia , Ceco/cirurgia , Movimento Celular , Interferon gama/biossíntese , Interleucina-12/deficiência , Interleucina-12/genética , Subunidade p40 da Interleucina-12 , Interleucina-18/deficiência , Interleucina-18/genética , Interleucina-18/metabolismo , Ligadura , Camundongos , Camundongos Knockout , Neutrófilos/citologia , Neutrófilos/imunologia , Neutrófilos/metabolismo , Óxido Nítrico/biossíntese , Fagocitose , Subunidades Proteicas/deficiência , Subunidades Proteicas/genética , Sepse/microbiologia , Sepse/prevenção & controle , Taxa de SobrevidaRESUMO
BACKGROUND/AIMS: Recent evidence shows a critical role of the CD4+ T cell with the Th1/Th2 paradigm as a possible effector mechanism in ischemia and reperfusion injury. We hypothesize that a polarized Th1 activation response may negatively influence the renal IRI through its relationship with chemokine production (MCP-1) and with a protective tissue response (HO-1). METHODS: We subjected mice to renal ischemia for 45 min using IL-4 and IL-12 knockout C57BL/6. We then measured serum urea levels, performed histomorphometric analysis for tubular necrosis and regeneration, and evaluated the mRNA expression of HO-1, t-bet, Gata-3 and MCP-1 by real-time PCR at 24, 48 and 120 h after surgery. RESULTS/CONCLUSIONS: The IL-4 knockout mice had a statistically significant rise in serum urea levels post IRI compared with control animals. The IL-12-deficient mice were not affected. The IL-4-deficient mice had a statistically significant increase in tubular injury and impairment in cell regeneration. The IRI in IL-4-deficient mice was accompanied by higher levels of HO-1, t-bet and later up-regulation of MCP-1. These findings suggest that the deleterious effects of the Th1 cell involve increased production of chemokines such as MCP-1.
Assuntos
Injúria Renal Aguda/imunologia , Rim/imunologia , Traumatismo por Reperfusão/imunologia , Células Th1/imunologia , Células Th2/imunologia , Animais , Quimiocina CCL2/genética , Heme Oxigenase-1/genética , Interleucina-12/deficiência , Interleucina-4/deficiência , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Regeneração/imunologia , Proteínas com Domínio T , Fatores de Transcrição/genéticaRESUMO
Protozoa of the genus Leishmania are intracellular parasites of macrophages and may cause diverse clinical forms of leishmaniasis, including cutaneous, diffuse cutaneous, mucocutaneous and visceral leishmaniasis. Infection with L. major in mice indicates that a protective immune response is achieved when Th1 cells are developed. Thus, adoptive or vaccine-induced protection against leishmaniasis is largely dependent on cell-mediated immunity and IFN-gamma production. Induction of a Th1 response is dependent on the presence of IL-12 whilst lymphocytes are activated. This study was aimed at evaluating the role of IL-12 during infection with L. amazonensis and after vaccination with Leishvacin (killed Leishmania amazonensis promastigotes), since the role of this cytokine in vaccine-induced immunity with this preparation in experimental models or in humans is not yet elucidated. Hence, C57BL/6 interleukin-12-deficient mice (IL-12p40(-/-)) and wild-type controls (wt) were infected with L. amazonensis and the course of infection, parasite burden and cytokine production were compared. IL-12p40(-/-) mice were more susceptible to L. amazonensis than wt: lesions and parasite burden were larger in IL-12p40(-/-) when compared to wt. Interestingly, IL-4 was not produced in the absence of IL-12 in response to infection with L. amazonensis. To evaluate the role of IL-12 in the vaccine-induced immunity against L. amazonensis infection, IL-12p40(-/-) wt mice were vaccinated in the base of the tail and subsequently challenged with L. amazonensis in the footpads. Surprisingly, vaccinated IL-12p40(-/-) mice developed smaller lesions and had fewer parasites in footpads than non-vaccinated controls. Lymph node and spleen cells from vaccinated IL-12p40(-/-) mice did not produce high levels of IFN-gamma in response do in vitro stimulus with antigen. Hence, partial protection against infection with L. amazonensis could be obtained in the absence of functional IL-12 and a typical Th1 response.
