Pungtungia herzi (Jinju, Korea), the second intermediate host of C. sinensis, was ground and digested as described by Dai et al. . Metacercariae were then collected from the saline-rinsed digestive leavings under a dissecting microscope. Next, New Zealand white rabbits (2.3 kg; Koatech, Seoul, Korea) were infected with 200 metacercariae per rabbit twice in 1 week. Adult C. sinensis were then recovered from the rabbit livers after 2 months and stored in a -80 °C freezer until use. Female 7 week-old BALB/c mice (Orient Bio Inc., Gyeonggi-do, Korea) were immunized with a bacterially-produced recombinant protein.