Gene targeting strategy for B-hIL5 mice. The exons 1-4 of mouse Il5 gene were replaced by human IL5 exons 1-4 in B-hIL5 mice.

Strain specific IL5 expression analysis in homozygous B-hIL5 mice by ELISA. Serum was collected from wild-type C57BL/6 mice (+/+) and homozygous B-hIL5 mice (H/H) stimulated with Con A in vivo, and analyzed by ELISA with species-specific IL5 ELISA kit. Mouse IL5 was detectable in wild-type mice. Human IL5 was exclusively detectable in homozygous B-hIL5 mice but not in wild-type mice.