Medicine and Health Sciences Commons^™

T-Cell Specific Avian Tdt: Characterization Of The Cdna And Recombinant Enzyme., Baoli Yang, K. Gathy, M. Coleman

Baoli Yang

A cDNA clone coding for avian terminal deoxynucleotidyl transferase (TdT) has been isolated and sequenced. The size of this cDNA was 2545 bp with an open reading frame of 1521 bp and a predicted translation product of 58 kDa. Comparison of this TdT sequence with other known TdT sequences has revealed a very high degree of homology at both the DNA and predicted amino acid levels. The chicken TdT cDNA was expressed in a bacterial system and the protein was purified by affinity chromatography. The purified recombinant enzyme, with a specific activity of approximately 1700 U/mg protein, was significantly less …

Fetal Hemorrhage And Platelet Dysfunction In Slp-76-Deficient Mice., J. Clements, J. Lee, B. Gross, Baoli Yang, J. Olson, A. Sandra, S. Watson, S. Lentz, G. Koretzky

Baoli Yang

The adapter protein SLP-76 is expressed in T lymphocytes and hematopoietic cells of the myeloid lineage, and is known to be a substrate of the protein tyrosine kinases that are activated after ligation of the T-cell antigen receptor. Transient overexpression of SLP-76 in a T-cell line potentiates transcriptional activation after T-cell receptor ligation, while loss of SLP-76 expression abrogates several T-cell receptor-dependent signaling pathways. Mutant mice that lack SLP-76 manifest a severe block at an early stage of thymocyte development, implicating SLP-76 in signaling events that promote thymocyte maturation. While it is clear that SLP-76 plays a key role in …

The Ubiquitin Ligase Adaptor Ndfip1 Regulates T Cell-Mediated Gastrointestinal Inflammation And Inflammatory Bowel Disease Susceptibility., H. Ramon, C. Riling, J. Bradfield, Baoli Yang, H. Hakonarson, P. Oliver

Baoli Yang

Nedd4 family interacting protein 1 (Ndfip1) is an adaptor protein that regulates Itch, an E3 ubiquitin ligase that ubiquitylates JunB, thereby preventing interleukin (IL)-4 and IL-5 production. Mice lacking Ndfip1 or Itch develop T helper type 2 (T(H)2)-mediated inflammation in the skin and lungs and die prematurely. In this study we show that Ndfip1-/- mice also develop inflammation in the gastrointestinal tract. Inflammation is characterized by infiltration of eosinophils and T cells and is accompanied by a failure to gain weight. T cells are both necessary and sufficient for eosinophil recruitment and inflammation. This is because Ndfip1-/- T cells become …

Requirement For The Leukocyte-Specific Adapter Protein Slp-76 For Normal T Cell Development., J. Clements, Baoli Yang, S. Ross-Barta, S. Eliason, R. Hrstka, R. Williamson, G. Koretzky

Baoli Yang

The leukocyte-specific adapter molecule SLP-76 (Src homology 2 domain-containing leukocyte protein of 76 kilodaltons) is rapidly phosphorylated on tyrosine residues after receptor ligation in several hematopoietically derived cell types. Mice made deficient for SLP-76 expression contained no peripheral T cells as a result of an early block in thymopoiesis. Macrophage and natural killer cell compartments were intact in SLP-76-deficient mice, despite SLP-76 expression in these lineages in wild-type mice. Thus, the SLP-76 adapter protein is required for normal thymocyte development and plays a crucial role in translating signals mediated by pre-T cell receptors into distal biochemical events.

Tacrolimus And Cyclosporine A Inhibit Allostimulatory Capacity And Cytokine Production Of Human Myeloid Dendritic Cells, Gyongyi Szabo, C. Gavala, Pranoti Mandrekar

Gyongyi Szabo

Myeloid dendritic cells (DCs) are pivotal in the recognition of alloantigens and, therefore, in the induction of allograft rejection. Induction of alloreactive T cell proliferation by myeloid DCs depends on the maturation of DCs, the expression of costimulatory molecules, and the cytokine environment. This study investigated the effects of tacrolimus and cyclosporine A (CsA) on DC maturation and allostimulatory capacity. Myeloid DCs were propagated from normal blood monocytes with interleukin (IL) 4 and GM-CSF for 7 days in the presence or absence of tacrolimus (FK506; 10 nM) or CsA (1 microg/mL). Exposure of DCs during maturation to tacrolimus or CsA …

