Assays

We describe a distinct macrophage population, whose presence in the liver during homoeostasis depends on recruitment signals mediated by the chemokine receptor CCR2. The identified polarization state of this population closely resembles that induced in co-culture experiments, where hepatocytes are reducing the availability of TGFb to macrophages. Accordingly, disruption of TGFb signal transduction in macrophages phenocopies the influence of hepatocytes on macrophage polarization.