References of "Martens, Henri"
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See detailDevelopment of thymus autografts under the kidney capsule in the pig: a new 'organ' for xenotransplantation
Lambrigts, Denis; Franssen, Colette ULg; Martens, Henri ULg et al

in Xenotransplantation (1996), 3

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See detailCellular and molecular mechanisms involved in thymic T-cell education to neuroendocrine self principles
Geenen, Vincent ULg; Benhida, Abdellah; Kecha, Ouafae et al

in International Journal of Thymology (1996), 4

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See detailCellular and molecular aspects of thymic T-cell education to neurohypophysial peptides
Geenen, Vincent ULg; Martens, Henri ULg; Vandersmissen, Eric et al

in Excerpta Medica (1995), 1098

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See detailCellular and molecular aspects of thymic T-cell education to neurohypophysial peptides
Geenen, Vincent ULg; Vandersmissen, Eric; Martens, Henri ULg et al

in Yoshida, Sho; Saito, Toshikazu; Kurokawa, Kiyoshi (Eds.) Neurohypophysis - Recent Progress of Vasopressin and Oxytocin Research (1995)

Our studies have shown that oxytocin (OT) is the dominant peptide of the neurohypophysial (NHP) family that is expressed by thymic epithelial/nurse cells (TEC/TNC). Both in specific RIA and ICC analyses ... [more ▼]

Our studies have shown that oxytocin (OT) is the dominant peptide of the neurohypophysial (NHP) family that is expressed by thymic epithelial/nurse cells (TEC/TNC). Both in specific RIA and ICC analyses, vasopressin (VP) immunoreactivity is considerably lower in TEC. OT is not secreted by TEC/TNC, but it is presented as the self antigen of the NHP family to developing pre-T cells. The process of T-cell education in recognizing the NHP family involves an active cooperation between this neuroendocrine gene/protein family and the immunoglobulin family. This cooperation is illustrated by the identification in plasma membranes of human TEC of a 55-kDa protein bearing a neurophysin (10 kDa), as well as a MHC class I heavy chain-related domain (45 kDa). Since both OT and VP genes are transcribed in the thymus, the site of this cooperation should be located at posttranscriptional level. From these data, it appears that thymic T-cell education to the NHP family involves specific pathways which are not strictly superimposible to those dlineated using peripheral dedicated APC. Although MHC class I pathways are needed, it appears that thymic T-cell education to NHP self is not restricted in an allelic fashion. This offers significant advantages for the selection of the human T-cell repertoire. Furthermore, the absence of a tight MHC allelic restriction in the process of T-cell education to neuroendocrine self opens novel perpectives for the prevention of autoimmune endocrine disorders such as insulin-dependent diabetes mellitus. [less ▲]

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See detailCryptocrine Signaling in the Thymus Network and T Cell Education to Neuroendocrine Self-Antigens
Geenen, Vincent ULg; Goxe, Béatrice; Martens, Henri ULg et al

in Journal of Molecular Medicine : Official Organ of the 'Gesellschaft Deutscher Naturforscher und Ärzte' (1995), 73(9), 449-55

Both during phylogeny and ontogeny the thymus appears as a nodal point between the two major systems of cell-to-cell signaling, the neuroendocrine and immune systems. This review presents the experimental ... [more ▼]

Both during phylogeny and ontogeny the thymus appears as a nodal point between the two major systems of cell-to-cell signaling, the neuroendocrine and immune systems. This review presents the experimental observations which support a dual role in T cell selection played by the thymic repertoire of neuroendocrine polypeptide precursors. Through the mode of cryptocrine intercellular signaling thymic neuroendocrine-related precursors synthesized in thymic epithelial cells have been shown to influence the early steps in T cell differentiation. In addition, thymic neuroendocrine-related polypeptides are a source of self-antigens which are presented by the major histocompatibility system of the thymic epithelium. Preliminary data also suggest that the intrathymic T cell education to neuroendocrine self-antigens is not strictly superimposible to the antigen presentation by dedicated presenting cells. Insulin-like growth factor-II (IGF-II) was identified as one dominant member of the insulin family expressed by thymic epithelial and nurse cells. The intrathymic presentation of IGF-II or IGF-II derived self-antigens is under current investigation. If further confirmed, the central tolerogenic properties of IGF-II could be considered in the elaboration of a strategy for an efficient and safe prevention of insulin-dependent diabetes. [less ▲]

