The interactionin vitrobetween bovine immunoglobulin and juvenileFasciola hepatica

Abstract

SUMMARYFreshly excystedFasciola hepaticapossess an outer glycocalyx which stimulates an antibody response in cattle infected withF. hepaticametacercariae. Sera from animals receiving either a single or a double infection were examined for levels of IgM, IgG1and IgG2specific for the outer glycocalyx of intact live juvenileF. hepatica. High levels of specific IgG1were found to predominate. Using positive sera in an indirect fluorescent antibody assay, the bovine immunoglobulins labelled the outer glycocalyx in a characteristic reticulated pattern. On incubation at 37 °C this pattern rapidly broke up into discrete clumps and progressed until the entire antibody–outer glycocalyx complex was shed. The shedding phenomenon was shown to be continuous and, by using preparations of Fab fragments, was not due to the bivalent binding of the sensitizing antibody.

The Liver Flukes Fasciola gigantica and Fasciola hepatica Express the Leucocyte Cluster of Differentiation Marker CD77 (Globotriaosylceramide) in Their Tegument

“…The humoral response is primarily of the IgG isotype and is directed against the glycocalyx of the susceptible juvenile fluke-integument (Duffus and Franks, 1981). It involves protein-bound carbohydrate epitopes (Dalton et al, 1985) and is non-protective (Bossaert et al, 2000).…”

Fasciola hepatica: development of monoclonal antibodies and their use to characterize a glycocalyx antigen in migrating flukes

“…In view of the superficial all-enveloping nature of the surface glycocalyx it is not surprising that it provides the earliest and strongest antigenic stimulus to the immune system of the definitive host and high levels of antibody against glycocalyx and TO/Tl vesicles build up in the serum soon after infection (Hanna 1980b). However, juvenile flukes moving through the peritoneal cavity and liver parenchyma appear to counteract immunological attack at the surface by sloughing the antibody-glycocalyx complex and renewing the glycocalyx by exocrine secretion of new glycoproteins (Hanna 1980c, Duffus & Franks 1981. After migration into the bile ducts where specific antibody levels are relatively low (Hughes, Hanna & Symonds 198 1) T1 production and glycocalyx turnover are considerably reduced.…”

UDP-galactose 4′-epimerase from the liver fluke,Fasciola hepatica: biochemical characterization of the enzyme and identification of inhibitors

“…If so, inhibition of FhGALE would have at least 2 negative consequences for the parasite: disruption of intermediary metabolism similar to that observed in type III galactosaemia and reduced ability to produce tegumental glycoproteins and glycolipids. These glycosylated molecules have been shown to be important in infection and host immune system evasion (Hanna, 1980; Duffus and Franks, 1981; Wilson et al 2011; Vukman et al 2013). In this context, it is interesting to note that galactose moieties have been observed in tegumental glycoproteins (Hanna, 1976).…”