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1.
Plants (Basel) ; 10(6)2021 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-34072503

RESUMO

Agriculture in a water-limited environment is critically important for today and for the future. This research evaluates the impact of deficit irrigation in different planting methods on the physio-morphological traits, grain yield and WUE of maize (Zea mays L.). The experiment was carried out in 2015 and 2016, consisting of three planting methods (i.e., BBF, SNF, and DWF) and four irrigation levels (i.e., I10D: irrigation once in ten days, I40: irrigation at 40% DASM, I50: irrigation at 50% DASM, and I60: irrigation at 60% DASM). The results reveal that varying degrees of water stress due to planting methods and irrigation levels greatly influenced the maize physio-morphological traits and yield attributes. The combined effect of DWF + I50 benefited the maize in terms of higher leaf area, RWC, SPAD values, CGR, and LAD, followed by the SNF method at 60 DAS. As a result, DWF + I50 and SNF + I50 had higher 100 grain weight (30.5 to 31.8 g), cob weight (181.4 to 189.6 g cob-1) and grain yield (35.3% to 36.4%) compared to other treatments. However, the reduction in the number of irrigations (24.0%) under SNF + I50 resulted in a 34% water saving. Thus, under a water-limited situation in semi-arid tropics, the practice of the SNF method + I50 could be an alternative way to explore the physio-morphological benefits in maize.

2.
Cell Rep ; 20(6): 1269-1277, 2017 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-28793252

RESUMO

The human gut is colonized by a large number of microorganisms (∼1013 bacteria) that support various physiologic functions. A perturbation in the healthy gut microbiome might lead to the development of inflammatory diseases, such as multiple sclerosis (MS). Therefore, gut commensals might provide promising therapeutic options for treating MS and other diseases. We report the identification of human gut-derived commensal bacteria, Prevotella histicola, which can suppress experimental autoimmune encephalomyelitis (EAE) in a human leukocyte antigen (HLA) class II transgenic mouse model. P. histicola suppresses disease through the modulation of systemic immune responses. P. histicola challenge led to a decrease in pro-inflammatory Th1 and Th17 cells and an increase in the frequencies of CD4+FoxP3+ regulatory T cells, tolerogenic dendritic cells, and suppressive macrophages. Our study provides evidence that the administration of gut commensals may regulate a systemic immune response and may, therefore, have a possible role in treatment strategies for MS.


Assuntos
Encefalomielite Autoimune Experimental/terapia , Microbioma Gastrointestinal , Prevotella/imunologia , Probióticos/uso terapêutico , Animais , Linfócitos T CD4-Positivos/imunologia , Células Cultivadas , Células Dendríticas/imunologia , Encefalomielite Autoimune Experimental/microbiologia , Fatores de Transcrição Forkhead/metabolismo , Genes MHC da Classe II , Humanos , Macrófagos/imunologia , Camundongos , Prevotella/patogenicidade , Células Th1/imunologia , Células Th17/imunologia
3.
J Immunol ; 198(11): 4413-4424, 2017 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-28468970

RESUMO

Mature peripheral double negative T (DNT) cells expressing αß TCR but lacking CD4/CD8 coreceptors play protective as well as pathogenic roles. To better understand their development and functioning in vivo, we concomitantly inactivated CD4 and CD8 genes in mice with intact MHC class I and class II molecules with the hypothesis that this would enable the development of DNT cells. We also envisaged that these DNT cells could be activated by bacterial superantigens in vivo as activation of T cells by superantigens does not require CD4 and CD8 coreceptors. Because HLA class II molecules present superantigens more efficiently than murine MHC class II molecules, CD4 CD8 double knockout (DKO) mice transgenically expressing HLA-DR3 or HLA-DQ8 molecules were generated. Although thymic cellularity was comparable between wild type (WT) and DKO mice, CD3+ αß TCR+ thymocytes were significantly reduced in DKO mice, implying defects in thymic-positive selection. Splenic CD3+ αß TCR+ cells and Foxp3+ T regulatory cells were present in DKO mice but significantly reduced. However, the in vivo inflammatory responses and immunopathology elicited by acute challenge with the staphylococcal superantigen enterotoxin B were comparable between WT and DKO mice. Choric exposure to staphylococcal enterotoxin B precipitated a lupus-like inflammatory disease with characteristic lympho-monocytic infiltration in lungs, livers, and kidneys, along with production of anti-nuclear Abs in DKO mice as in WT mice. Overall, our results suggest that DNT cells can develop efficiently in vivo and chronic exposure to bacterial superantigens may precipitate a lupus-like autoimmune disease through activation of DNT cells.