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See detailCryptocrine Signaling in the Thymus Network. Implications for Central T-Cell Tolerance of Neuroendocrine Functions
Geenen, Vincent ULg; Cormann-Goffin, Nadine; Vandersmissen, Eric et al

in Annals of the New York Academy of Sciences (1994), 741

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See detailLes choix stratégiques actuels dans la prévention du processus diabétogène auto-immun
Geenen, Vincent ULg; Martens, Henri ULg; Kecha, Ouafae et al

in Médecine et Hygiène (1994), 52

Le diabète insulino-dépendant (DID) est de plus en plus admis comme résultant d'une rupture de la tolérance immunitaire vis-à-vis de la cellule ß pancréatique. La compréhension des mécanismes centraux et ... [more ▼]

Le diabète insulino-dépendant (DID) est de plus en plus admis comme résultant d'une rupture de la tolérance immunitaire vis-à-vis de la cellule ß pancréatique. La compréhension des mécanismes centraux et périphériques de la tolérance vis-à-vis de la cellule ß doit logiquement aboutir à une prévention non toxique et efficace du DID. Deux choix stratégiques sont proposés à l'heure actuelle. D'une part, la tolérance périphérique à l'insuline en tant que cible du processus auto-immun pourrait être restaurée via l'administration d'insuline à faibles doses par voie sous-cutanée ou orale. D'autre part, le facteur de croissance apparenté à l'insuline de type 2 (IGF2) pourrait réinduire la tolérance centrale de l'insuline et, secondairement, de la cellule ß insulino-sécrétrice. [less ▲]

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See detailThymic neuroendocrine self peptides and T-cell selection
Geenen, Vincent ULg; Martens, Henri ULg; Vandersmissen, Eric et al

in Heinen, Ernst; Defresne, Marie-Paule; Boniver, Jacques (Eds.) et al In Vivo Immunology - Regulatory Processes during Lymphopoiesis and Immunopoiesis (1994)

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See detailMembrane Translocation and Relationship with MHC Class I of a Human Thymic Neurophysin-Like Protein
Geenen, Vincent ULg; Vandersmissen, E.; Cormann-Goffin, N. et al

in Thymus (1993), 22(1), 55-66

Thymic epithelial and nurse cells (TEC/TNC) synthesize an oxytocin (OT)-like peptide in association with a neurophysin (NP)-related protein in a way similar to in the hypothalamo-neurohypophysial (NHP ... [more ▼]

Thymic epithelial and nurse cells (TEC/TNC) synthesize an oxytocin (OT)-like peptide in association with a neurophysin (NP)-related protein in a way similar to in the hypothalamo-neurohypophysial (NHP) system. The central T-cell tolerance of the NHP neuroendocrine functions have been proposed to be mediated through these thymic NHP-related peptides due to their close homology with the NHP neurohormones OT and vasopressin (VP). In order to investigate their putative presentation by proteins of the major histocompatibility complex (MHC), human thymic membranes were purified and passed through an immunoaffinity column using mAb B9.12 directed to the monomorphic determinant of human MHC class I proteins. This methodology provided the following observations: (1) a NP-like protein is translocated in human thymic membranes and is retained by B9.12 on the column; (2) the MW of this NP-like material (50-55 kD) is quite different from the MW of hypothalamic NP proteins (10 kD), and (3) this thymic NP-like protein could be identified on Western blots with mAb B9.12. The precise extent of this relationship between the thymic NP-like protein and the Ig/MHC superfamily is actually investigated through the characterization of the genetic mechanisms responsible for the thymic expression of NHP-related peptides. Given the physiological importance of OT and of its binding to NP for transport along the axonal processes of the NHP tract, we postulate that, somewhat analogously, the thymic NP-/MHC class I-related protein could be involved in the presentation of the OT-like peptide to immature T-cells. [less ▲]

