• CEA (Carcino Embryonic Antigen, CD66e) is synthesized during development in the fetal gut, and re-expressed in increased amounts in intestinal carcinomas and several other tumors. CD66 plays a role in hemophilic and heterophilic adhesion. CD66e molecule is also called CEA or CEACAM5 and is primarily found on epithelial cells. CD66e binds to CD66a, c and e.
• The full coding sequences of human CEACAM5 gene, including the promoter, 5’UTR and 3’UTR are inserted into mouse Hipp11 (H11) locus in B-hCEACAM5 mice.
• Human CEACAM5 mRNA was exclusively detectable in homozygous B-hCEACAM5 mice but not in wild-type mice.
• Human CEACAM5 were detected in stomach, small intestine and colon tissues in homozygous mice but not wild-type C57BL/6JNifdc mice. Human CEACAM5 was exclusively detectable in colon of homozygous B-hCEACAM5 mice but not in wild-type mice.
• Humanized mice can be used to study the in vivo efficacy and safety evaluation of CEACAM5 antibody drug, ADC drug and CAR-T.

Gene targeting strategy for B-hCEACAM5 mice. The full coding sequences of human CEACAM5 gene, including the promoter, 5’UTR and 3’UTR are inserted into mouse Hipp11 (H11) locus in B-hCEACAM5 mice.

Strain specific analysis of CEACAM5 mRNA expression in wild-type C57BL/6JNifdc mice and B-hCEACAM5 mice by RT-PCR. Colon RNA were isolated from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hCEACAM5 mice (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with human CEACAM5 primers. Human CEACAM5 mRNA was exclusively detectable in homozygous B-hCEACAM5 mice but not in wild-type mice.

Western blot analysis of CEACAM5 protein expression in homozygous B-hCEACAM5 mice. Various tissue lysates were collected from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hCEACAM5 mice (H/H), and then analyzed by western blot with anti-CEACAM5 antibody (Invitrogen, PA5-88533). 40 μg total proteins were loaded for western blotting analysis. Human CEACAM5 were detected in stomach, small intestine and colon tissues in homozygous mice but not wild-type C57BL/6JNifdc mice.

Strain specific CEACAM5 expression analysis in homozygous B-hCEACAM5 mice by flow cytometry. Colon was collected from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hCEACAM5 mice (H/H) and analyzed by flow cytometry with species-specific anti-human CD66a/c/e Antibody (Biolegend, 342308). Human CEACAM5 was exclusively detectable in colon of homozygous B-hCEACAM5 mice but not in wild-type mice.