Assuntos
Antígenos CD4/genética , Antígenos CD4/imunologia , Antígenos CD8/genética , Antígenos CD8/imunologia , Enterotoxinas/imunologia , Superantígenos/imunologia , Subpopulações de Linfócitos T/imunologia , Animais , Antígenos HLA-DQ/genética , Antígenos HLA-DQ/imunologia , Antígeno HLA-DR3/genética , Antígeno HLA-DR3/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Baço/citologia , Baço/imunologia , Timo/citologia , Timo/imunologia
4.
Clin Immunol ; 178: 10-19, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-26057130

RESUMO

Rheumatoid arthritis (RA) occurs two times more often in women than men. B cell depletion has been shown to be efficacious in treating RA. Our previous studies suggested that antigen presentation via B cells results in a sex-specific immune response in DR4 and DR4/DQ8 mice. Here we evaluated the mechanism of efficacy of the B cell depletion in treating arthritis-susceptible DQ8 mice. The data show that arthritic DQ8 mice treated with anti-CD20 antibody in therapeutic protocols show milder disease severity in females as compared to males, which is associated with decreased antibodies to citrullinated proteins and reduced levels of IL-23 and CCL5. Treatment led to significantly increased numbers of T regulatory and monocyte-derived suppressor F4/80+Gr1hi cells in females as compared to male DQ8 mice. Our observations suggest that therapeutic strategies that target B cells may benefit females while functions of DCs might be relatively more important for men than women.


Assuntos
Artrite Experimental/imunologia , Artrite Reumatoide/imunologia , Linfócitos B/imunologia , Quimiocina CCL5/imunologia , Interleucina-23/imunologia , Células Supressoras Mieloides/imunologia , Linfócitos T Reguladores/imunologia , Animais , Antirreumáticos/farmacologia , Artrite Experimental/genética , Artrite Reumatoide/genética , Linfócitos B/efeitos dos fármacos , Antígenos CD28/imunologia , Antígenos CD40/imunologia , Proliferação de Células , Quimiocina CCL5/efeitos dos fármacos , Quimiocinas/efeitos dos fármacos , Quimiocinas/imunologia , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Feminino , Citometria de Fluxo , Cadeias beta de HLA-DQ/genética , Humanos , Interleucina-23/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Masculino , Camundongos , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos T/imunologia , Rituximab/farmacologia , Caracteres Sexuais , Linfócitos T Reguladores/efeitos dos fármacos
5.
Virulence ; 8(7): 1148-1159, 2017 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-27925510

RESUMO

Drugs such as linezolid that inhibit bacterial protein synthesis may be beneficial in treating infections caused by toxigenic Staphylococcus aureus. As protein synthesis inhibitors have no effect on preformed toxins, neutralization of pathogenic exotoxins with anti-toxin antibodies may be beneficial in conjunction with antibacterial therapy. Herein, we evaluated the efficacy of human-mouse chimeric high-affinity neutralizing anti-staphylococcal enterotoxin B (SEB) antibodies in the treatment of experimental pneumonia caused by SEB-producing S. aureus. Since HLA class II transgenic mice mount a stronger systemic immune response following challenge with SEB and are more susceptible to SEB-induced lethal toxic shock than conventional mice strains, HLA-DR3 transgenic mice were used. Lethal pneumonia caused by SEB-producing S. aureus in HLA-DR3 transgenic mice was characterized by robust T cell activation and elevated systemic levels of several pro-inflammatory cytokines and chemokines. Prophylactic administration of a single dose of linezolid 30 min prior to the onset of infection attenuated the systemic inflammatory response and protected from mortality whereas linezolid administered 60 min after the onset of infection failed to confer significant protection. Human-mouse chimeric high-affinity neutralizing anti-SEB antibodies alone, but not polyclonal human IgG, mitigated this response and protected from death when administered immediately after initiation of infection. Further, anti-SEB antibodies as well as intact polyclonal human IgG, but not its Fab or Fc fragments, protected from lethal pneumonia when followed with linezolid therapy 60 min later. In conclusion, neutralization of superantigens with high-affinity antibodies may have beneficial effects in pneumonia.


Assuntos
Anticorpos Antibacterianos/administração & dosagem , Anticorpos Monoclonais Humanizados/administração & dosagem , Enterotoxinas/imunologia , Imunização Passiva , Pneumonia/terapia , Infecções Estafilocócicas/terapia , Staphylococcus aureus/efeitos dos fármacos , Animais , Citocinas/genética , Citocinas/imunologia , Enterotoxinas/genética , Antígeno HLA-DR3/genética , Antígeno HLA-DR3/imunologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Pneumonia/genética , Pneumonia/imunologia , Pneumonia/microbiologia , Infecções Estafilocócicas/genética , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética , Staphylococcus aureus/imunologia , Linfócitos T/imunologia
6.
J Neuroinflammation ; 13(1): 293, 2016 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-27855706

RESUMO

BACKGROUND: We investigated the role of human HLA class I molecules in persistent central nervous system (CNS) injury versus repair following virus infection of the CNS. METHODS: Human class I A11+ and B27+ transgenic human beta-2 microglobulin positive (Hß2m+) mice of the H-2 b background were generated on a combined class I-deficient (mouse beta-2 microglobulin deficient, ß2m0) and class II-deficient (mouse Aß0) phenotype. Intracranial infection with Theiler's murine encephalomyelitis virus (TMEV) in susceptible SJL mice results in acute encephalitis with prominent injury in the hippocampus, striatum, and cortex. RESULTS: Following infection with TMEV, a picornavirus, the Aß0.ß2m0 mice lacking active immune responses died within 18 to 21 days post-infection. These mice showed severe encephalomyelitis due to rapid replication of the viral genome. In contrast, transgenic Hß2m mice with insertion of a single human class I MHC gene in the absence of human or mouse class II survived the acute infection. Both A11+ and B27+ mice significantly controlled virus RNA expression by 45 days and did not develop late-onset spinal cord demyelination. By 45 days post-infection (DPI), B27+ transgenic mice showed almost complete repair of the virus-induced brain injury, but A11+ mice conversely showed persistent severe hippocampal and cortical injury. CONCLUSIONS: The findings support the hypothesis that the expression of a single human class I MHC molecule, independent of persistent virus infection, influences the extent of sub frequent chronic neuronal injury or repair in the absence of a class II MHC immune response.


