Table 2.

Summary of immunohistochemical methodology.

Antibody	Clone	Commercial brand	Blocking solution	Dilution	Antigen retrieval
PD-L1	E1L3N	Cell Signaling Tech., USA	3% BSA	1:200	Tris/EDTA pH 91
CTLA-4	CAL49	Abcam, Cambridge, UK	2% BSA	1:500	Citrate pH 62
TIM-3	4C4G3	Proteintech Group, Manchester, UK	2% BSA	1:50	Protease XIV
CD200R1	PCT3	In house, INIA	2% BSA	Neat	Protease XIV

BSA, bovine serum albumin. ¹Tris/EDTA pH 9 pressure cooker treatment at 120°C for 5 min. ²Citrate pH 6, autoclave treatment at 121°C for 8 min. Protease XIV, enzymatic digestion (Sigma-Aldrich, USA) at 38°C for 6 min.