A simple and efficient purification method of native immunoreactive antigen for diagnosis of camel hydatidosis

Background: Cystic echinococcosis (CE), a zoonotic disease that affects animal and human health, is of increasing economic importance due to high morbidity rates and high economic losses in the livestock industry. Aim: The present study was conducted to purify the antigen from hydatid cyst fluid (HCF) with high diagnostic efficacy of camel hydatidosis using indirect enzyme-linked immunosorbent assay (ELISA). Materials and Methods: The HCF antigen was purified using Sephacryl S-300 column chromatography. Characterization of fractions was performed using reducing and non-reducing sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis. Further, antibodies against Echinococcus granulosus cysts in camel serum were detected using indirect ELISA. Results: The purification process resulted in three fractions of antigens: FI, FII, and FIII. Indirect ELISA showed that higher diagnostic efficacy was observed in FI than in FII and FIII. Indirect ELISA, in which FI was utilized, showed 88% sensitivity and 91.7% specificity. Non-reducing SDS-PAGE showed that FI had two bands of molecular weights 120 and 60 kDa. Western blot analysis of FI demonstrated that 60, 38, and 22 kDa were antigenic bands when reacted with naturally infected camel sera with E. granulosus cysts. Using indirect ELISA, F1 recorded an infection percentage of 81.7% in randomly collected camel serum samples. Conclusion: FI is a promising antigen for accurate diagnosis of camel CE using indirect ELISA.