Volume 1 (1994), Issue 2-3, Pages 233-239
Interactions Between Zinc and Thymulin
CNRS URA 1461, Hôpital Necker, 161, rue de Sèvres, Paris F - 75015, France
Received 29 September 1993
Copyright © 1994 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.
Thymulin (formerly called "Facteur Thymique Sérique or FTS) is a metallopeptidic hormone selectively produced by thymic epithelial cells (TEC) and known to induce intra and extra-thymic T cell differentiation. It was initially isolated from porcine serum and shown to be present in calf thymus extract. Its amino-acid sequence was determined (<Glu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn). It is a nonapeptide whose biological activity is dependent on the presence of zinc, in an equimolecular ratio. The metallopeptide thus formed bears a specific tridimensional conformation detected by nuclear magnetic resonance studies, and that yielded a new monoclonal antibody-defined epitope. The presence of zinc and metallothionein has been demonstrated within TEC which produce the peptide, suggesting that the molecule is secreted in its active zinc-containing form. The zinc/thymulin relationship, was further studied using various models of mild zinc deficiency in experimental animals and in humans. Serum thymulin activity was decreased as a result of zinc deficiency, and was corrected by in vivo and in vitro zinc supplementation, suggesting that this parameter could be a sensitive indicator of zinc deficiency. When considered together with the parallel variations seen in T-cell subpopulations and lymphokine production, these observations could provide a possible explanation of the role of zinc on T cell functions.