Radiolabeled Anti-PD-L1 Antibody Protocol

All chemicals were purchased from Sigma-Aldrich Chemical Co. or Thermo Fisher Scientific. EB-NH₂ was synthesized as described previously 26 (link), 27 (link). Cyclic-(Arg-Gly-Asp-D-Phe-Lys) (RGD) peptide was purchased from C.S. Bio. InvivoPlus anti-mouse PD-L1 mAb was purchased from BioXCell (Cat. No. BP0101). The murine colon adenocarcinoma cell line, MC38, was purchased from the China National Infrastructure of Cell Line Resource. Labeling efficiency and radiochemical purity were tested using a Mini-Scan radio-TLC Scanner (BioScan, USA) and Dionex Ulti-Mate 3000 high performance liquid chromatography (HPLC; Thermo Scientific, USA), with a flow-counter radioactivity detector (BioScan, USA). Radioactivity was measured using a γ-counter (WIZARD 2480; Perkin-Elmer, USA) and CRC-25R Dose Calibrators (CAPIN-TEC Inc., USA). SPECT imaging was performed using a nanoScan SPECT/CT scanner (Mediso, Hungary).