Gene targeting strategy for B-hCTLA4/hIL2RA mice. The exons 2-6 of mouse Il2ra gene that encode the extracellular domain were replaced by human IL2RA exons 2-6 in B-hCTLA4/hIL2RA mice. The exon 2 of mouse Ctla4 gene that encode the extracellular domain was replaced by human CTLA4 exon 2 in B-hCTLA4/hIL2RA mice.

Strain specific CTLA4 and IL2RA expression analysis in homozygous B-hCTLA4/hIL2RA mice by FACS. Splenocytes were collected from wild type (+/+) and homozygous B-hCTLA4/hIL2RA mice (H/H,H/H) stimulated with anti-mCD3ε antibody in vivo, and analyzed by FACS with species-specific anti-CTLA4 or anti-IL2RA antibodies. Mouse CTLA4 and IL2RA were detectable in wild type mice. Human CTLA4 and IL2RA were exclusively detectable in homozygous B-hCTLA4/hIL2RA mice but not in wild type mice.