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.

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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.