Immune stimulation and Hymenolepis nana cysticercoid expulsion in C3H/He and BALB/c mice.

Adoptive transfer of immunity with heterologous and homologous immune serum, and drug-abbreviated immunizations were used in C3H and BALB/c mice to determine the strain-characteristic time of expulsion of H. nana cysts. Transfer of immune serum did not accelerate worm expulsion in C3H, while elimination of worms was virtually complete by day 8 in BALB/c mice. Loss of worms was also obtained when BALB/c mice were stimulated with abbreviated infections using 20 or 1000 H. nana eggs. The immunizing infection terminated immediately after the tissue phase. After similar immunizations C3H mice again appeared slow responders but were able to affect the intestinal worms population after the higher immunizing infection. The data obtained suggest that the time of worm expulsion was related to the genetically-determined ability of the mice to respond and was independent of the stimulations used for immunization. A quantitative difference in response is proposed to explain the slow responder status of C3H.