Experimental immunisation of six-month old calves against infection with the cysticercus stage of Taenia saginata.

Three groups of calves aged 6 months were completely protected against oral challenge with Taenia saginata eggs following immunisation by three different methods. These were hyperimmunisation with six serial inoculations of a homogenate of T. saginata strobila in Freund's complete adjuvant, a single intramuscular inoculation with hatched T. saginata eggs or a single oral dose of unhatched T. saginata eggs. The calves immunised with tapeworm homogenate developed the strongest haemagglutinating and precipitating antibody response to the complex of antigens in an extract of tapeworm strobila, cysticercus tissue or cysticercus fluid. The orally infected calves developed a moderate antibody response to these antigens but the calves inoculated with hatched eggs showed only a very weak antibody response. The calves infected orally with eggs developed a peripheral eosinophilia but the other two methods of immunisation did not evoke this response. After challenge infection all groups showed an increase in peripheral eosinophil counts except the group immunised with tapeworm homogenate.