Effect of growth hormone on the immune function of dendritic cells.

Background: Dendritic cells (DCs) are one of the most important antigen presenting cells in the human body, and DCs at various stages of maturation possess different or even opposite functions. The aim of this study was to investigate the influence of growth hormones on the functional status of cord blood-derived DCs encompassing immunophenotype, ability to excrete interleukin (IL)-12 and provoke autologous leukomonocyte.

Methods: Mononuclear cells were isolated from fresh cord blood, with IL-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF) used to induce and stimulate the mononuclear cells. Growth hormone at different concentrations was used to modify DCs, and then DCs morphology, number and growth status were observed. The immunophenotype of DCs was detected with a flow cytometer. The concentration of IL-12 in the DCs supernatant was determined by enzyme linked immunosorbent assay (ELISA) and DCs functional status was evaluated by autologous mixed lymphocyte reactions.

Results: Mononuclear cells from cord blood can be differentiated into DCs by cytokine induction and growth hormone modification. With the increase in growth hormone concentrations (5 - 100 microg/L), the expression of DCs HLA-DR, CD1alpha, CD80 and CD83 were significantly increased (P < 0.05). The ability of DCs to secrete IL-12 was significantly improved (P < 0.05), and the ability of DCs to activate autologous lymphocytes was significantly enhanced (P < 0.05). Pegvisomant was able to ablate the effects of growth hormone on DCs.

Conclusions: Growth hormone may facilitate DCs induction and maturation, and improve the reproductive activity of autologous lymphocytes in a dose-dependent manner. Growth hormone may serve as a factor of modifying DCs to achieving maturity.