Assuntos
Infecções por Cardiovirus/patologia , Sistema Nervoso Central/patologia , Sistema Nervoso Central/virologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Theilovirus/fisiologia , Análise de Variância , Animais , Anticorpos/metabolismo , Modelos Animais de Doenças , Citometria de Fluxo , Antígeno HLA-A11/metabolismo , Antígeno HLA-B27/metabolismo , Antígenos de Histocompatibilidade Classe I/genética , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , RNA Mensageiro , Proteínas Virais/genética , Proteínas Virais/imunologia , Proteínas Virais/metabolismo
7.
Immunity ; 44(6): 1379-91, 2016 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-27287409

RESUMO

Two zoonotic coronaviruses (CoVs)-SARS-CoV and MERS-CoV-have crossed species to cause severe human respiratory disease. Here, we showed that induction of airway memory CD4(+) T cells specific for a conserved epitope shared by SARS-CoV and MERS-CoV is a potential strategy for developing pan-coronavirus vaccines. Airway memory CD4(+) T cells differed phenotypically and functionally from lung-derived cells and were crucial for protection against both CoVs in mice. Protection was dependent on interferon-γ and required early induction of robust innate and virus-specific CD8(+) T cell responses. The conserved epitope was also recognized in SARS-CoV- and MERS-CoV-infected human leukocyte antigen DR2 and DR3 transgenic mice, indicating potential relevance in human populations. Additionally, this epitope was cross-protective between human and bat CoVs, the progenitors for many human CoVs. Vaccine strategies that induce airway memory CD4(+) T cells targeting conserved epitopes might have broad applicability in the context of new CoVs and other respiratory virus outbreaks.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Infecções por Coronavirus/imunologia , Sistema Respiratório/imunologia , Síndrome Respiratória Aguda Grave/imunologia , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/imunologia , Vacinas Virais/imunologia , Animais , Antígenos Virais/imunologia , Linfócitos T CD4-Positivos/virologia , Linfócitos T CD8-Positivos/virologia , Células Cultivadas , Reações Cruzadas , Epitopos de Linfócito T/imunologia , Humanos , Imunidade , Memória Imunológica , Interferon gama/metabolismo , Camundongos , Camundongos Endogâmicos , Vacinação , Vírion/imunologia
8.
J Biol Chem ; 291(8): 4079-90, 2016 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-26703475

RESUMO

We previously showed that an HLA-DR variant containing arginine at position 74 of the DRß1 chain (DRß1-Arg74) is the specific HLA class II variant conferring risk for autoimmune thyroid diseases (AITD). We also identified 5 thyroglobulin (Tg) peptides that bound to DRß1-Arg74. We hypothesized that blocking the binding of these peptides to DRß1-Arg74 could block the continuous T-cell activation in thyroiditis needed to maintain the autoimmune response to the thyroid. The aim of the current study was to identify small molecules that can block T-cell activation by Tg peptides presented within DRß1-Arg74 pockets. We screened a large and diverse library of compounds and identified one compound, cepharanthine that was able to block peptide binding to DRß1-Arg74. We then showed that Tg.2098 is the dominant peptide when inducing experimental autoimmune thyroiditis (EAT) in NOD mice expressing human DRß1-Arg74. Furthermore, cepharanthine blocked T-cell activation by thyroglobulin peptides, in particular Tg.2098 in mice that were induced with EAT. For the first time we identified a small molecule that can block Tg peptide binding and presentation to T-cells in autoimmune thyroiditis. If confirmed cepharanthine could potentially have a role in treating human AITD.


Assuntos
Alcaloides/farmacologia , Apresentação de Antígeno/efeitos dos fármacos , Cadeias HLA-DRB1/imunologia , Tireoidite Autoimune/imunologia , Alcaloides/química , Animais , Cadeias HLA-DRB1/genética , Humanos , Ativação Linfocitária/efeitos dos fármacos , Camundongos , Camundongos Transgênicos , Peptídeos/genética , Peptídeos/imunologia , Linfócitos T/imunologia , Linfócitos T/patologia , Tireoglobulina/genética , Tireoglobulina/imunologia , Tireoidite Autoimune/genética , Tireoidite Autoimune/patologia
9.
Toxins (Basel) ; 7(12): 5308-19, 2015 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-26670252

RESUMO

Staphylococcus aureus, the most common cause of wound infection, produces several exotoxins, including superantigens (SAgs). SAgs are the potent activators of the immune system. Given this unique property, we hypothesized that SAgs produced by S. aureus in wounds would have local, as well as systemic immunologic effects. We tested our hypothesis using a novel staphylococcal skin wound infection model in transgenic mice expressing HLA-DR3. Skin wounds were left uninfected or colonized with S. aureus strains producing SAgs or an isogenic strain not producing any SAg. Animals with wounds challenged with SAg-producing S. aureus had increased morbidity and lower serum IL-17 levels compared to those challenged with the SAg non-producing S. aureus (p = 0.027 and p = 0.032, respectively). At Day 8 following microbial challenge, compared to mice with uninfected wounds, the proportion of Vß8⁺CD4⁺ T cells was increased, while the proportion of Vß8⁺CD8⁺ T cells was decreased only in the spleens of mice challenged with SAg-producing S. aureus (p < 0.001). No such changes were measured in mice challenged with SAg non-producing S. aureus. Lungs, livers and kidneys from mice challenged with SAg-producing, but not SAg non-producing, S. aureus showed inflammatory changes. Overall, SAg-mediated systemic immune activation in wounds harboring S. aureus may have clinical implications.