Assuntos
Interleucina-12/deficiência , Leishmania mexicana/imunologia , Leishmaniose Cutânea/imunologia , Leishmaniose Cutânea/prevenção & controle , Subunidades Proteicas/deficiência , Vacinas Protozoárias/farmacologia , Animais , Feminino , Interferon gama/biossíntese , Interleucina-12/genética , Subunidade p40 da Interleucina-12 , Interleucina-4/biossíntese , Leishmaniose Cutânea/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Subunidades Proteicas/genéticaRESUMO
BACKGROUND: Paracoccidioides brasiliensis is a facultative intracellular dimorphic fungus that causes paracoccidioidomycosis (PCM), the most important deep mycosis in Latin America. Only a small percentage of individuals infected by P. brasiliensis develop clinical PCM, possibly in part because of genetically determined interindividual variability of host immunity. However, no primary immunodeficiency has ever been associated with PCM. METHODS: We describe the first patient, to our knowledge, with PCM and a well-defined primary immunodeficiency in the beta 1 subunit of the interleukin (IL)-12/IL-23 receptor, a disorder previously shown to be specifically associated with impaired interferon (IFN)-gamma production, mycobacteriosis, and salmonellosis. RESULTS: Our patient had a childhood history of bacille Calmette-Guérin disease and nontyphoid salmonellosis and, at the age of 20 years, presented to our clinic with a disseminated (acute) form of PCM. He responded well to antifungal treatment and is now doing well at 24 years of age. CONCLUSIONS: This unique observation supports previous studies of PCM suggesting that IL-12, IL-23, and IFN-gamma play an important role in protective immunity to P. brasiliensis. Tuberculosis and PCM are thus not only related clinically and pathologically, but also by their immunological pathogenesis. Our study further expands the spectrum of clinical manifestations of inherited defects of the IL-12/IL-23-IFN-gamma axis. Patients with unexplained deep fungal infections, such as PCM, should be tested for defects in the IL-12/IL-23-IFN- gamma axis.
Assuntos
Hospedeiro Imunocomprometido/genética , Interferon gama/deficiência , Interleucina-12/deficiência , Interleucinas/deficiência , Paracoccidioides , Paracoccidioidomicose/imunologia , Receptores de Interleucina/deficiência , Adulto , Humanos , Interleucina-23 , Subunidade p19 da Interleucina-23 , Masculino , Mutação , Paracoccidioidomicose/genética , Receptores de Interleucina/genética , Receptores de Interleucina-12RESUMO
We have previously shown that macrophages from interleukin (IL)-12p40 gene knockout (IL-12/IL-23-/-) mice have a bias towards the M2 activation profile, spontaneously secreting large quantities of transforming growth factor-beta1 (TGF-beta1) and producing low levels of nitric oxide (NO) in response to lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). To verify whether the activation profile of dendritic cells (DCs) is also influenced by the absence of IL-12/IL-23, bone marrow-derived DCs from IL-12/IL-23-/- and C57BL/6 mice were evaluated. At first we noticed that approximately 50% of the C57BL/6 DCs were dead after LPS-induced maturation, whereas the mortality of IL-12/IL-23-/- DCs was < 10%, a protective effect that diminished when recombinant IL-12 (rIL-12) was added during maturation. Similarly to macrophages, mature IL-12/IL-23-/- DCs (mDCs) produced higher levels of TGF-beta1 and lower levels of NO than C57BL/6 mDCs. NO release was IFN-gamma-dependent, as evidenced by the poor response of IFN-gamma-/- and IL-12/IL-23-/-IFN-gamma-/- mDCs. Nevertheless, IFN-gamma deficiency was not the sole reason for the weak NO response observed in the absence of IL-12/IL-23. The high level of TGF-beta1 secretion by IL-12/IL-23-/- mDCs could explain why exogenous IFN-gamma partially restored the NO production of IFN-gamma-/- mDCs, while IL-12/IL-23-/- IFN-gamma-/- mDCs remained unresponsive. We also showed that CD4+ T-cell proliferation was inhibited by C57BL/6 mDCs, but not by IL-12/IL-23-/- mDCs. IFN-gamma and NO appear to mediate this antiproliferative effect because this effect was not observed in the presence of mDCs from IFN-gamma-/- or IL-12/IL-23-/- IFN-gamma-/- mice and it was attenuated by aminoguanidine. We conclude that the presence of IL-12/IL-23 during LPS-induced maturation influences the activation profile of DCs by a mechanism that is, only in part, IFN-gamma dependent.
