Flávia Ribeiro

Publications (2)6.66 Total impact

• Article: Mycobacterium tuberculosis heat-shock protein 70 impairs maturation of dendritic cells from bone marrow precursors, induces interleukin-10 production and inhibits T-cell proliferation in vitro.

  Adriana Motta, Carla Schmitz, Luiz Rodrigues, Flávia Ribeiro, Cesar Teixeira, Thiago Detanico, Carla Bonan, Heather Zwickey, Cristina Bonorino
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  ABSTRACT: In different inflammatory disease models, heat-shock proteins (hsp) and hsp-derived peptides have been demonstrated to possess anti-inflammatory properties. While some studies have shown that hsp can directly interact with antigen-presenting cells, others report that bacterial hsp can induce specific T cells with regulatory phenotypes. Effective characterization of the immunomodulatory effects of hsp 70, however, has historically been confounded by lipopolysaccharide (LPS) contamination. In this study, we compared the effects of LPS-free Mycobacterial tuberculosis hsp 70 (TBhsp70) and its possible contaminants on dendritic cells (DC). We demonstrate herein that LPS-free TBhsp70 inhibits murine DC maturation in vitro, while LPS-contaminated TBhsp70 induces DC maturation. Mock recombinant preparations have no effect. In contrast to LPS, TBhsp70 does not induce tumour necrosis factor-alpha production by DC, but interleukin-10. In vivo, only LPS-contaminated TBhsp70 induces up-regulation of CD86 in splenic mature DC. Finally, TBhsp70 inhibited phytohaemagglutinin-induced T-cell proliferation. Our results support the hypothesis that TBhsp70 does not have inflammatory potential, but rather has immunosuppressive properties.
  Immunology 09/2007; 121(4):462-72. · 3.32 Impact Factor
• Source

  Available from: Rodrigo Pestana Lopes

  Article: Dehydroepiandrosterone sulphate enhances IgG and Interferon-gamma production during immunization to tuberculosis in young but not aged mice.

  Flávia Ribeiro, Rodrigo Pestana Lopes, Cláudia Paiva Nunes, Fábio Maito, Cristina Bonorino, Moisés Evandro Bauer
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  ABSTRACT: Ageing of the endocrine system (endocrinosenescence) has been closely related to immunosenescence. Dehydroepiandrosterone sulphate (DHEAS), a steroid hormone produced by the adrenals with reported enhancing immunomodulatory properties, consistently decline during ageing in parallel to detrimental increase in peripheral glucocorticoids. We investigated here the adjuvant effects of DHEAS during intraperitoneal immunization to Mycobacterium tuberculosis heat shock protein 70 (mycHSP70) in old (24 months) as well as young (3 months) BALB/c mice. Both young and old mice had significantly higher Immunoglobulin G (IgG) levels following immunization. Young mice co-immunized with mycHSP70-DHEAS presented an early increase in specific IgG levels and showed increased Interferon-gamma production compared to old mice. Also, T cells of immunized young animals were consistently more resistant to the immunosuppressive effects of glucocorticoids and to DHEAS. DHEAS was not effective in modulating antigen-specific T-cell proliferation, Interleukin-2 production or percentage of recent activated T-cell subsets (CD4 + CD69 + and CD8 + CD69 +). Our data further indicate mycHSP70 as a putative good antigen in vaccine to tuberculosis. Our data also suggest that DHEAS produced adjuvant effects upon humoral and some cellular immune responses of young, but not old mice and indicate that immunization with DHEAS is capable of changing T-cell responses to steroids.
  Biogerontology 05/2007; 8(2):209-20. · 3.34 Impact Factor