Basic Information
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. T-cell immunoglobulin domain and mucin domain-3 (TIM3) is an activation-induced inhibitory molecule involved in immune tolerance and T-cell exhaustion in chronic viral infection and cancers. TIM3 maturation and cell surface expression is facilitated by forming a heterodimeric interaction with CD66a. Co-blockade of CD66a and TIM3 enhanced anti-tumor immune responses, and eliminated tumors in mouse colorectal cancer models.
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Targeting Strategy
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Gene targeting strategy of B-hPD-1/hPD-L1/hTIM3 mice.The targeting strategy of B-hPD-1 mice is to the exon 2 of mouse PD-1 gene that encode the extracellular domain were replaced by human PD-1 exon 2. The targeting strategy of B-hPD-L1 mice is to the exon 3 of mouse PD-L1 gene that encode the extracellular domain were replaced by human PD-L1 exon 3. The targeting strategy of B-hTIM3 mice is to the exon 2 of mouse Tim3 gene that encode the extracellular domain were replaced by human TIM3 exon 2 . The B-hPD-1/hPD-L1/hTIM3 three knock-in model, was developed by breeding the B-hPD-1 mice, the B-hPD-L1 mice and the B-hTIM3 mice, has a functional mouse immune system.
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Details
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Protein expression analysis
Strain specific PD-1 expression analysis in homozygous B-hPD-1/hPD-L1/hTIM3 mice by flow cytometry. Splenocytes were collected from WT and homozygous B-hPD-1/hPD-L1/hTIM3 (H/H) mice after stimulation with anti-CD3ε in vivo and without stimulation, and analyzed by flow cytometry with species-specific anti-PD-1 antibody. Mouse PD-1 was detectable in WT mice. Human PD-1 was exclusively detectable in homozygous B-hPD-1/hPD-L1/hTIM3 but not WT mice. After anti-CD3ε stimulation, hPD-1 protein expression was significantly increased.
Strain specific PD-L1 expression analysis in homozygous B-hPD-1/hPD-L1/hTIM3 mice by flow cytometry. Splenocytes were collected from WT and homozygous B-hPD-1/hPD-L1/hTIM3 (H/H) mice after stimulation with anti-CD3ε in vivo and without stimulation, and analyzed by flow cytometry with species-specific anti-PD-L1 antibody. Mouse PD-L1 was detectable in WT mice. Human PD-L1 was exclusively detectable in homozygous B-hPD-1/hPD-L1/hTIM3 but not WT mice. After anti-CD3ε stimulation, hPD-L1 protein expression was significantly increased.
Strain specific TIM3 expression analysis in homozygous B-hPD-1/hPD-L1/hTIM3 mice by flow cytometry. Splenocytes were collected from WT and homozygous B-hPD-1/hPD-L1/hTIM3 (H/H) mice after stimulation with anti-CD3ε in vivo and without stimulation, and analyzed by flow cytometry with species-specific anti-TIM3 antibody. Mouse TIM3 was detectable in WT mice. Human TIM3 was exclusively detectable in homozygous B-hPD-1/hPD-L1/hTIM3 but not WT mice. After anti-CD3ε stimulation, hTIM3 protein expression was significantly increased.