Assuntos
Medula Óssea/imunologia , Células Dendríticas/imunologia , Interleucina-12/deficiência , Ativação Linfocitária/fisiologia , Animais , Proliferação de Células , Células Cultivadas , Imunofenotipagem , Interferon gama/deficiência , Interferon gama/imunologia , Interleucina-12/imunologia , Interleucina-23 , Subunidade p19 da Interleucina-23 , Interleucinas/deficiência , Interleucinas/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico/metabolismo , Fator de Crescimento Transformador beta/metabolismoRESUMO
The interferon-gamma (IFN-gamma)/interleukin-12 (IL-12) pathway is a pivotal player in the immune system and is central to controlling mycobacterial infections. We highlight the most recent and relevant advances in understanding this pathway and their repercussions on basic and clinical science. Human mutations in IFN-gamma receptor-1 (IFN-gammaR1), IFN-gammaR2, IL-12p40, IL-12 receptor-beta1, signal transducer and activator of transcription-1, and nuclear factor-kappaB essential modulator are analyzed in the context of genetic susceptibility to mycobacterial diseases. A diagnostic and therapeutic approach is described. The IFN-gamma/IL-12 pathway is central in immune control of both environmental and autochthonous challenges, as reflected in human mutations and animal models. Besides being crucial for mycobacterial control, the IFN-gamma/IL-12 pathway is also involved in the pathogenesis of autoimmune disease as well as tumor development and control. Genotype-phenotype correlations have been established for certain genes in this pathway, some of which have therapeutic implications.
Assuntos
Interferon gama/genética , Interleucina-12/genética , Infecções por Mycobacterium/diagnóstico , Infecções por Mycobacterium/terapia , Receptores de Interferon/genética , Receptores de Interleucina/genética , Animais , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Humanos , Quinase I-kappa B , Interferon gama/deficiência , Interleucina-12/deficiência , Mutação , Infecções por Mycobacterium/genética , Proteínas Serina-Treonina Quinases/deficiência , Proteínas Serina-Treonina Quinases/genética , Receptores de Interferon/deficiência , Receptores de Interleucina/deficiência , Receptores de Interleucina-12 , Fator de Transcrição STAT1 , Transdução de Sinais , Transativadores/deficiência , Transativadores/genética , Receptor de Interferon gamaRESUMO
Resistance to infection by Leishmania major has been associated with the development of a Th1 type response that is dependent on the presence of interleukin 12 (IL-12). In this work the involvement of this cytokine in the response to infection by L. braziliensis, a less virulent species in the mouse model, was evaluated. Our results show that while interferon (IFN-gamma) deficient (-/-) mice inoculated L. braziliensis develop severe uncontrolled lesions, chronic lesions that remained under control up to 12 weeks of infection were observed in IL-12p40 -/- mice. IL 12p40 -/- mice had fewer parasites in their lesions than IFN-gamma (-/-) mice. Lymph node cells from IL-12p40 -/- were capable of producing low but consistent levels of IFN-gamma suggestive of its involvement in parasite control. Furthermore, as opposed to previous reports on L. major-infected animals, no switch to a Th2 response was observed in IL-12p40 -/- infected with L. braziliensis.
Assuntos
Interferon gama/imunologia , Interleucina-12/deficiência , Leishmania braziliensis/imunologia , Leishmaniose Cutânea/imunologia , Subunidades Proteicas/deficiência , Animais , Modelos Animais de Doenças , Feminino , Interferon gama/biossíntese , Interleucina-12/biossíntese , Interleucina-12/imunologia , Subunidade p40 da Interleucina-12 , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Subunidades Proteicas/biossíntese , Subunidades Proteicas/imunologia , Fatores de TempoRESUMO
Primary immunodeficiencies (PIDs) primarily affecting the phagocytes (neutrophils and macrophages) typically predispose patients to infections. However, one of the most clinically important features of these disorders is their relatively narrow spectrum of disease-specific infections. Invasive aspergillosis in the absence of immune suppression is essentially seen only in chronic granulomatous disease; disseminated nontuberculous mycobacterial infection in the absence of immune suppression is seen predominantly in patients with defects of the IFN-gamma/IL-12 axis. In contrast, infections that are relatively common in some of the PIDs affecting the lymphoid system (Pneumocystis jiroveci and Streptococcus pneumoniae) are extremely uncommon in PIDs affecting phagocytes. Therefore careful attention to the microbiology laboratory early in the course of evaluation of a patient with recurrent infections and suspected of having a PID will help steer the workup in the appropriate direction. Over the last few years, there have been major advances in the molecular and cellular understandings of PIDs affecting phagocytes. As the field of PIDs becomes broader and more clinical and molecular definition becomes available, it is increasingly important to be able to identify likely pathways for investigation early in the evaluation. Here we have updated some of the more rapidly evolving aspects of PIDs affecting phagocytes, with a special emphasis on the associated microbiology.
