In a recent post, I invited you to discover a cell line provided by BPS Bioscience over-expressing the checkpoint receptor PD-1. They have now just released a new kit which allows to generate a PD-L1 and TCR activator over-expressing target cell line.
PD-1 is a receptor present on the surface of activated T-cells and other immune cells. PD-1 has two ligands, PD-L1 and PD-L2, which are over-expressed in most human cancers. Binding of PD-L1 to PD-1 negatively regulates T cell signaling and inhibits cytotoxic T-cell activity (induced by the binding of the T-cell receptor to the Major Histocompatibility Complex [MHC] antigen). The same effect can be seen with other checkpoint pairs, such as CTLA-4 and its ligands B7.1 and B7.2, while for instance the interaction of checkpoint protein CD28 with the same ligands (B7.1 and B7.2) has a stimulatory effect on T cells (see Fig 1). In fact the first therapeutic antibodies which have been approved for the treatment of diverse cancer types over the past years are directed against the PD-1.
The Jurkat T cell described in the previous post expresses firefly luciferase gene under the control of NFAT (Nuclear Factor of Activated T-cells) response elements, furthermore it shows constitutive expression of human PD-1. The principle of the assay which can be done with this cell line is shown in Figure 2. The PD-1 over-expressing effector cells are co-cultured with target cells expressing PD-L1 (or PD-L2) and T cell receptor (TCR) activator.
How to construct the PD-L1 carrying target cells?
Of course, some labs might already have cells available which meet the requirements of a target cell in the above mentioned co-culture system. For those who intend to screen for inhibitory effects on PD-1 : PD-L1 binding or study PD-1 signalling without having these cells available, BPS Bioscience has just released a new kit which allows to generate a PD-L1 and TCR activator over-expressing target cell line: the TCR Activator / PD-L1 Mammalian Expression Kit. The kit comes with an expression vector constitutively expressing TCR activator and human PD-L1, and a control vector expressing TCR activator alone.
In combination with…
- the PD-1/NFAT Reporter – Jurkat Recombinant Cell Line
- the anti-PD-1 neutralizing antibody as a control antibody which inhibits PD-1 : PD-L1 binding
- and the ONE-StepTM Luciferase reagent which allows for highly sensitive detection of firefly luciferase activity
…the TCR Activator / PD-L1 Mammalian Expression Kit represents a complete co-culture model to…
- Screen for activators or inhibitors of PD-1 signaling in a cellular context
- Characterize the biological activity of PD-1 and its interactions with ligands
Interested in this kit or the complete co-culture system? Leave your questions or comments below, I’ll be pleased to answer you!
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