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Liana Verinaud - One of the best experts on this subject based on the ideXlab platform.
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Paracoccidioides brasiliensis infection promotes thymic disarrangement and premature egress of mature lymphocytes expressing prohibitive TCRs
BMC infectious diseases, 2016Co-Authors: Rosária Di Gangi, Eva Burger, Thiago Alves Da Costa, Rodolfo Thomé, Gabriela Peron, Liana VerinaudAbstract:Background Paracoccidioidomycosis, a chronic granulomatous fungal disease caused by Paracoccidioides brasiliensis yeast cells affects mainly rural workers, albeit recently cases in immunosuppressed individuals has been reported. Protective immune response against P. brasiliensis is dependent on the activity of helper T cells especially IFN-γ-producing Th1 cells. It has been proposed that Paracoccidioides brasiliensis is able to modulate the immune response towards a permissive state and that the thymus plays a major role in it.
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Paracoccidioides brasiliensis infection promotes thymic disarrangement and premature egress of mature lymphocytes expressing prohibitive TCRs
BMC Infectious Diseases, 2016Co-Authors: Rosária Di Gangi, Eva Burger, Rodolfo Thomé, Gabriela Peron, Thiago Alves Da Costa, Liana VerinaudAbstract:Background Paracoccidioidomycosis, a chronic granulomatous fungal disease caused by Paracoccidioides brasiliensis yeast cells affects mainly rural workers, albeit recently cases in immunosuppressed individuals has been reported. Protective immune response against P. brasiliensis is dependent on the activity of helper T cells especially IFN-γ-producing Th1 cells. It has been proposed that Paracoccidioides brasiliensis is able to modulate the immune response towards a permissive state and that the thymus plays a major role in it. Methods In this paper, we show that acute infection of BALB/c mice with P. brasiliensis virulent isolate (Pb18) might cause alterations in the thymic environment as well as the prohibitive TCR-expressing T cells in the spleens. Results After seven days of infection, we found yeast cells on the thymic stroma, the thymic epithelial cells (TEC) were altered regarding their spatial-orientation and inflammatory mediators gene expression was increased. Likewise, thymocytes (differentiating T cells) presented higher migratory ability in ex vivo experiments. Notwithstanding, P. brasiliensis -infected mice showed an increased frequency of prohibitive TCR-expressing T cells in the spleens, suggesting that the selection processes that occur in the thymus may be compromised during the acute infection. Conclusion In this paper, for the first time, we show that acute infection with Paracoccidioides brasiliensis yeast cells promotes thymic alterations leading to a defective repertoire of peripheral T cells. The data presented here may represent new mechanisms by which P. brasiliensis subverts the immune response towards the chronic infection observed in humans.
Rosária Di Gangi - One of the best experts on this subject based on the ideXlab platform.
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Paracoccidioides brasiliensis infection promotes thymic disarrangement and premature egress of mature lymphocytes expressing prohibitive TCRs
BMC infectious diseases, 2016Co-Authors: Rosária Di Gangi, Eva Burger, Thiago Alves Da Costa, Rodolfo Thomé, Gabriela Peron, Liana VerinaudAbstract:Background Paracoccidioidomycosis, a chronic granulomatous fungal disease caused by Paracoccidioides brasiliensis yeast cells affects mainly rural workers, albeit recently cases in immunosuppressed individuals has been reported. Protective immune response against P. brasiliensis is dependent on the activity of helper T cells especially IFN-γ-producing Th1 cells. It has been proposed that Paracoccidioides brasiliensis is able to modulate the immune response towards a permissive state and that the thymus plays a major role in it.
