Species specific analysis of PD-L2 gene expression in wild-type C57BL/6 mice and homozygous humanized B-hPD-1 plus/hPD-L1/hPD-L2 mice by RT-PCR. Thymus was collected from wild-type C57BL/6 mice (+/+) and homozygous B-hPD-1 plus/hPD-L1/hPD-L2 mice (H/H). Mouse PD-L2 mRNA was detectable only in wild-type C57BL/6 mice. Human PD-L2 mRNA was only detectable in homozygous B-hPD-1 plus/hPD-L1/hPD-L2 mice, but not in wild-type C57BL/6 mice. 

Strain specific PD-L2 expression analysis in wild-type C57BL/6 mice and homozygous humanized B-hPD-1 plus/hPD-L1/hPD-L2 mice by flow cytometry. Bone marrow was collected from wild-type C57BL/6 mice (+/+) and homozygous B-hPD-1 plus/hPD-L1/hPD-L2 mice (H/H) and cultured in vitro to induce the bone marrow-derived dendritic cells (BMDCs). The successfully induced BMDCs were stimulated with or without LPS in vitro. Expression of PD-L2 on BMDCs was analyzed by flow cytometry. Mouse PD-L2 was only detectable in wild-type C57BL/6 mice. Human PD-L2 was exclusively detectable in homozygous B-hPD-1 plus/hPD-L1/hPD-L2 mice, but not in wild-type C57BL/6 mice.