Anti cd8b clone 53 5

To establish a murine cancer model, 3 × 10⁵ to 10 × 10⁵ CT26 MMR-d cells in 100 µL of PBS were subcutaneously implanted into the right flanks of 6- to 8-wk-old female BALB/c mice. Tumor size and body weight were measured three to four times weekly. Tumor sizes were measured and calculated by the formula (length) × (width)²/2. When the mean tumor volume reached ∼70–100 mm³, animals were randomized into three groups (group A [control], group B [ATRi], and group C [ATRi⁺ anti-CD8b]) for treatment. Each group included at least four mice. For depletion experiments, C57BL/6J mice were treated with 200 μg of anti-CD8b (clone 53-5.8, Bio X Cell) via intraperitoneal injection every 3–4 d for the duration of the experiment starting 1 d before tumor implantation. Mice were monitored for 15 min after administration to ensure no difficulty breathing. During the observation period, animals bearing oversized tumors >2000 mm³ were sacrificed by CO₂ asphyxiation.