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Involvement of Thyroid Hormones in the Expression of MHC class I Antigens During Ontogeny in Xenopus

The major histocompatibility complex (MHC) is a cluster of genes encoding products central to all major functions of the vertebrate immune system. Evidence for an MHC can be found in all vertebrate groups that have been examined except the jawless fishes. Expression of MHC class I and class II antig...

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Autores principales: Rollins-Smith, Louise A., Flajnik, Martin F., Blair, Patrick J., Davis, A. Tray, Green, Wayne F.
Formato: Texto
Lenguaje:English
Publicado: Hindawi Publishing Corporation 1997
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2275975/
https://www.ncbi.nlm.nih.gov/pubmed/9587714
http://dx.doi.org/10.1155/1997/38464
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author Rollins-Smith, Louise A.
Flajnik, Martin F.
Blair, Patrick J.
Davis, A. Tray
Green, Wayne F.
author_facet Rollins-Smith, Louise A.
Flajnik, Martin F.
Blair, Patrick J.
Davis, A. Tray
Green, Wayne F.
author_sort Rollins-Smith, Louise A.
collection PubMed
description The major histocompatibility complex (MHC) is a cluster of genes encoding products central to all major functions of the vertebrate immune system. Evidence for an MHC can be found in all vertebrate groups that have been examined except the jawless fishes. Expression of MHC class I and class II antigens early in ontogeny is critically important for development of T lymphocytes capable of discriminating self from nonself. Because of this essential role in T-cell development, the ontogeny of MHC expression in the South African clawed frog, Xenopus laevis, was studied. Previous studies of MHC class I expression in Xenopus laevis suggested that class I antigens are virtually absent from tadpole tissues until climax of metamorphosis. We therefore examined the possible role of thyroid hormones (TH) in the induction of class I. By flow cytometry, a small amount of class I expression was detectable on splenocytes and erythrocytes in untreated frogs at prometamorphic stages 55-58, and the amount increased significantly at the conclusion of metamorphic climax. Thus, metamorphosis is associated with increased intensity of class I expression. Neither inhibition nor acceleration of metamorphosis altered the timing of onset of class I expression. However, inhibition of metamorphosis prevented the increase in class I expression characteristic of adult cell populations. Because expression was not accelerated in TH-treated frogs or delayed in metamorphosis-inhibited frogs, it is unlikely that TH are the direct developmental cues that induce expression, although they seem to be required for the upregulation of class I expression occurring at metamorphosis. Differences in the pattern of expression in different subpopulations of cells suggest a complex pattern of regulation of expression of class I antigens during ontogeny.
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spelling pubmed-22759752008-03-31 Involvement of Thyroid Hormones in the Expression of MHC class I Antigens During Ontogeny in Xenopus Rollins-Smith, Louise A. Flajnik, Martin F. Blair, Patrick J. Davis, A. Tray Green, Wayne F. Dev Immunol Research Article The major histocompatibility complex (MHC) is a cluster of genes encoding products central to all major functions of the vertebrate immune system. Evidence for an MHC can be found in all vertebrate groups that have been examined except the jawless fishes. Expression of MHC class I and class II antigens early in ontogeny is critically important for development of T lymphocytes capable of discriminating self from nonself. Because of this essential role in T-cell development, the ontogeny of MHC expression in the South African clawed frog, Xenopus laevis, was studied. Previous studies of MHC class I expression in Xenopus laevis suggested that class I antigens are virtually absent from tadpole tissues until climax of metamorphosis. We therefore examined the possible role of thyroid hormones (TH) in the induction of class I. By flow cytometry, a small amount of class I expression was detectable on splenocytes and erythrocytes in untreated frogs at prometamorphic stages 55-58, and the amount increased significantly at the conclusion of metamorphic climax. Thus, metamorphosis is associated with increased intensity of class I expression. Neither inhibition nor acceleration of metamorphosis altered the timing of onset of class I expression. However, inhibition of metamorphosis prevented the increase in class I expression characteristic of adult cell populations. Because expression was not accelerated in TH-treated frogs or delayed in metamorphosis-inhibited frogs, it is unlikely that TH are the direct developmental cues that induce expression, although they seem to be required for the upregulation of class I expression occurring at metamorphosis. Differences in the pattern of expression in different subpopulations of cells suggest a complex pattern of regulation of expression of class I antigens during ontogeny. Hindawi Publishing Corporation 1997 /pmc/articles/PMC2275975/ /pubmed/9587714 http://dx.doi.org/10.1155/1997/38464 Text en Copyright © 1997 Hindawi Publishing Corporation. http://creativecommons.org/licenses/by/ This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Rollins-Smith, Louise A.
Flajnik, Martin F.
Blair, Patrick J.
Davis, A. Tray
Green, Wayne F.
Involvement of Thyroid Hormones in the Expression of MHC class I Antigens During Ontogeny in Xenopus
title Involvement of Thyroid Hormones in the Expression of MHC class I Antigens During Ontogeny in Xenopus
title_full Involvement of Thyroid Hormones in the Expression of MHC class I Antigens During Ontogeny in Xenopus
title_fullStr Involvement of Thyroid Hormones in the Expression of MHC class I Antigens During Ontogeny in Xenopus
title_full_unstemmed Involvement of Thyroid Hormones in the Expression of MHC class I Antigens During Ontogeny in Xenopus
title_short Involvement of Thyroid Hormones in the Expression of MHC class I Antigens During Ontogeny in Xenopus
title_sort involvement of thyroid hormones in the expression of mhc class i antigens during ontogeny in xenopus
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2275975/
https://www.ncbi.nlm.nih.gov/pubmed/9587714
http://dx.doi.org/10.1155/1997/38464
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