Table 2.

Immunohistochemistry details.

TargetAntigen retrievalaPrimary Ab blockAb manufacturer and clonePrimary AbbScoringc
β5i (PSMB8)Citrate buffer 100°C 20 minBackground sniper BSA 1%Cell Signaling #13726 Mouse IgG1, IA51:400 1.5 h, RTTumor
PD-L1EDTA buffer 95°C 60 minBackground sniperCell Signaling #13684 Rabbit IgG, E1L3N1:200 2 h, RTsTILs, tumor
MHC-II (HLA-DP/Q/R)Citrate buffer 121°C 5 minGoat serum 10% BSA 1%Abcam #ab86261 Mouse IgG1, KUL/051:100 4°C RTStroma
MHC-I (HLA-A/B/C)Dako retrieval buffer pH 6.0 100°C 10 minBackground sniper BSA 1%Abcam #70328 Mouse IgG1, EMR8-51:800 1 h, RTTumor
PA28 (PSME2)NoneBackground sniper BSA 1%Abcam #ab183727 Rabbit IgG, EPR149311:1,000 1 h, RTTumor
  • a Citrate buffer: 0.01M citrate buffer, pH 6.0, EDTA buffer: 0.001M Tris–EDTA, pH 8.8.

  • d Primary antibodies diluted in Da Vinci Green Diluent.

  • e TILs were scored on whole breast tumor sections according to the International Working Group criteria (Salgado et al, 2015). Intensity and percentage of TILs stained were recorded as a Histo-score. A cut-off of ≥1% was considered positive. BSA, bovine serum albumin; ON, overnight; RT, room temperature.