Comparative assessment of ELISAs using recombinant saposin-like protein 2 and recombinant cathepsin L-1 from Fasciola hepatica for the serodiagnosis of human Fasciolosis

• Published in: PLoS neglected tropical diseases 2014-06, Vol.8 (6), p.e2860-e2860
• Main Authors: Gottstein, Bruno, Schneeberger, Marianne, Boubaker, Ghalia, Merkle, Bernadette, Huber, Cristina, Spiliotis, Markus, Müller, Norbert, Garate, Teresa, Doherr, Marcus G
• Format: Article
• Language: English
• Subjects: Accuracy; Adolescent; Adult; Aged; Aged, 80 and over; Animals; Antibodies, Helminth - blood; Antigens, Helminth; Biology and Life Sciences; Cancer; Diagnosis; Enzyme-linked immunosorbent assay; Enzyme-Linked Immunosorbent Assay - methods; Enzymes; Europe; Fasciola hepatica - immunology; Fascioliasis - diagnosis; Female; Fluke infections; Humans; Infections; Male; Medicine and Health Sciences; Middle Aged; Physiological aspects; Proteins; Recombinant Proteins; Sensitivity and Specificity; Serologic Tests - methods; Test systems; Young Adult
• ISSN: 1935-2735; 1935-2727; 1935-2735
• DOI: 10.1371/journal.pntd.0002860

Two recombinant Fasciola hepatica antigens, saposin-like protein-2 (recSAP2) and cathepsin L-1 (recCL1), were assessed individually and in combination in enzyme-linked immunosorbent assays (ELISA) for the specific serodiagnosis of human fasciolosis in areas of low endemicity as encountered in Central Europe. Antibody detection was conducted using ProteinA/ProteinG (PAG) conjugated to alkaline phosphatase. Test characteristics as well as agreement with results from an ELISA using excretory-secretory products (FhES) from adult stage liver flukes was assessed by receiver operator characteristic (ROC) analysis, specificity, sensitivity, Youdens J and overall accuracy. Cross-reactivity was assessed using three different groups of serum samples from healthy individuals (n=20), patients with other parasitic infections (n=87) and patients with malignancies (n=121). The best combined diagnostic results for recombinant antigens were obtained using the recSAP2-ELISA (87% sensitivity, 99% specificity and 97% overall accuracy) employing the threshold (cut-off) to discriminate between positive and negative reactions that maximized Youdens J. The findings showed that recSAP2-ELISA can be used for the routine serodiagnosis of chronic fasciolosis in clinical laboratories; the use of the PAG-conjugate offers the opportunity to employ, for example, rabbit hyperimmune serum for the standardization of positive controls.