Early Hepatic Changes in Goats Immunized with Recombinant Glutathione S Transferase (Sigma Class) and Challenged with Fasciola hepatica

Introduction
Understanding mechanisms of host response against Fasciola hepatica is crucial for improving vaccine efficiency against this parasite. In rats the protective response occurs during the early stages of infection, but in ruminants no studies have investigated early changes in vaccinated animals. The aim of the present work was to study the hepatic changes and host response in goats immunized with recombinant GST-sigma class (sGST).

Materials and Methods
Twenty-five, 4-month-old parasite-free goats were divided into three groups; group 1 (n = 10) was immunized twice with sGST in Quil A, group 2 (n = 10) was immunized with adjuvant Quil A and group 3 (n = 5) was used as uninfected control. Groups 1 and 2 were orally infected with 100 metacercariae of F. hepatica. Three goats from each group were killed at 7–9 days post-infection (dpi) and the remaining animals were killed at 15 weeks post-infection (wpi).

Results
At 7–9 dpi, sGST-vaccinated animals showed lower hepatic necrosis, higher iNOS expression by peritoneal macrophages and higher number of eosinophils surrounding migrating larvae than Quil A immunized animals.

Conclusions
The results of the present work suggest an early host response in vaccinated animals and encourage new studies using higher number of animals