Immunosuppression and inhibition of inflammation in mice induced by a small Taenia solium RNA-peptide to implanted T. solium metacestodes

Abstract

Subcutaneous implantation of Taenia solium metacestodes in mice induces an inflammatory reaction made up mainly of neutrophils and eosinophils after 12 days. Administration of a small RNA-peptide (metacestode factor, MF) purified from T. solium metacestodes significantly reduces the inflammatory site in both size and composition, yielding a very low number of eosinophils. The metacestodes implanted in control mice were completely destroyed and their remnants were surrounded by an intense inflammation predominantly made up of neutrophils and eosinophils. In contrast, metacestodes implanted in mice treated with MF showed apparently 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 metacestodes decreased the antibody (P < 0.05) and cellular responses (P < 0.05) to metacestode antigens. The antibody responses was even lower when both of these treatments were given simultaneously. These findings support the idea that MF plays a key role in the down-regulation of the host immune response, contributing to the parasite's survival.

A cysteine protease from Taenia solium metacestodes induce apoptosis in human CD4+ T-cells

“…We have reported that metacestodes of T. solium secrete in vitro a factor that depresses human and murine lymphocyte proliferation (Molinari et al 2000;Tato et al 1995). Also, this factor impairs the humoral and cellular responses to metacestode antigens and inhibits the inflammatory reaction around metacestodes implanted subcutaneously in mice (Tato et al 1996;Molinari et al 1998). Besides this, it inhibits IL-2, IFN-c, IL-4 and TNF-a synthesis in vitro and in ex vivo (Arechavaleta et al 1998).…”

“…Likewise, Arechavaleta et al (1998) reported that a factor released from T. solium metacestodes (MF) depresses T cell proliferative responses and cytokine production (IFN-c IL-2, IL-4 and TNF-a). This MF also impaired the inflammatory reaction on implanted T. solium metacestodes in mice (Tato et al 1996;Molinari et al 1998).…”

The implantation of Taenia solium metacestodes in mice induces down-modulation of T-cell proliferation and cytokine production

“…The stimulating effect of F2 on spleen cell proliferation and production of IFN-c has been reported (Garrido et al 2001). In addition, mice implanted with metacestodes showed inhibition of inflammation around the parasite and a decrease in the levels of antibodies and proliferative responses against parasite antigens (Tato et al 1996).…”

Taenia solium metacestode antigens which are protective for pigs induce Th1/Th2 mixed responses in mice

“…In mice, they induced a granulomatous process around metacestodes implanted subcutaneously that destroyed the parasite (Tato et al 1996;Molinari et al 1998). In all of these works, eosinophils (Th2 response) have been found in the inflammatory reactions surrounding the larvae and they have been related to the damage to the parasite.…”