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Is there a role for growth hormone upon intrathymic T-cell migration?
W Savino1, S Smaniotto, V De Mello-Coelho
1Laboratory on Thymus Research, Department of Immunology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Avenue Brasil 4365-Manguinhos, 21045-000 Rio de Janeiro, RJ, Brazil. savino@gene.dbbm.fiocruz.br
Annals of the New York Academy of Sciences
|March 28, 2001
Summary
Growth hormone (GH) enhances T-cell migration within the thymus by upregulating extracellular matrix (ECM) interactions between thymic epithelial cells and thymocytes. This promotes T-cell development and exit from the thymus.
Area of Science:
- Immunology
- Endocrinology
- Cell Biology
Background:
- The thymus microenvironment, rich in thymic epithelial cells and extracellular matrix (ECM), is crucial for T-cell differentiation.
- Thymocyte migration is partly regulated by interactions with ECM components.
Purpose of the Study:
- To investigate the role of growth hormone (GH) in intrathymic T-cell migration.
- To elucidate the mechanisms by which GH influences T-cell trafficking within the thymus.
Main Methods:
- Cultured thymic epithelial cells (TECs) and thymocytes were used to assess GH effects on ECM ligand/receptor expression and cell adhesion.
- Thymic nurse cells (TNCs) were employed to study GH's impact on thymocyte release and complex reconstitution.
- In vivo studies involved intrathymic GH injection and analysis of recent thymic emigrants in peripheral lymphoid organs.
Main Results:
- GH upregulated ECM ligands and receptors in TECs, increasing thymocyte adhesion.
- GH treatment enhanced thymocyte release from TNCs and promoted TNC reconstitution.
- In vivo, GH administration increased the proportion of recent thymic emigrants in lymph nodes.
Conclusions:
- Growth hormone stimulates intrathymic T-cell traffic.
- This effect is mediated, at least in part, by GH-induced extracellular matrix interactions.
- GH plays a significant role in regulating T-cell development and egress from the thymus.