E-cadherin binding to KLRG1 inhibits T-cell activation. (A) In vitro or (B) ex vivo approach using E-cadherin-expressing cells pulsed with or without ovalbumin and washed before incubation with parental cells or KLRG1 transfectants. Levels of mIL-2 were measured by ELISA. For the in vitro approach, results are representative of at least 5 independent experiments (*P < .001). For the ex vivo approach, results are representative of 4 independent experiments (*P < .005).