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Paracoccidioides brasiliensis infection promotes thymic disarrangement and premature egress of mature lymphocytes expressing prohibitive TCRs
BMC Infectious Diseases, 2016Co-Authors: Rosária Di Gangi, Eva Burger, Rodolfo Thomé, Gabriela Peron, Thiago Alves Da Costa, Liana VerinaudAbstract:Background Paracoccidioidomycosis, a chronic granulomatous fungal disease caused by Paracoccidioides brasiliensis yeast cells affects mainly rural workers, albeit recently cases in immunosuppressed individuals has been reported. Protective immune response against P. brasiliensis is dependent on the activity of helper T cells especially IFN-γ-producing Th1 cells. It has been proposed that Paracoccidioides brasiliensis is able to modulate the immune response towards a permissive state and that the thymus plays a major role in it. Methods In this paper, we show that acute infection of BALB/c mice with P. brasiliensis virulent isolate (Pb18) might cause alterations in the thymic environment as well as the prohibitive TCR-expressing T cells in the spleens. Results After seven days of infection, we found yeast cells on the thymic stroma, the thymic epithelial cells (TEC) were altered regarding their spatial-orientation and inflammatory mediators gene expression was increased. Likewise, thymocytes (differentiating T cells) presented higher migratory ability in ex vivo experiments. Notwithstanding, P. brasiliensis -infected mice showed an increased frequency of prohibitive TCR-expressing T cells in the spleens, suggesting that the selection processes that occur in the thymus may be compromised during the acute infection. Conclusion In this paper, for the first time, we show that acute infection with Paracoccidioides brasiliensis yeast cells promotes thymic alterations leading to a defective repertoire of peripheral T cells. The data presented here may represent new mechanisms by which P. brasiliensis subverts the immune response towards the chronic infection observed in humans.
Eva Burger - One of the best experts on this subject based on the ideXlab platform.
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Paracoccidioides brasiliensis infection promotes thymic disarrangement and premature egress of mature lymphocytes expressing prohibitive TCRs
BMC Infectious Diseases, 2016Co-Authors: Rosária Di Gangi, Eva Burger, Rodolfo Thomé, Gabriela Peron, Thiago Alves Da Costa, Liana VerinaudAbstract:Background Paracoccidioidomycosis, a chronic granulomatous fungal disease caused by Paracoccidioides brasiliensis yeast cells affects mainly rural workers, albeit recently cases in immunosuppressed individuals has been reported. Protective immune response against P. brasiliensis is dependent on the activity of helper T cells especially IFN-γ-producing Th1 cells. It has been proposed that Paracoccidioides brasiliensis is able to modulate the immune response towards a permissive state and that the thymus plays a major role in it. Methods In this paper, we show that acute infection of BALB/c mice with P. brasiliensis virulent isolate (Pb18) might cause alterations in the thymic environment as well as the prohibitive TCR-expressing T cells in the spleens. Results After seven days of infection, we found yeast cells on the thymic stroma, the thymic epithelial cells (TEC) were altered regarding their spatial-orientation and inflammatory mediators gene expression was increased. Likewise, thymocytes (differentiating T cells) presented higher migratory ability in ex vivo experiments. Notwithstanding, P. brasiliensis -infected mice showed an increased frequency of prohibitive TCR-expressing T cells in the spleens, suggesting that the selection processes that occur in the thymus may be compromised during the acute infection. Conclusion In this paper, for the first time, we show that acute infection with Paracoccidioides brasiliensis yeast cells promotes thymic alterations leading to a defective repertoire of peripheral T cells. The data presented here may represent new mechanisms by which P. brasiliensis subverts the immune response towards the chronic infection observed in humans.
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Paracoccidioides brasiliensis infection promotes thymic disarrangement and premature egress of mature lymphocytes expressing prohibitive TCRs
BMC infectious diseases, 2016Co-Authors: Rosária Di Gangi, Eva Burger, Thiago Alves Da Costa, Rodolfo Thomé, Gabriela Peron, Liana VerinaudAbstract:Background Paracoccidioidomycosis, a chronic granulomatous fungal disease caused by Paracoccidioides brasiliensis yeast cells affects mainly rural workers, albeit recently cases in immunosuppressed individuals has been reported. Protective immune response against P. brasiliensis is dependent on the activity of helper T cells especially IFN-γ-producing Th1 cells. It has been proposed that Paracoccidioides brasiliensis is able to modulate the immune response towards a permissive state and that the thymus plays a major role in it.
