RESUMO
N-[4-[[(2,4-diamino-6-pterdinyl)methyl]amino]benzoyl]-L/D-glutamic acid (L/D-AMT) is an investigational drug in phase 1 clinical development that consists of the L-and D-enantiomers of aminopterin (AMT). L/D-AMT is obtained from a novel process for making the L-enantiomer (L-AMT), a potent oral antiinflammatory agent. The purpose of these studies was to characterize oral uptake and safety in the dog and human of each enantiomer alone and in combination and provide in vitro evidence for a mechanism of intestinal absorption. This is the first report of L /D-AMT in humans. In dogs (n = 40) orally dosed with L-AMT or D-AMT absorption was stereoselective for the L-enantiomer (6- to 12-fold larger peak plasma concentration after oral administration and area under the plasma concentration-time curve at 0-4 h; p < 0.001). D-AMT was not toxic at the maximal dose tested (82.5 mg/kg), which was 100-fold larger than the maximal nonlethal L-AMT dose (0.8 mg/kg). Dogs (n = 10) and humans with psoriasis (n = 21) orally administered L-AMT and L /D-AMT at the same L-enantiomer dose resulted in stereoselective absorption (absent D-enantiomer in plasma), bioequivalent L-enantiomer pharmacokinetics, and equivalent safety. Thus, the D-enantiomer in L/D-AMT did not perturb L-enantiomer absorption or alter the safety of L-AMT. In vitro uptake by the human proton-coupled folate transporter (PCFT) demonstrated minimal transport of D-AMT compared with L-AMT, mirroring the in vivo findings. Enantiomer selectivity by PCFT was attributable almost entirely to decreased binding affinity rather than changes in transport rate. Collectively, our results demonstrate a strong in vitro-in vivo correlation implicating stereoselective transport by PCFT as the mechanism underlying stereoselective absorption observed in vivo.
Assuntos
Aminopterina/efeitos adversos , Aminopterina/farmacocinética , Absorção Intestinal/fisiologia , Transportador de Folato Acoplado a Próton/metabolismo , Psoríase/metabolismo , Administração Oral , Adulto , Aminopterina/administração & dosagem , Animais , Anti-Inflamatórios/efeitos adversos , Anti-Inflamatórios/farmacocinética , Anti-Inflamatórios/farmacologia , Transporte Biológico/efeitos dos fármacos , Células CHO , Células Cultivadas , Cricetinae , Estudos Cross-Over , Cães , Feminino , Humanos , Absorção Intestinal/efeitos dos fármacos , Mucosa Intestinal/metabolismo , Masculino , Proteínas de Membrana Transportadoras/metabolismo , Pessoa de Meia-Idade , Estereoisomerismo , Adulto JovemRESUMO
Tramadol is widely used globally and is the second most prescribed opioid in the United States. It treats moderate to severe pain but lethal opioid-induced respiratory depression is uncommon even in large overdose. It is unknown why tramadol spares respiration. Here we show its active metabolite, desmetramadol, is as effective as morphine, oxycodone and fentanyl in eliciting G protein coupling at the human µ opioid receptor (MOR), but surprisingly, supratherapeutic concentrations spare human MOR-mediated ßarrestin2 recruitment thought to mediate lethal opioid-induced respiratory depression.
