GIARDIA-DUODENALIS - ANALYSIS OF HUMORAL IMMUNE-RESPONSE IN EXPERIMENTALLY INFECTED GERBILS (MERIONES-UNGUICULATUS)

In this work, we have analyzed the humoral immune response in Mongolia n gerbils infected with Giardia duodenalis trophozoites of strains P-l and WE. The course of infection in the animals was assessed by monito ring cyst shedding in feces, and serum samples were collected at weekl y intervals to measure antibody levels by ELISA. Parallel studies were carried out to determine the patterns of total and surface antigens o f the parasite recognized by antibodies using Western blot and radioim munoprecipitation GRIP) assays with the use of homospecific enzyme con jugates. Typical patterns of cyst shedding were observed in the infect ed animals and cyst numbers per gram of feces were consistently higher in gerbils infected with WE strain. Antibody levels to G. duodenalis antigens were observed by week 2 post-infection and were still detecta ble 4 months after infection. G. duodenalis antigens showed a complex but quantitatively and qualitatively different recognition pattern by infection-induced antibodies in Western blot assays which related to i nfecting strain. However, RIP assays showed a more restricted and comm on pattern of recognition of surface antigens from either strain. Take n together, the data obtained in this study provides further informati on regarding direct comparisons among infecting strain, patterns of in fectivity, and host immune response toward G. duodenalis antigens in t he gerbil model.