Gene targeting strategy for B-hIL6ST mice. The exons 3~14 of mouse Il6st gene that encode the extracellular protein were replaced by human IL6ST exons 3~14 in B-hIL6ST mice.

Strain specific analysis of IL6ST gene expression in wild-type C57BL/6 mice and hIL6ST mice by RT-PCR. Mouse Il6st mRNA was detectable only in lung and bladder of wild-type C57BL/6 mice (+/+). Human IL6ST mRNA was detectable only in homozygous B-hIL6ST mice (H/H) but not in wild-type mice.

Strain specific IL6ST expression analysis in homozygous B-hIL6ST mice by ELISA. Serum was isolated from wild-type C57BL/6 mice (+/+) and homozygous B-hIL6ST mice (H/H) and analyzed by ELISA with species-specific IL6ST ELISA kit. Human IL6ST was exclusively detectable in homozygous B-hIL6ST mice but not in wild-type mice (A).