RESUMO
Desmetramadol is an investigational analgesic consisting of (+) and (-) enantiomers of the tramadol metabolite O-desmethyltramadol (M1). Tramadol is racemic and exerts analgesia by monoaminergic effects of (-)-tramadol and (-)-M1, and by the opioid (+)-M1. Tramadol labeling indicates cytochrome P450 (CYP) isozyme 2D6 ultrarapid metabolizer can produce dangerous (+)-M1 levels, and CYP2D6 poor metabolizers insufficient (+)-M1 for analgesia. We hypothesized that desmetramadol could provide the safety and analgesia of tramadol without its metabolic liabilities. We conducted consecutive double-blind, randomized, placebo-controlled, 3 segment cross-over trials A and B to investigate the steady-state pharmacokinetics and analgesia of 20 mg desmetramadol and 50 mg tramadol in 103 healthy participants without (nâ¯=â¯43) and with (nâ¯=â¯60) cotreatment with the CYP inhibitor paroxetine. In the absence of CYP inhibition (trial A), 20 mg desmetramadol and 50 mg tramadol dosed every 6 hours gave equivalent steady-state (+)-M1, similar adverse events, and analgesia significantly greater than placebo, but equal to each other. In trial B, CYP inhibition significantly depressed tramadol steady-state (+)-M1, reduced its adverse events, and led to insignificant analgesia comparable with placebo. In contrast, CYP inhibition in trial B had no deleterious effect on desmetramadol (+)-M1 or (-)-M1, which gave significant analgesia as in trial A and superior to tramadol (Pâ¯=â¯.003). Desmetramadol has the safety and efficacy of tramadol without its metabolic liabilities. CLINICALTRIALS.GOV REGISTRATIONS: NCT02205554, NCT03312777 PERSPECTIVE: To our knowledge, this is the first study of desmetramadol in humans and the first to show it provides the same safety and analgesia as tramadol, but without tramadol's metabolic liabilities and related drug-drug interactions. Desmetramadol could potentially offer expanded safety and usefulness to clinicians seeking an alternative to schedule II opioids.
Assuntos
Analgésicos Opioides/farmacologia , Citocromo P-450 CYP2D6/metabolismo , Percepção da Dor/efeitos dos fármacos , Tramadol/análogos & derivados , Tramadol/farmacologia , Adulto , Analgésicos Opioides/efeitos adversos , Analgésicos Opioides/metabolismo , Citocromo P-450 CYP2D6/genética , Método Duplo-Cego , Feminino , Humanos , Masculino , Tramadol/efeitos adversos , Tramadol/metabolismo , Adulto JovemRESUMO
Chronic infection with Trypanosoma cruzi causes significant morbidity and mortality. The parasite expresses on its surface and sheds into the extracellular milieu a large superfamily of trans-sialidase proteins. Previous studies have demonstrated that during T. cruzi infection, the trans-sialidase superfamily stimulates an antibody response, but how individuals respond to different proteins of the trans-sialidase superfamily remain poorly defined. In this report, we present an analysis of the antibody response of chronically infected individuals and inbred strains of mice to a panel of 11 different trans-sialidase proteins encoded by surface antigen 85 kD (SA85-1) genes. These data indicate that: (1) 90% of the individuals tested generated antibodies to one or more trans-sialidase proteins; (2) the individuals develop different patterns of antibody responsiveness to the panel of trans-sialidase proteins; (3) three inbred strains of mice develop trans-sialidase antibody responses, but each strain develops a different pattern of antibody response to the panel of trans-sialidase proteins; (4) the differences in the pattern of antibody response by the mouse strains are independent of MHC differences; and (5) trans-sialidase proteins that do not stimulate an antibody response during T. cruzi infection can stimulate a response following immunization. Together these data indicate that during T. cruzi infection individuals develop a diverse trans-sialidase antibody response that appears to be affected by genetic and environmental factors.
