IMMUNOSUPPRESSION AND INHIBITION OF INFLAMMATION IN MICE INDUCED BY ASMALL TAENIA-SOLIUM RNA-PEPTIDE TO IMPLANTED T-SOLIUM METACESTODES

Subcutaneous implantation of Taenia solium metacestodes in mice induce s an inflammatory reaction made up mainly of neutrophils and eosinophi ls after 12 days. Administration of a small RNA-peptide (metacestode f actor, MF) purified from T. solium metacestodes significantly reduces the inflammatory site in both size and composition, yielding a very lo w number of eosinophils. The metacestodes implanted in control mice we re completely destroyed and their remnants were surrounded by an inten se inflammation predominantly made up of neutrophils and eosinophils. In contrast, metacestodes implanted in mice treated with MF showed app arently intact suckers, rostellum, hooks, and tegument. Inhibition of inflammation around the parasites was also observed in mice immunized with T. solium metacestode antigens and inoculated simultaneously with MF. Mice immunized only with T. solium metacestode antigens produced a granulomatous process around metacestodes that destroyed most of the large metacestode structures: suckers, rostellum, hooks, and tegument -wall tissues. Furthermore, treatment of mice with MF or implanted met acestodes decreased the antibody (P<0.05) and cellular responses (P<0. 05) to metacestode antigens. The antibody response was even lower when both of these treatments were given simultaneously. These findings su pport the idea that MF plays a key role in the down-regulation of the host immune response, contributing to the parasite's survival.