A monoclonal antibody diagnoses active Fasciola infection in humans.

Monoclonal antibodies (MABs) were produced after fusion of spleen cells of Fasciola antigen immunized BALB/c mice and non secreting murine myloma cells (P3x63 Ag8). Six MAbs, showing the highest reactivity with purified Fasciola antigen, were prepared. All 6 MABs were IgG2 with Kappa light chain. Reactive epitopes recognized by the six MAbs were glycoprotein in nature, and each MAb recognized a single epitope of Fasciola antigen. No cros reactions were observed with Schistosomal AWSA, hydatid Ag and Entamoeba Ag. EITB technique showed a specific diagnostic band at 17.5 kDa for each of the six MAbs. Anti-Fasciola MAb (AD2) was conjugated with peroxidase and was used with anti-rabbit anti-Fasciola polyclonal antibody in sandwich-ELISA to detect circulating Fasciola antigen in serum and urine samples of 57 fascioliasis patients, 51 schistosomiasis patients, 45 patients infected with other parasites and 47 healthy controls. Sensitivity of the assay in detection of circulating Fasciola antigen in sera and urines of Fasciola infected patients was 100%. The specificity of the assay was calculated among patients infected with schistosomiasis and other parasites and was 98% in serum and 97% in urine. A positive correlation was found between levels of circulating Fasciola antigen in serum and urine samples of fascioliasis patients (r = 0.825, p < 0.05).

Evaluation of specific Fasciola antigen in the immunodiagnosis of human fascioliasis in Egypt.

Enzyme-linked immunosorbent assay (ELISA) and enzyme linked immunoelectrotransfer blot technique (EITB) were employed for the detection of circulating Fasciola antibodies in infected human sera using a specific Fasciola antigen, prepared by immunoaffinity purification of homogenates of Fasciola hepatica adult worms. Ninety two individuals diagnosed clinically and parasitologically were classified into: Fascioliasis group (21 patients), schistosomiasis group (21 patients) and subjects harbouring other parasitic infections (50 patients). Eighteen healthy individuals served as normal controls. ELISA was 100% sensitive and 93% specific with 96.5% diagnostic efficacy, whereas EITB was 100% sensitive and specific with 100% diagnostic efficacy. Our data revealed that ELISA can be used as a good screening test while EITB can serve as a confirmatory test for immunodiagnosis of fascioliasis.

Purification and characterization of a specific Fasciola antigen.

Specific Fasciola antigen was prepared from homogenates of Fasciola hepatica adult worms. The homogenate was ultracentrifuged and the supernatant containing crude Fasciola antigen was then passed over a cyanogen bromide activated sepharose 4B column coupled with antiserum against Schistosoma mansoni adult worm surface antigen. The specific, Schistosoma-free Fasciola antigen was tested for its specificity by immunodiffusion. Characterization of the specific Fasciola antigen was done by gradient poly-acrylamide gel electrophoresis and immunoblotting technique. The electrophoresis migration pattern of specific Fasciola antigen, stained with Coomassie blue, showed 7 bands in the 12-54 kDa regions. Using the immunoblotting technique, a batch of positive fascioliasis sera recognized two specific bands at the 33 and 54 kDa regions.