Cd19-DTR transgenic mice: A tool mouse strain generated for murine B cell depletion

• Gene Information: Mouse Cd19 located on chromosome 7F3, Involved in several processes, including B cell activation; positive regulation of release of sequestered calcium ion into cytosol; and regulation of signal transduction. Acts upstream of or within B cell receptor signaling pathway. Located in external side of plasma membrane. Is expressed in liver and spleen. Human ortholog(s) of this gene implicated in common variable immunodeficiency 3. Orthologous to human CD19 (CD19 molecule). 
• Protein Information: In this mouse line, Mouse Cd19 protein is expressed in a B cell‑restricted manner, as driven by its own promoter. The EGFP-DTR-Luc fusion is co-produced (via a linker or as a fusion) from the same transcript, inserted upstream of the Cd19 stop codon. This labels B cell with EGFP, renders them sensitive to diphtheria toxin (DT) via DTR, and allows bioluminescence tracking via luciferase. The mouse Cd19 protein itself here is not the functional focus; it merely serves as the carrier for the reporter cassette. 
• Functional Mechanism: Although the full mouse Cd19 coding sequence is present, the primary purpose of this model is to enable specific and inducible depletion of murine B cell, not to study Cd19  function. Upon DT injection, DTR on B cell mediates toxin internalization and triggers rapid apoptosis. EGFP facilitates ex vivo flow cytometric identification, while luciferase permits non-invasive in vivo imaging of B cell distribution, migration, and clearance. Thus, this strain offers a robust platform for investigating B cell roles in disease models.

Cd19-EGFP-DTR-Luciferase

•  The EGFP-DTR-Luc reporter cassette was inserted before the stop codon of mouse Cd19 gene site in B-Cd19-EGFP-DTR-Luc mice.

Frequencies of EGFP in B cells from spleen, blood and lymph node by flow cytometry. Splenocytes, blood and lymph node were isolated from wild-type C57BL/6 mice (+/+) and heterozygous B-Cd19-EGFP-DTR-luciferase mice (Mut/+) (n=3, 6-7-week-old) injected with DT (50 ng per g body weight) for four consecutive days. Flow cytometry analysis of the splenocytes, blood and lymph node was performed to assess the frequencies of EGFP cells in total B cells. The signal for EGFP in B cells in spleen(A), blood (B) and lymph node(C) were significant decreased in heterozygous mice injected with DT.

Frequencies of EGFP in leukocytes cell subpopulation from spleen, blood and lymph node by flow cytometry. Splenocytes, blood and lymph node were isolated from wild-type C57BL/6 mice (+/+) and heterozygous B-Cd19-EGFP-DTR-luciferase mice (Mut/+) (n=3, 6-7-week-old). Flow cytometry analysis of the splenocytes, blood and lymph node was performed to assess the frequencies of EGFP+ cells in leukocytes cell subpopulation from spleen(A), blood (B) and lymph node(C). EGFP+ cells was expressed at a high level in B cells from spleen, blood and lymph node in heterozygous mice. And there was no leaky expression of EGFP in other cell subpopulation.

Frequencies of CD19+ and EGFP+ cells in spleen, blood and lymph node by flow cytometry. Splenocytes, blood and lymph node were isolated from wild-type C57BL/6 mice (+/+) and heterozygous B-Cd19-EGFP-DTR-luciferase mice (Mut/+) (n=3, 6-7-week-old) injected with DT (50 ng per g body weight) for four consecutive days. Flow cytometry analysis of the splenocytes, blood and lymph node was performed to assess the frequencies of CD19+; EGFP+ cells in total CD45+ cells. The signal for CD19+;EGFP+ cells in spleen(A), in blood (B) and lymph node(C) were significant decreased in heterozygous mice injected with DT.

Frequencies of CD19+ cells and EGFP+ cells in spleen by flow cytometry. Splenocytes were isolated from wild-type C57BL/6 mice (+/+) and heterozygous B-Cd19-EGFP-DTR-luciferase mice (Mut/+) (n=3, 6-7-week-old) injected with DT (50 ng per g body weight) for four consecutive days. Flow cytometry analysis of the splenocytes was performed to assess the frequencies of CD19+ cells and EGFP+ cells in total CD45+ cells. The signal for CD19+ cells(A) and EGFP+ cells(B) were decreased in heterozygous mice injected with DT. C. Percentages of CD19+ cells and EGFP+ cells in total CD45+ populations. The frequencies of CD19+ cells and EGFP+ cells were significant decreased in heterozygous mice after DT injection.

Frequencies of CD19+ cells and EGFP+ cells in blood by flow cytometry. Blood were isolated from wild-type C57BL/6 mice (+/+) and heterozygous B-Cd19-EGFP-DTR-luciferase mice (Mut/+) (n=3, 6-7-week-old) injected with DT (50 ng per g body weight) for four consecutive days. Flow cytometry analysis of the blood was performed to assess the frequencies of CD19+ cells and EGFP+ cells in total CD45+ cells. The signal for CD19+ cells(A) and EGFP+ cells(B) were decreased in heterozygous mice injected with DT. C. Percentages of CD19+ cells and EGFP+ cells in total CD45+ populations. The frequencies of CD19+ cells and EGFP+ cells were significant decreased in heterozygous mice after DT injection.

Frequencies of CD19+ cells and EGFP+ cells in lymph node by flow cytometry. Lymph node were isolated from wild-type C57BL/6 mice (+/+) and heterozygous B-Cd19-EGFP-DTR-luciferase mice (Mut/+) (n=3, 6-7-week-old) injected with DT (50 ng per g body weight) for four consecutive days. Flow cytometry analysis of the lymph node was performed to assess the frequencies of CD19+ cells and EGFP+ cells in total CD45+ cells. The signal for CD19+ cells(A) and EGFP+ cells(B) were decreased in heterozygous mice injected with DT. C. Percentages of CD19+ cells and EGFP+ cells in total CD45+ populations. The frequencies of CD19+ cells and EGFP+ cells were significant decreased in heterozygous mice after DT injection.

Frequencies of B cells in spleen, blood and lymph node by flow cytometry. Splenocytes, blood and lymph node were isolated from wild-type C57BL/6 mice (+/+) and heterozygous B-Cd19-EGFP-DTR-luciferase mice (Mut/+) (n=3, 6-7-week-old) injected with DT (50 ng per g body weight) for four consecutive days. Flow cytometry analysis of the splenocytes, blood and lymph node was performed to assess the frequencies of B cells in total CD45+ cells. The signal for B cells in spleen(A), blood (B) and lymph node(C) were significant decreased in heterozygous mice injected with DT.

Analysis of B cells depletion in spleen, blood and lymph node by flow cytometry. Splenocytes, blood and lymph node were isolated from wild-type C57BL/6 mice (+/+) and heterozygous B-Cd19-EGFP-DTR-luciferase mice (Mut/+) (n=3, 6-7-week-old) injected with DT (50 ng per g body weight) for four consecutive days. The percentages of B cells in total CD45 cells from spleen, blood and lymph node(A) and EGFP+ cells in B cells from spleen, blood and lymph node(B) were significant decreased in heterozygous mice injected with DT.

Analysis of leukocyte subpopulations by flow cytometry in spleen. Splenocytes cells were isolated from male C57BL/6JNifdc and B-Cd19-EGFP-DTR-Luc Mice (male, 6-7-week-old, n = 3). Single live cells were gated on the CD45⁺ population and analyzed by flow cytometry as indicated. Values are expressed as mean ± SEM.