IL-23 plays a crucial role in various immune-mediated diseases, including inflammatory bowel disease, plaque psoriasis, and rheumatoid arthritis.

•  Gene Information: IL-23 is a heterodimeric cytokine composed of a unique p19 subunit (IL23A) and a shared p40 subunit (IL12B). It signals specifically through its receptor complex consisting of IL-23R and IL-12Rβ1 (in contrast to IL-12, which utilizes p35 and IL-12Rβ2).
•  Protein Expression: IL-23 expression is tightly regulated and predominantly produced by activated antigen-presenting cells, such as dendritic cells and macrophages, in response to microbial or inflammatory stimuli.
•  Signaling Pathway: IL-23 binding activates the JAK2/TYK2 pathway, predominantly triggering STAT3 phosphorylation. This signaling cascade is essential for maintaining and expanding Th17 cells, inducing key pro-inflammatory cytokines including IL-17A, IL-17F, and IL-22.
•  Therapeutic Inhibition: Selective inhibition of IL-23 effectively suppresses downstream Th17-mediated inflammation, providing robust clinical benefit.

IL23A

• The exons 1-4 of mouse Il23a gene that encode the full length of encoding regions were replaced by human IL23A counterpart gene sequences.
•  The promoter, 5′ UTR and 3′ UTR region of the mouse gene were also retained. The human IL23A expression was driven by endogenous mouse Il23a promoter, while mouse Il23a gene transcription and translation will be disrupted.

IL12B

•  The exons 2-8 of mouse Il12b gene that encode the full length of encoding regions and 3′ UTR were replaced by human IL12B counterpart gene sequences.
•  The promoter and 5′ UTR region of the mouse gene were also retained. The human IL12B expression was driven by mouse Il12b promoter, while mouse Il12b gene transcription and translation will be disrupted.

IL23R

•  A chimeric CDS that encodes mouse IL23R signal peptide, human IL23R extracellular domain, mouse IL23R transmembrane and cytoplasmic domain, followed by mouse 3′ UTR-STOP was inserted after exon 3 of mouse Il23r.
•  The chimeric IL23R protein expression will be driven by endogenous mouse Il23r promoter, while mouse Il23r gene transcription and translation will be disrupted.

IL12RB1

•  The exons 1-14 of mouse Il12rb1 gene that encode signal peptide and extracellular domain were replaced by human counterparts. The genomic region of mouse Il12rb1 gene that encodes transmembrane domain and cytoplasmic portion was retained.
•  The promoter, 5′ UTR and 3′ UTR region of the mouse gene were also retained. The human IL12RB1 expression was driven by endogenous mouse Il12rb1 promoter, while mouse Il12rb1 gene transcription and translation will be disrupted.

Note: The mice were obtained by crossbreeding B-hIL23A/hIL12B mice with B-hIL23R/hIL12RB1 Plus mice.

Strain-specific analysis of IL23R and IL12RB1 mRNA expression in wild-type C57BL/6JNifdc mice and homozygous B-hIL23A/hIL12B/hIL23R/hIL12RB1 Plus mice by RT-PCR. Spleen RNA was isolated from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hIL23A/hIL12B/hIL23R/hIL12RB1 Plus mice (H/H, H/H, H/H, H/H), followed by cDNA synthesis via reverse transcription and PCR amplification using primers specific for mouse or human IL23R and IL12RB1. Mouse Il23r and Il12rb1 mRNA were detectable in wild-type mice. Human IL23R and IL12RB1 mRNA were detectable in homozygous B-hIL23A/hIL12B/hIL23R/hIL12RB1 Plus mice.

Strain-specific IL-23 expression analysis in wild-type C57BL/6JNifdc mice and homozygous B-hIL23A/hIL12B/hIL23R/hIL12RB1 Plus mice by ELISA. Bone marrow-derived dendritic cells were isolated from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hIL23A/hIL12B/hIL23R/hIL12RB1 Plus mice (H/H, H/H, H/H, H/H) and stimulated with LPS in vitro for 24 h. Cell culture supernatants were collected and analyzed by ELISA using the Mouse IL-23 Quantikine ELISA Kit (R&D Systems, M2300) and Human IL-23 Quantikine ELISA Kit (R&D Systems, D2300B). Mouse IL-23 was detectable only in wild-type mice, whereas human IL-23 was exclusively detectable in homozygous B-hIL23A/hIL12B/hIL23R/hIL12RB1 Plus mice following LPS stimulation. Values are expressed as mean ± SEM.

Strain-specific IL-17A expression analysis in wild-type C57BL/6JNifdc mice and homozygous B-hIL23A/hIL12B/hIL23R/hIL12RB1 Plus mice by ELISA. Splenic CD4⁺ T-cell supernatants were collected from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hIL23A/hIL12B/hIL23R/hIL12RB1 Plus mice (H/H, H/H, H/H, H/H) following in vitro stimulation with mIL-23 or hIL-23 for 48 h. Expression levels of mouse IL-17A were analyzed by ELISA (Mouse IL-17A ELISA Kit, Proteintech, KE10020). Expression of mouse IL-17A was increased in both wild-type mice and homozygous B-hIL23A/hIL12B/hIL23R/hIL12RB1 Plus mice after stimulation with mIL-23 or hIL-23. Values are expressed as mean ± SEM.