Assuntos
Síndromes de Imunodeficiência/complicações , Infecções/etiologia , Fagócitos , Adesão Celular , Humanos , Interleucina-12/deficiência , Leucócitos , Isoformas de Proteínas/deficiência , Receptores de Interferon/deficiência , Receptor de Interferon gamaRESUMO
C3H mice infected with Leishmania mexicana fail to develop a protective Th1 response, and are unable to cure. In this study, we show that L. mexicana cysteine proteases suppress the antileishmanial immune response. Previous studies demonstrated that deletion of the entire multicopy cysteine protease B (CPB) gene array in L. mexicana is associated with decreased parasite virulence, potentially attributable to factors related to parasite fitness rather than to direct effects on the host immune response. We now show that C3H mice infected with the L. mexicana deletion mutant (Deltacpb) initially develop lesions that grow at rates comparable to those of wild-type L. mexicana-infected mice. However, in contrast to controls, Deltacpb-induced lesions heal with an accompanying Th1 immune response. Lesion resolution was Th1 dependent, as Deltacpb-infected IL-12p40(-/-) and STAT4(-/-) mice developed high parasite burdens and progressive disease. Moreover, when L. major was transfected with a cosmid expressing multiple L. mexicana CPB genes, this parasite induced a significantly lower IFN-gamma response compared with wild-type L. major. These data indicate that cysteine proteases of L. mexicana are critical in suppressing protective immune responses and that inhibition of CPB may prove to be a valuable immunomodulatory strategy for chronic forms of leishmaniasis.
Assuntos
Catepsina B/fisiologia , Regulação para Baixo/imunologia , Leishmania mexicana/enzimologia , Leishmania mexicana/imunologia , Leishmaniose Cutânea/imunologia , Células Th1/imunologia , Células Th1/parasitologia , Animais , Catepsina B/deficiência , Catepsina B/genética , Catepsina B/imunologia , Células Cultivadas , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/fisiologia , Regulação para Baixo/genética , Regulação Enzimológica da Expressão Gênica/imunologia , Imunidade Inata , Interferon gama/antagonistas & inibidores , Interferon gama/biossíntese , Interleucina-12/deficiência , Interleucina-12/genética , Interleucina-12/fisiologia , Subunidade p40 da Interleucina-12 , Leishmania mexicana/genética , Leishmaniose Cutânea/genética , Leishmaniose Cutânea/parasitologia , Leishmaniose Cutânea/prevenção & controle , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Knockout , Subunidades Proteicas/deficiência , Subunidades Proteicas/genética , Subunidades Proteicas/fisiologia , Vacinas Protozoárias/administração & dosagem , Vacinas Protozoárias/genética , Vacinas Protozoárias/imunologia , Fator de Transcrição STAT4 , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Células Th1/metabolismo , Transativadores/deficiência , Transativadores/genética , Transativadores/fisiologiaRESUMO
Studies in humans and in experimental models suggest the involvement of the immune system for efficacy of drug treatment against protozoan parasites. This study tested this hypothesis by using various cytokine and inducible nitric oxide synthase (iNOS) knockout (KO) mice infected with Trypanosoma cruzi and treated with benznidazole. In contrast with the 100% parasitologic cure rate achieved in wild-type animals, benznidazole failed to cure 100%, 42%, 35%, and 28% of interferon-gamma, interleukin-12 (protein 40), protein 55-tumor necrosis factor receptor, and iNOS KO mice, respectively. These results suggest that activation of the immune system by the parasite and endogenous interferon-gamma play a major role in the efficacy of benznidazole against infection with T. cruzi.
Assuntos
Doença de Chagas/tratamento farmacológico , Doença de Chagas/imunologia , Interferon gama/imunologia , Nitroimidazóis/uso terapêutico , Trypanosoma cruzi/imunologia , Animais , Antígenos CD/genética , Doença de Chagas/parasitologia , Feminino , Deleção de Genes , Interferon gama/deficiência , Interferon gama/genética , Interleucina-12/deficiência , Interleucina-12/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico Sintase/deficiência , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase Tipo II , Receptores do Fator de Necrose Tumoral/deficiência , Receptores do Fator de Necrose Tumoral/genética , Receptores Tipo I de Fatores de Necrose Tumoral , Fatores de Tempo , Tripanossomicidas/uso terapêuticoRESUMO
Recent studies have provided evidence that macrophages from Th1-prone mouse strains respond with an M1 profile, and macrophages from Th2-prone mouse strains respond with an M2 profile, characterized by the dominant production of NO or TGF-beta 1, respectively. We have shown that peritoneal macrophages from IL-12p40 gene knockout mice have a bias toward the M2 profile, spontaneously secreting large amounts of TGF-beta 1 and responding to rIFN-gamma with weak NO production. Moreover, IL-12p40KO macrophages are more permissive to Trypanosoma cruzi replication than their wild-type littermate cells. Prolonged incubation with rIL-12 fails to reverse the M2 polarization of IL-12p40KO macrophages. However, TGF-beta 1 is directly implicated in sustaining the M2 profile because its inhibition increases NO release from IL-12p40KO macrophages. IFN-gamma deficiency is apparently not the reason for TGF-beta 1 up-regulation, because rIFN-gamma KO macrophages produce normal amounts of this cytokine. These findings raise the possibility that IL-12 has a central role in driving macrophage polarization, regulating their intrinsic ability to respond against intracellular parasites.
