Pepsin

The T. papuae used in this study were laboratory strains maintained in the Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Thailand. Six-week-old female ICR mice were orally infected with 100 larvae. After 2 months of infection, muscle stage larvae (L1) were obtained from the muscle tissue by pepsin digestion (0.7% pepsin [BDH, UK], 0.7% HCl). All procedures performed on animals in this study were approved by the Faculty of Tropical Medicine Animal Care and Use Committee (FTM-ACUC), Mahidol University. The approval number was FTM-ACUC No. 009/2555. All experiments were performed in accordance with relevant guidelines and regulations

Sodium hydroxide (NaOH), sulfuric acid (H₂SO₄), copper sulfate (CuSO_4.5H₂O), potassium sulfate (K₂SO₄), hydrochloric acid (HCl), pepsin, petroleum ether, and ethanol were from BDH and used without further purification. Phosphate buffers (pH 8, 9, 10, 11, 12, 13 and 14) were prepared by mixing proper amount of 0.1 M disodium hydrogen phosphate and 0.1 M Sodium hydroxide.