Basic Information

Strain Name
C57BL/6-Pdcd1tm1(PDCD1) Cd274tm1(CD274) Tnfrsf18tm1(TNFRSF18)/Bcgen
Stock Number
131108
Common Name
B-hPD-1/hPD-L1/hGITR mice
Background
C57BL/6
Related Genes
PDCD1 also known as PD1, PD-1, CD279, SLEB2, hPD-1, hPD-l, hSLE1  CD274 also known as B7-H, B7H1, PDL1, PD-L1, hPD-L1, PDCD1L1, PDCD1LG1  TNFRSF18  also known as AITR, GITR, CD357, GITR-D, ENERGEN
Target Strategy
The exon 2 of mouse Pdcd1 gene that encodes the IgV domain was replaced by human PDCD1 exon 2 in B-hPD-1/hPD-L1/hGITR mice. The exon 3 of mouse Cd274 gene that encodes the IgV domain was replaced by human CD274 exon 3 in B-hPD-L1/hPD-L1/hGITR mice. The exons 1-4 of mouse Tnfrsf18 gene that encode the extracellular domain were replaced by human TNFRSF18 exons 1-4 in B-hPD-1/hPD-L1/hGITR mice.

Description

PD-1 (Programmed death-1) is mainly expressed on the surface of T cells and primary B cells. The two PD-1 ligands, PD-L1 and PD-L2, are widely expressed on antigen-presenting cells (APCs). PD-1 interacts with its ligands and plays an important role in the negative regulation of the immune response. PD-L1 protein expression is detected in many human tumor tissues. PD-L1 expression in tumor cells could be induced by the microenvironment of tumor cells. PD-L1 expression is favorable for tumorigenesis and growth, for induction of anti-tumor T Cell apoptosis, and for escaping responses by the immune system. Inhibition of PD-1 binding to its ligand can result in tumor cells that are exposed to the killing version of the immune system, and thus is a target for cancer treatments.

PD-L1 (Programmed cell death ligand-1), also known as B7-H1 and CD274, is mainly expressed in antigen-presenting cells (APCs) and activated T cells, and is one of the two ligands of PD-1. The interaction between PD1 and PD-L1 plays an important role in the negative regulation of the immune response. PD-L1 is highly expressed in a variety of solid tumors. PD-1 and PD-L1 interactions can reduce T Cell activation and promote tumor immune escape. The PD-1/PD-L1 signaling pathway can be blocked and antitumor immune response can be restored by using by anti-PD-1 or anti-PD-L1 antibodies to block the binding of PD1 to PD-L1.

TNFRSF18 (TNF Receptor Superfamily Member 18) is also known as Glucocorticoid-induced TNFR-related protein (GITR), which is expressed on many immune cells including T cells. As a co-stimulatory signal of T cells, TNFRSF18 is upregulated upon the activation of T cells, and in turn promotes T cell proliferation. CD25+/CD4+ regulatory T cell is known to mediate immune tolerance, and GITR agonist antibodies can reverse this immune tolerance, and show anti-tumor effect in multiple tumor models.

Details

Protein expression analysis

Strain specific PD-1 expression analysis in homozygous B-hPD-1/hPD-L1/hGITR mice by flow cytometry. Splenocytes were collected from wild-type mice (+/+) and homozygous B-hPD-1/hPD-L1/hGITR mice (H/H) stimulated with or without anti-CD3ε in vivo, and analyzed by flow cytometry with species-specific anti-PD-1 antibody. Mouse PD-1 was detectable in wild-type mice but not in homozygous B-hPD-1/hPD-L1/hGITR mice. Human PD-1 was exclusively detectable in homozygous B-hPD-1/hPD-L1/hGITR mice but not in wild-type mice.

Strain specific PD-L1 expression analysis in homozygous B-hPD-1/hPD-L1/hGITR mice by flow cytometry. Splenocytes were collected from wild-type mice (+/+) and homozygous B-hPD-1/hPD-L1/hGITR mice (H/H) stimulated with or without anti-CD3ε in vivo, and analyzed by flow cytometry with species-specific anti-PD-L1 antibody. Mouse PD-L1 was detectable in wild-type mice but not in homozygous B-hPD-1/hPD-L1/hGITR mice. Human PD-L1 was exclusively detectable in homozygous B-hPD-1/hPD-L1/hGITR mice but not in wild-type mice.

Strain specific GITR expression analysis in homozygous B-hPD-1/hPD-L1/hGITR mice by flow cytometry. Splenocytes were collected from wild-type mice (+/+) and homozygous B-hPD-1/hPD-L1/hGITR mice (H/H) stimulated with or without anti-CD3ε in vivo, and analyzed by flow cytometry with species-specific anti-GITR antibody. Mouse GITR was detectable in wild-type mice but not in homozygous B-hPD-1/hPD-L1/hGITR mice. Human GITR was exclusively detectable in homozygous B-hPD-1/hPD-L1/hGITR mice but not in wild-type mice.

 

Combination therapy of anti-human PD-1 antibody and anti-human GITR antibody

Antitumor activity of anti-human PD-1 antibody combined with anti-human GITR antibody in B-hPD-1/hPD-L1/hGITR mice. (A) Anti-human PD-1 antibody combined with anti-human GITR antibody inhibited MC38 tumor growth in B-hPD-1/hPD-L1/hGITR mice. All antibodies used in the experiment were prepared in-house. Murine colon cancer MC38 cells were subcutaneously implanted into homozygous B-hPD-1/hPD-L1/hGITR mice (female, 6-7 weeks old, n=5). Mice were grouped when tumor volume reached approximately 100 mm3, at which time they were treated with human PD-1 and human GITR antibodies (in house) indicated in the panel. (B) Body weight changes during treatment. As shown in panel A, the antibodies were efficacious in controlling tumor growth in B-hPD-1/hPD-L1/hGITR mice, demonstrating that the B-hPD-1/hPD-L1/hGITR mice provide a powerful preclinical model for in vivo evaluation of PD-1 and GITR antibodies. Values are expressed as mean ± SEM.