Gene targeting strategy for B-hIL3 mice. The exons 1-5 of mouse Il3 gene that encodes the full-length protein were replaced by human IL3 exons 1-5 in B-hIL3 mice.

Strain specific analysis of IL3 gene expression in wild-type C57BL/6 mice and homozygous B-hIL3 mice by RT-PCR. Mouse splenocytes were collected and stimulated with ConA for 48 hrs in vitro. Mouse Il3 mRNA was detectable in wild-type C57BL/6 mice (+/+). Human IL3 mRNA was detectable only in homozygous B-hIL3 mice (H/H) but not in wild-type mice.

Strain specific IL3 expression analysis in homozygous B-hIL3 mice by ELISA. Splenocytes culture supernatant was collected from wild-type C57BL/6 mice (+/+) and homozygous B-hIL3 mice (H/H) stimulated with PMA/ionomycin in vitro, and analyzed by ELISA with species-specific IL3 ELISA kit. Mouse IL3 was detectable in wild-type mice. Human IL3 was exclusively detectable in homozygous B-hIL3 mice but not in wild-type mice.