Assuntos
Antígenos de Bactérias/imunologia , Dermatopatias/imunologia , Infecções Estafilocócicas/imunologia , Staphylococcus aureus/imunologia , Superantígenos/imunologia , Cicatrização/imunologia , Animais , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Interleucina-17/sangue , Rim/patologia , Fígado/patologia , Pulmão/patologia , Camundongos Transgênicos , Pele/imunologia , Pele/lesões , Dermatopatias/sangue , Infecções Estafilocócicas/sangue
10.
J Immunol ; 195(10): 4660-7, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-26475924

RESUMO

MHC, especially HLA-DR3 and HLA-DR2, is one of the most important genetic susceptibility regions for systemic lupus erythematosus. Human studies to understand the role of specific HLA alleles in disease pathogenesis have been hampered by the presence of strong linkage disequilibrium in this region. To overcome this, we produced transgenic mice expressing HLA-DR3 (DRß1*0301) and devoid of endogenous class II (both I-A and I-E genes, AE(0)) on a lupus-prone NZM2328 background (NZM2328.DR3(+)AE(0)). Both NZM2328 and NZM2328.DR3(+)AE(0) mice developed anti-dsDNA and glomerulonephritis, but anti-dsDNA titers were higher in the latter. Although kidney histological scores were similar in NZM2328 and NZM2328.DR3(+)AE(0) mice (7.2 ± 4.3 and 8.6 ± 5.7, respectively, p = 0.48), the onset of severe proteinuria occurred earlier in NZM2328.DR3(+)AE(0) mice compared with NZM2328 mice (median, 5 and 9 mo respectively, p < 0.001). Periarterial lymphoid aggregates, classic wire loop lesions, and occasional crescents were seen only in kidneys from NZM2328.DR3(+)AE(0) mice. Interestingly, NZM2328.DR3(+)AE(0) mice, but not NZM2328 mice, spontaneously developed anti-Smith (Sm) Abs. The anti-Sm Abs were seen in NZM2328.DR3(+)AE(0) mice that were completely devoid of endogenous class II (AE(-/) (-)) but not in mice homozygous (AE(+/+)) or heterozygous (AE(+/-)) for endogenous MHC class II. It appears that only HLA-DR3 molecules can preferentially select SmD-reactive CD4(+) T cells for generation of the spontaneous anti-Sm immune response. Thus, our mouse model unravels a critical role for HLA-DR3 in generating an autoimmune response to SmD and lupus nephritis in the NZM2328 background.


Assuntos
Anticorpos Antinucleares/imunologia , Glomerulonefrite/imunologia , Antígeno HLA-DR3/imunologia , Nefrite Lúpica/imunologia , Proteínas Centrais de snRNP/imunologia , Animais , Anticorpos Antinucleares/genética , Linfócitos T CD4-Positivos/imunologia , DNA/imunologia , Modelos Animais de Doenças , Predisposição Genética para Doença , Glomerulonefrite/genética , Antígeno HLA-DR2/imunologia , Antígeno HLA-DR3/genética , Cadeias HLA-DRB1/genética , Cadeias HLA-DRB1/imunologia , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/imunologia , Nefrite Lúpica/genética , Camundongos , Camundongos Knockout
11.
Hepatology ; 62(5): 1536-50, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26185095

RESUMO

UNLABELLED: Autoimmune hepatitis (AIH) in humans is a severe inflammatory liver disease characterized by interface hepatitis, the presence of circulating autoantibodies, and hyper-gammaglobulinemia. There are two types of AIH, type 1 (AIH-1) and type 2 (AIH-2), characterized by distinct autoimmune serology. Patients with AIH-1 are positive for anti-smooth muscle and/or antinuclear autoantibodies, whereas patients with AIH-2 have anti-liver kidney microsomal type 1 and/or anti-liver cytosol type 1 autoantibodies. Cytochrome P4502D6 is the antigenic target of anti-liver kidney microsomal type 1, and formiminotransferase cyclodeaminase is the antigenic target of anti-liver cytosol type 1. It is known that AIH, both types 1 and 2, is strongly linked to the human leukocyte antigen (HLA) alleles -DR3, -DR4, and -DR7. However, direct evidence of the association of HLA with AIH is lacking. We developed a novel mouse model of AIH using the HLA-DR3 transgenic mouse on the nonobese-diabetic background by immunization of HLA-DR3- and HLA-DR3+ nonobese-diabetic mice with a DNA plasmid, coding for human cytochrome P4502D6/formiminotransferase cyclodeaminase fusion protein. Immunization with cytochrome P4502D6/formiminotransferase cyclodeaminase leads to a sustained elevation of alanine aminotransferase, development of antinuclear autoantibodies and anti-liver kidney microsomal type 1/anti-liver cytosol type 1 autoantibodies, chronic immune cell infiltration, and parenchymal fibrosis on liver histology in HLA-DR3+ mice. Immunized mice also showed an enhanced T helper 1 immune response and paucity of the frequency of regulatory T cells in the liver. Moreover, HLA-DR3+ mice with exacerbated AIH showed reduced diversity and total load of gut bacteria. CONCLUSION: Our humanized animal model has provided a novel experimental tool to further elucidate the pathogenesis of AIH and to evaluate the efficacy and safety of immunoregulatory therapeutic interventions in vivo.


