Immune responses to oral infection with Echinococcus multilocularis protoscoleces in gerbils: modified lymphocyte...

Immune responses to oral infection with Echinococcus multilocularis protoscoleces in Mongolian gerbils were investigated. Gerbils not treated with prednisolone expelled most of the parasites within 3 days post-infection and induced parasite-specific intestinal IgA secretion after the oral inoculation with protoscoleces. In contrast, prednisolone-treated gerbils harbored notable numbers of parasites, and the parasite-specific intestinal IgA secretion was lower. In gerbils not treated and orally inoculated with protoscoleces (infected group), parasite-specific antibody levels in sera and intestinal washings were elevated, but blastogenesis against protoscolex antigens was observed only in cells from Peyer's patches at 14 days post-infection. Concanavalin A-induced proliferative lymphocytes from both infected and naive gerbils were suppressed by adding protoscolex somatic antigen. These data indicate that while parasite-specific antibody responses were observed, lymphocyte proliferative responses were suppressed by parasite infection/antigens in the Mongolian gerbil, prednisolone-untreated rodent definitive host model.