A Taenia solium metacestode factor nonspecifically inhibits cytokine production.
Studies of the immune response in chronic helminth infections suggest that parasites modulate the host's immune response. Taenia solium metacestodes, in particular, produce molecules that down-regulate cell-mediated immunity. We have described a small RNA peptide termed metacestode factor (MF) that depresses the murine immune response to Salmonella typhimurium antigens. MF inhibits mitogen-induced proliferation, humoral and cellular responses to metacestode antigens, and inflammation surrounding metacestodes implanted subcutaneously in mice. To assess the effects of MF on cytokine production we stimulated murine spleen cells in vitro with concanavalin A and measured cytokine concentrations in the culture supernatants by enzyme-linked immunosorbent assay. When cultured with MF, the cells showed significantly decreased production of interleukin 2 (IL-2), interferon-gamma (IFN-gamma), and IL-4 as compared with mitogen alone. Exogenous rIL-2 and rIL-4 largely restored the proliferative response (85% and 71% of control cells, respectively). MF also decreased production of tumor necrosis factor-alpha (TNF-alpha) by macrophages stimulated with lipopolysaccharide and IFN-gamma. The TNF-alpha concentration was inversely correlated with the MF concentration. Experiments using spleen cells from mice treated with MF also showed a significant reduction in IL-4 concentration. These results suggest that MF inhibits cytokine production without regard to cell type or cytokine. This may explain the function of this molecule as an inhibitor of the host inflammatory and immune responses.
Arechavaleta
F
F
Departamento de Genética Molecular, Instituto de Fisiología Celular, U.N.A.M., México.
Molinari
J L
JL
Tato
P
P
D000818:Animals; D002478:Cells, Cultured; D003551:Cysticercosis / Q000469:parasitology; D016207:Cytokines / Q000096:biosynthesis*; D015801:Helminth Proteins / Q000276:immunology* / Q000302:isolation & purification; D006790:Host-Parasite Interactions; D007166:Immunosuppressive Agents; D007371:Interferon-gamma / Q000096:biosynthesis; D007378:Interleukins / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D018510:RNA, Helminth; D013154:Spleen / Q000166:cytology; D013552:Swine; D013621:Taenia / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D016207:Cytokines; D015801:Helminth Proteins; D007166:Immunosuppressive Agents; D007378:Interleukins; D018510:RNA, Helminth; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma