Navegando por Palavras-chave "interferon-gamma"

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    Effect of cyclosporin A on nitric oxide production in cultured LLC-PK1 cells
    (Marcel Dekker Inc, 2001-01-01) Lima, R.; Serone, A. P.; Schor, N.; Higa, EMS; Universidade Federal de São Paulo (UNIFESP)
    The effect of Cyclosporin A on nitric oxide production was studied in cultured LLC- PK1 cells. for this purpose the cells were incubated with vehicle (olive oil, 10 mug/ml in DMSO), Cyclosporin A (CsA, 10 mug/ml), tumor necrosis factor (TNF-alpha, 150 U/ml) + interferon (IFN-gamma, 500 U/ml) to upregulate NOS synthesis, and therefore, NO production (used as a positive control), or CsA + TNF-alpha + IFN-gamma. After 72 hours the culture medium was collected and nitrite was determined by the Griess method. the results were normalized to the protein harvested from these cells as measured by the Lowry method. Viability was determined by the exclusion of the fluorescent dyes (acridine orange and ethidium bromide). Intracellular calcium was measured spectrophotometrically using the fluorescent calcium indicator fura-2 AM. in CsA treated cells, the nitrite (pmoles/mg of protein) was decreased when compared to control (12.8 +/- 0.5 vs. 18.3 +/- 0.6; p < 0.05; both n = 8). TNF- + IFN-gamma increased the nitrite synthesis (52.0 +/- 0.2; p < 0.05 vs. control; n = 6). This effect was decreased significantly by the simultaneous treatment with CsA (38.8 +/- 0.3; p < 0.05; n = 6). Cell viability in CsA group was decreased when compared to the cdntrol (84.7 +/- 0.2% vs. 93.6 +/- 0,1%; p < 0.05: both n = 10). TNF- +/- IFN-gamma had no effect on viability (93.0 +/- 0.3%; n = 10). However, when combined with CsA, viability was decreased relative to the control (85.0 +/- 0.2%; p < 0.05; n = 10). Acute (1 h) or chronic (72 h) treatment of LLC- PK1 cells with CsA had no effect on basal calcium levels.Our results demonstrate a reduced level of nitric oxide production in LLC- PK1 cells treated with CsA. There was no effect of the drug on intracellular calcium levels, however CsA treatment did reduce cellular viability. We suggest that, in part, the decreased levels of NO production are a secondary consequence of direct cell damage. However, CsA may also be exerting direct effects on NO synthesis through its interactions with both iNOS and cNOS. These results also provide a dual mechanism of action for CsA induced nephrotoxicity, that is, direct cell damage and interference with the NO system within the nephron.
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    Gene therapy with interleukin-10 receptor and interleukin-12 induces a protective interferon-gamma-dependent response against B16F10-Nex2 melanoma
    (Nature Publishing Group, 2011-02-01) Marchi, L. H. L. [UNIFESP]; Paschoalin, T. [UNIFESP]; Travassos, L. R. [UNIFESP]; Rodrigues, E. G. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Antitumor immune responses are associated with proinflammatory cytokines, whereas tumor-developing animals generally have increased the production of immunosuppressive cytokines. Here, we show that splenocytes from C57Bl/6 mice resistant to low doses of B16F10-Nex2 melanoma cells produced twofold or higher interferon-gamma (IFN-gamma)/interleukin-10 (IL-10) ratios, whereas cells from tumor-bearing animals produced predominantly IL-10. IL-10-knockout (IL-10KO) mice were significantly more resistant to B16F10-Nex2 development, producing increased amounts of IL-12 and IFN-gamma. To neutralize IL-10 in vivo, aiming at cancer therapy, recombinant eukaryotic plasmid expressing the soluble extracellular region of the murine IL-10 receptor alpha-chain was constructed (pcDNA3-sIL-10R). Plasmid-treated melanoma-challenged animals showed extended survival time, the protective response was IFN-gamma dependent and enhanced by co-immunization with a plasmid expressing IL-12. Dendritic cells (DCs) from IL-10KO mice, primed with B16F10-Nex2 antigens (TAg), secreted increased amounts of T-helper 1-type cytokines and increased the expression of surface activation markers. Vaccination of C57Bl/6 mice with TAg-activated IL-10KO DCs, as well as with TAg-primed DCs from C57Bl/6 mice transfected with pcDNA3-sIL10R plasmid, significantly increased animal survival. in conclusion, an IFN-gamma-dependent protective response was induced against B16F10-Nex2 cells by neutralization of IL-10 with pcDNA3-sIL10R plasmid. This effect was enhanced by association with IL-12 gene therapy (80% protection), and could be mediated by TAg-primed DCs. Cancer Gene Therapy (2011) 18, 110-122; doi: 10.1038/cgt.2010.58; published online 1 October 2010
