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Grit-Carsta Bulwin,
Stephanie Wälter,
Mirko Schlawinsky, Thomas Heinemann,
Anke Schulze,
Wolfgang Höhne,
Gerd Krause,
Wiltrud Kalka-Moll,
Patricia Fraser,
Hans-Dieter Volk,
Jürgen Löhler,
Edgar L Milford,
Nalân Utku
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ABSTRACT: Classically, HLA-DR expressed on antigen presenting cells (APC) initiates lymphocyte activation via presentation of peptides to TCR bearing CD4+ T-Cells. Here we demonstrate that HLA-DR alpha 2 domain (sHLA-DRalpha2) also induces negative signals by engaging TIRC7 on lymphocytes. This interaction inhibits proliferation and induces apoptosis in CD4+ and CD8+ T-cells via activation of the intrinsic pathway. Proliferation inhibition is associated with SHP-1 recruitment by TIRC7, decreased phosphorylation of STAT4, TCR-zeta chain & ZAP70, and inhibition of IFN-gamma and FasL expression. HLA-DRalpha2 and TIRC7 co-localize at the APC-T cell interaction site. Triggering HLA-DR - TIRC7 pathway demonstrates that sHLA-DRalpha2 treatment inhibits proinflammatory-inflammatory cytokine expression in APC & T cells after lipopolysaccaride (LPS) stimulation in vitro and induces apoptosis in vivo. These results suggest a novel antiproliferative role for HLA-DR mediated via TIRC7, revise the notion of an exclusive stimulatory interaction of HLA-DR with CD4+ T cells and highlights a novel physiologically relevant regulatory pathway.
PLoS ONE 01/2008; 3(2):e1576. · 4.09 Impact Factor
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ABSTRACT: The membrane protein T-cell immune response cDNA 7 (TIRC7) is transiently expressed in subsets of lymphocytes following antigen stimulation. The importance of TIRC7 in immune activation is demonstrated by the effect of antibodies directed against extracellular domains of TIRC7. In vitro targeting of TIRC7 inhibits proliferation and cytokine expression in human, mouse and rat lymphocytes, and these inhibitory effects have been associated with induction of cytotoxic T-lymphocyte antigen 4 mRNA and protein in the presence of TIRC7 antibodies. In vivo, anti-TIRC7 antibodies prevent kidney transplant rejection in rats and heart allograft rejection in mice. Treatment with an anti-TIRC7 antibody as monotherapy or in combination with TNFalpha blockade inhibits disease progression in collagen-induced arthritis. TIRC7 expression decreases in the peripheral blood of humans who have undergone cardiac transplant prior to clinical rejection, and is therefore a promising noninvasive tool for the prediction of rejection. Thus, targeting of TIRC7 may lead to the development of specific and effective therapeutic and diagnostic approaches by unifying relevant cellular and molecular responses in T- and B-cell subsets, and represents a promising new pathway for immune regulation in transplantation and autoimmune disease.
Current opinion in investigational drugs (London, England: 2000) 06/2007; 8(5):401-10. · 3.31 Impact Factor
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Grit-Carsta Bulwin, Thomas Heinemann,
Volker Bugge,
Michael Winter,
Anke Lohan,
Mirko Schlawinsky,
Anke Schulze,
Stephanie Wälter,
Robert Sabat,
Ralf Schülein,
Burkhard Wiesner,
Rüdiger W Veh,
Jürgen Löhler,
Richard S Blumberg,
Hans-Dieter Volk,
Nalân Utku
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ABSTRACT: Ab targeting of TIRC7 has been shown previously to inhibit T cell proliferation and Th1 lymphocyte-associated cytokine production. In this study, we demonstrate that Ab targeting of TIRC7 induces early cell surface expression of CTLA-4. The majority of stimulated CD4+ and CD8+ human T cells coexpress CTLA-4 and TIRC7. Similar to CTLA-4, TIRC7 rapidly accumulates at the site of Ag adhesion upon T cell activation. TIRC7 seems to colocalize with CTLA-4 in human T cells, and both molecules are associated with clathrin-coated vesicles, indicating they share intracellular transport systems. Moreover, Ab targeting of TIRC7 results in an early activation of CTLA-4 transcription. The inhibition of cell proliferation mediated by TIRC7 is dependent on CTLA-4 expression because the TIRC7-mediated inhibitory effects on cell proliferation and cytokine expression are abolished by Ab blockade of CTLA-4. Splenocytes obtained from CTLA-4-deficient mice are not responsive to TIRC7 Ab targeting. Thus, TIRC7 acts as an upstream regulatory molecule of CTLA-4 expression.
