Membrane proteins were extracted from eggs, schistosomulum, adult male and female worms of Schistosoma japonicum in order to analyze the differently expressed profile by two dimensional electrophoresis. Schistosomulum and adult worms were obtained from rabbits infected with 1 500 cercariaes on 14 and 42 days after challenge, respectively. Adult male and female worms on 42 days were manually detached and stored into liquid nitrogen until use. Eggs were collected by Percoll TM from the liver of rabbits. ProteoPrep Membrane Extraction Kit TM was employed to extracted membrane proteins by reducing and alkylating with TBP and iodoacetamide from 200 mg of eggs, schistosomulums, adult male worm and female worms, respectively. Immobilized pH gradient strips with a linear pH range of 3-10 (130 mm) were rehydrated together with membrane proteins (30 μg) in 250 μl solution containing 7 mol urea, 2 mol thiourea, 2% SB3-10, 4% CHAPS, 40 mmol Tris, 30 mmol DTT, then separated on 12.5% SDS polyacrylamide gel for the second dimensional electrophoresis. Gels were stained with silver, scanned by Labscan, and analyzed using ImageMaster TM Analysis software. The 2D maps of egg, schistosomulum, adult female worm and male worm were showed 78±3、67±3、108±4 and 122±4 spots respectively. There were 35±1 spots which showed specific expression in female worm as compared with male worm, but 45±2 spots were in male worms. Most differently expressed spots between male and female worms were located in the area of 40-70 kD and pI 4-7. The large number of unique spots from schistosomulum was located in the area of alkalescence. The 2D map of for adult male worms uniquely showed 5 spots as compared with that of schistosomulum and female worm. The female worm showed 4 unique spots as compared with that of schistosomulum, egg and male worm. The unique spots between male and female worms were identified by the database of SWISS 2D-PAGE according to the molecular weight and isoelectronic point. Calreticulin 1, methyltransferase, outer memb
