The 14-3-3 protein is secreted by the adult worm of Echinococcus granulosus

The 14-3-3 protein, already described in the metacestode of Echinococcus mu ltilocularis, has been characterized in the Echinococcus granulosus adult w orm. Immunolocalization studies show the presence of the 14-3-3 protein in the periphery of testes and externally associated with the epical rostellum and adjacent worm tegument. The alcian blue staining in consecutive parasi te sections gave similar reactivity patterns, suggesting that the 14-3-3 pr otein is produced and secreted by rostellar glands. Immunoblot analysis sho wed the presence of the 14-3-3 protein in somatic and excretory-secretory w orm products with higher and smaller apparent molecular masses respectively , than those detected in E. multilocularis or E. granulosus metacestode tis sues. Conversely, the 14-3-3 protein was not detected in metacestode secret ory products. Detection of anti-E. granulosus 14-3-3 reactivity in sera of experimentally infected dogs was achieved at early stages of infection. Spe cific antibody titres decreased during the course of infection. The possibl e origin and functions of the 14-3-3 protein produced by the adult worm are discussed.