Gene targeting strategy for B-hIL2 mice. The targeted mouse Il2 whole genomic sequence was replaced by human IL2 whole genomic sequence in B-hIL2 mice.

Strain specific IL2 expression analysis in heterozygous B-hIL2 mice by ELISA.Serum were collected from WT and heterozygous B-hIL2 (H/+) mice stimulated with anti-CD3ε and anti-CD28 in vivo, and analyzed by ELISA with species-specific IL2 ELISA kit. Mouse IL2 was detectable in WT and heterozygous B-hIL2 mice. Human IL2 was exclusively detectable in heterozygous B-hIL2 mice but not in WT mice.