Diagnosis of hydatidosis (Echinococcosis) using paramagnetic nanoparticles by immunomagnetic bead ELISA

Abstract

This work is designed to evaluate the role of prepared protoscolex antigen in the detection of the infection through raising anti-E. granulosus immunoglobulin G polyclonal antibody (IgG pAb). Comparative evaluation of sandwich ELISA in relation to sandwich ELISA with paramagnetic nanoparticles for the detection of circulating antigen in sera of tested samples were done using rabbit anti-E. granulosus IgG pAb. Detection of E. granulosus antigens is a better immunodiagnostic tool than determination of the antibody level. The circulating protoscolex antigen (CPA) used was obtained from lung and liver cysts of sheep and camel and injected in rabbits to raise specific polyclonal antibodies (pAb) against E. granulosus. A novel immunomagnetic bead ELISA based on immunoglobulin G (IgG) for detection of CPA in sera of rabbit infected with E. granulosus was developed. The cut-off value for positivity in sandwich ELISA for protoscoleces antigen was equal to 0.26 in serum. All values equal to or above these cut-off values were considered positive. Detection of CPA in serum by sandwich ELISA gave a sensitivity of 90.48%, a specificity of 91.3%, PPV of 95% and NPV of 91.3%. On the other hand, detection of CPA in serum by sandwich ELISA with paramagnetic nanoparticles gave a sensitivity of 95.2%, a specificity of 95.5%, PPV of 97.6% and NPV of 95.5%. Therefore, the novel assay appears to be sensitive for detection of echinococcosis antigen more than sandwich ELISA technique. Key words: Hydatidosis – Echinococcus granulosus- Immunomagnetic bead ELISA technique – Paramagnetic nanoparticles - Circulating protoscolex antigen (CPA).