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the source of the growth promoting factor s affects the plating efficiency of Paracoccidioides brasiliensis
Medical Mycology, 1992Co-Authors: L M Singervermes, M C Ciavaglia, Suely Sanae Kashino, Eva Burger, Vera Lúcia Garcia CalichAbstract:We studied the influence of the growth factor (GF) source, concentration and production time on the plating efficiency of Paracoccidioides brasiliensis yeast cells. The highest plating efficiencies were achieved when the GF was derived from a fast growing P. brasiliensis isolate which was not homologous to the plated samples.
Gioconda San-blas - One of the best experts on this subject based on the ideXlab platform.
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Paracoccidioides brasiliensis AND Paracoccidioides lutzii, A SECRET LOVE AFFAIR.
Revista Do Instituto De Medicina Tropical De Sao Paulo, 2015Co-Authors: Thales Domingos Arantes, Gioconda San-blas, Gustavo Niño-vega, Eduardo Bagagli, Raquel Cordeiro TheodoroAbstract:To commemorate Prof. Carlos da Silva Lacaz's centennial anniversary, the authors have written a brief account of a few, out of hundreds, biological, ecological, molecular and phylogenetic studies that led to the arrival of Paracoccidioides lutzii, hidden for more than a century within Paracoccidioides brasiliensis. Lacaz's permanent interest in this fungus, and particularly his conviction on the benefits that research on paracoccidioidomycosis would bring to patients, were pivotal in the development of the field.
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Caspofungin Affects Growth of Paracoccidioides brasiliensis in Both Morphological Phases
Antimicrobial agents and chemotherapy, 2010Co-Authors: Sabrina Rodríguez-brito, Gustavo Niño-vega, Gioconda San-blasAbstract:Five Paracoccidioides brasiliensis isolates were grown in the presence of caspofungin (0 to 1 μg/ml). Inhibition of the yeast phase ranged from 20 to 65%, while in the mycelial form it ranged from 75% to 82%. Such variability was loosely related to the amount of cell wall β-1,3-glucan. No association with point mutations in the β-1,3-glucan synthase was detected. Caspofungin induced physical changes and cytoplasmic deterioration in both fungal phases.
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Primers for Clinical Detection of Paracoccidioides brasiliensis
Journal of clinical microbiology, 2005Co-Authors: Gioconda San-blas, Gustavo Niño-vega, Laura Barreto, Flavia Hebeler-barbosa, Eduardo Bagagli, Rosa Olivero De Briceño, Rinaldo Poncio MendesAbstract:From a 0.72-kb fragment universally generated in Paracoccidioides brasiliensis strains, primers were designed and tested on genomic DNA of this and other pathogenic fungi. They were specific and highly sensitive for P. brasiliensis DNA. Positive results were obtained when these were tested in clinical samples.
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Random sequencing of Paracoccidioides brasiliensis genes
Medical mycology, 2005Co-Authors: Cristina Reinoso, Gioconda San-blas, Gustavo Niño-vega, Angel DomínguezAbstract:Paracoccidioides brasiliensis genome has been reported as having a size of about 30 Mb. By digestion of genomic DNA from strain IVICPb 73 (ATCC 32071), we have constructed a DNA library with an insert size average of 8 kb in Escherichia coli XL1 Blue. We have fully sequenced 7 clones comprising 51,022 bp which represent 20 putative protein-coding sequences (seven of them, partial) and one tRNA. The 20 coding sequences cover 46% of the total 51,022 bp with introns present in 10 out of the 20 sequences. Database similarity analysis reveals the presence of genes conserved in other fungal species and higher organisms, including humans.
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Cytosolic Neutral Proteinases of Paracoccidioides brasiliensis
Current microbiology, 1998Co-Authors: Gioconda San-blas, Gustavo Niño-vega, Françoise Sorais, Cioly Méndez, Felipe San-blasAbstract:Cytosolic proteinases were assayed in both morphological phases of Paracoccidioides brasiliensis. Preparations from the mycelial phase were more active in vitro than those from the yeast cells. Optimal proteinase activities for both phases occurred at pH's between 6.0 and 9.0, and at 45°C. Gelatin-SDS-PAGE electrophoresis separated several bands (58–112 kDa) in mycelial preparations; a single band (70 kDa) was seen in yeast preparations. Enzymatic activities were inhibited by antipain, phenyl methyl sulfonyl fluoride (PMSF), and chymostatin, suggestive of serine proteinases. Partial inhibition of the mycelial enzymes by ethylene diamine tetraacetic acid (EDTA), 1,10-phenanthroline, and iodoacetamide, also suggested the presence of cysteine- and metallo-proteinases. The enzymatic activity increased in preparations extracted from yeast cells transforming to mycelia, and decreased in preparations obtained from the reverse process.
