Cancer Immunotherapy: Generate your PD-L1 target cell line

T cell - Cancer cell CAR-T Cells, Cancer Immuno-therapy, Immune-checkpoints
T cell - APC effects

Fig 1: Immuno checkpoint proteins on T cell interact with ligands on APCs or cancer cells

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.

Assay principle

Fig 2: Assay run with the PD-1 / NFAT Reporter – Jurkat Cell Line

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 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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Written by Ali El Baya, PhD
Ali el Bayâ is the Sales Manager at tebu-bio for the North of Europe.