Immunohistochemical Analysis of Lung Tissue

Paraffin blocks of the left lobe of the lung were sectioned, and hydrogen peroxide was used to quench endogenous peroxidase activity. Sections were immunostained with antibodies against CD206 (1:200, Abcam), CD8 (1:40, 53–6.7, Biolegend), cleaved caspase 3 (1:100, 5A1E, Cell Signaling), PCNA (1:200, sc-56, Santa Cruz Biothechonlogies), F4/80 (1:50, BM8, Invitrogen), CD107a (1:50, Biolegend), p-ERK (1:50, Cell Signaling) and visualized with biotinylated anti-rabbit or anti-rat secondary antibodies (Cell Signaling or Vector Labs), as previously described^{53 (link)}. Signal was detected using a DAB substrate (Cell Signaling) following the manufacturer’s recommendations. Sections were counterstained with hematoxylin (Vector Labs).