2.9 Hematoxylin and eosin (H&E) staining and
immunofluorescence
The tumor tissue was fixed with 4% formalin, embedded in paraffin, and
cut into 4 µm sections. The sections were stained with H&E.
Immunofluorescence analysis was performed with slight modifications
based on the method described by Dai18. Briefly,
sections were dewaxed and rehydrated. We used citrate antigen retrieval
solution for antigen repair (12 min), 3%
H2O2 for inactivation of endogenous
peroxidase (10 min), and 3% BSA for blocking (15 min). Slices were then
incubated with rabbit anti-mouse
CD11b and rat anti-mouse CD206 (Abcam, Cambridge, UK) antibodies
overnight at 4 °C. Next, the cells were incubated with goat anti-rat
IgG-TR and goat anti-rabbit IgG-FITC secondary antibodies. Cells were
incubated with DAPI for 40 min at 37 °C. Finally, slides were observed
and photographed using a fluorescence microscope.