title: Lymphokine-induced secretion of plasminogen activator by murine macrophages.
abstract: Thioglycollate-stimulated macrophages are known to release a plasminogen activator (PA) into the medium. In this study it was investigated whether macrophages could be activated to release PA after exposure to lymphokines. Macrophage monolayers obtained by 24 h culture of proteose peptone-elicited murine exudate cells were incubated with lymphocyte culture supernatants. After 48 h the supernatants were replaced by serum-free medium and the macrophages were incubated for another 24-48 h. These supernatants were assayed for PA as measured by the lysis of 125I-labeled fibrin. The following results were obtained: (a) Supernatants of antigen or mitogen-stimulated spleen cells induced PA secretion by macrophages whereas control supernatants were ineffective. The same was found with supernatants of mitogen-stimulated lymph node cells. (b) PA secretion by macrophages seems to be induced by a rather narrow concentration range of lymphokines. (c) Lymphokine-induced PA secretion by macrophages is enhanced after phagocytosis of latex beads. The results show that PA secretion by activated macrophages can be considered as a parameter of immunoactivation.
mesh_terms: D000818:Animals; D008213:Lymphocyte Activation; D008222:Lymphokines; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D010461:Peptones / Q000494:pharmacology; D010587:Phagocytosis; D010960:Plasminogen Activators / Q000096:biosynthesis*
chemical_list: D008222:Lymphokines; D010461:Peptones; D010960:Plasminogen Activators