Strain specific CD40 and PD-L1 expression analysis in homozygous B-hPD-L1/hCD40 mice by flow cytometry. Splenocytes were collected from WT and homozygous B-hPD-L1/hCD40 (H/H) mice analyzed by flow cytometry with species-specific anti-PD-L1 antibody and anti-CD40 antibody. Mouse CD40 and PD-L1 were detected in WT. Human CD40 and PD-L1 were exclusively detected in H/H B-hPD-L1/hCD40 but not WT mice.

Strain specific CD40 and PD-L1 expression analysis in homozygous B-hPD-L1/hCD40 mice by flow cytometry. Splenocytes were collected from WT and homozygous B-hPD-L1/hCD40 (H/H) mice stimulated with anti-CD3ε in vivo (7.5 μg/mice), and analyzed by flow cytometry with species-specific anti-PD-L1 antibody. Mouse CD40 and PD-L1 were detected in WT. Human CD40 and PD-L1 were exclusively detected in H/H B-hPD-L1/hCD40 but not WT mice.

Antitumor activity of anti-hCD40 antibody combined with anti-hPD-L1 antibody in B-hPD-L1/hCD40 mice. (A) Anti-hCD40 antibody combined with anti-hPD-L1 antibodies inhibited MC38-hPD-L1 tumor growth in B-hPD-L1/hCD40 mice. Murine colon cancer MC38-hPD-L1 cells (5×10⁵) were subcutaneously implanted into homozygous B-hPD-L1/hCD40 mice (female, 6-8 week-old, n=5). Mice were grouped when tumor volume reached approximately 80-120 mm³, at which time they were treated with Anti-hCD40 antibody combined with anti-hPD-L1 antibody and schedules indicated in panel. (B) Body weight changes during treatment. As shown in panel A, combination of anti-hCD40 antibody and anti-hPD-L1 antibody shows more inhibitory effects than individual groups, demonstrating that the B-hPD-L1/hCD40 mice provide a powerful preclinical model for in vivo evaluating combination therapy efficacy of hCD40 antibodies and hPD-L1 antibodies. Statistical results showed significant weight loss in both G2 and G4 groups. As shown in panel B, anti-CD40 antibody significantly reduced body weight, combination with PD-L1 antibody could relieve this symptom well. Values are expressed as mean ± SEM.