|Detection of TIGIT in Mouse Splenocytes by Flow Cytometry. Mouse splenocytes treated with 50 ng/mL PMA and 500 ng/mL Calcium ionomycin for 24 hours were stained with Sheep Anti-Mouse TIGIT Antigen Affinity-purified Polyclonal Antibody (Catalog # AF7267) followed by Allophycocyanin-conjugated Anti-Sheep IgG Secondary Antibody (Catalog # F0127) and Rat Anti‑Mouse CD4 PE‑conjugated Monoclonal Antibody (Catalog # FAB554P). Quadrant markers were set based on control antibody staining (Catalog # 5-001-A).|
TIGIT (T cell Immunoreceptor with Ig and ITIM domains; also Vstm3 and Vsig9) is a 30-34 kDa (in human) member of the CD28 family, Ig superfamily of molecules. It is expressed by NK cells and multiple subsets of mature T cells, and binds to PVR/CD155 and PVR2/CD112 that appear on dendritic cells (DC) and endothelium. Along with CD226, the TIGIT:CD226/DNAM1 and PVR:PVR2 pairings appear to form a network that parallels the well-characterized B7-1:B7-2 and CD28:CTLA4 system. Binding of TIGIT by DC induces DC IL-10 release and inhibits IL-12 production. Ligation of TIGIT on T cells dampens TCR-mediated activation, while NK cell TIGIT ligation blocks NK cell cytotoxicity. Mature mouse TIGIT is a type I transmembrane protein 215 amino acids (aa) in length. It contains a 116 aa extracellular region (aa 26-141) with a V-type Ig-like domain (aa 27-125), and a 79 aa cytoplasmic domain with one ITIM motif. There is one isoform variant that is quite unusual and shows an addition of nine amino acids spread over three insertion sites (SwissProt #:P86176). Mouse and human TIGIT are highly divergent, and over aa 26-143, mouse TIGIT shares only 68% aa sequence identity with human TIGIT.