BALB/c Mice Immunity to Hydatidosis Induced by In-vitro Reared Echinococcus granulosus Adult Worm Antigens.

BACKGROUND Echinococcosis is a zoonotic parasitic disease caused by the larval stage of Echinococcus granulosus. Several native and recombinant antigens, derived from different stages of E. granulosus life cycle, have been used for vaccine trials. In vitro reared adult worms are good candidates for vaccination as they do not produce fertile egg/s and do not have any risk of contamination for researchers. OBJECTIVE To evaluate different antigens derived from in vitro reared E. granulosus adult worms for the immunization of BALB/c mice against secondary hydatidosis. METHODS Viable protoscoleces (PCSs) of sheep hydatid cyst were cultivated in S.10E.H media. Excretory secretory (E/S) and crude antigens were prepared from reared adult worms. A total of fifty BALB/c mice, each 8-weeks-old, were divided into 5 groups of 10 mice. Three groups were subcutaneously immunized with crude, E/S and immunodominant antigens on days 1 and 28. The fourth group received only PBS and the fifth group had no injection. Three weeks following the second immunization, all groups were challenged, intraperitoneal, with viable PSCs. After the autopsy of the mice and opening their abdominal wall, cysts were counted and measured followed by histopathological observations. RESULTS The highest protective immunity (98.7%) against hydatidosis was induced by crude antigen, followed by E/S and immunodominant antigens. CONCLUSION Antigens (crude antigens in particular) derived from in vitro reared E. granulosus adult worms, and their different protein components are suitable candidates for the vaccination of intermediate hosts against hydatidosis.