Jens Markus Chemnitz

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CTLA-4 and PD-1 are receptors that negatively regulate T-cell activation. Ligation of both CTLA-4 and PD-1 blocked CD3/CD28-mediated upregulation of glucose metabolism and Akt activity, but each accomplished this regulation using separate mechanisms. CTLA-4-mediated inhibition of Akt phosphorylation is sensitive to okadaic acid, providing direct evidence(More)
To study the cis- and trans-acting factors that mediate programmed death 1 (PD-1) signaling in primary human CD4 T cells, we constructed a chimeric molecule consisting of the murine CD28 extracellular domain and human PD-1 cytoplasmic tail. When introduced into CD4 T cells, this construct mimics the activity of endogenous PD-1 in terms of its ability to(More)
Many tumors, including Hodgkin's lymphoma, are associated with decreased cellular immunity and elevated levels of prostaglandin E(2) (PGE(2)), a known inhibitor of CD4+ T cell activation, suggested to be involved in immune deviation in cancer. To address the molecular mechanisms tumor-derived PGE(2) might have on primary human CD4+ T cells, we used a whole(More)
A hallmark of various human malignancies is the expression of immunoinhibitory factors within the tumor microenvironment. There is indirect evidence based on in vitro experiments that tumor-infiltrating T cells in human malignancies are suppressed by such factors. Still, direct evidence of the influence of individual inhibitory factors on immune cells in(More)
The only established treatment for patients with thrombotic thrombocytopenic purpura (TTP) is plasma exchange against fresh frozen plasma. For cases refractory to plasma exchange, no generally treatment schedule exists. One option is immunosuppressive therapy with corticosteroids and vincristine. Rituximab is a chimeric monoclonal antibody directed against(More)
Hintergrund: Die 1924 erstmals durch Moschcowitz beschriebene thrombotisch-thrombozytopenische Purpura (TTP) stellt ein heterogenes klinisches Syndrom dar, das durch Thrombozytopenie, Coombs-negative hämolytische Anämie, neurologische Ausfälle, Nierenfunktionsstörung und Fieber charakterisiert ist. Die Ätiologie der Erkrankung ist nicht vollständig(More)
Immune tolerance is a central mechanism counteracting tumor-specific immunity and preventing effective anticancer immunotherapy. Induction of tolerance requires a specific environment in which tolerogenic dendritic cells (DCs) play an essential role deviating the immune response away from effective immunity. It was recently shown that maturation of DCs in(More)
The B and T lymphocyte attenuator (BTLA) is a recently identified member of the CD28 family of cell receptors. Initial reports demonstrated that mice deficient in BTLA expression were more susceptible to experimental autoimmune encephalomyelitis, indicating that BTLA was likely to function as a negative regulator of T cell activation. However, cross-linking(More)
Based on studies in knockout mice, several inhibitory factors such as TGFbeta, IL-10, or CTLA-4 have been implicated as gate keepers of adaptive immune responses. Lack of these inhibitory molecules leads to massive inflammatory responses mainly mediated by activated T cells. In humans, the integration of these inhibitory signals for keeping T cells at a(More)
BACKGROUND Thrombotic thrombocytopenic purpura (TTP), in 1924 first described by Moschcowitz, is a clinically heterogeneous syndrome associated with thrombocytopenia, Coombs-negative hemolytic anemia, neurologic changes, renal impairment, and fever. TTP is found after various bacterial or viral infectious diseases, autoimmune diseases and also in(More)