title: Regulation of endotoxin-induced inhibition of macrophage migration by fresh serum.
abstract: Purified endotoxin (LPS) caused macrophage migration inhibition (MMI) in capillary tube cultures of guinea pig peritoneal macrophages in medium prepared with 15% fresh-frozen guinea pig serum. The inactivation of serum by heating at 56 degrees C for 30 min or by zymosan absorption prevented LPS-induced MMI. LPS was fully inhibitory in fresh C4-deficient guinea pig serum. Heat treatment of normal serum at 50 to 52 degrees C for 30 min to inactivate the alternate complement (C) pathway prevented or significantly decreased LPS-induced MMI, but heating C4-deficient serum at 50 to 52 degrees C for 30 min prevented LPS-MMI in all instances. These results suggest that the reaction was effected via the alternate C pathway but that some inhibition of migration was permitted via the classical C pathway, presumably due to antibodies for LPS in some normal sera. Pretreatment of normal serum with cobra venom factor decreased or prevented LPS-MMI in most instances, but similar results were obtained with C4-deficient serum. Experiments with chelated sera were unsuccessful because of the immobilization of macrophages by 10 mM ethylenediamine-tetraacetic acid and by 10 mM Mg-ethyleneglycol-bis (beta-aminoethyl)-N,N-tetraacetic acid. Low doses of concanavalin A and staphylococcal enterotoxin B and large doses of pokeweed mitogen caused MMI in "inactivated serum" medium, but MMI was enhanced in fresh serum.
mesh_terms: D000818:Animals; D001202:Ascitic Fluid / Q000166:cytology; D002464:Cell Migration Inhibition; D002478:Cells, Cultured; D003165:Complement System Proteins; D004731:Endotoxins / Q000494:pharmacology*; D004926:Escherichia coli; D006168:Guinea Pigs; D006358:Hot Temperature; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects / Q000276:immunology*; D008934:Mitogens / Q000494:pharmacology; D011135:Polysaccharides, Bacterial / Q000494:pharmacology*; D012485:Salmonella typhi
chemical_list: D004731:Endotoxins; D008070:Lipopolysaccharides; D008934:Mitogens; D011135:Polysaccharides, Bacterial; D003165:Complement System Proteins