Few data exist regarding mechanisms of mucosal CD8+ T-cell reactivity to epithelial-specific antigen. To dissect the immunologic mechanisms underlying CD8+ T-cell dysregulation, reactivity to a self-antigen expressed in intestinal epithelium of mice bearing a major histocompatibility complex class I-restricted T-cell receptor specific for this antigen was studied. In addition, antigen-specific regulatory CD4+ T cells induced in vivo were tested to control these autoreactive CD8+ T cells.
Transgenic VILLIN-HA mice were mated with CL4-TCR transgenic mice. Alternatively, adoptive transfer of CL4-TCR transgenic CD8+ T cells into VILLIN-HA transgenic mice was performed to mimic spontaneous encounter of neoantigen. Mucosal CD8+ T cells were characterized under different conditions of tolerance, immunopathology, and active immunosuppression.
Transgenic CD8+ T cells from VILLIN-HA x CL4-TCR transgenic mice preferentially migrated and expanded in mucosal lymphoid tissues. Although transgenic CD8+ T cells showed signs of T-cell activation, they failed to cause tissue damage. This was accompanied by the induction/expansion of CD4+ and CD8+, Foxp3-expressing T cells. In contrast, adoptive transfer of naive transgenic CD8+ T cells from CL4-TCR transgenic mice into VILLIN-HA transgenic mice induced severe intestinal inflammation with poor clinical course of disease. Transgenic CD8+ T cells secreted vigorous amounts of proinflammatory cytokines like interferon gamma/tumor necrosis factor alpha. Strikingly, this acute wasting disease was significantly ameliorated by cotransfer of antigen-specific regulatory CD4+ T cells.
Epithelial-specific antigen expression is sufficient to trigger severe antigen-specific CD8+ T-cell-mediated intestinal inflammation; this might be controlled by antigen-specific regulatory T cells under physiological conditions.
"While the spontaneously arising endogenous MDSCs present in many forms of autoimmune diseases appear to be defective and ineffective in controlling the disease (reviewed in ), it was shown that adoptive transfer of MDSCs can limit autoimmune pathology [61-63], providing a rationale for the development of methods to expand or induce MDSCs ex vivo. "
[Show abstract][Hide abstract] ABSTRACT: Myeloid-derived suppressor cells (MDSCs) are natural immunosuppressive cells and endogenous inhibitors of the immune system. We describe a simple and clinically compatible method of generating large numbers of MDSCs using the cultures of peripheral blood-isolated monocytes supplemented with prostaglandin E2 (PGE2). We observed that PGE2 induces endogenous cyclooxygenase (COX)2 expression in cultured monocytes, blocking their differentiation into CD1a+ dendritic cells (DCs) and inducing the expression of indoleamine 2,3-dioxygenase 1, IL-4Rα, nitric oxide synthase 2 and IL-10 - typical MDSC-associated suppressive factors. The establishment of a positive feedback loop between PGE2 and COX2, the key regulator of PGE2 synthesis, is both necessary and sufficient to promote the development of CD1a+ DCs to CD14+CD33+CD34+ monocytic MDSCs in granulocyte macrophage colony stimulating factor/IL-4-supplemented monocyte cultures, their stability, production of multiple immunosuppressive mediators and cytotoxic T lymphocyte-suppressive function. In addition to PGE2, selective E-prostanoid receptor (EP)2- and EP4-agonists, but not EP3/1 agonists, also induce the MDSCs development, suggesting that other activators of the EP2/4- and EP2/4-driven signaling pathway (adenylate cyclase/cAMP/PKA/CREB) may be used to promote the development of suppressive cells. Our observations provide a simple method for generating large numbers of MDSCs for the immunotherapy of autoimmune diseases, chronic inflammatory disorders and transplant rejection.
[Show abstract][Hide abstract] ABSTRACT: In this work described about the static and dynamic magnetic and magnetostrictive properties of polymer bonded Co-ferrite composites in order to optimize its behaviour as a stress sensor and fore transducer.
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