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KACTUS: Immune Checkpoint Proteins

KACTUS: Immune Checkpoint Proteins

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. Tumour 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.

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

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 KACTUS’ SAMS™ protein engineering and production platform, they have 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

Product Applications

  • HEK293 Expression
  • His, His-Avi, hFc Tags
  • Bioactivity verified (ELISA & SPR)
  • High Purity
  • Human, Mouse, Cynomolgus, Rhesus Macaque, Rat, Canine
  • Biotinylated Proteins
  • Antibody Discovery
  • Antibody Affinity Assays
  • Cell-Based Assays
  • Drug Discovery
  • Pharmacokinetics Analysis

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 tumour cells from NK cell destruction makes it a target for enhancing anti-tumour immune responses.

Human TIGIT, His tag was immobilised 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).
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 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).

Caltag Medsystems is the distributor of KACTUS products in the UK and Ireland. If you have any questions about these products, please contact us.

KACTUS: Immune Checkpoint Proteins
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