A proteoglycan form of macrophage colony-stimulating factor that binds to bone-derived collagens and can be extracted from bone matrix.

We previously found that the human osteoblastic cell line MG-63 produces two molecular types of macrophage colony-stimulating factor (M-CSF). One is an 85-kD M-CSF, and the other is a proteoglycan form of M-CSF (PG-M-CSF) that has a binding affinity to type V collagen. The latter type of M-CSF showed dose-dependent binding to wells coated by pepsin-extracted bone collagens, whereas the 85-kD M-CSF did not. Immunoblot analysis of urea-extracted bone M-CSF revealed the presence of PG-M-CSF. PG-M-CSF contained in bone matrix may have physiological importance in the bone metabolism.