Gene targeting strategy for B-hIL9R mice. The exons 2-7 of mouse Il9r gene that encode the extracellular coding sequence were replaced by human IL9R exons 2-7 in B-hIL9R mice.

Strain specific IL9R expression analysis in homozygous B-hIL9R mice by flow cytometry. Splenocytes were collected from wild-type mice (+/+) and homozygous B-hIL9R mice (H/H) stimulated with anti-CD40 in vitro (10 μg/mL), and analyzed by flow cytometry with species-specific anti-IL9R antibody. Mouse IL9R was detectable in wild-type mice. Human IL9R was exclusively detectable in homozygous B-hIL9R mice but not in wild-type mice.