• CD3 consists of four protein chains (CD3E, CD3D, CD3G and CD3Z), which are important biological markers on the T cell membrane. CD3 can form a TCR/CD3 complex with the T cell receptor, participating in the regulation of T cell antigen recognition, signal transduction and T cell development. CD22 is an adhesion molecule specifically expressed on the surface of B cells. It suppresses excessive immune responses by modulating B cell receptor (BCR) signaling and is closely associated with autoimmune diseases (e.g., systemic lupus erythematosus, rheumatoid arthritis) and B-cell malignancies.
• B-hCD3E/hCD22 mice were obtained by mating B-hCD3E mice(110008) and B-hCD20 mice(110775). In this mice, the exons 2-6 of mouse Cd3e gene that encode the extracellular domain were replaced by human CD3E exons 2-7. The exons 4-11 of mouse Cd22 gene that encode the extracellular domain were replaced by human CD22 exons 2-9 in B-hCD3E/hCD22 mice.
• Human CD3E can be detected on T cells from spleen and blood of homozygous B-hCD3E/hCD22 mice, but not in wild-type mice. Human CD22 can be detected on B cells from spleen and blood of homozygous B-hCD3E/hCD22 mice. 
• This product is used for the pharmacological and safety evaluation of therapeutic drugs, such as anti-CD22 antibodies, bi or tri-specific antibodies, CAR-T cell therapies, and other drugs. Disease areas include oncology and autoimmune diseases.

Gene targeting strategy for B-hCD3E/hCD22 mice. The exons 2-6 of mouse Cd3e gene that encode the extracellular domain were replaced by human CD3E exons 2-7 in B-hCD3E/hCD20 mice. The exons 4-11 of mouse Cd22 gene that encode the extracellular domain were replaced by human CD22 exons 2-9 in B-hCD3E/hCD22 mice.

Strain specific CD3E and CD22 expression analysis in wild-type C57BL/6 mice and homozygous humanized B-hCD3E/hCD22 mice by flow cytometry. Splenocytes were collected from wild-type C57BL/6 mice (+/+) and homozygous B-hCD3E/hCD22 mice (H/H) (female, 8-week-old, n=1). Protein expression was analyzed with anti-human CD3E antibody (BD Horizon™, 562426), anti-mouse CD3E antibody (Biolegend, 100312), anti-human CD22 antibody (Biolegend, 363505) and anti-mouse CD22 antibody (Biolegend, 126105) by flow cytometry. Human CD3E and human CD22 was exclusively detectable in homozygous B-hCD3E/hCD22 mice, but not in wild-type C57BL/6 mice.

Strain specific CD3E and CD22 expression analysis in wild-type C57BL/6 mice and homozygous humanized B-hCD3E/hCD22 mice by flow cytometry. Blood cells were collected from wild-type C57BL/6 mice (+/+) and homozygous B-hCD3E/hCD22 mice (H/H) (female, 8-week-old, n=1). Protein expression was analyzed with anti-human CD3E antibody (BD Horizon™, 562426), anti-mouse CD3E antibody (Biolegend, 100312), anti-human CD22 antibody (Biolegend, 363505) and anti-mouse CD22 antibody (Biolegend, 126105) by flow cytometry. Human CD3E and human CD22 was exclusively detectable in homozygous B-hCD3E/hCD22 mice, but not in wild-type C57BL/6 mice.