Increased inflammatory response in splenic and hepatic macrophages from LPS-treated ID mice. Splenic and liver macrophages were isolated from IR and ID mice treated or not with LPS (4 mice for each group), as described in “Isolation of resident macrophages.” TfR1 (A,D), IL6 (B,E), and TNFα (C,F) mRNA expression was quantified by SybrGreen qRT-PCR. Gapdh was used as the housekeeping gene. mRNA expression ratio was normalized to an IR mean value of 1. Error bars indicate SE; ns, not significant; *P < .05; **P < .005; and ***P < .0001.