Assuntos
Anticorpos Antiprotozoários/efeitos dos fármacos , Formação de Anticorpos/efeitos dos fármacos , Doença de Chagas/imunologia , Neuraminidase/genética , Trypanosoma cruzi/enzimologia , Animais , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Neuraminidase/farmacologia , Trypanosoma cruzi/genéticaRESUMO
BACKGROUND: Options are limited for patients with atopic dermatitis (AD) who do not respond to topical treatments. Antifolate therapy with systemic methotrexate improves the disease, but is associated with adverse effects. The investigational antifolate LD-aminopterin may offer improved safety. It is not known how antifolate dose and dosing frequency affect efficacy in AD, but a primary mechanism is thought to involve the antifolate-mediated accumulation of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR). However, recent in vitro studies indicate that AICAR increases then decreases as a function of antifolate concentration. To address this issue and understand how dosing affects antifolate efficacy in AD, we examined the efficacy and safety of different oral doses and schedules of LD-aminopterin in the canine model of AD. METHODS AND FINDINGS: This was a multi-center, double-blind trial involving 75 subjects with canine AD randomized to receive up to 12 weeks of placebo, once-weekly (0.007, 0.014, 0.021 mg/kg) or twice-weekly (0.007 mg/kg) LD-aminopterin. The primary efficacy outcome was the Global Score (GS), a composite of validated measures of disease severity and itch. GS improved in all once-weekly cohorts, with 0.014 mg/kg being optimal and significant (43%, P<0.01). The majority of improvement was seen by 8 weeks. In contrast, GS in the twice-weekly cohort was similar to placebo and worse than all once-weekly cohorts. Adverse events were similar across all treated cohorts and placebo. CONCLUSIONS: Once-weekly LD-aminopterin was safe and efficacious in canine AD. Twice-weekly dosing negated efficacy despite having the same daily and weekly dose as effective once-weekly regimens. Optimal dosing in this homologue of human AD correlated with the concentration-selective accumulation of AICAR in vitro, consistent with AICAR mediating LD-aminopterin efficacy in AD.
Assuntos
Aminopterina/farmacologia , Dermatite Atópica/tratamento farmacológico , Antagonistas do Ácido Fólico/farmacologia , Administração Oral , Aminopterina/administração & dosagem , Animais , Cães , Esquema de Medicação , Antagonistas do Ácido Fólico/administração & dosagem , Antagonistas do Ácido Fólico/efeitos adversos , Humanos , Prednisona/administração & dosagem , Resultado do TratamentoRESUMO
Healthy Indian adult volunteers, with or without a history of leishmaniasis, were evaluated for evidence of previous infection with Leishmania donovani based on the direct agglutination test (DAT). Three cohorts of 6 DAT-negative and 6 DAT-positive subjects were enrolled in an open-label, dose-escalating, uncontrolled clinical trial and received three injections of the LEISH-F1+MPL-SE vaccine (consisting of 5µg, 10µg, or 20µg recombinant Leishmania polyprotein LEISH-F1 antigen+25µg MPL®-SE adjuvant). The study injections were given subcutaneously on days 0, 28, and 56, and the subjects were followed through day 168 for safety and immunological endpoints. The vaccine was safe and well-tolerated in DAT-negative and DAT-positive subjects and induced T-cell production of IFN-γ and other cytokines in response to stimulation with the LEISH-F1 antigen. This clinical trial shows that the LEISH-F1+MPL-SE vaccine is safe and immunogenic in healthy subjects with and without history of previous infection with Leishmania donovani.
Assuntos
Vacinas contra Leishmaniose/imunologia , Leishmaniose Visceral/prevenção & controle , Lipídeo A/análogos & derivados , Adjuvantes Imunológicos/administração & dosagem , Adulto , Citocinas/biossíntese , Feminino , Humanos , Imunidade Celular , Esquemas de Imunização , Leishmania/imunologia , Vacinas contra Leishmaniose/administração & dosagem , Vacinas contra Leishmaniose/efeitos adversos , Lipídeo A/administração & dosagem , Lipídeo A/imunologia , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
Protein kinase A (PKA) has been suggested as a regulator of stage differentiation in Trypanosoma cruzi. Using a yeast two-hybrid system we have begun to characterize the downstream substrates of T. cruzi PKA. We identified several members of the trans-sialidase super family by this approach. Immunoprecitation demonstrated that a TcPKAc monoclonal antibody was able to pull-down proteins recognized by trans-sialidase antibodies as well as a SA85-1.1 antibody and vice versa. An in vitro phosphorylation assay demonstrated that PKA phosphorylated the recombinant protein of an active trans-sialidase. In addition, a phospho-(Ser/Thr) PKA substrate antibody detected bands on immunoblot analysis of trans-sialidase antibody precipitated proteins from parasite lysate and the media of L(6)E(9) myoblasts infected with trypomastigotes as well as from a SA85-1.1 antibody precipitated proteins from parasite lysate. Immunofluorescence analysis suggested that some TcPKAc localizes to the plasma membrane surface of trypomastigotes. The identified trans-sialidases have PKA consensus phosphorylation sites located near the endoplasmic reticulum retention motif in the N-terminal. These data support that PKA phosphorylates trans-sialidase super family members in vivo.
Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Glicoproteínas/metabolismo , Interações Hospedeiro-Patógeno , Neuraminidase/metabolismo , Proteínas de Protozoários/metabolismo , Trypanosoma cruzi/patogenicidade , Animais , Domínio Catalítico , Linhagem Celular , Membrana Celular/enzimologia , Immunoblotting , Imunoprecipitação , Microscopia de Fluorescência , Fosforilação , Ligação Proteica , Ratos , Técnicas do Sistema de Duplo-HíbridoRESUMO
Adult patients with mucosal leishmaniasis (ML) were enrolled in a randomized, double-blind, placebo-controlled, dose-escalating clinical trial and were randomly assigned to receive three injections of either the LEISH-F1+MPL-SE vaccine (consisting of 5, 10, or 20 µg recombinant Leishmania polyprotein LEISH-F1 antigen+25 µg MPL(®)-SE adjuvant) (n=36) or saline placebo (n=12). The study injections were given subcutaneously on Days 0, 28, and 56, and the patients were followed through Day 336 for safety, immunological, and clinical evolution endpoints. All patients received standard chemotherapy with sodium stibogluconate starting on Day 0. The vaccine was safe and well tolerated, and induced both humoral and cell-mediated immune responses. Furthermore, intracellular cytokine staining showed an increase in the proportion of memory LEISH-F1-specific IL-2(+) CD4 T-cells after vaccination, which was associated with clinical cure. This clinical trial shows that the LEISH-F1+MPL-SE vaccine is safe and immunogenic in patients with ML.
Assuntos
Antígenos de Protozoários/imunologia , Gluconato de Antimônio e Sódio/uso terapêutico , Antiprotozoários/uso terapêutico , Vacinas contra Leishmaniose/imunologia , Leishmaniose Mucocutânea/prevenção & controle , Adulto , Anticorpos Antiprotozoários/sangue , Anticorpos Antiprotozoários/imunologia , Formação de Anticorpos , Gluconato de Antimônio e Sódio/administração & dosagem , Antiprotozoários/administração & dosagem , Citocinas/imunologia , Método Duplo-Cego , Determinação de Ponto Final , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Vacinas contra Leishmaniose/administração & dosagem , Vacinas contra Leishmaniose/efeitos adversos , Leishmaniose Mucocutânea/imunologia , Masculino , Pessoa de Meia-Idade , Células Th1/imunologia , Adulto JovemRESUMO
Forty-four adult patients with cutaneous leishmaniasis (CL) were enrolled in a randomized, double-blind, controlled, dose-escalating clinical trial and were randomly assigned to receive three injections of either the LEISH-F1+MPL-SE vaccine (consisting of 5, 10, or 20 µg recombinant Leishmania polyprotein LEISH-F1 antigen+25 µg MPL-SE adjuvant) (n=27), adjuvant alone (n=8), or saline placebo (n=9). The study injections were given subcutaneously on Days 0, 28, and 56, and the patients were followed through Day 336 for safety, immunological, and clinical evolution endpoints. All patients received chemotherapy with meglumine antimoniate starting on Day 0. The vaccine was safe and well tolerated. Nearly all vaccine recipients and no adjuvant-alone or placebo recipients demonstrated an IgG antibody response to LEISH-F1 at Day 84. Also at Day 84, 80% of vaccine recipients were clinically cured, compared to 50% and 38% of adjuvant-alone and placebo recipients. The LEISH-F1+MPL-SE vaccine was safe and immunogenic in CL patients and appeared to shorten their time to cure when used in combination with meglumine antimoniate chemotherapy.
