Antigen-Independent Maturation of CD2, CD11a-CD18, CD44, and CD58 Expression on Thymic Emigrants in Fetal and Postnatal SheepReportar como inadecuado

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Developmental Immunology - Volume 4 1995, Issue 3, Pages 199-209

Laboratory for Foetal and Neonatal Immunology, The University of Melbourne, Cnr. Flemington Road and Park Drive, Parkville, Victoria 3052, Australia

IGBMC, BP163, Illkirch Cedex, C.U. de Strasbourg 67404, France

Department of Molecular Medicine, University of Auckland, New Zealand

Received 20 October 1995

Copyright © 1995 Hindawi Publishing Corporation. 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.


We have compared the expression of CD2, CD11a-CD18, CD44, and CD58 on αβ and γδT cells emigrating from the fetal and postnatal thymus. We report that both γδ and theCD4


and CD4


subsets of αβ T cells express mature levels of the adhesionmolecules CD11a-CD18, CD44, and CD58 upon emigration from the thymus. WhereasCD44 is up-regulated on γδ

thymocytes prior to export, down-regulation of bothCD11a-CD18 and CD58 occurs prior to emigration from the thymus, suggesting thatdown-regulation of these molecules may be a final maturational step taken by developingγδ T cells before their export from the thymus. In contrast, there is continued up-regulationof CD2 on αβ and γδ T cells upon emigration from the thymus and as they move into themature peripheral T-cell pool. There was also a marked reduction in the number of CD2

γδ T cells exported during fetal development that was associated with a marked reductionin the percentage of CD2

γδ thymocytes exported. The postthymic maturation of CD2 andthe other changes in adhesion-molecule expression appear to be independent of extrinsicantigen, as the same changes were observed in the antigen-free environment of the fetusas in the postnatal lamb, which has been exposed to extrinsic antigen. It thus appears thatthese changes in adhesion-molecule expression are as a result of the normal maturationpathway from a developing thymocyte to a mature peripheral T cell.

Autor: Deborah A. Witherden, Nevin J. Abernethy, Wayne G. Kimpton, and Ross N. P. Cahill



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