Search results for "thymus gland"

The thymus at the crossroad of neuroimmune interactions.

2006

The numerous relationships existing between the nervous and the immune systems suggest that the neural networks present in the intrathymic microenvironment may influence T-cell development. We previously reported that thymic neural-crest-derived stromal cells are involved in a neural differentiation pathway and are able to produce neurotrophic factors and neurokines that are in turn able to increase and/or modulate thymic-stromal cell neuronal phenotype. We also showed that EGF promotes a neural phenotype in thymic epithelial cells by enhancing the expression of neuronal-specific markers, neurotransmitters, and neuropoietic cytokines, such as IL-6 and CNTF. More recently we showed that the …

Differential mode of inhibition of terminal deoxynucleotidyl transferase by 3′-dATP, ATP, βaraATP and αaraATP

1978

Thymoma and paraneoplastic myasthenia gravis

2010

Paraneoplastic autoimmune diseases associate occasionally with small cell lung cancers and gynecologic tumors. However, myasthenia gravis (MG) occurs in at least 30% of all patients with thymomas (usually present at MG diagnosis). These epithelial neoplasms almost always have numerous admixed maturing polyclonal T cells (thymocytes). This thymopoiesis-and export of mature CD4(+)T cells-particularly associates with MG, though there are rare/puzzling exceptions in apparently pure epithelial WHO type A thymomas. Other features potentially leading to inefficient self-tolerance induction include defective epithelial expression of the autoimmune regulator (AIRE) gene and/or of major histocompatib…

Thymic transplantation for relief of immunodeficiency diseases.

1979

Tremendous advances have been made in replacement therapy regimens for the correction of immunodeficiency in transplant patients. Recently, cultured thymic fragments were shown to be devoid of lethal graft-versus-host cells and research in this area indicates that thymic transplantation may have a sustained positive effect in immunosuppressed patients.

Characterization of a multimeric polypeptide complex on the surface of thymus-derived cells in the Mexican axolotl.

1993

We previously raised a rabbit antiserum (L12) against a 38 kD polypeptide which is expressed on the surface of thymocytes and peripheral T cells of an Urodele Amphibian, the Mexican axolotl (Ambystoma mexicanum). Here we show that L12 antibodies immunoprecipitate several labelled molecules from surface iodinated axolotl spleen cells, including the 38 kD molecule, but also two polypeptides of 43 and 22 kD which are covalently linked to other elements. Another rabbit antiserum (L10) was raised against detergent-solubilized axolotl thymocyte membranes and shown to recognize the majority of thymocytes and about half of the splenocytes in immunofluorescence. In Western blotting, L10 antibodies r…

Bioengineering Thymus Organoids to Restore Thymic Function and Induce Donor-Specific Immune Tolerance to Allografts.

2015

One of the major obstacles in organ transplantation is to establish immune tolerance of allografts. Although immunosuppressive drugs can prevent graft rejection to a certain degree, their efficacies are limited, transient, and associated with severe side effects. Induction of thymic central tolerance to allografts remains challenging, largely because of the difficulty of maintaining donor thymic epithelial cells in vitro to allow successful bioengineering. Here, the authors show that three-dimensional scaffolds generated from decellularized mouse thymus can support thymic epithelial cell survival in culture and maintain their unique molecular properties. When transplanted into athymic nude …

The deubiquitinating enzyme CYLD regulates the differentiation and maturation of thymic medullary epithelial cells.

2014

The cross talk between thymocytes and the thymic epithelium is critical for T-cell development and the establishment of central tolerance. Medullary thymic epithelial cells (mTECs) are located in the thymic medulla and mediate the elimination of self-reactive thymocytes, thereby preventing the onset of autoimmunity. Previous studies identified the deubiquitinating enzyme CYLD as a critical regulator of T-cell development by activating proximal T-cell receptor signaling during the transition of double-positive to single-positive thymocytes. Here we evaluated the impact of the naturally occurring short-splice variant of the cyld gene (sCYLD) on the development and maturation of mTECs. We foun…

Molecular anatomy of the neuro-immune connection.

1991

Light microscopic immunohistochemistry was employed to elucidate and compare the presence, distribution, and coexistence of various peptides, neuroendocrine markers and enzymes of the catecholamine pathway in nerves supplying lymphoid tissues in a variety of mammalian species. All lymphoid organs and tissues receive innervation by fibers containing dopamine-beta-hydroxylase and/or tyrosine hydroxylase, neural markers like protein gene product 9.5, synaptophysin and neurofilament and a varied spectrum of peptides. The prominent peptides were tachykinins (substance P, neurokinin A), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY), and vasoactive intestinal polypeptide/peptide his…

Interrelation of peptidergic innervation with mast cells and ED1-positive cells in rat thymus

1991

The peptidergic innervation of rat thymus has been investigated by immunohistochemical methods, focusing on the spatial interrelationship of peptidergic nerve fibers with mast cells and macrophages in the rat. An antiserum directed against the protein gene product 9.5 (PGP 9.5) regarded as a pan-neuronal marker revealed a rich innervation, especially in the subcapsular cortex, in interlobular septa, and of the vasculature in the cortex and the corticomedullary boundary. A minor proportion of PGP 9.5-immunoreactive (ir) fibers supplied the thymic parenchyma. The main component of peptidergic innervation consisted of fibers costaining for tachykinins (TKs) and calcitonin gene-related peptide …

Retarded thymic involution and massive germinal center formation in NF-ATp-deficient mice.

1998

NF-ATp and NF-ATc are the most prominent nuclear NF-AT transcription factors in peripheral T lymphocytes. After T cell activation both factors bind to and control the promoters and enhancers of numerous lymphokine and receptor ligand genes. In order to define a specific role for NF-ATp in vivo we have inactivated the NF-ATp gene by gene targeting in mice. We show that NF-ATp deficiency leads to the accumulation of peripheral T cells with a “preactivated” phenotype, enhanced immune responses of T cells after secondary stimulation in vitro and severe defects in the proper termination of antigen responses, as shown by a reduced deletion of superantigen-reactive CD4+ T cells. These alterations …