CTL activity of splenocytes from vaccinated mice 8 weeks after the first immunization. These splenocytes were tested for ROP18-specific CTL activity of ROP18 target cells loaded with CAV-2-ROP18 (triangle), CAV-2 (circle), PBS (crossing) or nothing (diamond). Data shown represent one experiment of three performed with similar results. E/T ratios are indicated on the horizontal axis. The vertical axis shows T.gondii-specific lysis as a percentage of the total possible lysis (% specific lysis).