Effect of human recombinant cytokines on the induction of macrophage procoagulant activity

A panel of human recombinant cytokines was tested for induction of procoagulant activity (PCA) in human monocyte-derived macrophages. Nonadherent culture conditions were used, and PCA was determined with whole cells rather than cell lysates. It was assured by Limulus amebocyte lysate assay that tested cytokines displayed low levels of endotoxin activity within the range of biologic activity. Additional evidence to rule out an endotoxin effect was provided by heat- inactivation experiments. Interferon-gamma (IFN-gamma), interleukin-1 beta (IL-1 beta), and tumor necrosis factor-alpha (TNF-alpha) were strong macrophage PCA inducers. The low level of PCA induced by IL-2, granulocyte-macrophage colony-stimulating factor (GM-CSF), M-CSF, IL-4, IL-6, IL-10, and IFN-alpha could not be distinguished from that induced by traces of endotoxin contaminating the preparations. Transforming growth factor-beta decreased constitutively expressed PCA within 24 hours of exposure. PCA induced by IFN-gamma, IL-1 beta, and TNF-alpha depended largely on tissue factor expression, as evidenced by experiments with factor X-deficient plasma and antitissue factor antibodies. In macrophages subcultured in adherence, IL-1 beta was a strong PCA inducer, whereas IFN-gamma and TNF-alpha promoted little PCA increase. This observation and different kinetics of PCA induction suggested that mechanisms of PCA induction are distinct for the three cytokines. Thus, we showed that well-characterized cytokines critically involved in the promotion of cell-mediated antimicrobial defense/delayed-type hypersensitivity and considered for clinical application promote local fibrin deposition by a direct effect on macrophages.     

Absence of TNFRp55 influences virus-induced autoimmunity despite efficient lymphocytic infiltration

Tumor necrosis factor (TNF)-alpha is a multipotent cytokine associated with many cellular functions, including inflammation and anti-viral defense. Many studies have implicated TNF-alpha in the pathogenesis of autoimmune diseases. TNF-alpha responses are mediated through binding to specific cell surface receptors, TNFRp55 and TNFRp75. The objective of the present study was to investigate the contribution of the TNFRp55 in the inflammatory response associated with autoimmune diabetes development in a viral transgenic model. In this model, the animals express lymphocytic choriomeningitis virus (LCMV)-glycoprotein (gp) in the beta cells of the pancreas under the control of the rat insulin promoter (RIP-gp). Diabetes is induced following LCMV infection due to beta cell destruction by LCMV-specific CD8+ cytotoxic T lymphocytes. TNFRp55-deficient RIP-gp animals were examined to assess the importance of the TNFRp55. The kinetics and onset of lymphocytic infiltration into the pancreatic islets and hyperglycemia was not altered in the absence of TNFRp55 after LCMV infection. Animals were evaluated following recombinant LCMV-gp vaccinia virus infection to test whether properties of the infectious agent influence autoimmunity. Interestingly, the kinetics were accelerated and the frequency of diabetes was increased in TNFRp55-deficient mice compared with control animals. This accelerated onset of diabetes is likely a result of increased viral replication in the TNFRp55-deficient host. Thus, these data demonstrate that TNFRp55 is not essential for producing the local inflammatory effects which contribute to organ-specific autoimmunity in this transgenic model. However, the absence of TNFRp55 altered the kinetics and incidence of the disease in a pathogen-dependent fashion.      

Normal thymic selection, superantigen-induced deletion and Fas-mediated apoptosis of T cells in IL-2 receptor beta chain-deficient mice

Mice lacking the IL-2 receptor beta chain (IL-2R beta) exhibit an autoimmune reaction characterized by generalized T cell activation, production of autoantibodies, myeloproliferation and severe anemia. T cells of IL-2R beta-/- mice were examined to elucidate the mechanism responsible for their abnormal activation and to determine how such abnormal activation might affect other cell lineages. Elevated levels of IgG, IgE and autoantibodies in IL-2R beta-/- mice were found to be associated with activated CD4+ T cells which secreted elevated levels of IL-4. Thymocytes in IL-2R beta-/- mice showed normal negative and positive selection patterns when analyzed in transgenic mice bearing a TCR specific for HY antigen, suggesting that neither IL-2 nor IL-15 is essential for thymic selection. Peripheral T cells in IL-2R beta- deficient mice underwent normal programmed cell death in response to staphylococcal enterotoxin B superantigen, in contrast to cells from mice deficient for either IL-2 or IL-2R alpha. Activated T cells in IL- 2R beta-deficient mice expressed normal levels of Fas antigen and underwent normal apoptosis in response to induction with anti-Fas mAb. Thus, the accumulation of activated T cells in IL-2R beta-/- mice does not appear to be derived from abnormalities in either thymic selection or Fas-mediated apoptosis.      

A three-country comparison of psychotropic medication prevalence in youth

Background  

The study aims to compare cross-national prevalence of psychotropic medication use in youth.