Taenia solium: immunity in hogs to the Cysticercus

Protection was induced in hogs against Taenia solium cysticercosis using an immunogenic complex obtained from its larval "bladder worm" form, Cysticercus cellulosae. Immunoelectrophoresis revealed that this complex contained at least eight antigens. In immunized hogs a total of 71 (mean 11.8) cysticerci were found, whereas in the control animals 397 (mean 74.9) were found. Histopathological studies showed that more than 40% of larvae obtained from immunized hogs were completely destroyed and the others were seen in various stages of degeneration. Eosinophils and mononuclear cells were observed infiltrating the internal structures of the larvae. Intense granulomatous reactions of eosinophils, lymphocytes, macrophages, epithelioid cells, plasma cells, and fibroblasts surrounded the larvae. Larvae from control hogs were intact and surrounded by a small inflammatory reaction. The cellular response was measured by the macrophage migration inhibition test, which was higher in immunized hogs when compared with control animals, either before the infection with T. solium eggs or before slaughter. No significant difference was found in the humoral response of immunized and control hogs.