The Journal of Immunology 12/2006; 177(10):6833-41. · 5.79 Impact Factor
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ABSTRACT: The membrane protein T cell immune response cDNA 7 (TIRC7) was recently identified and was shown to play an important role in T cell activation. To characterize the function of TIRC7 in more detail, we generated TIRC7-deficient mice by gene targeting. We observed disturbed T and B cell function both in vitro and in vivo in TIRC7(-/-) mice. Histologically, primary and secondary lymphoid organs showed a mixture of hypo-, hyper-, and dysplastic changes of multiple lymphohemopoietic compartments. T cells from TIRC7(-/-) mice exhibited significantly increased proliferation and expression of IL-2, IFN-gamma, and IL-4 in response to different stimuli. Resting T cells from TIRC7(-/-) mice exhibited decreased CD62L, but increased CD11a and CD44 expression, suggesting an in vivo expansion of memory/effector T cells. Remarkably, activated T cells from TIRC7(-/-) mice expressed lower levels of CTLA-4 in comparison with wild-type cells. B cells from TIRC7-deficient mice exhibited significantly higher in vitro proliferation following stimulation with anti-CD40 Ab or LPS plus IL-4. B cell hyperreactivity was reflected in vivo by elevated serum levels of various Ig classes and higher CD86 expression on B cells. Furthermore, TIRC7 deficiency resulted in an augmented delayed-type hypersensitivity response that was also reflected in increased mononuclear infiltration in the skin obtained from TIRC7-deficient mice food pads. In summary, the data strongly support an important role for TIRC7 in regulating both T and B cell responses.
The Journal of Immunology 09/2004; 173(4):2342-52. · 5.79 Impact Factor
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Yusuke Kumamoto,
Antje Tomschegg,
Fatima Bennai-Sanfourche,
Anke Boerner,
Arthur Kaser,
Isabella Schmidt-Knosalla, Thomas Heinemann,
Mirko Schlawinsky,
Richard S Blumberg,
Hans-Dieter Volk,
Nalan Utku
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ABSTRACT: T cell immune response c-DNA (TIRC7) is up-regulated during the early stages of T-cell activation in response to alloantigens. In this study, we analyzed the effects of newly developed monoclonal antibodies (mAb) against TIRC7 in acute cardiac allograft rejection. Fully vascularized heterotopic allogeneic heart transplantation was performed in mice across a full-mismatch barrier (C57Bl/10 into CBA). Recipients received seven injections (day 0-7) of a novel anti-TIRC7 mAb or remained untreated. Graft survival, histology and ex vivo lymphocyte functions were tested. Targeting of TIRC7 with an anti-TIRC7 mAb diminishes lymphocyte infiltration into grafts resulting in delay of morphological graft damage and prolongation of allograft survival. The lymphocytes from anti-TIRC7 mAb-treated animals exhibit hypo-responsiveness without evidence of lymphocyte depletion against the donor allo-antigens. Proliferation and expression of interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) were down-regulated while interleukin-4 (IL-4) and IL-10 expression were spared. Moreover, anti-TIRC7 mAb enhanced up-regulation of CTLA-4 expression but suppressed up-regulation of CD25 on stimulated lymphocytes in vitro and in vivo. Ligation of TIRC7 has important effects on the regulation of co-stimulatory signaling pathways associated with suppressing of T-cell activation. Targeting of TIRC7 may therefore provide a novel therapeutic approach for modulating T cell immune responses during organ transplantation.
American Journal of Transplantation 05/2004; 4(4):505-14. · 6.39 Impact Factor
