Cytokine production by calvariae of osteopetrotic mice,

In the osteopetrotic oplop mouse, the absence of macrophage colony-stimulating factor (M-CSF) prevents the growth of macrophages and osteoclasts and, consequently, bone resorption. In the present study, we investigated whether this deficiency in M-CSF production alters the production of cytokines in oplop bones. Calvariae of phenotypically normal (+/?) and oplop mice were stimulated in vitro with lipopolysaccharide or Pasteurella multocida toxin to produce cytokines. Interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) synthesis was the same both in calvaria from osteopetrotic and phenotypically normal animals. However, the production of granulocyte colony-stimulating factor (G-CSF), interleukin-6 (IL-6), and tumor necrosis factor-α (TNFα) was lower in calvaria from op/op animals than was the case in +/? calvaria. Thus, the lack of biologically active M-CSF causes defects which are not compensated by cells independent of M-CSF.