Relationship between the efficacy of mebendazole and immune level of mice infected with secondary cysts of Echinococcus granulosus

The proliferative response of lymphocytes to Con A and enzyme-linked absorbent assay were used to determine the levels of cellular and humoral immunity of mice infected with ip 2000 protoscolices of Echinococcus granulosus for 2, 4 or 8 months and treated twice with ip BCG 0.2 mg/mouse at an interval of 10 d, or with ip cyclophosphamide (Cy) 10 mg/(kg.d) x 5 d. The results showed that the immune levels of the host were stimulated by BCG, but depressed by Cy significantly. When the mice were treated with ip mebendazole (Meb) 25 mg/(kg.d) x 10 d in combination with ip BCG 0.2 mg/mouse on d 3 before Meb treatment and on d 7 after the beginning of Meb treatment, or with ip Cy 10 mg/(kg.d) x 5 d before Meb treatment, the inhibition rates of cyst weight and the alterations of germinal layers induced by the drugs were similar to those of corresponding groups treated with Meb alone. Cy also exhibited an apparent effect on mice infected with protoscolices for 2 months. Even so, no apparent synergic effect was seen after combined treatment with Cy and Meb. The results suggest that the effect of Meb on secondary cysts of E granulosus was not affected by the host immune level.