Fig. 1.

Serum retinol is bound to freely circulating SAAs in the bloodstream of infected mice. (A) Schematic representation of the experiment. (B) Wild-type mice or mice lacking the entire Saa locus (Saa^−/−) were infected i.p. with S. typhimurium, and serum was collected 5 h later. The serum was fractionated by size-exclusion chromatography (Top), and SAA proteins in each fraction were detected by immunoblotting with a pan-SAA antibody (Bottom). (C) Fractions from wild-type or Saa^−/− mice were hexane-extracted and analyzed by LC-MS/MS for retinol, cholesterol, and triglyceride. Data were derived from 3 independent experiments and plotted as mean ± SEM, *P < 0.05 as determined by 2-tailed Student's t test. WT, wild-type.