Growth hormone stimulates the selective trafficking of thymic CD4+CD8- emigrants to peripheral lymphoid organs.
Growth hormone (GH) has been shown to stimulate T cell development. However, its mechanisms of action on the peripheral T cell pool remain unknown. To address this question, intrathymic injection of GH in combination with fluorescein isothiocyanate (FITC) was used to assess the effects of GH on T cell trafficking from the thymus to the periphery. GH promoted a significant increase in the percentage and differential distribution of thymic CD4+CD8-FITC+ cells in secondary lymphoid organs. A significantly higher percentage of CD4+CD8-FITC+ cells was observed in the lymph nodes, while a relative decrease of these cells was found in the spleen. Moreover, we verified that GH treatment resulted in increased numbers of CD62L+CD4+CD8-FITC+ T cells in the lymph nodes, while the same treatment resulted in a decline in the percentage of VLA-6+CD4+CD8-FITC+ T cells in the spleen. Together, these findings suggest that GH is a potent immunoregulatory molecule which selectively stimulates the preferential homing of CD4+CD8- thymic emigrants to the subcutaneous lymph nodes possibly via the differential expression of CD62L and VLA-6.
Laboratory on Thymus Research, Department of Immunology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
Salete
S
Smaniotto
Marilza Moura
MM
Ribeiro-Carvalho
Mireille
M
Dardenne
Wilson
W
Savino
Valéria
V
de Mello-Coelho
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects* / Q000276:immunology*; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology*; D039041:Integrin alpha4beta1 / Q000378:metabolism; D019041:L-Selectin / Q000378:metabolism; D008221:Lymphoid Tissue / Q000166:cytology; D051379:Mice; D008807:Mice, Inbred BALB C; D015213:Neuroimmunomodulation / Q000187:drug effects / Q000502:physiology; D013950:Thymus Gland / Q000166:cytology
D039041:Integrin alpha4beta1; D019041:L-Selectin; D013006:Growth Hormone