NCPP treatment alleviates ConA-induced hepatitis via reducing CD4+T activation and NO production.
ABSTRACT Corynebacterium parvum (CP), a kind of immunomodulator, has been well documented in many diseases. Non-cell C. parvum product (NCPP) is a newly-found nano-preparation. To investigate the effect of NCPP on Con A-induced murine severe hepatitis, we pretreated mice with NCPP intraperitoneally. After 12 h , ConA (25 μg/g body wt) was injected intravenously to provoke severe hepatitis and the degree of liver injury was evaluated by serum transaminase analysis and heptatic tissue pathology. Results have shown that levels of serum transaminase and degree of liver injury in ConA/NCPP groups had significantly declined than those in ConA/PBS groups. Notably, results of flow cytometry have demonstrated that activation of CD4+T cells in ConA/NCPP groups has been down-regulated, compared with ConA/PBS groups. Further, levels of serum and KC-related nitric oxide (NO) was displayed significantly lower in ConA/NCPP groups than those in ConA/PBS groups. The results indicate that NCPP may alleviate ConA-induced hepatitis by reducing CD4+T activation and NO production.
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ABSTRACT: Male NMRI or BALB/c mice developed severe liver injury as assessed by transaminase release within 8 h when an intravenous dose greater than 1.5 mg/kg concanavalin A (Con A) was given. Histopathologically, only the liver was affected. Electron micrographs revealed leukocyte sticking to endothelial cells and bleb formation of hepatocytes. The hepatotoxicity of the lectin correlated neither with its agglutination activity nor with its sugar specificity. Administration of 0.5 mg/kg dexamethasone or 50 mg/kg cyclosporine A or 50 mg/kg FK 506 (Fujimycin) resulted in protection of the animals whereas indomethacin pretreatment failed to protect. Con A hepatitis was accompanied by the release of IL-2 into the serum of the animals. Mice with severe combined immunodeficiency syndrome lacking B as well as T lymphocytes were resistant against Con A. Athymic nude mice with immature T lymphocytes were also resistant. Pretreatment of mice with an antibody against T lymphocytes fully protected against Con A as did monoclonal anti-mouse CD4. Monoclonal anti-mouse CD8 failed to protect. Pretreatment of mice with silica particles, i.e., deletion of macrophages, prevented the induction of hepatitis. These findings provide evidence that Con A-induced liver injury depends on the activation of T lymphocytes by macrophages in the presence of Con A. The model might allow the study of the pathophysiology of immunologically mediated hepatic disorders such as autoimmune chronic active hepatitis.Journal of Clinical Investigation 08/1992; 90(1):196-203. · 13.77 Impact Factor
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ABSTRACT: Con A administration results in dose-dependent immune-mediated liver injury. Cytokines are important to determine the outcome of liver failure in this model, and especially TNF-alpha and IFN-gamma directly contribute to hepatocyte damage. The intracellular pathways of these two cytokines, which eventually result in tissue destruction, are not well defined. Here we used anti-IFN-gamma Abs and adenoviral vectors that express molecules inhibiting distinct TNF-alpha-dependent pathways in hepatocytes to better understand the relevance of specific intracellular signaling cascades for Con A-induced liver failure. We show that activation of TNF-alpha- and IFN-gamma-dependent intracellular pathways occurs prior to the influx of immune-activated cells into the liver and that anti-TNF-alpha and anti-IFN-gamma neutralizing Abs cannot block infiltration of these cells. Blocking experiments with Abs and adenoviral vectors showed that NF-kappaB activation and the Fas-associated death domain protein/caspase 8 cascade in hepatocytes during Con A-induced liver failure have no impact on tissue injury. Additionally, STAT1 activation alone after Con A injection in liver cells does not result in liver damage. In contrast, IFN-gamma-dependent expression of IFN regulatory factor-1 and TNF-alpha-dependent activation of c-Jun N-terminal kinase in liver cells correlates with liver cell damage after Con A injection. Therefore, our experiments indicate that 11418690The Journal of Immunology 08/2001; 167(1):514-23. · 5.36 Impact Factor
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ABSTRACT: Cytokines released by infiltrating T cells may contribute to the hepatic injury in chronic hepatitis. Therefore, we characterized peripheral blood- and liver-infiltrating T cells from patients with chronic hepatitis of different etiology and determined the T cell phenotypes and the cytokine release. Liver tissue and peripheral blood-derived T cells from patients with autoimmune hepatitis and primary biliary cirrhosis predominantly expressed CD4-molecules and the alpha- and beta-chains of the T cell receptor (TCR). In chronic viral hepatitis B and C, liver- and blood-derived T cells were preferentially CD8+ T cells expressing the alpha beta TCR. Mitogenic stimulation with irradiated Daudi lymphoma cells and phytohemagglutinin led to a strong release of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and interleukin-2 (IL-2) by T cells in patients with chronic hepatitis and in healthy controls. T cells from patients with primary biliary cirrhosis and some patients with autoimmune hepatitis showed a significantly higher secretion of interleukin-4 (IL-4) and interleukin-10 (IL-10) than T cells from patients with chronic viral hepatitis or healthy controls. Histologic inflammatory activity did not correlate with the amount of cytokines released after mitogenic activation. In conclusion, liver tissue and peripheral blood T cells of patients with autoimmune hepatitis and primary biliary cirrhosis were dominated by CD4+ TCR alpha beta+ T helper/inducer cells, whereas in chronic viral hepatitis an enrichment of CD8+ TCR alpha beta + cytotoxic/suppressor T cells was observed.(ABSTRACT TRUNCATED AT 250 WORDS)Liver International 07/1994; 14(3):161-6.