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    Immunolocalization of IFN-gamma in the lesions of resistant and susceptible mice to Paracoccidioides brasiliensis infection
    (Wiley-Blackwell, 2011-11-01) Nishikaku, Angela Satie [UNIFESP]; Sanchez Molina, Raphael Fagnani; Albe, Bernardo Paulo; Cunha, Claudia da Silva; Scavone, Renata; Pinto Pizzo, Celia Regina; Camargo, Zoilo Pires de [UNIFESP]; Burger, Eva; Univ Fed Alfenas; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    The important role of interferon-gamma (IFN-gamma) in protective immunity in mycosis is well established, except for its participation in fungal granulomas. Herein, we employ immunohistochemical reactions to describe the in situ localization of IFN-gamma in granulomas of susceptible (B10.A) and resistant (A/J) mice to infection with Paracoccidioides brasiliensis (Pb). After infection with the highly virulent Pb18, IFN-gamma-positive lymphomononuclear cells were localized mainly at the periphery of granulomas in both mouse strains. the numbers of positive cells found in compact granulomas of A/J mice increased significantly from 15 to 120 days postinfection. At this time, significantly more positive cells were detected in the compact granulomas of resistant mice than in the loose, multifocal lesions of the susceptible ones. in infection with the slightly virulent Pb265, the same pattern of IFN-gamma localization was found as in Pb18 infection, but there was decreased staining at 120 days due to the presence of only residual lesions in both mouse strains. the marked IFN-gamma staining observed in the granulomas of resistant mice at the later stage of Pb infection confirms its importance in fungal dissemination control, and suggests a contribution to the development of paracoccidioidal granuloma.
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    Lower cytokine secretion ex vivo by natural killer T cells in HIV-infected individuals is associated with higher CD161 expression
    (Lippincott Williams & Wilkins, 2009-09-24) Snyder-Cappione, Jennifer E.; Loo, Christopher P.; Carvalho, Karina I. [UNIFESP]; Kuylenstierna, Carlotta; Deeks, Steven G.; Hecht, Frederick M.; Rosenberg, Michael G.; Sandberg, Johan K.; Kallas, Esper Georges [UNIFESP]; Nixon, Douglas F.; Univ Calif San Francisco; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP); Karolinska Univ Hosp; San Francisco Gen Hosp; Albert Einstein Coll Med
    Objective: Natural killer T (NKT) cells are efficiently targeted by HIV and severely reduced in numbers in the circulation of infected individuals. the functional capacity of the remaining NKT cells in HIV-infected individuals is poorly characterized. This study measured NKT cell cytokine production directly ex vivo and compared these responses with both the disease status and NKT subset distribution of individual patients.Methods: NKT cell frequencies, subsets, and ex-vivo effector functions were measured in the peripheral blood mononuclear cells of HIV-infected patients and healthy controls by flow cytometry. We measured cytokines from NKT cells after stimulation with either a-galactosyl ceramide-loaded CD1d dimers (DimerX-alpha GalCer) or phorbol myristate acetate and ionomycin.Results: the frequencies of NKT cells secreting interferon-gamma and tumor necrosis factor-alpha were significantly lower in HIV-infected patients than healthy controls after DimerX-alpha GalCer treatment, but responses were similar after treatment with phorbol myristate acetate and ionomycin. the magnitude of the interferon-gamma response to DimerX-alpha GalCer correlated inversely with the number of years of infection. Both interferon-gamma and tumor necrosis factor-alpha production in response to DimerX-alpha GalCer correlated inversely with CD161 expression.Conclusion: the ex-vivo Th1 responses of circulating NKT cells to CD1d-glycolipid complexes are impaired in HIV-infected patients. NKT cell functions may be progressively lost over time in HIV infection, and CD161 is implicated in the regulation of NKT cell responsiveness. (C) 2009 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins