1Department of Pathobiology, School of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
2Department of Parasitology, School of Veterinary Medicine Specialized Sciences, Islamic Azad University of Tehran, Tehran, Iran
Exsheathing fluid (EF) and excretory-secretory products (ES) of infective third-stage cultured larvae of Ostertagia circumcincta were analysed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDSPAGE). Five and seven predominant proteins were found in the EF and ES products, respectively. Immunoblotting by sheep pre-infection serum did not react with any of the EF and ES proteins, but the postinfection serum recognized four proteins of 44.5, 41.5, 38 and 24 kDa of the ES products. None of the EF products was recognized by the post-infection serum. Protectivity of the four proteins remains to be determined.