title: Dissociation of hepatitis B surface antigen (HBsAg) from immobilised anti-HBsAg antibody in a two site immunoradiometric assay: its relevance to hook effect and recycled assay.
abstract: The mechanism of the hook effect in a two site immunometric assay of hepatitis B surface antigen (HBsAg) was studied using a novel method. The results showed that HBsAg dissociated from immobilized anti-HBsAg at low as well as high doses of antigen (Ag). This probably was not due to lack of immobilized antibody (Ab) or dissociation of HBsAg non-specifically bound to the immobilized Ab. The dissociated Ag sequestered the labelled Ab in the second reaction and contributed to the decrease in percent binding (B%) of the assay and thus the hook effect. The dissociated Ag could contaminate the recovered pooled labelled Ab in recycled assay and give rise to high non-specific binding. Prolonged washing decreased the side reaction but also the B% of the assay.
mesh_terms: D000937:Antigen-Antibody Reactions; D006510:Hepatitis B Antibodies / Q000276:immunology / Q000378:metabolism*; D006514:Hepatitis B Surface Antigens / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D006801:Humans; D008863:Microspheres; D011863:Radioimmunoassay / Q000379:methods*
chemical_list: D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens