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Programmed Cell Death Protein 1 (PD-1), a receptor expressed on activated T cells, binds to its ligands PD-L1 and PD-L2 to negatively regulate immune responses. PD-1 ligands are present in most cancers, and the PD-1-PD-L1/2 interaction inhibits T cell activity, allowing cancer cells to evade immune surveillance. Binding of PD-1 to PDL1 can weaken T cell-mediated immune surveillance, leading to impaired immune responses and even T cell apoptosis. PD-1-PD-L1 inhibitors can relieve immune suppression of anti-tumor T cells, resulting in T cell proliferation, infiltration into the tumor microenvironment, and induction of anti-tumor responses. The PD-1-PD-L1 signaling pathway is an important component of tumor immune suppression, which can inhibit T lymphocyte activation, enhance tumor cell immune tolerance, and thus achieve tumor immune escape.

  
TIGIT, also known as WUCAM, Vstm3, or VSIG9, is a co-inhibitory receptor belonging to the immunoglobulin superfamily. TIGIT is highly expressed on effector CD4+ and CD8+ T cells, regulatory T cells, and NK cells. TIGIT ligands include CD112 and the poliovirus receptor (PVR, also known as CD155, Necl-5, and Tage4), with PVR being a high-affinity homologous receptor for TIGIT. Additionally, TIGIT competes with CD226 (DNAM-1) and CD96 (TACTILE) for ligands. TIGIT can effectively block the binding of CD155 to CD96 or CD226, further demonstrating TIGIT's highest affinity for CD155. TIGIT not only competes with CD226 for ligands but also directly cis-binds to CD226 to prevent its homodimerization, thereby preventing CD226 from binding to CD155 and exerting co-stimulatory effects.

  
Studies have shown that in mice treated with anti-PD1 therapy, blocking TIGIT (T cell immunoglobulin and ITIM domain) can enhance the effector activity of CD8+ T cells by secreting IFNγ and TNF-α, leading to significant tumor and viral clearance. TIGIT is highly upregulated on tumor-infiltrating T cells, and functional blockade of CD226 can counteract tumor regression induced by combination therapy in mice. This research reveals the potential of combined PD-1 and TIGIT therapy in improving immune responses in patients with cancer or chronic viral infections.

The Jurkat E6.1 Human PD1&TIGIT Dual Effector Reporter Cell model effectively mimics the in vivo PD1&TIGIT signaling transduction process. The principle is illustrated in the figure below.

Figure 1. Schematic diagram of the Jurkat E6.1 Human PD1&TIGIT Dual Effector Reporter Cell model.

Figure 2. Recombinant PD1/TIGIT Dual Effector Reporter Cell constitutively expressing PD1/TIGIT.

Figure 3. Dose Response of Blocking Antibodies in PD1&TIGIT Dual Effector Reporter Cell (C7) with PDL1&CD155 TCR Activator CHO.

Cell Passage Procedures

1.This cell line grows in suspension.
2.Upon receipt, cells should be thawed immediately or stored in liquid nitrogen until use.
3.Before thawing, pre-warm the water bath and culture medium to 37 °C, and prepare a small amount of dry ice.
4.Remove the cryovial from storage and transport it to the cell culture laboratory on dry ice.
5.Rapidly thaw the cells in a 37 °C water bath. Once the cells are completely thawed, spray the cryovial with 70% ethanol for disinfection and transfer it to a biosafety cabinet.
6.Add 10 mL of pre-warmed culture medium into a 15 mL centrifuge tube. Transfer the contents of the cryovial into the tube and centrifuge at 1000 rpm for 5 minutes.
7.Carefully discard the supernatant. Resuspend the cell pellet in 5 mL of pre-warmed culture medium by gentle pipetting. Immediately perform cell counting and adjust the cell density to 3–6 × 10⁵ cells/mL based on the counting results, then transfer the cells into a culture flask.
8.Count the cells every 1–2 days. When the cell density exceeds 1 × 10⁶ cells/mL, passage the cells promptly or add fresh culture medium. Maintain the cell density between 2 × 10⁵ and 1 × 10⁶ cells/mL.

Suspension Cell Cryopreservation Procedure:

1.Collect 8 × 10⁶ cells, centrifuge, and discard the supernatant.
2.Add 1 mL of cell freezing medium (90% FBS + 10% DMSO) and gently pipette to mix thoroughly. Transfer the suspension into a cryovial.
3.Immediately place the cryovial into a controlled-rate freezing container (Nalgene 5100-0001), fill with isopropanol up to the indicated level, and store at −80 °C.
4.After 24 hours, transfer the cryovial to liquid nitrogen for long-term storage.