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1.  Impaired Innate Immunity in Tlr4−/− Mice but Preserved CD8+ T Cell Responses against Trypanosoma cruzi in Tlr4-, Tlr2-, Tlr9- or Myd88-Deficient Mice 
PLoS Pathogens  2010;6(4):e1000870.
The murine model of T. cruzi infection has provided compelling evidence that development of host resistance against intracellular protozoans critically depends on the activation of members of the Toll-like receptor (TLR) family via the MyD88 adaptor molecule. However, the possibility that TLR/MyD88 signaling pathways also control the induction of immunoprotective CD8+ T cell-mediated effector functions has not been investigated to date. We addressed this question by measuring the frequencies of IFN-γ secreting CD8+ T cells specific for H-2Kb-restricted immunodominant peptides as well as the in vivo Ag-specific cytotoxic response in infected animals that are deficient either in TLR2, TLR4, TLR9 or MyD88 signaling pathways. Strikingly, we found that T. cruzi-infected Tlr2−/−, Tlr4−/−, Tlr9−/− or Myd88−/− mice generated both specific cytotoxic responses and IFN-γ secreting CD8+ T cells at levels comparable to WT mice, although the frequency of IFN-γ+CD4+ cells was diminished in infected Myd88−/− mice. We also analyzed the efficiency of TLR4-driven immune responses against T. cruzi using TLR4-deficient mice on the C57BL genetic background (B6 and B10). Our studies demonstrated that TLR4 signaling is required for optimal production of IFN-γ, TNF-α and nitric oxide (NO) in the spleen of infected animals and, as a consequence, Tlr4−/− mice display higher parasitemia levels. Collectively, our results indicate that TLR4, as well as previously shown for TLR2, TLR9 and MyD88, contributes to the innate immune response and, consequently, resistance in the acute phase of infection, although each of these pathways is not individually essential for the generation of class I-restricted responses against T. cruzi.
Author Summary
Innate and acquired immune responses are triggered during infection with T. cruzi, the etiologic agent of Chagas' disease, and are critical for host survival. Parasite burden is usually controlled by the time the adaptive response becomes operational. Nevertheless, T. cruzi manages to subsist within intracellular niches and establishes a chronic infection, leading to the development of cardiomyopathy in approximately one-third of infected individuals. Recently, Toll-like receptors (TLRs) have been shown to recognize T. cruzi molecules and mice lacking MyD88, the key adaptor for most TLRs, are extremely susceptible to infection. Although TLRs are known to link innate and adaptive responses, their role in the establishment of crucial effector mechanisms mediated by CD8+ T cells during T. cruzi infection has not yet been determined. We analyzed the induction of IFN-γ and cytotoxic activity in vivo in TLR2-, TLR4-, TLR9- or MyD88-deficient mice during infection, and found intact responses compared to WT mice. We also demonstrated that TLR4 is required for optimal production of inflammatory cytokines and nitric oxide and, consequently, for a better control of parasitemia levels. Understanding how TLR activation leads to resistance to infection might contribute to the development of better strategies to improve immune responses against this pathogen.
doi:10.1371/journal.ppat.1000870
PMCID: PMC2861687  PMID: 20442858
2.  Swine and Poultry Pathogens: the Complete Genome Sequences of Two Strains of Mycoplasma hyopneumoniae and a Strain of Mycoplasma synoviae†  
Vasconcelos, Ana Tereza R. | Ferreira, Henrique B. | Bizarro, Cristiano V. | Bonatto, Sandro L. | Carvalho, Marcos O. | Pinto, Paulo M. | Almeida, Darcy F. | Almeida, Luiz G. P. | Almeida, Rosana | Alves-Filho, Leonardo | Assunção, Enedina N. | Azevedo, Vasco A. C. | Bogo, Maurício R. | Brigido, Marcelo M. | Brocchi, Marcelo | Burity, Helio A. | Camargo, Anamaria A. | Camargo, Sandro S. | Carepo, Marta S. | Carraro, Dirce M. | de Mattos Cascardo, Júlio C. | Castro, Luiza A. | Cavalcanti, Gisele | Chemale, Gustavo | Collevatti, Rosane G. | Cunha, Cristina W. | Dallagiovanna, Bruno | Dambrós, Bibiana P. | Dellagostin, Odir A. | Falcão, Clarissa | Fantinatti-Garboggini, Fabiana | Felipe, Maria S. S. | Fiorentin, Laurimar | Franco, Gloria R. | Freitas, Nara S. A. | Frías, Diego | Grangeiro, Thalles B. | Grisard, Edmundo C. | Guimarães, Claudia T. | Hungria, Mariangela | Jardim, Sílvia N. | Krieger, Marco A. | Laurino, Jomar P. | Lima, Lucymara F. A. | Lopes, Maryellen I. | Loreto, Élgion L. S. | Madeira, Humberto M. F. | Manfio, Gilson P. | Maranhão, Andrea Q. | Martinkovics, Christyanne T. | Medeiros, Sílvia R. B. | Moreira, Miguel A. M. | Neiva, Márcia | Ramalho-Neto, Cicero E. | Nicolás, Marisa F. | Oliveira, Sergio C. | Paixão, Roger F. C. | Pedrosa, Fábio O. | Pena, Sérgio D. J. | Pereira, Maristela | Pereira-Ferrari, Lilian | Piffer, Itamar | Pinto, Luciano S. | Potrich, Deise P. | Salim, Anna C. M. | Santos, Fabrício R. | Schmitt, Renata | Schneider, Maria P. C. | Schrank, Augusto | Schrank, Irene S. | Schuck, Adriana F. | Seuanez, Hector N. | Silva, Denise W. | Silva, Rosane | Silva, Sérgio C. | Soares, Célia M. A. | Souza, Kelly R. L. | Souza, Rangel C. | Staats, Charley C. | Steffens, Maria B. R. | Teixeira, Santuza M. R. | Urmenyi, Turan P. | Vainstein, Marilene H. | Zuccherato, Luciana W. | Simpson, Andrew J. G. | Zaha, Arnaldo
Journal of Bacteriology  2005;187(16):5568-5577.
This work reports the results of analyses of three complete mycoplasma genomes, a pathogenic (7448) and a nonpathogenic (J) strain of the swine pathogen Mycoplasma hyopneumoniae and a strain of the avian pathogen Mycoplasma synoviae; the genome sizes of the three strains were 920,079 bp, 897,405 bp, and 799,476 bp, respectively. These genomes were compared with other sequenced mycoplasma genomes reported in the literature to examine several aspects of mycoplasma evolution. Strain-specific regions, including integrative and conjugal elements, and genome rearrangements and alterations in adhesin sequences were observed in the M. hyopneumoniae strains, and all of these were potentially related to pathogenicity. Genomic comparisons revealed that reduction in genome size implied loss of redundant metabolic pathways, with maintenance of alternative routes in different species. Horizontal gene transfer was consistently observed between M. synoviae and Mycoplasma gallisepticum. Our analyses indicated a likely transfer event of hemagglutinin-coding DNA sequences from M. gallisepticum to M. synoviae.
doi:10.1128/JB.187.16.5568-5577.2005
PMCID: PMC1196056  PMID: 16077101

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