Basic Information

Strain Name
C57BL/6-Garptm1(GARP)TGFB1tm1(TGFB1)/Bcgen
Common Name
B-hGARP/hTGFB1 mice
Background
C57BL/6N
Catalog number
112241
Related Genes
GARP(LRRC32,CPPRDD,D11S833E);  TGFB1(CED,LAP,DPD1,TGFB,IBDIMDE,TGFbeta,TGF-beta1)
NCBI Gene ID
GARP: 2615; TGFB1: 7040

Gene targeting strategy

Gene targeting strategy for B-hGARP/TGFB1 mice. The exons 1~2 of mouse Garp gene that encode the extracellular domain were replaced by human GARP exon 1~2 in B-hGARP/TGFB1 mice. The human TGFB1 gene that encodes the full-length protein was inserted following part of the exon 2 of the mouse Tgfb1 gene in the B-hGARP/hTGFB1 mice.

Protein expression analysis

Strain specific GARP expression analysis in wild-type C57BL/6 mice and homozygous B-hGARP/hTGFB1 mice by flow cytometry. Splenocytes were isolated from wild-type C57BL/6 mice and homozygous B-hGARP/hTGFB1 mice. Mouse GARP was detectable in wild-type mice. Human GARP was only detectable in homozygous B-hGARP/hTGFB1 mice.

Species-specific TGFB1 protein expression analysis in wild-type and humanized B-hGARP/hTGFB1 mice. Splenocytes were isolated from wild-type C57BL/6 (+/+) and homozygous B-hGARP/hTGFB1 (H/H) mice and analyzed by flow cytometry using species-specific anti-TGFB1 antibodies. Murine TGFB1 protein was detected in wild-type mice, while human TGFB1 protein was detected in B-hGARP/hTGFB1 mice.

Protein expression analysis in blood

Species-specific GARP protein expression analysis in wild-type and humanized B-hGARP/hTGFB1 mice. Blood was extracted from wild-type C57BL/6 (+/+) and homozygous B-hGARP/hTGFB1 (H/H) mice and analyzed by flow cytometry using species-specific anti-GARP antibodies. Murine GARP protein was detected in wild-type mice, while human GARP protein was detected in B-hGARP/hTGFB1 mice.

Species-specific TGFB1 protein expression analysis in wild-type and humanized B-hGARP/hTGFB1 mice. Blood was extracted from wild-type C57BL/6 (+/+) and homozygous B-hGARP/hTGFB1 (H/H) mice and analyzed by flow cytometry using species-specific anti-TGFB1 antibodies. Murine TGFB1 protein was detected in wild-type mice, while human TGFB1 protein was detected in B-hGARP/hTGFB1 mice.

Analysis of leukocytes cell subpopulation in spleen

Analysis of spleen leukocyte subpopulations by FACS. Splenocytes were collected from WT and homozygous B-hGARP/hTGFB1 mice (n=3, 6-week-old). Flow cytometry analysis of the splenocytes was performed to assess leukocyte subpopulations. A. Representative FACS plots. Single live cells were gated for the CD45+ population and used for further analysis as indicated here. B. Results of FACS analysis. Percent of T cells, B cells, NK cells, dendritic cells, granulocytes, monocytes and macrophages in homozygous B-hGARP/hTGFB1 mice were similar to those in the C57BL/6 mice, demonstrating that introduction of hGARP/hTGFB1 in place of its mouse counterpart does not change the overall development, differentiation or distribution of these cell types in spleen. Values are expressed as mean ± SEM.

Analysis of T cell subpopulation in spleen

Analysis of spleen T cell subpopulations by FACS. Splenocytes were isolated from female C57BL/6 and homozygous B-hGARP/hTGFB1 mice (n=3, 6-week-old). Flow cytometry analysis of the splenocytes was performed to assess leukocyte subpopulations. A. Representative FACS plots. Single live CD45+ cells were gated for CD3+ T cell population and used for further analysis as indicated here. B. Results of FACS analysis. The percent of CD8+ T cells, CD4+ T cells, and Tregs in homozygous B-hGARP/hTGFB1 mice were similar to those in the C57BL/6 mice, demonstrating that introduction of hGARP/hTGFB1 in place of its mouse counterpart does not change the overall development, differentiation or distribution of these T cell subtypes in spleen. Values are expressed as mean ± SEM.

Antibody binding assay

Antibody binding assay using wild-type and humanized B-hGARP/hTGFB1 mice. Splenocytes were isolated from wild-type C57BL/6 (+/+) and homozygous B-hGARP/hTGFB1 (H/H) mice and analyzed by flow cytometry to assess anti-human GARP/latent-TGFB1 antibody ABBV151 (10ug/mL) binding. Tregs from homozygous B-hGARP/hTGFB1 mice showed enhanced binding potential to ABBV151 versus isotype control.

Combination therapy of anti-mouse PD-1 antibody and anti-human GARP/latent-TGFβ1 antibody

Antitumor activity of anti-mouse PD-1 antibody combined with anti-human GARP/latent-TGFβ1 antibody in B-hGARP/hTGFB1 mice. (A) Anti-mouse PD-1 antibody combined with anti-human GARP/latent-TGFβ1 antibody (in-house) inhibited MC38 tumor growth in B-hGARP/hTGFB1 mice. Murine colon cancer MC38 cells (5E5) were subcutaneously implanted into homozygous B-hGARP/hTGFB1 mice (female, 7-week-old, n=6). Mice were grouped when tumor volume reached approximately 50~80 mm3, at which time they were treated with anti-mouse PD-1 antibody and anti-human GARP/latent-TGFβ1 antibody with doses and schedules indicated in panel A. (B) Body weight changes during treatment. As shown in panel A, a combination of anti-mPD-1 antibody and anti-human GARP/latent-TGFβ1 antibody were efficacious in controlling tumor growth in B-hGARP/hTGFB1 mice, demonstrating that the B-hGARP/hTGFB1 mice provide a powerful preclinical model for in vivo evaluation of anti-human GARP/latent-TGFβ1 antibodies. Values are expressed as mean ± SEM.

Posters

Generation and validation of humanized GARP/TGFB1 mice for testing novel anti-human GARP antibodies

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