Immunohistochemical staining of FFPE mouse spleen with Rb monoclonal PD-L1 C/N (TA591004, clone OR-5E3) at 0.9mg/mL at 1:300. Rb anti-PD-L1 clone OR-5E3 requires heat-induced epitope retrieval (HIER) at 120°C for 3min with TE (EDTA-Tris pH9 ). Detection was done with D13 Polink1 polymer detection system and visualized with DAB.