The T cell-mediated immune response is a powerful machinery that leads to a rapid expansion, differentiation, and effector functions by T lymphocytes. T cell receptors like cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death protein-1 (PD-1) serve as negative regulators, that, in concert with positive regulators, help ensure a controlled T cell-mediated immune response. However, tumor cells can also express high levels of immune checkpoint proteins, essentially exploiting T cell suppressive effects and evading the immune response for tumor survival. Research looks to unblock this suppression or activate a productive immune response.


We offer an expanding selection of bioactive recombinant immune checkpoint proteins, from leading targets like PD-1, PD-L1 and CTLA-4 to emerging ones such as TIGIT and LAG-3. BSA or other equivalent carrier proteins are typically added to improve protein stability and shelf life. However, addition of carrier proteins may produce nonrelated or undesired effects on experiments. Our recombinant immune checkpoint proteins are formulated carrier-free for use in applications where carriers would interfere with the experiment.


Find your immune checkpoint proteins.


We also offer biotinylated recombinant immune checkpoint proteins, which are ideal tools for studying cancer biology. Our Avi-tag biotinylated proteins offer consistent labeling, uniform orientation of the protein, equivalent bioactivity to that of non-biotinylated proteins, and lot-to-lot consistency.


Human CTLA4 inhibition of IL-2 induced by B7.1 (500 ng/ml) in Jurkat acute T cell leukemia cells. BioLegend’s protein was compared side-by-side and it outperformed the competitor’s equivalent product.

When human PD-1-Fc Chimera is coated at 1 µg/mL (100 µL/well), biotinylated human B7-H1/PD-L1 binds with an EC50 of 40 – 160 ng/mL.

You can learn more about this field from our blog ‘Targeting Immune Checkpoints as Cancer Therapy‘ that covers immune checkpoints and inhibitors as immunotherapy. There, you will also learn about other resources such as biotinylated proteins, functional antibodies, and assays that precisely measure proteins involved.


Explore our helpful cancer website that provides you the right tools and applications to help you solve the complexity of cancer. You’ll find links to on-demand webinars and other informative and educational content covering the basic tenets of cancer biology.


Learn more about the growing field of immunotherapy and how it is revolutionizing cancer treatment. Along with immune checkpoint inhibitors, bispecific antibodies and CAR-T cells are considered the most promising immunotherapies.



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