EFFECTS OF INTERLEUKIN-4 ON HUMAN OSTEOBLAST-LIKE CELLS

Interleukin-4 (IL-4) modulates the activity of a variety of lymphoid, hemopoietic and mesenchymal cells, but little is known about its influ ence on bone cells. We have studied the effects of IL-4 on the human o steoblast-like cell line MG63. IL-4 (0.1-50 ng/ml) inhibited cell prol iferation. The effect did not depend on cell density, but it was more marked in serum-free cultures than in the presence of serum. IL-4 also induced a dose-dependent increase in the expression of alkaline phosp hatase stimulated by 1,25-dihydroxyvitamin D3, a marker of differentia ted osteoblast activity. However, IL-4 did not modify the secretion of interleukin-6 or tumor necrosis factor. These results suggest that in terleukin-4 may play a role as a modulator of osteoblast activity.