S‐Protein Is Synthesized by Human Monocytes and Macrophages in Vitro

Abstract

Human monocytes and alveolar and peritoneal macrophages were cultured in serum‐free medium with or without endotoxin (ET), agarose beads, or cycloheximide. The cell culture supernatants were collected after various intervals and examined by a monoclonal anti‐S‐protein antibody in Western blot and in a solid‐phase enzyme immunoassay. We found that the phagocytes synthesize and secrete S‐protein. ET stimulation or prolonged incubation of the cells did not favour S‐protein production, which was inhibited by cycloheximide. Agarose stimulation increased the S‐protein level in supernatants from monocyte but not from macrophage cultures.