Discovery and validation of serum biomarkers expressed over the first twelve weeks of Fasciola hepatica infection in sheep

Abstract

Serum biomarkers associated with Fasciola hepatica infection of Corriedale sheep were analysed during the first 12 weeks of infection using surface-enhanced laser desorption ionisation time of flight mass spectrometry (SELDI-TOF MS). In the discovery phase of analysis, pooled sera collected at week 0 and at each week p.i. to week 12 were fractionated by anion-exchange chromatography and the protein mass fingerprints obtained in individual fractions were in the M/z range 1.5-150 kDa. A total of 2302 protein clusters (peaks) were identified that varied between time-points following infection with peaks increasing or decreasing in intensity, or showing transient variation in intensity, during the 12 weeks of parasite challenge. In the validation phase, candidate biomarkers in sera of individual sheep at weeks 3 and 9 p.i. were analysed, identifying 100 protein peaks, many of which are small peptides <10 kDa in size: 54% of these peaks were up-regulated in intensity at week 3 or 9 p.i. Twenty-six biomarkers were chosen for further study, ranging in size from 1832 to 89,823 Da: six biomarkers were up-regulated at weeks 3 and 9 p.i., 16 biomarkers were up-regulated only at week 9 p.i. and four biomarkers were down-regulated at week 9 p.i. Two biomarkers up-regulated at week 9 were identified as transferrin (77.2 kDa) and Apolipoprotein A-IV (44.3 kDa), respectively. The results show that the interaction between the host and F. hepatica is complex, with changes in biomarker patterns beginning within 3 weeks of infection and either persisting to weeks 9-12 or showing transient changes during infection. Identification of biomarkers expressed during ovine fasciolosis may provide insights into mechanisms of pathogenesis and immunity to Fasciola and may assist in the rational development and delivery of vaccines.

Identification of Novel Diagnostic Serum Biomarkers for Chagas' Disease in Asymptomatic Subjects by Mass Spectrometric Profiling

“…This platform has been used primarily as a discovery tool for biomarkers under neoplastic and inflammatory conditions (53). However, we and others have applied SELDI-TOF MS to studies of human infections, such as African sleeping sickness (37), hepatitis C (43), severe acute respiratory syndrome (SARS) (54), and bacterial endocarditis (19), as well as to studies of fasciolosis in sheep (38) and cysticercosis in pigs (16). There has been some justified criticism of protein profiling efforts, including SELDI-TOF data, when authors have failed to proceed to identification and validation of putative biomarkers (50).…”

Food-Borne Trematodiases

“…In another recent study, serum biomarkers in sheep consequential to an F. hepatica infection were recovered and validated over the course of the first 12 weeks of infection by using surface-enhanced laser desorption ionization-time of flight mass spectrometry. Among other biomarkers, transferrin and apoliprotein A-IV were significantly upregulated at 9 weeks postinfection (86).…”

Proteomics and Genomics in Veterinary Parasitology – A Diagnostic Tool

“…These platforms have made "population-based proteomics" feasible for the first time. SELDI technique has been applied to the study of serum biomarkers of parasitic diseases such as fascioliosis and cysticercosis [14,15].…”