Mouse liver tissues were fixed in 10% buffered formalin for 24 h at room temperature. Formalin-fixed, paraffin-embedded sections were cut with thickness of 5-μm. H&E staining was performed on deparaffinized and rehydrated sections according to manufacturer’s protocol (Leica Biosystems, Buffalo Grove, IL, USA). Immunochemistry for F4/80 and HA staining were carried out by established procedures as previously described (Yang et al. 2019 (link)). F4/80 monoclonal antibody or biotin-labeled HA-binding protein were applied to mouse liver sections. VECTASTAIN Elite ABC kit and DAB Peroxidase Substrate kits were used as directed by the manufacturer (Vector Laboratories, Burlingame, CA, USA). HA-positive area was evaluated from randomly selected 10 fields of × 200 magnification per slide and quantified with NIH Image J software.