MIP-1α enhances IL-6–stimulated osteoclast formation in human CFU-GM–derived cell cultures.

CFU-GM–derived cells were prepared and treated with MIP-1α (200 pg/mL) or IL-6 (100 pg/mL) or their combination. Control cultures were treated with 10⁻⁸ M 1,25-(OH)₂D₃. MIP-1α or IL-6 alone significantly stimulated osteoclast formation. However, the combination enhanced osteoclast formation to levels that were greater than either IL-6 or MIP-1α alone. Results represent the mean ± SEM for quadruplicate determinations for a typical experiment. Similar results were seen in 3 independent experiments. *P < .05 compared to IL-6 or MIP-1α alone.