Immunofluorescence (IF) staining was performed on formalin-fixed skin tissue sections as described previously.32 (link) Briefly, following a series of deparrafinization and rehydration steps, skin sections from vehicle- or lewisite-treated groups were incubated with unmasking reagent, washed with PBS, and then blocked with blocking buffer. Following overnight incubation at 4°C with primary antibodies against ZO-1 (sc-33725, Santa Cruz), ZO-2 (sc-515115, Santa Cruz), claudin-4 (sc-376643, Santa Cruz), α-E-catenin (3236, CST), Yap (sc-376830, Santa Cruz), MerTK (53–5751-82, Invitrogen), and CD170 (Singlec F) (14–1702-82, Invitrogen), these skin sections were washed with PBS. Next, fluorophore-conjugated secondary antibody was used to visualize protein expression/disruption and their localization. Sections were counterstained with DAPI and imaged with a Keyence fluorescence microscope (model BZ-X710; Osaka, Japan). At least 3–5 skin sections were analyzed from each group (n = 3–5 control vs. lewisite).