Chemotactic factors for macrophages produced in inflamed skin

A newly discovered macrophage-chemotactic factor (MCFS-1) was extracted and purified (488-fold) from skin sites of guinea pigs showing delayed hypersensitivity to bovine gamma-globulin. MCFS-1 is a heat-labile glycoprotein with a molecular weight of 150,000, consisting of two polypeptide chains. It has in vivo as well as in vitro chemotactic activity for macrophages and shared 50% of the chemotactic activities for macrophages in the extract. It is produced by limited proteolysis of endogenous trypsin-like protease(s) of plasma precursor protein (Pre-MCFS-1). Enzyme immunohistochemistry reveals that Pre-MCFS-1 is produced in the liver and distributed in the normal skin as a proinflammatory factor. ELISA reveals that the concentrations of the factor are: 140 micrograms/ml in plasma, 7.1 micrograms/ml in inflamed skin extract, and 2.8 micrograms/ml in normal skin extract.