TIGIT, also known as WUCAM and Vstm3, is an immune checkpoint protein expressed on lymphocytes. Highest expression levels are observed on effector CD4+ and CD8+ T cells, regulatory T cells and NK cells. TIGIT has several distinct mechanisms of action that inhibit lymphocyte activation. First, TIGIT is an inhibitory counterpart of the co-stimulatory receptor CD226. When TIGIT is present on the surface of lymphocytes, it outcompetes CD226 for CD155 binding and thus negates CD226 signaling. Second, TIGIT inhibits CD226 homodimerization in cis, preventing CD226 signaling. Third, the cytoplasmic tail of TIGIT contains an immunoreceptor tyrosine-based inhibitory motif (ITIM), which could potentially lead to inhibitory signaling.
The TIGIT/CD155 Blockade Bioassay reflects the mechanism of action (MOA) of biologics designed to block the TIGIT/CD155 interaction.
Control Ab, Anti-TIGIT, is a mouse monoclonal antibody that shows blocking activity of TIGIT with its ligand, CD155. It is intended for use as a control with the PD-1+TIGIT Combination Bioassay and the TIGIT/CD155 Blockade Bioassay. These assays can be used to measure the potency and stability of antibodies and other biologics designed to block the TIGIT/CD155 interaction.
TIGIT Negative Cells are for use as a negative control in the TIGIT/CD155 Blockade Bioassay. TIGIT Negative Cells are activated by engagement of the TCR/CD3 complex and costimulatory receptor CD28 co-engagement.