Taeniosis-cysticercosis caused by Taenia crassiceps (Zeder, 1800) is a useful experimental model for biomedical research, in substitution of Taenia solium Linnaeus, 1758, studied during decades to develop effective vaccination, novel anti-helminthic drugs and diagnostic tools. Cysticercosis in mouse (Mus musculus Linnaeus) is achieved by the larval subculturing of the Wake Forest University (WFU) strain of T. crassiceps. Golden hamster, Mesocricetus auratus (Waterhouse), has been shown to be the most suitable host for adult forms of parasite in experimental taeniosis. Metacestodes of T. crassiceps WFU multiply by budding without restrictions once inoculated into the mouse, while the number of tapeworms developed from these larvae in hamsters remains highly variable. Three objectives have been proposed to improve the infection of T. crassiceps WFU in hamsters: (1) to re-evaluate the need of immune suppression; (2) to investigate the advantage of infecting hamsters with metacestodes with in vitro protruded scolices; and (3) to compare a number of tapeworms developed from metacestodes subcultured in hamsters against those proliferated in mice. Our results demonstrated that when the evagination of murine metacestodes was high, the number of T. crassiceps WFU adults obtained from hamsters was also high. Immunosuppressive treatment remains relevant for this experimental rodent model. The hamster-to-hamster cysticercosis-taeniosis by T. crassiceps overcame the mouse-to-hamster model in the yield of adult specimens. In vitro scolex evagination and metacestode asexual proliferation in hamsters place this rodent model by T. crassiceps WFU as the most affordable experimental models with taeniids.
First step in developing an epitope-based vaccine is to predict peptide binding to the major histocompatibility complex (MHC) molecules. We performed computational analysis of unique available EgA31 sequence to locate appropriate antigenic propensity positions. T-cell epitopes with best binding affinity values of < 50% inhibitory concentration were selected using different available servers (Propred and IEDB). Peptides with 100% population coverage were selected. A DNA fragment corresponding to the furin linker enriched in Golgi apparatus was inserted sequentially between each epitope sequences in a synthetic DNA in order to cleave the chimeric protein into four separated peptides. Subsequently, the synthetic DNA was cloned into the pGEX4T-1 and pEGFP-N1 vectors and GST-ChEgA31 was expressed in E. coli strain BL21-DE3. The recombinant protein was detected by western blotting using an HRP-conjugated polyclonal anti-GST antibody. Fusion protein purified by affinity chromatography was used to raise antisera in rabbits. Results in agar gel immunodiffusion assay indicated induction of specific antibodies against multiepitope antigen in the tested rabbits. Cytokine assay was carried out in C57Bl/6 mice and the levels of cytokines were analyzed by sandwich ELISA. Interestingly, production of specific IFN-γ was prominently higher in mice immunized with GST-ChEgA31 and pEGFP-ChEgA31 (650-1 300 pg/ml) compared to control groups. No difference was observed in the level of IL-10 and IL-4 in immunized and GST control group. Challenge study with 500 live protoscolices of Echinococcus granulosus on immunized mice demonstrated protectivity level (50-60%). Based on our results, it appeared that the chimeric protein in the study was able to stimulate T-helper cell-1 (Th1) development and high level of cell mediated immunity in mice.