Humoral immune responses during experimental infection with Fascioloides magna and Fasciola hepatica in goats and comparison of their excretory/secretory products

This study investigated the humoral immune responses of goats experimentally infected with Fascioloides magna and Fasciola hepatica to F. magna excretory/secretory products (FmESP) or F. hepatica excretory/secretory products (FhESP), respectively. An enzyme-linked immunosorbent assay (ELISA) was used to determine serum antibody responses and for possible discrimination of F. magna and F. hepatica infections in goats. Comparison of ESPs of both flukes and evaluation of ESP antigenicity was also studied applying immunoblotting techniques. In all infected goats, antibody level was significantly increased (against negative control) since 2 weeks post infection (WPI). However, the dynamics of antibodies varied between F. magna and F. hepatica groups during the course of the infection. The cross-reaction of antibodies developed against F. magna and F. hepatica with ESP proteins was recorded by ELISA. The species-specific proteins 40, 120 kDa from FmESP and 80, 160 kDa from FhESP (with no antibody cross-reaction) were detected by two dimensional electrophoresis and immunoblot as the potential immunodiagnostic markers. Our results suggest that F. magna and F. hepatica infection could be distinguished by common immunological techniques based on species-specific antigen–antibodies interaction.