Assuntos
Leishmaniose Cutânea/terapia , Meglumina/administração & dosagem , Compostos Organometálicos/administração & dosagem , Vacinas Protozoárias/imunologia , Adjuvantes Imunológicos/administração & dosagem , Adolescente , Adulto , Anticorpos Antiprotozoários/sangue , Formação de Anticorpos , Antígenos de Protozoários/imunologia , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Humanos , Imunoglobulina G/sangue , Leishmaniose Cutânea/imunologia , Masculino , Meglumina/imunologia , Antimoniato de Meglumina , Pessoa de Meia-Idade , Compostos Organometálicos/imunologia , Poliproteínas/imunologia , Vacinas Protozoárias/efeitos adversos , Proteínas Recombinantes/imunologia , Adulto JovemRESUMO
Healthy Colombian adult volunteers with no history of leishmaniasis were evaluated for evidence of previous subclinical infection with Leishmania based on the Montenegro skin test (MST). Twelve MST-positive subjects were enrolled in an open-label, uncontrolled clinical trial (the "MST-positive trial") and received three injections of the LEISH-F1+MPL-SE vaccine (consisting of 10 microg recombinant Leishmania polyprotein LEISH-F1 antigen [TSA+LmSTI1+LeIF]+25 microg MPL-SE adjuvant). Sixty-eight MST-negative subjects were enrolled in a randomized, double-blind, controlled trial (the "MST-negative trial") and were randomly assigned to receive three injections of either the vaccine (n=34), 10 microg LEISH-F1 protein alone (n=17), or saline placebo (n=17). In both trials, the study injections were given subcutaneously on Days 0, 28, and 56, and subjects were followed for safety and immunological endpoints. The LEISH-F1+MPL-SE vaccine was safe and well tolerated in MST-positive and MST-negative subjects. In both trials, an IFN-gamma response to the LEISH-F1 antigen at Day 84 was observed in more than half of the vaccine recipients. In the MST-negative trial, the IFN-gamma response was significantly more frequent and of greater magnitude in vaccine recipients than in protein-alone or placebo recipients. An IgG antibody response to LEISH-F1 was observed in all vaccine recipients. In both trials, delayed-type hypersensitivity (DTH) to LEISH-F1 was observed in most of the vaccine recipients. In the MST-negative trial, DTH was significantly higher in vaccine than placebo recipients. These clinical trials of the first defined vaccine for leishmaniasis show that the LEISH-F1+MPL-SE vaccine is safe and immunogenic in healthy subjects with and without evidence of previous subclinical infection with Leishmania.
Assuntos
Vacinas contra Leishmaniose/imunologia , Leishmaniose Cutânea/imunologia , Leishmaniose Cutânea/prevenção & controle , Adolescente , Adulto , Método Duplo-Cego , Feminino , Humanos , Vacinas contra Leishmaniose/efeitos adversos , Masculino , Adulto JovemRESUMO
STUDY DESIGN: A comprehensive literature review. OBJECTIVES: To review and critically evaluate the past literature focusing on incidence and clinical presentation of complications associated with interlaminar cervical epidural steroid injection (ICESI). The overall goal is to guide the direction of future research and improve clinical care by increasing awareness of complications, their presentations, and management. SUMMARY OF BACKGROUND DATA: Although ICESI is considered a relatively safe procedure, a number of minor and major complications have been reported across the literature. Thus far, reports of complications are limited to retrospective studies, case reports, and data extrapolated from lumbar and thoracic procedures. As a result, the past literature has been of limited value with regard to facilitating both clinical care and future research efforts. METHODS: Medical databases were searched for studies of ICESI. The bibliographies of these papers were then searched as well. Papers focusing on cervical techniques that did not involve injection into the epidural space were discarded, as were studies of thoracic and lumbar spine injections. Reports of complications associated with ICESI were further subdivided into major and minor categories. RESULTS: The reported rate of complications associated with ICESI varied between 0 and 16.8%. CONCLUSION: There are significant limitations in the available literature discussing the complications associated with ICESI, but they strongly suggest that ICESI is a relatively safe procedure. Numerous potential adverse reactions have been associated with ICESI, with the vast majority being minor and transient in nature. However, serious complications may also result and may be technique related. Injectionists should be aware of the clinical presentations, rates, potential consequences, and appropriate techniques to avoid these complications. More studies are needed with specific focus on cervical complication rates, standardization of injection techniques, and differentiation between complications and poor efficacy. In addition, the use of a prospective randomized blinded controlled design would be beneficial.
