Immunological identification of Fasciola hepatica antigens containing major human T-cell and B-cell epitopes.

Fasciola hepatica whole worm homogenate (Fhwwh) separated fractions were used in enzyme linked immunoelectrotransfer blot (EITB) to identify the antigen(s) which induces antibody formation in human fascioliasis. The immuno-reactive antigens recognized by the infected patients were 25-29 kDa and 12 kDa. Antigens were biochemically purified by model 491-prep cell fraction (BIO-RAD). The capability of the purified target antigens to induce humoral and cellular responses with cells and sera of infected patients was investigated using enzyme linked immunosorbent assay (ELISA) and lymphoproliferative responses techniques. The 25-29 kDa cluster of antigen(s) were found to be more efficient in inducing lymphoproliferative response than 12 KDa, thus, it was considered as the target antigens used in the generation of human monospecific polyclonal immunopurified antibody probes (IPAb). The specificity and immunoreactivity of the IPAb with Fhwwh, F. hepatica excretory secretory products (FhESP) and S. mansoni adult worm antigen (SAWA) were evaluated by using EITB. Results showed that IPAb was immunoreactive with 25-29 and 12 kDa antigens of both Fhwwh and FhESP. It was concluded that the most immunogenic F. hepatica target antigen(s) were 25-29 and12 KDa antigens and there is a cross-reactivity between 25-29 and 12 KDa antigens in both Fhwwh and FhESP. The involvement of IPAb in antibody dependent cell mediated cytotoxicity in-vitro technique was studied. Results indicated that human neturophils were more effective in adhering to the IPAb-coated flukes at early stages of development.