INTERLEUKIN-2 UP-REGULATES GLUCOCORTICOID RECEPTOR NUMBER IN HUMAN PERIPHERAL-BLOOD MONONUCLEAR-CELLS AND THE OSTEOSARCOMA CELL-LINE SAOS-2IN-VITRO

Glucocorticoids ale well-recognized modulators of immunocytes and oste oblasts via specific receptor-mediated mechanisms. We have evaluated t he in vitro effect of interleukin 2 (IL-2) oil the expression of gluco corticoid receptors (GRs) in peripheral blood mononuclear cells (PBMCs ) obtained from healthy donors and osteoblastlike Saos-2 cells. Aliquo ts of PBMC or Saos-2 cells were incubated for 20 h in the presence or absence of recombinant human IL-2 (100 IU/mL) at 37 degrees C. After i ncubation, a [H-3]dexamethasone radioligand-binding assay and Scatchar d analysis were used to determine GR-binding parameters in both cell p opulations. Saos-2 cells basalt express higher numbers of GR than PBMC s. After IL-2, a significant increase in GR number was found for both PBMCs and Saos-2 cells. The relative increase was higher in Saos-2 cel ls; in PBMCs, the apparent affinity fell to almost half: These data re present an additional piece of evidence that cytokine and steroid horm ones may act in a complementary way to regulate specific cell function s. (C) 1998 by Elsevier Science Inc.