Strain specific PD-L1 and LAG3 expression analysis in homozygous B-hPD-L1/hLAG3 mice by flow cytometry. Splenocytes were collected from WT and homozygous B-hPD-L1/hLAG3 (H/H) mice stimulated with anti-CD3ε in vivo, and analyzed by flow cytometry with species-specific anti-LAG3 antibody. Mouse PD-L1 was detectable in WT mice, mouse LAG3 was detectable in WT and homozygous B-hLAG3 mice due to the anti-mouse LAG3 antibody cross-reacts with human LAG3. Human PD-L1 and LAG3 were exclusively detectable in homozygous hPD-L1/hLAG3 but not WT mice.