Protein expression analysis

Strain specific PD-L1 expression analysis in homozygous B-hPD-L1 mice by flow cytometry. Splenocytes were collected from WT and homozygous B-hPD-L1 (H/H) mice stimulated with anti-CD3ε in vivo and analyzed by flow cytometry with species-specific anti-PD-L1 antibody. Mouse PD-L1 was only detectable in WT mice. Human PD-L1 was exclusively detectable in homozygous B-hPD-L1 but not in WT mice.

Antitumor activity of anti-human PD-L1 antibody in B-hPD-L1 mice. (A) Anti human PD-L1 antibody inhibited MC38-hPD-L1 tumor growth in B-hPD-L1 mice. Murine colon cancer MC38-hPD-L1 cells (5×10⁵) were subcutaneously implanted into homozygous B-hPD-L1 mice (female, 6-week-old, n=5). Mice were grouped when tumor volume reached approximately 100 mm³, at which time they were treated with anti-human PD-L1 antibody with doses and schedules indicated in panel. (B) Body weight changes during treatment. As shown in panel A, anti-human PD-L1 antibody was efficacious in controlling tumor growth in B-hPD-L1 mice, demonstrating that the B-hPD-L1 mice provide a powerful preclinical model for in vivo evaluation of anti-human PD-L1 antibodies. Values are expressed as mean ± SEM.