Creative Biolabs has successfully established a novel technology platform offering comprehensive characterization of antibody-immune checkpoint interactions. Our world-class service aims at benefiting various projects in developing revolutionary immunotherapy drugs.
The immune checkpoint represents a group of membrane proteins expressing on effector cells (e.g. T/B cells, NK cells), composed of multiple co-inhibitory and co-stimulatory pathways. They are involved in eliminating unwanted substances while maintaining self-tolerance, which play a crucial role in immunomodulation. Tumor cells, on the other hand, often tend to take advantage of immune checkpoints, for instance, by activating inhibitory checkpoint pathways in situ, to evade immune responses. Typical representatives include programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), two inhibitory checkpoint proteins. Through expressing their corresponding ligands (PD-L1/PD-L2, CD80/CD86) on the cell surface, tumors cells can engage and activate inhibitory receptors, thus suppressing anti-tumor immunity (i.e. release of inhibitory cytokines and metabolites). Therefore, cancer immunotherapies, which target key immune checkpoints to restore effective anti-tumor immune function, emerge as a revolutionary strategy during recent years. In contrast to traditional antigen-specific therapies, this approach reveals more durable responses across a broad spectrum of cancer types. It also demonstrates strikingly encouraging clinical efficacy in combination with chemotherapies, radiotherapies, or targeted therapies.
Fig. 1 The expression and interactions of immune checkpoints on cells.1
To evaluate the binding affinity and specificity of antibodies to immune checkpoints, Creative Biolabs offers ligand binding assay using different techniques, such as surface plasmon resonance (SPR) assay (Biacore system) and bio-layer interferometry (BLI) assay (Octet system).
To exhaustively validate the mechanism of action for such antibodies, Creative Biolabs has integrated a series of cell-based assays with our state-of-the-art technologies and profound knowledge in this area. In general, there are two types of immune checkpoints: activating receptors and inhibitory receptors. Hence, two major mechanisms of immunotherapy antibodies can be defined as blockade of inhibitory pathways (antagonist) and enhancing activating pathways (agonist).
Creative Biolabs can utilize primary lymphocytes as effector cells. Custom cell lines or well-qualified tumor cell lines from our abundant collections (over 100) can be employed as the target. Assay readout will be physiological-relevant biomarkers (e.g. IL-2 release for PD-1/PD-L1 and CTLA-4; IL-8 release for OX-40), or cell-binding properties using ELISA or flow cytometry.
Creative Biolabs also introduces several engineered cell lines stably expressing indicated receptors, in place of primary cells. In this way, effector cell motivation will be monitored via luciferase activity. By measuring effector activation in the presence or absence of test antibody candidates, we can deduct its potential to interact with checkpoint pathways and restore immune functions. We focus on a full range of checkpoint receptors, including but not limited to:
| Activating Receptors | Inhibitory Receptors |
| GITR | PD-1 Receptor |
| 4-1BB Receptor | TIGIT Receptor |
| CD40 Receptor | CTLA-4 Receptor |
| OX40 | LAG3 |
| CD27 | TIM-3 Receptor |
| VEGF | BTLA |
| HVEM | TNFα |
We can employ clinical-grade reference antibody as positive controls, i.e. Keytruda® for PD-1, Yervoy® for CTLA-4, to ensure assay validity. Besides, we can also offer immune checkpoint functional assays to ascertain antibody-checkpoint interactions can indeed translate into desirable therapeutic outcomes. For more detailed information, please feel free to contact us or directly sent us an inquiry.
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Related Products:
Immune Checkpoint Functional Assays kit
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