Study of surface carbohydrates in Galba truncatula tissues before and after infection with Fasciola hepatica

The presence and distribution of surface carbohydrates in the tissues of Galba truncatula snails uninfected or after infection with Fasciola hepatica as well as on the surface of the snail-pathogenic larval stages of the parasite were studied by lectin labelling assay. This is an attempt to find similarities that indicate possible mimicry, utilised by the parasite as an evasion strategy in this snail-trematode system. Different binding patterns were identified on head-foot-mantle, hepatopancreas, genital glands, renopericardial complex of the host as well as of the snail-pathogenic larval stages of F. hepatica. The infection with F. hepatica leads to changes of labelling with Glycine max in the head-mantle cells and Arachis hypogaea in the tubular epithelium of the hepatopancreas. The lectin binding on the other snail tissues is not changed by the development of the larvae. Our data clearly demonstrated the similarity in labelling of G. truncatula tissues and the surface of the snail-pathogenic larval stages of F. hepatica. The role of glycosylation of the contact surfaces of both organisms in relation to the host-parasite interactions is also discussed.

Purificación de la fracción antigénica 27-28 KDa a partir del antígeno metabólico secretado-excretado de Fasciola hepatica / Purification of antigenic fraction 27-28 KDa from the metabolic antigen from metabolic secreted-excreted from Fasciola hepatica

En el presente estudio, las fracciones antigénicas de 27-28 KDa de Fasciola hepatica fueron purificadas por cromatografía de exclusión molecular para su aplicación en el diagnóstico de la fascioliasis humana. Se obtuvieron antígenos de excreción y secreción a partir de fasciolas adultas vivas obtenida de hígado de ovino y bovino, y cultivados en medio mínimo esencial. La reactividad y eficacia del antígeno purificado fueron evaluadas por la prueba de inmunoblot empleando cuatro sueros con fascioliasis humana; cuatro sueros con otras parasitosis, y dos sueros negativos. Se concluye que las fracciones antigénicas purificadas no presentan reacción cruzada con otras parasitosis, por inmunoblot, por lo que se considera a las proteínas purificadas como potenciales candidatas a ser utilizadas para el diagnóstico de fascioliasis humana.

Antigenic fractions of 27-28 kDa from Fasciola hepatica were purified by size-exclusion chromatography for use in the diagnosis of human fasciolosis. Excretion and secretion antigens were obtained from living adult flukes collected from sheep and cattle liver, and cultured in minimum essential medium. The reactivity of the purified antigen and efficacy were assessed by immunoblot test using four sera with human fascioliasis; four sera with other parasites, and two negative sera. We conclude that the purified antigenic fractions do not cross-react with other parasites by immunoblot. Therefore, purified proteins are considered as potential candidates to be used for the diagnosis of human fascioliasis.