Antero Silva Ribeiro De Andrade - One of the best experts on this subject based on the ideXlab platform.
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Mouse Immunization with Radioattenuated Yeast Cells of Paracoccidioides brasiliensis.
Methods in molecular biology (Clifton N.J.), 2017Co-Authors: Estefânia Mara Do Nascimento Martins, Antero Silva Ribeiro De AndradeAbstract:Paracoccidioides brasiliensis is the agent of paracoccidioidomycosis, the most prevalent mycosis in Latin America, and currently there is no effective vaccine. The present chapter describes the methodology to obtain radioattenuated yeast cells of P. brasiliensis and a protocol to evaluate protective response elicited by this immunogen in experimental paracoccidioidomycosis. The radioattenuated yeast provides a valuable tool for immunological studies in experimental paracoccidioidomycosis and vaccine research.
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Ultrastructural changes in Paracoccidioides brasiliensis yeast cells attenuated by gamma irradiation.
Mycoses, 2007Co-Authors: Marina Cortez Demicheli, Alfredo M. Goes, Antero Silva Ribeiro De AndradeAbstract:Paracoccidioides brasiliensis is a thermally dimorphic fungus agent of paracoccidioidomycosis, a deep-seated systemic infection of humans with high prevalence in Latin America. Until now no vaccine has been reported. Ionizing radiation can be used to attenuate pathogens for vaccine development and we have successfully attenuated yeast cells of P. brasiliensis by gamma irradiation. The aim of the present study was to examine at ultrastructural level the effects of gamma irradiation attenuation on the morphology of P. brasiliensis yeast cells. Paracoccidioides brasiliensis (strain Pb-18) cultures were irradiated with a dose of 6.5 kGy. The irradiated cells were examined by scanning and also transmission electron microscopy. When examined 2 h after the irradiation by scanning electron microscopy, the 6.5 kGy irradiated cells presented deep folds or were collapsed. These lesions were reversible since when examined 48 h after irradiation the yeast had recovered the usual morphology. The transmission electron microscopy showed that the irradiated cells plasma membrane and cell wall were intact and preserved. Remarkable changes were found in the nucleus that was frequently in a very electrondense form. An extensive DNA fragmentation was produced by the gamma irradiation treatment.
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Paracoccidioides brasiliensis: attenuation of yeast cells by gamma irradiation
Mycoses, 2006Co-Authors: Marina Cortez Demicheli, Bernardo S. Reis, Alfredo M. Goes, Antero Silva Ribeiro De AndradeAbstract:Summary Paracoccidioides brasiliensis is the agent of paracoccidioidomycosis, the most prevalent mycosis in Latin America, and currently there is no effective vaccine. The aim of this study was to attenuate the yeast form of P. brasiliensis by gamma irradiation for further studies on vaccine research. Paracoccidioides brasiliensis (strain Pb 18) cultures were irradiated at doses between 0.5 and 8.0 kGy. After each dose the viability, reproductive ability and protein metabolism were evaluated. The comparison between the antigenic profile of irradiated and control yeast was made by Western blot and the virulence evaluated by the inoculation in C57Bl/J6 mice. At 6.5 kGy the yeast lost its reproductive capacity. The viability and the incorporation of [L-35S]-methionine were the same in control and up to 6.5 kGy irradiated cells, but 6.5 kGy-irradiated yeast secreted 40% less proteins. The Western blot profile was clearly similar in control and 6.5 kGy-irradiated yeast. No colony-forming unit (CFU) could be recovered from the tissues of the mice infected with the radioattenuated yeast. We concluded that for P. brasiliensis yeast it is possible to find a dose in which the pathogen loses its reproductive ability and virulence, while retaining its viability, metabolic activity and the antigenic profile.