Assuntos
Hepatite Autoimune/etiologia , Intestinos/microbiologia , Microbiota , Animais , Autoanticorpos/imunologia , Sequência de Bases , Citocromo P-450 CYP2D6/imunologia , Citocinas/biossíntese , Modelos Animais de Doenças , Antígeno HLA-DR3/imunologia , Humanos , Imunização , Fígado/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Dados de Sequência Molecular , Linfócitos T Reguladores/imunologia
12.
J Leukoc Biol ; 98(2): 271-81, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25979434

RESUMO

SAgs, produced by Staphylococcus aureus, play a major role in the pathogenesis of invasive staphylococcal diseases by inducing potent activation of the immune system. However, the role of SAgs, produced by S. aureus, associated with indwelling devices or tissues, are not known. Given the prevalence of device-associated infection with toxigenic S. aureus in clinical settings and the potency of SAgs, we hypothesized that continuous exposure to SAgs produced by catheter-associated S. aureus could have systemic consequences. To investigate these effects, we established a murine in vivo catheter colonization model. One centimeter long intravenous catheters were colonized with a clinical S. aureus isolate producing SAgs or isogenic S. aureus strains, capable or incapable of producing SAg. Catheters were subcutaneously implanted in age-matched HLA-DR3, B6, and AE(o) mice lacking MHC class II molecules and euthanized 7 d later. There was no evidence of systemic infection. However, in HLA-DR3 transgenic mice, which respond robustly to SSAgs, the SSAg-producing, but not the nonproducing strains, caused a transient increase in serum cytokine levels and a protracted expansion of splenic CD4(+) T cells expressing SSAg-reactive TCR Vß8. Lungs, livers, and kidneys from these mice showed infiltration with CD4(+) and CD11b(+) cells. These findings were absent in B6 and AE(o) mice, which are known to respond poorly to SSAgs. Overall, our novel findings suggest that systemic immune activation elicited by SAgs, produced by S. aureus colonizing foreign bodies, could have clinical consequences in humans.


Assuntos
Infecções Relacionadas a Cateter/imunologia , Enterotoxinas/biossíntese , Infecções Estafilocócicas/imunologia , Staphylococcus aureus/patogenicidade , Superantígenos/biossíntese , Animais , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/microbiologia , Linfócitos T CD4-Positivos/patologia , Infecções Relacionadas a Cateter/genética , Infecções Relacionadas a Cateter/microbiologia , Infecções Relacionadas a Cateter/patologia , Cateteres de Demora , Enterotoxinas/imunologia , Deleção de Genes , Antígenos de Histocompatibilidade/genética , Antígenos de Histocompatibilidade/imunologia , Humanos , Rim/imunologia , Rim/microbiologia , Rim/patologia , Fígado/imunologia , Fígado/microbiologia , Fígado/patologia , Pulmão/imunologia , Pulmão/microbiologia , Pulmão/patologia , Ativação Linfocitária , Camundongos , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Baço/imunologia , Baço/microbiologia , Baço/patologia , Infecções Estafilocócicas/genética , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/patologia , Staphylococcus aureus/imunologia , Superantígenos/imunologia
13.
Mol Cell Proteomics ; 14(4): 893-904, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25635267

RESUMO

The cytotoxic T-lymphocyte-mediated killing of virus-infected cells requires previous recognition of short viral antigenic peptides bound to human leukocyte antigen class I molecules that are exposed on the surface of infected cells. The cytotoxic T-lymphocyte response is critical for the clearance of human respiratory syncytial virus infection. In this study, naturally processed viral human leukocyte antigen class I ligands were identified with mass spectrometry analysis of complex human leukocyte antigen-bound peptide pools isolated from large amounts of human respiratory syncytial virus-infected cells. Acute antiviral T-cell response characterization showed that viral transcription determines both the immunoprevalence and immunodominance of the human leukocyte antigen class I response to human respiratory syncytial virus. These findings have clear implications for antiviral vaccine design.


