Il6 expression in total tissue extracts from various organs and IL-6 levels in peripheral blood and BM lysates of reciprocal Il6^−/− BM chimeric mice as well as LeprCre;Il6^fl/fl and Rag1^−/− mice after a single LPS injection. (A) Experimental outline illustrating induction of LPS-induced inflammation in WT, reciprocal Il6^−/− BM chimeric, Rag1^−/−, and LeprCre;Il6^fl/fl mice before isolation of major solid organs and collection of plasma and BM lysates for qRT-PCR and ELISA, respectively. This schedule is applicable to experimental data depicted in panels B to E. (B) Il6 expression relative to Gapdh after LPS stimulation in whole tissue extracts from total bone, spleen, lung, kidney, heart, and liver of WT mice. IL-6 protein levels in steady-state (PBS-injected) plasma and BM lysates or after LPS stimulation in reciprocal Il6^−/− BM chimeric mice (C), Rag1^−/− mice (D), and Lepr-Cre;Il6^fl/fl mice (E). *P < .05, **P < .01, ***P < .001, ****P < .0001. i.p., intraperitoneal; n.d., not detectable; ns, nonsignificant; w.d., weakly detectable.