Fig. 4.

TIGIT inhibits CIK cell cytotoxicity upon interaction with CD155. a Flow cytometric analysis of A375, 786-O, and K562 cell expression of CD155 stained with anti-CD155 antibody. b Blocking of TIGIT activity enhances the killing of CIK cells. Starting on day 10, CIK cells were stimulated with anti-TIGIT or isotype-matched control antibody in the presence of IL-2 for 4 days. The CIK cells were then incubated with A375, 786-O, and K562 cells at an E:T ratio of 10:1, and specific lysis was determined 4 h later. Data are shown as mean ± SD of four replicates. c Blocking of TIGIT–CD155 interactions. A375 cells were pre-incubated with anti-CD155 or isotype-matched control antibody overnight, and then incubated with CIK cells expressing TIGIT at the indicated E:T ratios, and specific lysis was determined 4 h later. Data are shown as mean ± SD of four replicates. *p < 0.05, **p < 0.001 compared to control group