Gene targeting strategy for B-hIL17RB/hIL25 mice. The exons 2-10 of mouse Il17rb gene that encode the extracellular domain were replaced by human IL17RB exons 2-10 in B-hIL17RB/hIL25 mice. The exons 2-3 of mouse Il25 gene that encode the full-length protein were replaced by human IL25 exons 2-7 in B-hIL17RB/hIL25 mice.

Strain specific analysis of IL17RB and IL25 gene expression in wild type (WT) mice and B-hIL17RB/hIL25 mice by RT-PCR.

Mouse Il25 mRNA was detectable only in ovary of WT mice (+/+). Human IL25 mRNA was detectable only in homozygous B-hIL17RB/hIL25 mice (H/H; H/H) but not in WT mice (+/+). Mouse Il17rb mRNA was detectable only in thymus of WT mice (+/+). Human IL17RB mRNA was detectable only in homozygous B-hIL17RB/hIL25 mice (H/H; H/H) but not in WT mice (+/+).

Strain specific IL17RB expression analysis in homozygous B-hIL17RB/hIL25 mice by flow cytometry. Splenocytes were collected from wild type (WT) mice (+/+) and homozygous B-hIL17RB/hIL25 mice (H/H; H/H), and analyzed by flow cytometry with anti-IL17RB antibody. IL17RB was detectable in WT mice (+/+) and homozygous B-hIL17RB/hIL25 mice (H/H; H/H) due to the cross-reactivity of antibodies.

Splenocytes from wild type (WT) mice and homozygous B-hIL17RB/hIL25 mice produce IL-5 in response to IL-25 stimulation. Splenocytes were collected from WT mice (+/+) and homozygous B-hIL17RB/hIL25 mice (H/H) and stimulated with mouse IL-25 or human IL-25. Mouse IL-5 concentrations were measured in cell culture supernatants by ELISA. Bars represent the mean ±SEM from three mice. The results showed that cultured splenocytes from WT mice and homozygous B-hIL17RB/hIL25 mice could produce mouse IL-5 in response to human IL-25 or mouse IL-25 stimulation.