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Braz. j. med. biol. res ; 50(4): e5928, 2017. graf
Article in English | LILACS | ID: biblio-839283


Paracoccidioides brasiliensis and P. lutzii are fungi that cause paracoccidioidomycosis (PCM), the most prevalent systemic mycosis in South America. For serological diagnosis, although 43-kDa glycoprotein (gp43) is regarded as highly specific for PCM, the occurrence of false negative reactions in sera from patients infected with P. lutzii suggests that preparation with only one antigen is not recommended. Heat shock proteins are feasible alternatives as a second antigen because they are often highly immunogenic. In this study, we evaluated the usefulness of recombinant 60-kDa heat shock protein from P. brasiliensis (rPbHsp60) for the serological diagnosis of PCM. Using western blotting assay, we observed that 77.3% of the sera from PCM patients were positive to rPbHsp60, with 90.9% positivity to recombinant gp43 (rgp43). More importantly, sera from healthy subjects had 27% positivity to rPbHsp60 and none to rgp43. When rPbHsp60 was used in ELISA, we did not observe significant differences between the reactions with sera from PCM patients and healthy subjects, while the difference was clearly evident when the antigen was rgp43. Furthermore, rPbHsp60 was recognized by sera from patients with histoplasmosis, aspergillosis, sporotrichosis or tuberculosis in an ELISA test. These results show that rPbHsp60 is not a good antigen for PCM diagnosis.

Humans , Antigens, Fungal/blood , Chaperonin 60/blood , Fungal Proteins/blood , Paracoccidioides/immunology , Paracoccidioidomycosis/diagnosis , Serologic Tests/methods , Blotting, Western , Electrophoresis, Polyacrylamide Gel , Enzyme-Linked Immunosorbent Assay , Paracoccidioidomycosis/blood , Recombinant Proteins/blood , Reference Values , Reproducibility of Results , Statistics, Nonparametric
Braz. j. med. biol. res ; 48(12): 1095-1100, Dec. 2015. graf
Article in English | LILACS | ID: lil-762920


In DNA vaccines, the gene of interest is cloned into a bacterial plasmid that is engineered to induce protein production for long periods in eukaryotic cells. Previous research has shown that the intramuscular immunization of BALB/c mice with a naked plasmid DNA fragment encoding the Mycobacterium leprae 65-kDa heat-shock protein (pcDNA3-Hsp65) induces protection against M. tuberculosis challenge. A key stage in the protective immune response after immunization is the generation of memory T cells. Previously, we have shown that B cells capture plasmid DNA-Hsp65 and thereby modulate the formation of CD8+ memory T cells after M. tuberculosis challenge in mice. Therefore, clarifying how B cells act as part of the protective immune response after DNA immunization is important for the development of more-effective vaccines. The aim of this study was to investigate the mechanisms by which B cells modulate memory T cells after DNA-Hsp65 immunization. C57BL/6 and BKO mice were injected three times, at 15-day intervals, with 100 µg naked pcDNA-Hsp65 per mouse. Thirty days after immunization, the percentages of effector memory T (TEM) cells (CD4+ and CD8+/CD44high/CD62Llow) and memory CD8+ T cells (CD8+/CD44high/CD62Llow/CD127+) were measured with flow cytometry. Interferon γ, interleukin 12 (IL-12), and IL-10 mRNAs were also quantified in whole spleen cells and purified B cells (CD43−) with real-time qPCR. Our data suggest that a B-cell subpopulation expressing IL-10 downregulated proinflammatory cytokine expression in the spleen, increasing the survival of CD4+ TEM cells and CD8+ TEM/CD127+ cells.

Animals , Male , Mice , B-Lymphocytes/immunology , Heat-Shock Proteins/immunology , Immunomodulation/genetics , /genetics , RNA, Messenger/immunology , T-Lymphocyte Subsets/immunology , B-Lymphocytes/metabolism , Flow Cytometry , Gene Expression/genetics , Heat-Shock Proteins/therapeutic use , Immunologic Memory/physiology , Immunophenotyping/classification , Inflammation Mediators/analysis , Interferon-gamma/analysis , /immunology , /analysis , Mice, Knockout , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , RNA, Messenger/genetics , Spleen/cytology , Spleen/immunology , T-Lymphocyte Subsets/classification , Vaccines, DNA/immunology , Vaccines, DNA/therapeutic use