Immunisation of calves against Taenia saginata infection using antigens collected by in vitro incubation of T saginata oncospheres or ultrasonic disintegration of T saginata and T hydatigena oncospheres

Abstract

The intramuscular injection of calves with antigens (in oil adjuvant) collected during 14 day in vitro cultivation of Taenia saginata oncospheres and centrifuged at 500 g, stimulated a high level of resistance against challenge infection with eggs. When calves were immunised with antigens which had been collected during short-term (24 hour and 72 hour) in vitro incubation in culture medium and centrifuged at 3000 g, a significant but much less striking degree of immunity was produced. Calves immunised with a single injection (in oil adjuvant) of 30,000 T saginata oncospheres, disrupted by ultrasonic disintegration, also developed a high level of immunity to a subsequent challenge infection. A supernatant of the sonicated T saginata oncospheres centrifuged at 100,000 g stimulated a lesser degree of immunity. Sonicated T hydatigena oncospheres were less effective than T saginata oncospheres although they did stimulate a significant level of protection. The results suggest that prolonged periods of in vitro incubation of hatched and activated taeniid oncospheres are not necessary to collect antigens which will stimulate immunity to infection and that the antigens which stimulate protective immunity may initially be membrane associated or particulate in nature. Sonication produces only partial solubilisation of these antigens.