ECHINOCOCCUS-MULTILOCULARIS - CELL-MEDIATED IMMUNE-RESPONSE IN EARLY AND CHRONIC ALVEOLAR MURINE HYDATIDOSIS

The in vivo cell-mediated immune response of C57L/J mice infected with E. multilocularis cysts was investigated using a homologous antigen [Ag], a T [thymus-derived] cell-dependent heterologous Ag (oxazolone) and an allo-Ag at 6 and 12 wk post-infection. Mice infected for 12 and 14 wk harbored a 9-18 times larger larval cyst mass than those infected for 6 wk and showed splenomegaly and elevated anti-hydatid antibody titers. In mice infected for 6 wk and challenged with hydatid Ag the 48-h footpad swelling and histological picture of footpad were consistent with cell-mediated immunity. These parameters were significantly reduced in the mice infected for 12 wk. Their response to skin allograft and oxazolone remained comparable to the mice 6 wk post-infection and uninfected controls. The lymphoid tissues of the mice 6 wk post-infection were histologically intact and showed moderate to intense lymphoproliferation. In the mice 14 wk post-infection disorganization of lymphoid tissue, plama- and histiocytosis in the thymus-dependent areas coincided with a large larval cyst mass.