Reduced Alloreactive T-Cell Activation After Alcohol Intake Is Due To Impaired Monocyte Accessory Cell Function And Correlates With Elevated Il-10, Il-13, And Decreased Ifngamma Levels, Gyongyi Szabo, Pranoti Mandrekar, Angela Dolganiuc, Donna Catalano, Karen Kodys

Gyongyi Szabo

BACKGROUND: Immunosuppression associated with chronic alcohol use is characterized by reduced antigen-specific T-cell response and impaired delayed type hypersensitivity. Increasing evidence suggests in chronic alcohol consumption models that reduced antigen-specific T-cell proliferation is due to insufficient accessory cell function. Accessory cell function, a critical step in recognition of viral antigens, is reduced in chronic hepatitis C. The severity of hepatitis C is increased by alcohol consumption. Thus, we investigated the effects of alcohol consumption on accessory cell activity of monocytes in supporting alloreactive T-cell proliferation. METHODS: Alloreactive T-cell proliferation was evaluated in a one-way mixed lymphocyte reaction (MLR). Mononuclear cells …

Human Macrophages Degrade Tryptophan Upon Induction By Interferon-Gamma, Ernst Werner, Gabriele Bitterlich, Dietmar Fuchs, Arno Hausen, Gilbert Reibnegger, Gyongyi Szabo, Manfred Dierich, Helmut Wachter

Gyongyi Szabo

Human peripheral blood mononuclear cells, monocytes-macrophages and T-cells were stimulated with human recombinant interferon-gamma, interferon-alpha and phytohemagglutinin. The culture supernatants were analyzed for tryptophan, kynurenine, 3-hydroxyanthranilic acid, anthranilic acid and neopterin by high performance liquid chromatography. Tryptophan was decreased and the four other compounds were increased in supernatants of peripheral blood mononuclear cells activated by interferon-gamma (250 U/ml), interferon-alpha (10.000 U/ml) and phytohemagglutinin (1 microgram/ml). After splitting of peripheral blood mononuclear cells by adherence, the monocytes and macrophages but not the T-cells degraded tryptophan upon stimulation by interferon-gamma in a dose dependent manner. Supernatants of phytohemagglutinin stimulated but not of …

Ethanol-Mediated Regulation Of Transcription Factors In Immunocompetent Cells, Gyongyi Szabo, Pranoti Mandrekar

Gyongyi Szabo

The immunomodulatory effects of acute and chronic alcohol use are characterized by impaired antigen-specific immune activation and by increased susceptibility to infections due to alterations in innate immune responses and inflammatory mediator production. The central feature of cellular responses to inflammatory and stress signals is the activation of the nuclear regulatory kappa B/Rel family of transcriptional factors via various surface receptor systems in immunocompetent cells. Activation of NF-kappa B, however, is regulated at multiple levels including I-kappa B degradation, nuclear translocation, and by interaction of NF-kappa B/Rel with other transcription factors. Data from our and other laboratories demonstrate that acute …

Additive Inhibition Of Dendritic Cell Allostimulatory Capacity By Alcohol And Hepatitis C Is Not Restored By Dc Maturation And Involves Abnormal Il-10 And Il-2 Induction, Angela Dolganiuc, Karen Kodys, Andrea Kopasz, Christopher Marshall, Pranoti Mandrekar, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND: Excessive alcohol use results in impaired immunity, and it is associated with increased incidence and progression of chronic hepatitis C virus (HCV) infection. Here we investigated the effects of HCV infection and alcohol on myeloid dendritic cells (DC) that are critical in antiviral immunity.

METHODS: Immature and mature DCs were generated from monocytes of chronic HCV infected patients (HCV-DC) and controls (N-DC) with IL-4 plus granulocyte-macrophage colony stimulating factor (GM-CSF) in the presence or absence of alcohol (25 mM). DC allostimulatory capacity was tested in mixed lymphocyte reaction (MLR) and cytokine production by ELISA.

RESULTS: Allostimulatory capacity of HCV-DCs …

Hepatitis C And Innate Immunity: Recent Advances, Gyongyi Szabo, Angela Dolganiuc

Gyongyi Szabo

Eradication of hepatitis C virus (HCV) infection requires a complex and coordinated interplay between innate and adaptive immune responses that, when it fails, leads to chronic infection. In this review, the innate immune mechanisms by which HCV is sensed and by which HCV undermines host defense are discussed. The critical role of dendritic cells in antigen presentation and T-cell activation in addition to type I interferon production and interference of HCV with innate immune cell functions are reviewed. Finally, current and emerging therapeutic approaches targeting innate immune pathways are evaluated.