• TFR1, a membrane protein expressed across various cell and tissue types in the human body, plays a crucial role in facilitating iron transport and metabolism. TFR1 is markedly expressed in numerous types of cancer cells. Studies have demonstrated that targeting TFR1 can effectively suppress tumor growth and metastasis. Moreover, utilizing its endocytosis mechanism, TFR1 can serve as a pathway for mediating the transport of biotherapeutics across the blood-brain barrier. 

• This product is used to evaluate the pharmacodynamics and safety of treatments for tumors and neurodegenerative diseases, as well as to assess the potential of drugs to penetrate the blood-brain barrier.

• Human TFR1 protein was exclusively detectable in B-hTFR1, Rag2 KO mice. 
• Frequency of various immune cells including T cells, B cells, NK cells, dendritic cells, neutrophils, monocytes, macrophages, CD4+ T cells, CD8+ T cells and Tregs in spleen and blood of B-hTFR1/Rag2 KO mice were similar to those in B-Rag2 KO mice

Gene targeting strategy for B-hTFR1, Rag2 KO mice. The exons 4-19 of mouse Tfr1 gene that encode extracellular domain were replaced by human counterparts in B-hTFR1, Rag2 KO mice. The genomic region of mouse Tfr1 gene that encodes cytoplasmic and transmembrane portion was retained. The promoter, 5’UTR and 3’UTR region of the mouse gene are also retained. The chimeric TFR1 expression is driven by endogenous mouse Tfr1 promoter, while mouse Tfr1 gene transcription and translation will be disrupted. 

The exon 3 and 3’UTR region of mouse Rag2 were knocked out in B-hTFR1, Rag2 KO mice, resulting in a disruption of the Rag2 gene.

This mouse model is obtained by crossing B-Rag2 KO mice (110809) with B-hTFR1 mice (110861).

Strain specific TFR1 expression analysis in homozygous B-hTFR1, Rag2 KO mice  by flow cytometry. Bone marrow were collected from wild-type C57BL/6 mice (+/+), homozygous B-Rag2 KO mice (-/-), homozygous B-hTFR1 mice (H/H) and homozygous B-hTFR1, Rag2 KO mice (H/H, -/-), and analyzed by flow cytometry with species-specific anti-mouse TFR1 antibody (BioLegend, 113807) and anti-human TFR1 antibody (BioLegend, 334107). Mouse TFR1 was only detectable in homozygous B-Rag2 KO mice and wild-type C57BL/6 mice, and human TFR1 was exclusively detectable in B-hTFR1 mice and B-hTFR1, Rag2 KO mice.

Frequency of leukocyte subpopulations in spleen by flow cytometry. Splenocytes were isolated from female wild-type C57BL/6 mice (n=3, 7 week-old), homozygous B-Rag2 KO mice (n=3, 6 week-old), homozygous B-hTFR1 mice (n=3, 9 week-old) and homozygous B-hTFR1/Rag2 KO mice (n=3, 10-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, DCs, neutrophils, monocytes, macrophages, CD4+ T cells, CD8+ T cells and Tregs in B-hTFR1 mice were similar to those in C57BL/6 mice. Percentages of T cells, B cells, NK cells, DCs, neutrophils, monocytes, macrophages, CD4+ T cells, CD8+ T cells and Tregs in B-hTFR1/Rag2 KO mice were similar to those in B-Rag2 KO mice. Values are expressed as mean ± SEM. 

Frequency of leukocyte subpopulations in blood by flow cytometry. Blood cells were isolated from female wild-type C57BL/6 mice (n=3, 7 week-old), homozygous B-Rag2 KO mice (n=3, 6 week-old), homozygous B-hTFR1 mice (n=3, 9 week-old) and homozygous B-hTFR1/Rag2 KO mice (n=3, 10-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, DCs, neutrophils, monocytes, macrophages, CD4+ T cells, CD8+ T cells and Tregs in B-hTFR1 mice were similar to those in C57BL/6 mice. Percentages of T cells, B cells, NK cells, DCs, neutrophils, monocytes, macrophages, CD4+ T cells, CD8+ T cells and Tregs in B-hTFR1/Rag2 KO mice were similar to those in B-Rag2 KO mice. Values are expressed as mean ± SEM.