Strain specific NRP1 expression analysis in homozygous B-hNRP1 mice by flow cytometry. Splenocytes were collected from wild-type C57BL/6 mice (+/+) and homozygous B-hNRP1 mice (H/H), and analyzed by flow cytometry with species-specific anti-NRP1 antibody. Mouse NRP1 was detectable in wild-type mice. Human NRP1 was exclusively detectable in homozygous B-hNRP1 but not in wild-type mice.