Proteomic analysis of Fasciola hepatica excretory-secretory products.

This paper describes a global investigation of the components of Fasciola hepatica excretory-secretory (ES) products by a proteomic approach. Despite the absence of a F. hepatica genome sequencing project we have shown that it was possible to identify 29 of the 60 prominent proteins found using two-dimensional gel electrophoresis. As well as cathepsin L proteases, a number of enzymes implicated in parasite protection from the host immune system were also found to be present in relatively large abundance. These included superoxide dismutase, thioredoxin peroxidase, glutathione S-transferases and fatty acid binding proteins, all of which may play a part in the detoxification of reactive oxygen intermediates. Interestingly, ovine superoxide dismutase was the only protein from the host identified on the gel. We suggest that the relative abundance and protective nature of the components of the ES products of this organism play an important role in its survival within the host. The precise identification, to individual NCBI database entries, of a number of glutathione S-transferases and cathepsin Ls from F. hepatica, by peptide mass fingerprinting, was hampered by multi-database submissions of the two protein superfamilies from this organism.