Immune Checkpoint Proteins → Learn more about our Immune Checkpoint Proteins

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Background

Immune checkpoints are a series of molecules expressed on immune cells that regulate the degree of immune activation, preventing excessive activation of the immune system. Dysfunction in the expression or function of immune checkpoints is a significant cause of many diseases. Tumor cells often keep immune checkpoints activated, preventing antigens from being presented to T cells, thereby impairing the normal immune function of T cells and enabling immune evasion. Common immune checkpoints include CTLA-4 (cytotoxic T lymphocyte-associated antigen-4) and PD-1 (programmed death receptor-1), which are receptors on the surface of T lymphocytes.

Illustration of immune checkpoint blockade showing how PD-1/PD-L1 and CTLA-4 pathways inhibit T cells, and how checkpoint inhibitors like nivolumab and ipilimumab restore T cell activation to kill cancer cells.

Mechanism of action of immune checkpoint inhibitors (Giusy Elia, et al, 2020)

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Comprehensive Catalog of Immune Checkpoint Proteins

PD-1, PD-L1, CTLA-4, TIGIT, CD40 & more

Currently, immune checkpoints remain a hot topic in clinical research, with new targets and drugs emerging continuously. Based on our SAMS™ protein engineering and production platform, KACTUS has developed a series of immune checkpoint proteins with various tags, covering targets such as PD-1, PD-L1, CTLA-4, TIM-3, OX40, TIGIT, 4-1BB, and CD40. These proteins have undergone rigorous quality control and are suitable for antibody functional validation, cell function validation, pharmacokinetic analysis, and other disease-related research.

Product Features

→ HEK293 Expression
→ His, His-Avi, hFc Tags
→ Bioactivity verified (ELISA & SPR)
→ High Purity
→ Human, Mouse, Cynomolgus, Rhesus Macaque, Rat, Canine
→ Biotinylated Proteins

Product Applications

→ Antibody Discovery
→ Antibody Affinity Assays
→ Cell-Based Assays
→ Drug Discovery
→ Pharmacokinetics Analysis

Browse Immune Checkpoint Proteins

Product Validation Data

Human TIGIT

TIGIT, a newly discovered immune checkpoint protein found on T cells and Natural Killer (NK) cells, plays a crucial role in modulating the immune response. As an inhibitory receptor, TIGIT acts as an "off switch" by competing with the activating receptor CD226 (DNAM-1) for ligand binding. This mechanism mirrors the relationship between CTLA4 and CD28, making TIGIT a promising target for cancer immunotherapy. TIGIT interacts with several ligands, including CD155 (PVR) and CD112 (PVRL2), with varying affinities. Through its inhibitory motif (ITIM), TIGIT suppresses T cell activation and NK cell cytotoxicity, contributing to immune homeostasis. Its ability to protect tumor cells from NK cell destruction makes it a target for enhancing anti-tumor immune responses.

Human TIGIT, His tag was immobilized at a concentration of 0.5 µg/ml (100 µl/well) on the plate. A dose-response curve for the Anti-TIGIT Antibody with an hFc tag was generated, showing an EC50 of 8.3 ng/ml as determined by ELISA (QC Test).

Dose-response curve showing inhibition of human TIGIT and CD155 binding by anti-TIGIT antibody, indicating effective blocking activity in a competitive ELISA assay

ELISA demonstrates that the binding of Human TIGIT to CD155 can be specifically blocked by the Anti-TIGIT Antibody. Serial dilutions of the Anti-TIGIT Antibody were added to the binding reactions of Human TIGIT with a His tag and Biotinylated CD155 with an hFc tag. The half-maximal inhibitory concentration (IC50) for this inhibition is 0.46 μg/mL.

SPR sensorgram illustrating real-time binding kinetics of TIGIT interaction at multiple analyte concentrations, showing rapid association and dissociation phases.

SPR analysis shows that Human TIGIT, His Tag, can specifically bind to Human CD155, hFc Tag captured on Protein A chip, with an affinity constant of 0.17 μM (Biacore T200).