Alpha 2-macroglobulin 'fast' forms inhibit superoxide production by activated macrophages.
Mouse peritoneal macrophages activated by bacillus Calmette-Guerin (BCG) were incubated with human alpha 2-macroglobulin converted to its 'fast' form with either trypsin or methylamine before being stimulated with phorbol myrystate acetate. Both alpha 2-macroglobulin-trypsin and alpha 2-macroglobulin-methylamine inhibited macrophage production of superoxide anion (O2-) while native alpha 2-macroglobulin had little effect except at high concentration. The alpha 2-macroglobulin 'fast' forms, which bind with a Kd of about 8 nM, inhibited 50% generation of O2- (ID50) at a concentration of 7 nM while alpha 2-macroglobulin inhibited O2- production with an ID50 of 141 nM. The 'fast' forms of alpha 2-macroglobulin may play a role in the feedback regulation of inflammatory reactions.
D000818:Animals; D066298:In Vitro Techniques; D008262:Macrophage Activation; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D013481:Superoxides / Q000096:biosynthesis*; D000511:alpha-Macroglobulins / Q000494:pharmacology*
D000511:alpha-Macroglobulins; D013481:Superoxides