Immune response and immunodepression inHymenolepis diminuta infection in rats

Maximum size range ofHymenolepis diminuta was found in rats 22 days postinfection (p.i.) with single or several (3–6) tapeworms. Immunologic reactions of the host were connected with the growth and development of parasites. Positive results of macrophage migration inhibition test (MMI) were recorded from 7 until 22 days p.i. in infection with a single and to 16 days p.i. in those with 3–6H. diminuta. The negative results of the MMI test observed at later postinfection times are considered as a manifestation of immunosuppression caused by the presence ofH. diminuta. The expulsion of tapeworm by anthelmintic treatment with Yomesan ® restored for a short time cell-mediated immunity, as demonstrated by MMI test. The level of antibodies, as determined by passive hemagglutination test (HA), varied during the infection; it was highest at 22 days p.i. The removal of tapeworms as a results of drug treatment caused a rise in titers.