Supplementary Material for: In vivo Lipopolysaccharide Tolerance Recruits CD11b+ Macrophages to the Liver with Enhanced Bactericidal Activity and Low Tumor Necrosis Factor-Releasing Capability, Resulting in Drastic Resistance to Lethal Septicemia

<p><b><i>Objectives:</i></b> In vivo lipopolysaccharide (LPS) tolerance on bacterial infection was investigated, focusing on liver macrophages. <b><i>Methods:</i></b> LPS tolerance was induced by intraperitoneal injections with 5 μg/kg of LPS for 3 consecutive days, and then mice were intravenously infected with <i>Escherichia coli</i>. <b><i>Results:</i></b> All LPS-primed mice survived lethal bacterial infection. Drastic enhancement of bactericidal activity of liver macrophages strongly contributed to bacterial clearance. Although LPS-primed mice produced substantial amounts of tumor necrosis factor (TNF) inside the liver, TNF efflux into the systemic circulation was markedly suppressed. These mice showed a dramatic increase in CD11b<sup>+</sup> monocyte- derived macrophages in the liver. The CD11b<sup>+</sup> macrophages that increased in LPS-primed mice were those with strong phagocytic/bactericidal activity and an upregulated expression of Fcγ receptor I, but the subfraction with a potent TNF-producing capacity and poor phagocytic activity diminished. The adoptive transfer of CD11b<sup>+</sup> macrophages from LPS-primed mice to control mice increased survival after bacterial infection and reduced the elevation of plasma TNF. LPS priming did not affect the CD68<sup>+</sup> resident Kupffer cells, and CD68<sup>+</sup> Kupffer cell-depleted mice still exhibited LPS tolerance with strong resistance to bacteremia. <b><i>Conclusions:</i></b> LPS tolerance recruits CD11b<sup>+</sup> macrophages to the liver with enhanced bactericidal activity, which plays a central role in resistance to lethal bacteremia.</p>