Assuntos
Analgesia/efeitos adversos , Anti-Inflamatórios/administração & dosagem , Radiculopatia/tratamento farmacológico , Traumatismos da Medula Espinal/etiologia , Esteroides/administração & dosagem , Vértebras Cervicais , Humanos , Injeções Epidurais/efeitos adversos , Guias de Prática Clínica como Assunto , Índice de Gravidade de Doença , Síndrome , Resultado do TratamentoRESUMO
Trypanosoma cruzi infection causes Chagas' disease, a chronic inflammatory disease. The specific inflammatory responses that cause Chagas' disease remain unclear, but data argue that parasites that persist in the host stimulate chronic self-damaging immune responses. Because T. cruzi appears to stimulate self-damaging responses, the enthusiasm to develop vaccines that boost antiparasite responses that might increase self-damaging responses has been limited. We previously demonstrated that immunization with a T. cruzi trans-sialidase protein or adoptive transfer of trans-sialidase-specific T-cell clones decreased parasitemia, morbidity, and mortality. Here we report that immunization or adoptive transfer with the protein or clones, before or during T. cruzi infection, boosts the anti-T. cruzi immune response without exacerbating acute or chronic tissue inflammation. These results argue that prophylactic and therapeutic immunotherapy for Chagas' disease can be developed safely.
Assuntos
Antígenos de Protozoários/imunologia , Doença de Chagas/fisiopatologia , Doença de Chagas/terapia , Imunoterapia Adotiva , Inflamação/fisiopatologia , Inflamação/terapia , Glicoproteínas de Membrana/imunologia , Proteínas de Protozoários/imunologia , Trypanosoma cruzi/imunologia , Animais , Antígenos de Protozoários/administração & dosagem , Doença de Chagas/imunologia , Doença de Chagas/parasitologia , Doença Crônica , Feminino , Imunização , Imunoterapia/métodos , Inflamação/imunologia , Glicoproteínas de Membrana/administração & dosagem , Camundongos , Camundongos Endogâmicos C57BL , Proteínas de Protozoários/administração & dosagem , Resultado do Tratamento , Trypanosoma cruzi/patogenicidadeRESUMO
The protective immune response against Trypanosoma cruzi is improved by treatment with the natural killer (NK) T-cell glycolipid antigen alpha-galactosylceramide (alpha-GalCer). A single alpha-GalCer treatment of mice before T. cruzi infection decreases parasitaemia and prolongs survival. This protection is dependent on CD1d-restricted NKT cells and interferon-gamma (IFN-gamma) suggesting that alpha-GalCer-activated NKT cells produce IFN-gamma, which stimulates the cells of the innate and adaptive immune responses to provide protection. To learn which cells provide protection we investigate here alpha-GalCer treatment of mice deficient in different immune cells. Surprisingly, although NK cells provide protection against T. cruzi, and are a major source of IFN-gamma following alpha-GalCer treatment, NK cells are not required for the alpha-GalCer-induced protection. The alpha-GalCer treatment of NK-cell-depleted mice controlled parasitaemia and prevented death. In contrast, phagocytes, helper T cells and cytotoxic T cells are required. Furthermore, alpha-GalCer treatment of MHC II(-/-) or CD8alpha(-/-) mice exacerbated the infection, demonstrating that alpha-GalCer treatment induces some responses that favour the parasite. In summary alpha-GalCer protection against T. cruzi required multiple cellular responses, but not the response of NK cells. These results provide useful information because alpha-GalCer is being developed as therapy for infections, autoimmune diseases, allergy and cancers.