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See detailThe Dual Role of Thymic Neurohypophysial-Related Self Peptides in T Cell Selection. Physiological and Pharmacological Implications
Geenen, Vincent ULg; Martens, Henri ULg; Robert, Françoise et al

in Annals of the New York Academy of Sciences (1993), 689

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See detailThymic neurohypophysial-related peptides and T cell selection
Geenen, Vincent ULg; Cormann-Goffin, Nadine; Martens, Henri ULg et al

in Regulatory Peptides (1993), 45(1-2), 273-278

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See detailEvidence for the association between human thymic MHC class I molecules and a dominant neurohypophysial thymic peptide
Geenen, Vincent ULg; Vandersmissen, Eric; Martens, Henri ULg et al

in Journal of Immunology (1993), 150

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See detailEvidence that insulin-like growth factor 2 (IGF2) is the dominant thymic peptide of the insulin superfamily
Geenen, Vincent ULg; Achour, Imane; Martens, Henri ULg et al

in The Endocrine Society (Ed.) Proceedings of the 75th Annual Meeting of the Endocrine Society (1993)

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See detailThe central role of the thymus in the education of T cells to neuroendocrine self principles
Geenen, Vincent ULg; Martens, Henri ULg; Cormann-Goffin, Nadine et al

in Archives Internationales de Physiologie et de Biochimie (1993), 101

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See detailLa fonction centrale du thymus dans la reconnaissance des fonctions neuroendocrines par les lymphocytes T au cours de leur développement
Geenen, Vincent ULg; Martens, Henri ULg; Cormann-Goffin, N. et al

in Archives Internationales de Physiologie, de Biochimie et de Biophysique (1993), 101(4, Jul-Aug), 19-22

The dual physiological role of the thymus in T cell positive and negative selection appears prominent in the establishment of appropriate host immune defenses. However, the cellular and molecular ... [more ▼]

The dual physiological role of the thymus in T cell positive and negative selection appears prominent in the establishment of appropriate host immune defenses. However, the cellular and molecular mechanisms underlying those thymic functions begin only to be understood. On the basis of our previous investigations about the thymic expression of different neuroendocrine-related signals, we have advanced a model which transposes at the peptide level the intervention of this primary lymphoid organ in both T cell positive and negative selective processes. There is now ample evidence that the thymic subcapsular and medullary epithelium is the site for synthesis of neurohypophysial (NHP)-related peptides (reviewed in Geenen et al., 1992a). We have also demonstrated that the epithelial component of thymic "nurse" cells (TNC) synthesizes NHP-related peptides and expresses a neuroendocrine-like phenotype (Geenen et al., 1988a). This observation was a remarkable example of the intimate neuroendocrine-immune interactions that take place during T cell ontogeny. Further immunocytochemical analyses have confirmed that one dominant NHP-related epitope belongs to the oxytocin (OT) lineage of the NHP peptide superfamily (Robert et al., 1991, 1992). The intrathymic coexpression of this OT-like epitope with a neurophysin protein domain is a strong argument for a local synthetic process similar to the hypothalamo-NHP one. However, the absence of ir-OT in secretory granules of thymic epithelial cells (TEC), as well as of NHP-related peptides in the supernatant of TEC cultures questioned the application to the thymus of the classical neurosecretory model established for hypothalamic magnocellular neurons (Scharrer [less ▲]

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See detailThe thymic repertoire of neuroendocrine self antigens and the central immune tolerance of neuroendocrine functions
Geenen, Vincent ULg; Cormann, Nadine; Robert, Françoise et al

in European Journal of Medicine (The) (1992), 1(3), 158-165

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See detailThe Recognition of Hypothalamo-Neurohypophysial Functions by Developing T Cells
Robert, F. R.; Martens, Henri ULg; Cormann, N. et al

in Developmental Immunology (1992), 2(2), 131-40

Neuropeptide signals and specific neuropeptide receptors have been described in the thymus supporting the concept of a close dialogue between the neuroendocrine and the immune systems at the level of ... [more ▼]

