Cellular immunity in experimental Echinococcus multilocularis infection. II. Sequential and comparative phenotypic study of the periparasitic mononuclear cells in resistant and sensitive mice.

Cellular immune responses have been shown to be associated with differential evolutions of E. multilocularis infection in intermediate hosts. A relationship between course of delayed-type hypersensitivity (DTH) against parasitic antigens and receptivity of murine strains has been demonstrated recently. The aim of this study was to correlate resistance and sensitivity to E. multilocularis infection with the phenotypic patterns of cells within the periparasitic granuloma. Evolution of the ratios, macrophages/T lymphocyte and Ly1/Ly2 T lymphocytes, was associated with the receptivity of the strains. Persistence of numerous L3T4 + T lymphocytes and low numbers of macrophages and Ly2 + T lymphocytes were observed in the 'resistant' C57BL.10 mice. Comparison of the results with course of the DTH against E. multilocularis antigens showed that the particular phenotypic pattern observed in resistant mice was associated with a particular profile of DTH after infection. These results and similar observations in human alveolar echinococcosis suggest that cell composition of the periparasitic granuloma might be of crucial importance in controlling the spontaneous development of E. multilocularis larvae in the intermediate host.