Assuntos
Doença de Chagas/prevenção & controle , Galactosilceramidas/uso terapêutico , Células Matadoras Naturais/imunologia , Tripanossomicidas/uso terapêutico , Doença Aguda , Animais , Antígenos CD8/análise , Linfócitos T CD8-Positivos/imunologia , Doença de Chagas/imunologia , Doença de Chagas/fisiopatologia , Feminino , Ativação Linfocitária/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Parasitemia/imunologia , Parasitemia/prevenção & controle , Subpopulações de Linfócitos T/imunologia , Redução de Peso/efeitos dos fármacosRESUMO
Natural killer T (NKT) cells regulate aspects of pro-inflammatory and anti-inflammatory responses and contribute to the control of infections and chronic inflammatory diseases. During Trypanosoma cruzi infection both NKT cells and NK cells are critical to the protective response. How NKT cells interact and possibly regulate NK cells during infections remains uncertain. In vivo studies have demonstrated that specific activation of NKT cells with alpha-galactosylceramide (alpha-GalCer) leads to NK cell activation. These results suggest that during some infections activated NKT cells might regulate NK cell activation and functions. Therefore, using gene-deficient mice that lack NKT cells and antibody-treated mice that lack NK cells, we investigated the interactions of NKT cells and NK cells during experimental T. cruzi infection. We report here that during acute T. cruzi infection spleen and liver NK cell activation and cytolytic activity occur independently of NKT cells. Moreover, NK cell protection occurs independently of NKT cells. In contrast to these results that fail to demonstrate an interdependence, at day 4 of infection the number of liver NK cells is controlled by NKT cells. Thus, during T. cruzi infection, regulation of the number of liver NK cells requires NKT cells, but the activation of NK cells and protection by NK cells does not. The data presented here argue that during infections NK cell activation and protection occur independently of NKT cells.
Assuntos
Doença de Chagas/imunologia , Células Matadoras Naturais/imunologia , Ativação Linfocitária/imunologia , Subpopulações de Linfócitos T/imunologia , Trypanosoma cruzi/imunologia , Alanina Transaminase/metabolismo , Animais , Fígado/imunologia , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Baço/imunologiaRESUMO
Trypanosoma cruzi infects 15 to 20 million people in Latin America and causes Chagas disease, a chronic inflammatory disease with fatal cardiac and gastrointestinal sequelae. How the immune response causes Chagas disease is not clear, but during the persistent infection both proinflammatory and anti-inflammatory responses are critical. Natural killer T (NKT) cells have been shown to regulate immune responses during infections and autoimmune diseases. We report here that during acute T. cruzi infection NKT-cell subsets provide distinct functions. CD1d(-/-) mice, which lack both invariant NKT (iNKT) cells and variant NKT (vNKT) cells, develop a mild phenotype displaying an increase in spleen and liver mononuclear cells, anti-T. cruzi antibody response, and muscle inflammation. In contrast, Jalpha18(-/-) mice, which lack iNKT cells but have vNKT cells, develop a robust phenotype involving prominent spleen, liver, and skeletal muscle inflammatory infiltrates comprised of NK, dendritic, B and T cells. The inflammatory cells display activation markers; produce more gamma interferon, tumor necrosis factor alpha, and nitric oxide; and show a diminished antibody response. Strikingly, most Jalpha18(-/-) mice die. Thus, in response to the same infection, vNKT cells appear to augment a robust proinflammatory response, whereas the iNKT cells dampen this response, possibly by regulating vNKT cells.
