Partial characterization of the macrophage factor that stimulates fibroblasts to produce collagenase and to degrade collagen.

Rabbit bone marrow-derived macrophages in culture produce and release a soluble factor that activates collagenase secretion and collagen degradation by cultured skin fibroblasts from either rabbit, mouse or human origin. The factor is heat-labile and is inactivated by phenylglyoxal. After gel filtration, it is recovered in both an apparent high-Mr (67000-76000) and a low-Mr (9000-14000) form. Chromatography on cation exchangers suggests two molecular species with different charge properties. These characteristics are compatible with known properties of rabbit interleukin 1.