Impairment of the inflammatory reaction on implanted Taenia solium metacestodes in mice by a T. solium RNA-peptide: a scanning electron microscopy study

Inhibition of inflammation by a Taenia solium RNA-peptide (metacestode factor, MF) was studied by scanning electron microscopy (SEM). Viable (96%) T. solium metacestodes obtained from a naturally infected pig were dissected and implanted in treated and control mice, removed at 6 and 12 days postimplantation (p.i.), and studied by SEM. At day 6, metacestodes in control mice showed vigorous inflammation, whereas in mice treated with MF they were apparently intact with exiguous inflammation. Mice immunized with T. solium metacestode antigens showed a moderate inflammation; those treated with both MF and T. solium antigens presented scanty inflammation. At day 12, metacestodes presented copious inflammation and severe damage to the sucker tissues in mice immunized with T. solium; in mice treated with either MF or MF and T. solium antigens there was only discrete inflammation. These observations illustrate the central role of MF in the inhibition of the early events leading to the parasite's destruction by means of an inflammatory response.