T-cell immunoreceptor with Ig and ITIM domains protein (TIGIT)

T-cell immunoreceptor with Ig and ITIM domains (TIGIT) is an immune checkpoint receptor expressed on subsets of T cells and natural killer (NK) cells, where it functions as an inhibitory regulator of cellular immune responses. It contains immunoglobulin (Ig) and immunoreceptor tyrosine-based inhibitory motif (ITIM) domains, binding with high affinity to CD155 (poliovirus receptor, PVR) and with lower affinity to CD112 (PVRL2) on antigen-presenting cells. Through these interactions, TIGIT dampens immune activation and cytotoxic activity by mediating inhibitory signals. TIGIT is considered a validated therapeutic target in oncology and infectious diseases, and is currently being tested in clinical trials as a target for monoclonal antibody therapy, both alone and in combination with other immune checkpoint inhibitors such as anti-PD-1/PD-L1 antibodies. Elevated TIGIT on immune cells is a hallmark of T cell exhaustion in cancer and chronic viral infections, and therapeutic blockade reverses immune dysfunction and enhances anti-tumor/anti-viral activity

Other names

TIGITT cell immunoreceptor with Ig and ITIM domainsVSIG9VSTM3V-set and immunoglobulin domain-containing protein 9V-set and transmembrane domain-containing protein 3Washington University cell adhesion molecule (WUCAM)

Blockade of TIGIT: enhances T-cell and NK-cell activation, increases anti-tumor and anti-viral immunity by blocking inhibitory signaling Combination with PD-1/PD-L1 blockade: synergistic immune activation