Assuntos
Antígenos CD1/fisiologia , Doença de Chagas/imunologia , Células Matadoras Naturais/imunologia , Miosite/etiologia , Animais , Anticorpos Antiprotozoários/sangue , Antígenos CD1d , Antígenos de Diferenciação de Linfócitos B/fisiologia , Antígenos de Histocompatibilidade Classe II/fisiologia , Imunidade Inata , Interferon gama/biossíntese , Fígado/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Músculo Esquelético/imunologia , Óxido Nítrico/biossíntese , Baço/imunologia , Trypanosoma cruzi/imunologia , Fator de Necrose Tumoral alfa/biossínteseRESUMO
Mechanisms of natural killer T (NKT)-cell activation remain unclear. Here, we report that during Trypanosoma cruzi infection, interleukin-12 (IL-12) deficiency or anti-CD1d antibody treatment prevents normal activation. The required IL-12 arises independently of MyD88. The data support a model of normal NKT-cell activation that requires IL-12 and TCR stimulation.
Assuntos
Apresentação de Antígeno/imunologia , Antígenos CD1/metabolismo , Doença de Chagas/imunologia , Interleucina-12/metabolismo , Células Matadoras Naturais/imunologia , Ativação Linfocitária/imunologia , Trypanosoma cruzi/patogenicidade , Animais , Antígenos CD1d , Doença de Chagas/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BLRESUMO
Trypanosoma cruzi, a protozoan parasite, chronically infects many mammalian species and triggers a chronic inflammatory disease. Invariant Valpha14 NK T (iNKT) cells are a regulatory subset of T cells that can contribute to protection against pathogens and to control of chronic inflammatory diseases. alpha-Galactosylceramide (alpha-GalCer) is an iNKT cell-specific glycolipid Ag: a single immunization with alpha-GalCer stimulates robust IFN-gamma and IL-4 production by iNKT cells, while multiple immunizations stimulate IL-4 production, but limited IFN-gamma production. We recently demonstrated that iNKT cells help control T. cruzi infection and affect the chronic Ab response. Therefore, alpha-GalCer treatment might be used to increase protection or decrease chronic inflammation during T. cruzi infection. In this report, we show that a single dose of alpha-GalCer before T. cruzi infection decreases parasitemia. This protection is independent of IL-12, but dependent upon iNKT cell IFN-gamma. In addition, alpha-GalCer treatment of the IFN-gamma(-/-) mice exacerbates parasitemia through IL-4 production. Furthermore, a multiple dose regimen of alpha-GalCer before T. cruzi infection does not lower parasitemia and, surprisingly, after parasitemia has resolved, causes poor weight gain. These data demonstrate that during T. cruzi infection glycolipids can be used to manipulate iNKT cell responses and suggest the possibility of developing glycolipid treatments that can increase protection and possibly decrease the chronic inflammatory pathology.
Assuntos
Doença de Chagas/prevenção & controle , Insuficiência de Crescimento/induzido quimicamente , Galactosilceramidas/farmacologia , Animais , Anticorpos Antiprotozoários/sangue , Interferon gama/fisiologia , Interleucina-12/fisiologia , Células Matadoras Naturais/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Parasitemia/prevenção & controleRESUMO
Trypanosoma cruzi is a protozoan parasite that chronically infects many mammalian species and in humans causes Chagas' disease, a chronic inflammatory disease. The parasite expresses glycophosphoinositol (GPI), which potently stimulates interleukin 12 (IL-12) production. During T. cruzi infection IL-12, and possibly GPI, might stimulate NK T cells to affect the protective and chronic inflammatory responses. Here we report that during T. cruzi infection CD1d-restricted NK T cells are stimulated as NK T-cell-deficient mice have greater parasitemia. Furthermore, during T. cruzi infection the percentages of NK T cells in the liver and spleen become decreased for prolonged periods of time, and in vitro stimulation of NK T cells derived from livers of chronically infected mice, compared to uninfected mice, results in increased gamma interferon and IL-4 secretion. Moreover, in NK T-cell-deficient mice the chronic-phase antibody response to a GPI-modified surface protein is decreased. These results indicate that, during the acute infection, NK T cells limit parasitemia and that, during the chronic phase, NK T cells augment the antibody response. Thus, during T. cruzi infection the quality of an individual's NK T-cell response can affect the level of parasitemia and parasite tissue burden, the intensity of the chronic inflammatory responses, and possibly the outcome of Chagas' disease.