• 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. CD19 is a biomarker for normal and neoplastic B cells, as well as follicular dendritic cells. CD19 is critically involved in establishing intrinsic B cell signaling thresholds through modulating both B cell receptor-dependent and independent signaling. CD20 is a marker of B cells, and it begins to express in Pre-B cells and loses expression after differentiating into plasma cells. CD20 is expressed on the surface of normal and about 95% malignant B lymphocytes, but not expressed in hematopoietic stem cells, plasma cells, or other normal tissues. CD20 is regarded as an ideal target for the treatment of B-cell lymphoma and autoimmune diseases
• B-hCD3EDG/hCD19/hCD20 mice were obtained by mating B-hCD3EDG mice(110039), B-hCD19 mice(112657) and B-hCD20 mice(111231). In this mice, chimeric human CD3EDG was expressed, while mouse Cd3edg were knocked out. The chimeric CD19 coding sequence containing the extracellular region of human CD19 gene is inserted into mouse Cd19 gene locus site. The exons 2-7 of mouse Cd20 gene that encode the whole molecule (ATG to STOP codon) are replaced by human counterparts in B-hCD3EDG/hCD19/hCD20 mice.
• Human CD3E can be detected on T cells from spleen of homozygous B-hCD3EDG/hCD19/hCD20 mice, but not in wild-type mice. Human CD19 and CD20 can be detected on B cells from spleen of homozygous B-hCD3EDG/hCD19/hCD20 mice. Following humanization of CD3EDG, CD19, and CD20, the percentages of CD4+ T cells and Tregs in B-hCD3EDG/hCD19/hCD20 mice decreased compared to those in wild-type C57BL/6JNifdc mice, while CD8+ T cells increased.
• This product is used for the pharmacological and safety evaluation of therapeutic drugs, such as anti-CD19 or anti-CD20 antibodies, bi or tri-specific antibodies, CAR-T cell therapies, and other drugs. Disease areas include oncology and autoimmune diseases.

Strain specific CD3E expression analysis in wild-type C57BL/6JNifdc mice and homozygous humanized B-hCD3EDG/hCD19/hCD20 mice by flow cytometry. Splenocytes were collected from wild-type C57BL/6JNifdc mice and homozygous B-hCD3EDG/hCD19/hCD20 mice (female, 7-week-old, n=1). Protein expression was analyzed with anti-mouse CD3E antibody (Biolegend, 100312) and anti-human CD3E antibody (BD Horizon™, 562426) by flow cytometry. Mouse CD3E was only detectable in wild-type C57BL/6JNifdc mice. Human CD3E was exclusively detectable in homozygous B-hCD3EDG/hCD19/hCD20 mice, but not in wild-type C57BL/6JNifdc mice.

Strain specific CD19 expression analysis in wild-type C57BL/6JNifdc mice and homozygous humanized B-hCD3EDG/hCD19/hCD20 mice by flow cytometry. Splenocytes were collected from wild-type C57BL/6JNifdc mice and homozygous B-hCD3EDG/hCD19/hCD20 mice (female, 7-week-old, n=1). Protein expression was analyzed with anti-mouse CD19 antibody (Biolegend, 115507) and anti-human CD19 antibody (Biolegend, 302234) by flow cytometry. Mouse CD19 was only detectable in wild-type C57BL/6JNifdc mice. Human CD19 was exclusively detectable in homozygous B-hCD3EDG/hCD19/hCD20 mice, but not in wild-type C57BL/6JNifdc mice.

Strain specific CD20 expression analysis in wild-type C57BL/6JNifdc mice and homozygous humanized B-hCD3EDG/hCD19/hCD20 mice by flow cytometry. Splenocytes were collected from wild-type C57BL/6JNifdc mice and homozygous B-hCD3EDG/hCD19/hCD20 mice (female, 7-week-old, n=1). Protein expression was analyzed with anti-mouse CD20 antibody (Biolegend, 150410) and anti-human CD20 antibody (Biolegend, 302306) by flow cytometry. Mouse CD20 was only detectable in wild-type C57BL/6JNifdc mice. Human CD20 was exclusively detectable in homozygous B-hCD3EDG/hCD19/hCD20 mice, but not in wild-type C57BL/6JNifdc mice.

Frequency of leukocyte subpopulations in spleen by flow cytometry. Splenocytes were isolated from wild-type C57BL/6JNifdc mice (female, n=3, 7-week-old) and homozygous B-hCD3EDG/hCD19/hCD20 mice (female, n=3, 7-week-old). A. Flow cytometry analysis of the splenocytes was performed to assess the frequency of leukocyte subpopulations. B. Frequency of T cell subpopulations. Percentages of T cells, B cells, NK cells, dendritic cells, neutrophils, monocytes and macrophages in B-hCD3EDG/hCD19/hCD20 mice were similar to those in wild-type C57BL/6JNifdc mice. Values are expressed as mean ± SEM.

Frequency of leukocyte subpopulations in blood by flow cytometry. Blood were isolated from wild-type C57BL/6JNifdc mice (female, n=3, 7-week-old) and homozygous B-hCD3EDG/hCD19/hCD20 mice (female, n=3, 7-week-old). A. Flow cytometry analysis of the blood was performed to assess the frequency of leukocyte subpopulations. B. Frequency of T cell subpopulations. Percentages of T cells, B cells, NK cells, dendritic cells, neutrophils, monocytes and macrophages in B-hCD3EDG/hCD19/hCD20 mice were similar to those in wild-type C57BL/6JNifdc mice. Values are expressed as mean ± SEM.

Frequency of leukocyte subpopulations in lymph nodes by flow cytometry. Lymph nodes cells were isolated from wild-type C57BL/6JNifdc mice (female, n=3, 7-week-old) and homozygous B-hCD3EDG/hCD19/hCD20 mice (female, n=3, 7-week-old). A. Flow cytometry analysis of the lymph nodes cells was performed to assess the frequency of leukocyte subpopulations. B. Frequency of T cell subpopulations. Percentages of T cells, B cells and NK cells in B-hCD3EDG/hCD19/hCD20 mice were similar to those in wild-type C57BL/6JNifdc mice. Values are expressed as mean ± SEM.