Fasciola hepatica and Schistosoma mansoni: identification of common proteins by comparative proteomic analysis

Abstract

It is not unusual to find common molecules among parasites of different species, genera, or phyla. When those molecules are antigenic, they may be used for developing drugs or vaccines that simultaneously target different species or genera of parasite. In the present study, we used a proteomic-based approach to identify proteins that are common to adult Fasciola hepatica and Schistosoma mansoni. Whole-worm extracts from each parasite were separated by 2-dimensional electrophoresis (2-DE), and digital images of both proteomes were superimposed using imaging software to identify proteins with identical isoelectric points and molecular weights. Protein identities were determined by mass spectrometry. Imaging and immunoblot analyses identified 28 immunoreactive proteins that are common to both parasites. Among these molecules are antioxidant proteins (thioredoxin and glutathione-S-transferase), glycolytic enzymes (glyceraldehyde 6-phosphate dehydrogenase and enolase), proteolytic enzymes (cathepsin-L and -D), inhibitors (Kunitz-type, Stefin-1), proteins with chaperone activity (heat shock protein 70 and fatty acid-binding protein), and structural proteins (calcium-binding protein, actin, and myosin). Some of the identified proteins could be used to develop drugs and vaccines against fascioliasis and schistosomiasis.

Figure 1

(A) Overview of Coomassie Blue–stained 2-DE gels showing numerous spots from F. hepatica and S. mansoni whole-worm extracts (F. hepatica [F.h.] and S. mansoni [S.m.]). Two-DE analyses were performed on an 11-cm, pH 3–10 strip in the first dimension and 4–20% continuous polyacrylamide gradient in the second dimension. A 3-dimensional (3D) rendering of matching spots between F. hepatica and S. mansoni whole-worm extracts is shown in the middle of figure. Numbers on 2-DE represent the standard spot number (SSP) designated for each matching spot, which were selected for spot picking and MS analysis. (B) Overlaid images of S. mansoni and F. hepatica proteomes with computer-generated color-coded intensity variations on the x- and y-axes.

Figure 2

Immunoblot analysis of Fasciola hepatica whole-worm extract (F.h.) tested with a pool of sera from patients with chronic Schistosoma mansoni infection. Common immunoreactive spots are numbered as described in Figure 1 and Table I.