Neuropeptide signals and specific neuropeptide receptors have been described in the thymus supporting the concept of a close dialogue between the neuroendocrine and the immune systems at the level of early T-cell differentiation. In this paper, we review recent data about neurohypophysial (NHP)-related peptides detected in the thymus from different species. We suggest that we are dealing in fact with other member(s) of the NHP hormone family, which seems to exert its activity locally through a novel model of cell-to-cell signaling, that of cryptocrine communication. This model involves exchange of signals between thymic epithelial cells and developing thymocytes. The NHP-related peptides have been shown to trigger thymocyte proliferation and could induce immune tolerance of this highly conserved neuroendocrine family. [less ▲]

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See detailThe thymic education of developing T cells in self neuroendocrine principles
Geenen, Vincent ULg; Robert, Françoise; Martens, Henri ULg et al

in Journal of Endocrinological Investigation (1992), 15

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See detailLa communication cryptocrine et la reconnaissance des fonctions neuroendocrines par les cellules T au cours de leur différenciation
Geenen, Vincent ULg; Robert, Françoise; Martens, Henri ULg et al

in Revue Française d'Endocrinologie Clinique, Nutrition, et Métabolisme (La) (1992), 33

Le thymus, organe lymphoïde primaire responsable du développement des lymphocytes T, est le site d'expression de différents peptides appartenant à des familles hormonales distinctes. Le modèle classique ... [more ▼]

Le thymus, organe lymphoïde primaire responsable du développement des lymphocytes T, est le site d'expression de différents peptides appartenant à des familles hormonales distinctes. Le modèle classique de la neurosécrétion établi pour l'axe hypothalamo-neurohypophysaire ne peut cependant s'appliquer à la sécrétion de tels signaux par les cellules épithéliales thymiques. Un nouveau modèle de communication cellulaire, celui de la communication cryptocrine, a été proposé par John W. Funder pour décrire les échanges d'information entre une cellule épithéliale fixe et des cellules mobiles en différenciation à leur contact. Dans le thymus, la communication cryptocrine est étroitement associée à la présentation de la structure moléculaire du Soi par les molécules d'histocompatibilité (CMH) aux lymphocytes T au cours de leur différenciation. Sur la base de nos observations, le modèle du répertoire thymique des autoantigènes neuroendocrines permet de transposer au niveau moléculaire le double rôle physiologique du thymus dans les phénomènes de sélections négative et positive des cellules T, et d'apporter un éclairage nouveau sur les mécanismes responsables de la tolérance immunitaire centrale aux fonctions neuroendocrines. [less ▲]

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See detailImmunomodulatory properties of cyclic hexapeptide oxytocin antagonists
Geenen, Vincent ULg; Martens, Henri ULg; Robert, Françoise et al

in Thymus (1992), 20

A pharmacological manipulation of cryptocrine cell-to-cell signaling was tested by the investigation of the immunomodulatory properties of novel cyclic hexapeptide oxytocin (OT) antagonists (MSD Research ... [more ▼]

A pharmacological manipulation of cryptocrine cell-to-cell signaling was tested by the investigation of the immunomodulatory properties of novel cyclic hexapeptide oxytocin (OT) antagonists (MSD Research Laboratories). The compounds were found to significantly inhibit the productions of IL-1ß and IL-6 elicited by anti-CD3 treatment oh human whole blood cells cultures (WBC). Cytokine productions were more significantly reduced by OT antagonists in WBC derived from female volunteers than in those obtained from male donors, suggesting an influence of sex steroids on the expression of NHP receptors by immune cells. These observations support the concept of novel immunomodulating approaches through immune-specific neuropeptide antagonists, as well as the pharmacological value of such strategies in selective immunotherapy. [less ▲]

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