Assuntos
Antígenos de Histocompatibilidade Classe I/imunologia , Imunidade Celular/imunologia , Vírus Sincicial Respiratório Humano/genética , Vírus Sincicial Respiratório Humano/imunologia , Transcrição Gênica , Sequência de Aminoácidos , Animais , Apresentação de Antígeno/imunologia , Extratos Celulares , Linhagem Celular , Humanos , Epitopos Imunodominantes/imunologia , Ligantes , Camundongos Transgênicos , Dados de Sequência Molecular , Peptídeos/química , Peptídeos/imunologia , Proteoma/metabolismo , Vírus Sincicial Respiratório Humano/química , Linfócitos T/imunologia , Espectrometria de Massas em Tandem
14.
Diagn Microbiol Infect Dis ; 81(3): 201-7, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25619753

RESUMO

Staphylococcus aureus is a common cause of prosthetic joint infection (PJI). The prevalence of superantigens (SAgs) among PJI-associated S. aureus is unknown. Eighty-four S. aureus isolates associated with PJI isolated between 1999 and 2006 were studied. SAg genes, sea, seb, sec, sed, see, seg, seh, sei, and tst, were assayed by PCR. Seventy-eight (92.9%) isolates carried at least 1 SAg gene studied, with 61 (72.6%) harboring more than 1. seg was most commonly (70.2%), and seh was least frequently (4.8%) detected. tst-positive isolates were associated with early infection and increased erythrocyte sedimentation rate at diagnosis (P=0.006 and P=0.021, respectively). seg and sei were associated with methicillin resistance (P=0.008 and P=0.002, respectively). A majority of PJI-associated isolates studied produced biologically active SAgs in both planktonic and biofilm growth modes. SAg genes are prevalent in S. aureus causing PJI.


Assuntos
Artrite/microbiologia , Infecções Relacionadas à Prótese/microbiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética , Superantígenos/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Feminino , Genótipo , Humanos , Leucócitos Mononucleares/efeitos dos fármacos , Masculino , Camundongos Transgênicos , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Staphylococcus aureus/isolamento & purificação , Superantígenos/análise
15.
J Immunol ; 193(10): 4859-70, 2014 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-25339670

RESUMO

Multiple sclerosis is an inflammatory, demyelinating disease of the CNS of presumed autoimmune origin. Of all the genetic factors linked with multiple sclerosis, MHC class II molecules have the strongest association. Generation of HLA class II transgenic (Tg) mice has helped to elucidate the role of HLA class II genes in chronic inflammatory and demyelinating diseases. We have shown that the human HLA-DRB1*0301 gene predisposes to proteolipid protein (PLP)-induced experimental autoimmune encephalomyelitis (EAE), whereas HLA-DQß1*0601 (DQ6) was resistant. We also showed that the DQ6 molecule protects from EAE in DRB1*0301.DQ6 double-Tg mice by producing anti-inflammatory IFN-γ. HLA-DQß1*0302 (DQ8) Tg mice were also resistant to PLP(91-110)-induced EAE, but production of proinflammatory IL-17 exacerbated disease in DRB1*0301.DQ8 mice. To further confirm the role of IFN-γ in protection, we generated DRB1*0301.DQ8 mice lacking IFN-γ (DRB1*0301.DQ8.IFN-γ(-/-)). Immunization with PLP(91-110) peptide caused atypical EAE in DRB1*0301.DQ8.IFN-γ(-/-) mice characterized by ataxia, spasticity, and dystonia, hallmarks of brain-specific disease. Severe brain-specific inflammation and demyelination in DRB1*0301.DQ8.IFN-γ(-/-) mice with minimal spinal cord pathology further confirmed brain-specific pathology. Atypical EAE in DRB1*0301.DQ8.IFN-γ(-/-) mice was associated with increased encephalitogenicity of CD4 T cells and their ability to produce greater levels of IL-17 and GM-CSF compared with DRB1*0301.DQ8 mice. Further, areas with demyelination showed increased presence of CD68(+) inflammatory cells, suggesting an important role for monocytes/microglia in causing brain pathology. Thus, our study supports a protective role for IFN-γ in the demyelination of brain through downregulation of IL-17/GM-CSF and induction of neuroprotective factors in the brain by monocytes/microglial cells.


Assuntos
Encéfalo/imunologia , Encefalomielite Autoimune Experimental/imunologia , Interferon gama/imunologia , Interleucina-17/imunologia , Microglia/imunologia , Monócitos/imunologia , Animais , Encéfalo/patologia , Encefalomielite Autoimune Experimental/induzido quimicamente , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/patologia , Regulação da Expressão Gênica , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Fator Estimulador de Colônias de Granulócitos e Macrófagos/imunologia , Antígenos HLA-DQ/genética , Antígenos HLA-DQ/imunologia , Cadeias beta de HLA-DQ/genética , Cadeias beta de HLA-DQ/imunologia , Cadeias HLA-DRB1/genética , Cadeias HLA-DRB1/imunologia , Humanos , Interferon gama/deficiência , Interferon gama/genética , Interleucina-17/genética , Camundongos , Camundongos Knockout , Microglia/patologia , Monócitos/patologia , Proteína Proteolipídica de Mielina , Transdução de Sinais
16.
J Immunol ; 193(6): 2919-30, 2014 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-25092888

