Published online by Cambridge University Press: 05 June 2009
100 male T.O. strain laboratory mice were divided into 4 equal groups: (I) 25 were injected intramuscularly with an antigen prepared together with Freund's adjuvant; (II) 25 injected with antigen alone; (III) 25 infected subcutaneously with 8 live plerocercoids of the same species; (IV) 25 served as controls. 4 weeks later all mice were given 6 live plerocercoids orally. The presence of acquired immunity in group III was shown by a significant reduction in the numbers, size and motility of challenge worms. The host response was greater in all the immunized groups than in the controls.