Blocking solution

The magnum portions of the adult hen oviducts were fixed in 4% paraformaldehyde for 24 hours and washed in phosphate buffered saline (PBS) for 30 minutes. After that, the tissue was embedded in paraffin and sectioned into 5 μm slices with a Thermo HM550 system (Thermo, America). After rehydration and antigen retrieval, the slides were blocked in blocking solution (ZSGB-BIO, China) for 1 hour. Then they were incubated with mouse monoclonal anti-Human Lysozyme antibody (1:200 dilution; US Biological, L9200-05J, USA) overnight at 4°C, followed by incubation in the secondary antibody (1:400 dilution; Invitrogen, USA) for 1 hour at room temperature. Samples were visualized and imaged using a Leica DM5500 B microscope (Leica, Germany).

Resected xenograft tumor tissues were fixed with 4% paraformaldehyde before embedded in paraffin. Prepared tissue sections (4 μm) were deparaffinized with xylene and rehydrated with graded alcohol. Tissue sections were then treated with blocking solution (ZSGB-Bio) for 30 min at room temperature, before primary antibody incubation for overnight at 4 °C, followed by secondary antibody incubation for 1 h at room temperature. Tissue samples were stained using a peroxidase IHC assay kit (ZSGB-Bio, Beijing) according to the manufacturer’s instructions. Mounted sections were examined by light microscopy (Leica) and acquired images were analyzed with Image-Pro Plus software (version 6.0).