The assay consists of two genetically engineered cell lines:
PD-1+TIGIT Effector Cells: Jurkat T cells engineered to express human PD-1 and human TIGIT with a luciferase reporter driven by a native promoter that can respond to both TCR activation and CD226 co-stimulation
PD-L1+CD155 aAPC/CHO-K1 Cells: CHO-K1 cells engineered to express human PD-L1 and human CD155 with an engineered cell-surface protein designed to activate the TCR complex in an antigen-independent manner
When the two cell types are co-cultured, PD-1 binds to PD-L1 and inhibits TCR-induced activation and promoter-mediated luminescence. In addition, TIGIT inhibits CD226 activation and promoter-mediated luminescence. Addition of an anti-PD-1 Ab or an anti-TIGIT Ab blocks the interaction of PD-1 with PD-L1 or TIGIT with CD155, respectively, and results in a modest enhancement in promoter-mediated luminescence. Addition of antibodies that block both PD-1/PD-L1 and TIGIT/CD155 will result in much higher promoter-mediated luminescence due to synergy between these pathways.
The PD-1+TIGIT Combination Bioassay, Propagation Model, allows propagation and banking of the PD-1+TIGIT Effector Cells. Bio-Glo™ Luciferase Assay System (Cat.# G7940, G7941) is the required reagent for use with the PD-1+TIGIT Combination Bioassay, Propagation Model.