B6-hCD47 Mice

Catalog Number: C001419

Genetic Background: C57BL/6JCya

Reproduction: Homozygote x Homozygote

Strain Description

CD47, also known as Integrin Associated Protein (IAP), is a transmembrane protein that belongs to the immunoglobulin superfamily. It is widely expressed on the surface of almost all normal cells and is highly expressed in tumor cells. ^[1]

SIRPα, a signal regulatory protein mainly expressed on macrophages, inhibits their phagocytosis of target cells by transmitting inhibitory signals when binding to CD47 on other cells. However, some tumor cells can evade phagocytosis and cause tumor immune escape by highly expressing CD47 and binding to SIRPα on macrophages, sending a “don’t eat me” signal. Targeting CD47 antibodies can initiate anti-tumor T cell immune responses and promote cancer-specific lymphocyte activation through macrophage-mediated phagocytosis of tumors. As a result, the CD47-SIRPα signaling pathway has great therapeutic potential and is a highly competitive target in tumor immunotherapy after PD-1/PD-L1.^[1-2]

CD47 is a transmembrane protein with its extracellular domain serving as the receptor/ligand binding region and its intracellular domain responsible for signal transduction.[3] B6-hCD47 mice are obtained by replacing the fragment encoding the extracellular domain of CD47 protein in the mouse Cd47 gene with the corresponding human CD47 gene sequence, resulting in a model expressing the extracellular domain of human CD47 protein and the intracellular domain of mouse CD47 protein. This ensures normal binding with human antibodies and other protein drugs while completely retaining the intracellular part of mouse CD47 protein, maintaining normal intracellular signal transduction. B6-hCD47 mice can successfully express human CD47 protein and can be used for research on CD47-targeted inhibitors or antibody drug development and screening, pharmacology and safety evaluation, tumor immunotherapy evaluation, and mechanisms of tumor immune escape systems.

Strain Strategy

Figure 1. Diagram of the gene editing strategy for the generation of B6-hCD47 mice

Validation

1. The expression of mouse CD47 and human CD47

Figure 2. Detection of mouse CD47 and human CD47 expression in B6-hCD47 Mice and C57BL/6J mice. Peripheral blood (PB), thymus, spleen, and lung tissues from hCD47 and C57BL/6J mice were analyzed by flow cytometry to detect the expression of mouse and human CD47. Results showed that B6-hCD47 mice expressed high levels of human CD47 and almost no mouse CD47, indicating successful humanization of the mouse Cd47 gene.

 

2. Binding strength of B6-hCD47 mouse erythrocytes to Anti-CD47 antibody

Figure 3. Average fluorescence intensity of B6-hCD47 mouse erythrocytes bound to different antibodies*. The data show that the average fluorescence intensity of B6-hCD47 mouse erythrocytes binding to various sources of human CD47 antibody increases as the antibody concentration increases. In contrast, the fluorescence intensity of binding to the non-CD47 antibody remains at 0, indicating no binding.
*This data comes from a Cyagen customer, where antibody 1 and antibody 2 are preclinical human CD47 antibodies.

 

3. Anti-CD47 antibody induces an agglutination reaction in erythrocytes of B6-hCD47 mice

Figure 4. Agglutination reaction induced by different antibodies to erythrocytes of B6-hCD47 mice*. The data show high concentrations of Antibody 1 and Antibody 2 can significantly induce erythrocyte agglutination in B6-hCD47 mice.
*This data comes from a Cyagen customer, where both antibody 1 and antibody 2 are preclinical human CD47 antibodies, and B6H12 is a monoclonal antibody specific to the human CD47 protein.

Reference

[1] Logtenberg MEW, Scheeren FA, Schumacher TN. The CD47-SIRPα Immune Checkpoint. Immunity. 2020 May 19;52(5):742-752.

[2] Jiang Z, Sun H, Yu J, Tian W, Song Y. Targeting CD47 for cancer immunotherapy. J Hematol Oncol. 2021 Oct 30;14(1):180.

[3] Barclay AN, Van den Berg TK. The interaction between signal regulatory protein alpha (SIRPα) and CD47: structure, function, and therapeutic target. Annu Rev Immunol. 2014;32:25-50.