RESUMO

Life-threatening infections caused by Staphylococcus aureus, particularly the community-acquired methicillin-resistant strains of S. aureus, continue to pose serious problems. Greater virulence and increased pathogenicity of certain S. aureus strains are attributed to higher prevalence of exotoxins. Of these exotoxins, the superantigens (SAg) are likely most pathogenic because of their ability to rapidly and robustly activate the T cells even in extremely small quantities. Therefore, countering SAg-mediated T cell activation using T regulatory cells (Tregs) might be beneficial in diseases such as toxic shock syndrome (TSS). As the normal numbers of endogenous Tregs in a typical host are insufficient, we hypothesized that increasing the Treg numbers by administration of IL-2/anti-IL-2 Ab immune complexes (IL2C) or by adoptive transfer of ex vivo expanded Tregs might be more effective in countering SAg-mediated immune activation. HLA-DR3 transgenic mice that closely recapitulate human TSS were treated with IL2C to increase endogenous Tregs or received ex vivo expanded Tregs. Subsequently, they were challenged with SAg to induce TSS. Analyses of various parameters reflective of TSS (serum cytokine/chemokine levels, multiple organ pathology, and SAg-induced peripheral T cell expansion) indicated that increasing the Tregs failed to mitigate TSS. On the contrary, serum IFN-γ levels were increased in IL2C-treated mice. Exploration into the reasons behind the lack of protective effect of Tregs revealed IL-17 and IFN-γ-dependent loss of Tregs during TSS. In addition, significant upregulation of glucocorticoid-induced TNFR family-related receptor on conventional T cells during TSS could render them resistant to Treg-mediated suppression, contributing to failure of Treg-mediated immune regulation.


Assuntos
Enterotoxinas/imunologia , Choque Séptico/imunologia , Superantígenos/imunologia , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/transplante , Transferência Adotiva , Animais , Anticorpos/imunologia , Anticorpos/farmacologia , Complexo Antígeno-Anticorpo/imunologia , Complexo Antígeno-Anticorpo/farmacologia , Proteína Relacionada a TNFR Induzida por Glucocorticoide/biossíntese , Glucocorticoides , Cadeias alfa de HLA-DR/genética , Cadeias alfa de HLA-DR/imunologia , Cadeias beta de HLA-DR/genética , Cadeias beta de HLA-DR/imunologia , Antígeno HLA-DR3/genética , Antígeno HLA-DR3/imunologia , Interferon gama/sangue , Interferon gama/imunologia , Interleucina-17/imunologia , Interleucina-2/imunologia , Interleucina-2/farmacologia , Ativação Linfocitária/imunologia , Staphylococcus aureus Resistente à Meticilina/imunologia , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Camundongos , Camundongos Transgênicos , Receptores do Fator de Necrose Tumoral/biossíntese , Choque Séptico/microbiologia , Infecções Estafilocócicas/imunologia , Regulação para Cima
17.
Eur J Immunol ; 44(11): 3429-38, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25103892

RESUMO

HLA-DRB1*0401 expression in humans has been associated with a predisposition to developing rheumatoid arthritis (RA) and collagen-induced arthritis (CIA), while HLA-DRB1*0402 is not associated with susceptibility. Here, we determined if mice transgenic (Tg) for human *0401 have a CD4+ T-cell repertoire that predetermines proinflammatory cytokine production. The data show that both *0401 and *0402 Tg mice can produce TH1/TH17 cytokines, although the kinetics of response may be different. However, in the context of antigen-specific responses in a CIA model, *0402 Tg mice generate a TH2 response that may explain their resistance to developing arthritis. In addition, a significant subset of naïve CD4+ T cells from *0402 Tg mice can be activated in polarizing conditions to differentiate into Treg cells that produce IFN-γ. *0401 Tg mice harbor memory CD4+ T cells that differentiate into IL-17(+) cells in various polarizing conditions. Our data suggest that *0401 Tg mice generate a strong immune response to lipopolysaccharide and may be efficient in clearing infection, and may *0401 have been evolutionarily selected for this ability. Autoimmunity, such as RA, could likely be a bystander effect of the cytokine storm that, along with the presence of low Treg-cell numbers in *0401 Tg mice, causes immune dysregulation.


Assuntos
Artrite Experimental/imunologia , Cadeias HLA-DRB1/imunologia , Linfócitos T Reguladores/citologia , Animais , Artrite Reumatoide/imunologia , Diferenciação Celular/imunologia , Proliferação de Células , Células Cultivadas , Feminino , Cadeias HLA-DRB1/genética , Inflamação/imunologia , Interleucina-17/biossíntese , Lipopolissacarídeos/imunologia , Masculino , Camundongos , Camundongos Transgênicos , Linfócitos T Reguladores/imunologia , Células Th1/imunologia , Células Th17/imunologia , Células Th2/imunologia
18.
Mediators Inflamm ; 2014: 468285, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25024509

RESUMO

Staphylococcus aureus is capable of causing a spectrum of human illnesses. During serious S. aureus infections, the staphylococcal pathogen-associated molecular patterns (PAMPs) such as peptidoglycan, lipoteichoic acid, and lipoproteins and even intact S. aureus, are believed to act in conjunction with the staphylococcal superantigens (SSAg) to activate the innate and adaptive immune system, respectively, and cause immunopathology. However, recent studies have shown that staphylococcal PAMPs could suppress inflammation by several mechanisms and protect from staphylococcal toxic shock syndrome, a life-threatening systemic disease caused by toxigenic S. aureus. Given the contradictory pro- and anti-inflammatory roles of staphylococcal PAMPs, we examined the effects of S. aureus-derived molecular patterns on immune responses driven by SSAg in vivo using HLA-DR3 and HLA-DQ8 transgenic mice. Our study showed that neither S. aureus-derived peptidoglycans (PGN), lipoteichoic acid (LTA), nor heat-killed Staphylococcus aureus (HKSA) inhibited SSAg-induced T cell proliferation in vitro. They failed to antagonize the immunostimulatory effects of SSAg in vivo as determined by their inability to attenuate systemic cytokine/chemokine response and reduce SSAg-induced T cell expansion. These staphylococcal PAMPs also failed to protect HLA-DR3 as well as HLA-DQ8 transgenic mice from either SSAg-induced toxic shock or pneumonia induced by a SSAg-producing strain of S. aureus.


