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Pellegrini M.,Walter and Eliza Hall Institute of Medical Research | Pellegrini M.,University of Melbourne | Pellegrini M.,Campbell University | Calzascia T.,Campbell University | And 17 more authors.
Cell | Year: 2011

Understanding the factors that impede immune responses to persistent viruses is essential in designing therapies for HIV infection. Mice infected with LCMV clone-13 have persistent high-level viremia and a dysfunctional immune response. Interleukin-7, a cytokine that is critical for immune development and homeostasis, was used here to promote immunity toward clone-13, enabling elucidation of the inhibitory pathways underlying impaired antiviral immune response. Mechanistically, IL-7 downregulated a critical repressor of cytokine signaling, Socs3, resulting in amplified cytokine production, increased T cell effector function and numbers, and viral clearance. IL-7 enhanced thymic output to expand the naive T cell pool, including T cells that were not LCMV specific. Additionally, IL-7 promoted production of cytoprotective IL-22 that abrogated liver pathology. The IL-7-mediated effects were dependent on endogenous IL-6. These attributes of IL-7 have profound implications for its use as a therapeutic in the treatment of chronic viral diseases. © 2011 Elsevier Inc.

Akhmetzyanova I.,University of Duisburg - Essen | Zelinskyy G.,University of Duisburg - Essen | Schimmer S.,University of Duisburg - Essen | Brandau S.,University of Duisburg - Essen | And 3 more authors.
Cancer Immunology, Immunotherapy | Year: 2013

The important role of tumor-specific cytotoxic CD8+ T cells is well defined in the immune control of the tumors, but the role of effector CD4+ T cells is poorly understood. In the current research, we have used a murine retrovirus-induced tumor cell line of C57BL/6 mouse origin, namely FBL-3 cells, as a model to study basic mechanisms of immunological control and escape during tumor formation. This study shows that tumor-specific CD4 + T cells are able to protect against virus-induced tumor cells. We show here that there is an expansion of tumor-specific CD4+ T cells producing cytokines and cytotoxic molecule granzyme B (GzmB) in the early phase of tumor growth. Importantly, we demonstrate that in vivo depletion of regulatory T cells (Tregs) and CD8+ T cells in FBL-3-bearing DEREG transgenic mice augments IL-2 and GzmB production by CD4+ T cells and increases FV-specific CD4+ T-cell effector and cytotoxic responses leading to the complete tumor regression. Therefore, the capacity to reject tumor acquired by tumor-reactive CD4+ T cells largely depends on the direct suppressive activity of Tregs. We suggest that a cytotoxic CD4 + T-cell immune response may be induced to enhance resistance against oncovirus-associated tumors. © 2012 The Author(s).

Meyer Zu Horste G.,Heinrich Heine University Dusseldorf | Meyer Zu Horste G.,Harvard University | Cordes S.,Heinrich Heine University Dusseldorf | Mausberg A.K.,Heinrich Heine University Dusseldorf | And 7 more authors.
PLoS ONE | Year: 2014

Inflammatory neuropathies represent disabling human autoimmune disorders with considerable disease variability. Animal models provide insights into defined aspects of their disease pathogenesis. Forkhead box P3 (FoxP3)+ regulatory T lymphocytes (Treg) are anti-inflammatory cells that maintain immune tolerance and counteract tissue damage in a variety of immune-mediated disorders. Dysfunction or a reduced frequency of Tregs have been associated with different human autoimmune disorders. We here analyzed the functional relevance of Tregs in determining disease manifestation and severity in murine models of autoimmune neuropathies. We took advantage of the DEREG mouse system allowing depletion of Treg with high specificity as well as anti-CD25 directed antibodies to deplete Tregs in mice in actively induced experimental autoimmune neuritis (EAN). Furthermore antibody-depletion was performed in an adoptive transfer model of chronic neuritis. Early Treg depletion increased clinical EAN severity both in active and adoptive transfer chronic neuritis. This was accompanied by increased proliferation of myelin specific T cells and histological signs of peripheral nerve inflammation. Late stage Treg depletion after initial disease manifestation however did not exacerbate inflammatory neuropathy symptoms further. We conclude that Tregs determine disease severity in experimental autoimmune neuropathies during the initial priming phase, but have no major disease modifying function after disease manifestation. Potential future therapeutic approaches targeting Tregs should thus be performed early in inflammatory neuropathies. © 2014 Meyer zu Horste et al.

Teng M.W.L.,Peter MacCallum Cancer Center | Teng M.W.L.,University of Melbourne | Ngiow S.F.,Peter MacCallum Cancer Center | Ngiow S.F.,University of Melbourne | And 5 more authors.
Cancer Research | Year: 2010

Foxp3 is a central control element in the development and function of regulatory T cells (Treg), and mice expressing a diphtheria toxin (DT) receptor - enhanced green fluorescent protein fusion protein under the control of the foxp3 gene locus (DEREG mice) allow conditional and efficient depletion of Foxp3+ Treg by DT injection. Herein, we use DEREG mice and a mouse model of carcinogenesis to show that conditional and effective Treg depletion can both protect mice from carcinogenesis by innate control, yet permanently eradicate a proportion of de novo - established tumors in mice in a largely CD8+ T-cell - and IFN-γ - dependent manner. Tumors displayed a heterogeneous response to Treg depletion, and suppression of established tumors was accompanied by an increase in the tumor-infiltrating CD8+ T-cell/B-cell ratio. Tumor rejection occurred in the absence of overt autoimmunity, suggesting that effective transient Treg depletion strategies may be therapeutic in at least a proportion of spontaneous tumors developing in the host. ©2010 AACR.

Villalta S.A.,University of California at San Francisco | Rosenthal W.,University of California at San Francisco | Martinez L.,University of California at Los Angeles | Kaur A.,University of California at San Francisco | And 5 more authors.
Science Translational Medicine | Year: 2014

We examined the hypothesis that regulatory T cells (Tregs) modulate muscle injury and inflammation in the mdx mouse model of Duchenne muscular dystrophy (DMD). Although Tregs were largely absent in the muscle of wildtype mice and normal human muscle, they were present in necrotic lesions, displayed an activated phenotype, and showed increased expression of interleukin-10 (IL-10) in dystrophic muscle from mdx mice. Depletion of Tregs exacerbated muscle injury and the severity of muscle inflammation, which was characterized by an enhanced interferon-γ (IFN-γ) response and activation of M1 macrophages. To test the therapeutic value of targeting Tregs in muscular dystrophy, we treated mdx mice with IL-2/anti-IL-2 complexes and found that Tregs and IL-10 concentrations were increased in muscle, resulting in reduced expression of cyclooxygenase-2 and decreased myofiber injury. These findings suggest that Tregs modulate the progression of muscular dystrophy by suppressing type 1 inflammation in muscle associated with muscle fiber injury, and highlight the potential of Treg-modulating agents as therapeutics for DMD.

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