title: Murine model for human secondary amyloidosis: genetic variability of the acute-phase serum protein SAA response to endotoxins and casein.
abstract: The serum precursor SAA of the secondary amyloid protein AA has been detected by solid-phase radioimmunoassay as a normal serum alpha-globulin of mol wt 160,000, which dissociates to a more stable 12,500 dalton moiety on treatment with formic acid. In 12 strains of mice, including T-cell-deficient nude mice, treated with the amyloid-inducing agents lipopolysaccharide (LPS) or casein, SAA behaved as an acute-phase reactant. SAA concentration rose to about 750 mug/ml by 24 h and returned to less than 1 mug/ml by 48 h. Since the amyloid-resistant colchicine-treated mice and AJ mice had a normal SAA response to LPS, it appears that their resistance to amyloid induction is due to the nature of their SAA processing rather than decreased SAA production. C3H/HeJ mice, which have defective B-lymphocyte responses to LPS, required extremely high dosages of LPS to cause SAA elevation, although their SAA response to casein was normal. This suggests that SAA is an acute-phase protein produced as a result of B-lymphocyte stimulation. Preliminary evidence suggests that at the height of an acute SAA response, liver homogenates are particularly rich in protein AA cross-reacting material.
mesh_terms: D000208:Acute Disease; D000682:Amyloid / Q000378:metabolism*; D000686:Amyloidosis / Q000097:blood*; D000818:Animals; D001798:Blood Proteins / Q000378:metabolism*; D002364:Caseins; D004195:Disease Models, Animal; D014644:Genetic Variation; D051379:Mice; D008815:Mice, Inbred Strains; D011135:Polysaccharides, Bacterial; D011863:Radioimmunoassay; D013045:Species Specificity
chemical_list: D000682:Amyloid; D001798:Blood Proteins; D002364:Caseins; D011135:Polysaccharides, Bacterial