Assuntos
Pneumonia/imunologia , Pneumonia/metabolismo , Choque Séptico/imunologia , Choque Séptico/metabolismo , Staphylococcus aureus/imunologia , Staphylococcus aureus/patogenicidade , Superantígenos/imunologia , Animais , Antígenos HLA-DQ/genética , Antígeno HLA-DR3/genética , Ativação Linfocitária/genética , Ativação Linfocitária/imunologia , Camundongos Transgênicos , Pneumonia/induzido quimicamente , Choque Séptico/induzido quimicamente
19.
Am J Physiol Gastrointest Liver Physiol ; 307(3): G302-12, 2014 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-24924747

RESUMO

Celiac disease (CD) is an enteropathy caused by the ingestion of wheat gluten in genetically susceptible individuals. A complete understanding of the pathogenic mechanisms in CD has been hindered because of the lack of adequate in vivo models. In the present study, we explored the events after the intragastric administration of gliadin and of the albumin/globulin fraction from wheat in human leukocyte antigen-DQ8 transgenic mice (DQ8 mice) treated with indomethacin, an inhibitor of cyclooxygenases (COXs). After 10 days of treatment, mice showed a significant reduction of villus height, increased crypt depth, increased number of lamina propria-activated macrophages, and high basal interferon-γ secretion in mesenteric lymph nodes, all of which were specifically related to gliadin intake, whereas the albumin/globulin fraction of wheat was unable to induce similar changes. Cotreatment with NS-398, a specific inhibitor of COX-2, also induced the intestinal lesion. Enteropathy onset was further characterized by high levels of oxidative stress markers, similar to CD. Biochemical assessment of the small intestine revealed the specific activation of matrix metalloproteinases 2 and 9, high caspase-3 activity, and a significant increase of tissue transglutaminase protein levels associated with the intestinal lesion. Notably, after 30 days of treatment, enteropathic mice developed serum antibodies toward gliadin (IgA) and tissue transglutaminase (IgG). We concluded that gliadin intake in combination with COX inhibition caused a basal inflammatory status and an oxidative stress condition in the small intestine of DQ8 mice, thus triggering the mucosal lesion and, subsequently, an antigen-specific immunity.


Assuntos
Doença Celíaca/induzido quimicamente , Inibidores de Ciclo-Oxigenase 2/toxicidade , Ciclo-Oxigenase 2/metabolismo , Gliadina , Antígenos HLA-DQ/metabolismo , Indometacina/toxicidade , Mucosa Intestinal/efeitos dos fármacos , Intestino Delgado/efeitos dos fármacos , Animais , Apoptose , Caspase 3/metabolismo , Doença Celíaca/genética , Doença Celíaca/imunologia , Doença Celíaca/metabolismo , Doença Celíaca/patologia , Modelos Animais de Doenças , Proteínas de Ligação ao GTP/imunologia , Proteínas de Ligação ao GTP/metabolismo , Gliadina/imunologia , Antígenos HLA-DQ/genética , Humanos , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Intestino Delgado/imunologia , Intestino Delgado/metabolismo , Intestino Delgado/patologia , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Camundongos , Camundongos Transgênicos , Nitrobenzenos/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Proteína 2 Glutamina gama-Glutamiltransferase , Sulfonamidas/toxicidade , Fatores de Tempo , Transglutaminases/imunologia , Transglutaminases/metabolismo
20.
Diagn Microbiol Infect Dis ; 79(2): 119-24, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24745820

RESUMO

The frequency of superantigen production among Staphylococcus aureus isolates associated with endocarditis is not well defined. We tested 154 S. aureus isolates from definite infective endocarditis cases for the presence of staphylococcal enterotoxins A-E, H, and TSST-1 by PCR, enzyme-linked immunosorbent assay, and using an HLA-DR3 transgenic mouse splenocyte proliferation assay. Sixty-three isolates (50.8%) tested positive for at least 1 superantigen gene, with 21 (16.9%) testing positive for more than 2. tst (28.6%) was most common, followed by seb (27%), sea (22.2%), sed (20.6%), see (17.5%), and sec (11.1%). Of 41 methicillin-resistant S. aureus, 21 had superantigen genes, with sed being more frequently detected in this group compared to methicillin-susceptible S. aureus (P < 0.05). Superantigen genes were not associated with mortality (P = 0.81). 75% of PCR-positive isolates induced robust splenocyte proliferation. Overall, more than half of S. aureus isolates causing endocarditis carry superantigen genes, of which most are functional.


Assuntos
Endocardite/microbiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Superantígenos/análise , Superantígenos/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Proliferação de Células , Ensaio de Imunoadsorção Enzimática , Feminino , Genótipo , Humanos , Leucócitos Mononucleares/imunologia , Masculino , Camundongos Transgênicos , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Adulto Jovem
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