Assuntos
Interleucina-12/deficiência , Ativação de Macrófagos , Macrófagos Peritoneais/metabolismo , Óxido Nítrico/biossíntese , Fator de Crescimento Transformador beta/metabolismo , Animais , Feminino , Regulação da Expressão Gênica , Interferon gama/farmacologia , Interleucina-12/genética , Ativação de Macrófagos/genética , Macrófagos Peritoneais/parasitologia , Camundongos , Camundongos Knockout , Proteínas Recombinantes , Trypanosoma cruzi/fisiologia , Regulação para Cima/efeitos dos fármacosRESUMO
The role of cytokines in the control of tissue parasitism and pathogenesis of experimental Chagas' disease was investigated. Wild-type and different cytokine as well as inducible nitric oxide synthase (iNOS) knockout mice were infected with the Colombian strain of Trypanosoma cruzi, and the kinetics of tissue parasitism, inflammatory reaction, parasitemia, and mortality were determined. We demonstrate the pivotal role of the interleukin (IL)-12/interferon (IFN)-gamma/iNOS axis and the antagonistic effect of IL-4 in controlling heart tissue parasitism, inflammation, and host resistance to acute infection with T. cruzi. Further, the heart and central nervous system were shown the main sites of reactivation of T. cruzi infection in mice lacking functional genes for IFN-gamma and IL-12, respectively. Our results also show that in contrast to IFN-gamma knockout (KO) mice, splenocytes from IL-12 KO mice infected with T. cruzi produced low levels of IFN-gamma upon stimulation with antigen. Consistently, high levels of anti-T. cruzi IgG2a antibodies were detected in the sera from IL-12 KO, but not from IFN-gamma KO mice, infected with the Colombian strain of T. cruzi. Thus, our results suggest that the level of IFN-gamma deficiency is a major determinant of the site of reactivation of T. cruzi infection in immunocompromised host.
Assuntos
Doenças do Sistema Nervoso Central/patologia , Doenças do Sistema Nervoso Central/parasitologia , Cardiomiopatia Chagásica/patologia , Cardiomiopatia Chagásica/parasitologia , Doença de Chagas/patologia , Doença de Chagas/parasitologia , Interferon gama/fisiologia , Interleucina-12/fisiologia , Animais , Sistema Nervoso Central/parasitologia , Sistema Nervoso Central/patologia , Suscetibilidade a Doenças , Feminino , Coração/parasitologia , Interferon gama/deficiência , Interferon gama/genética , Interleucina-12/deficiência , Interleucina-12/genética , Interleucina-4/deficiência , Interleucina-4/genética , Interleucina-4/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout/genética , Miocardite/parasitologia , Miocardite/patologia , Miocárdio/patologia , Óxido Nítrico Sintase/deficiência , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase/fisiologia , Óxido Nítrico Sintase Tipo II , RecidivaRESUMO
IL-4-dependent and -independent IgG1 Abs differ in their ability to induce mast cell degranulation as measured by passive cutaneous anaphylaxis (PCA). Mice immunized with OVA or PIII (fraction of Ascaris suum) produced high titers of IgG1 as shown by ELISA and PCA. In contrast, another A. suum fraction, PI, elicited IgG1 Abs with no PCA activity. IgG1 with anaphylactic activity required IL-4, as IgG1 responses to OVA and PIII in IL-4-/- mice gave no PCA. PI-specific IgG1 was IL-4-independent, because no difference was found between the responses of IL-4-/- and IL-4+/+ mice. Significant PCA reactions were elicited, however, with PI-specific IgG1 from IL-12-/- or anti-IFN-gamma Ab-treated mice, although less Ab was measured by ELISA. These results indicate that one type of IgG1 has anaphylactic activity and its synthesis is IL-4-dependent, being inhibited by IL-12 or IFN-gamma; the other lacks this activity and its synthesis is stimulated by IL-12 or IFN-gamma.