Sensitive enzyme immunoassay for the detection of delta antigen and anti‐delta, Using serum as the delta antigen source

Abstract

A sensitive enzyme-linked immunosorbent assay (ELISA, EIA) was developed for the detection of delta antigen in serum treated with Tween 20. The serum delta antigen so derived was used in an ELISA for anti-delta. Both tests were specific and more sensitive than radioimmunoassay (RIA) when applied to testing parenteral drug abusers. It is concluded that the different sources of delta-antigen used may account for the different sensitivities noted, and that delta antigenaemia in acute infection may be more frequently detectable than was first thought, amounting to 71% of those with delta infection in this study and that these sera are a convenient alternative source of antigen.

New Enzyme-Linked Immunosorbent Assay for Detection of Antibodies against Hepatitis Delta Virus Using a Hepatitis Delta Antigen Derived from a Taiwanese Clone and Comparison to the Abbott Radioimmunoassay

“…For anti-HD antibody detection, various RIAs and enzyme immunoassays (EIAs) have been developed (4,8,9,17,18). One major drawback of these tests is that they use HDAg derived from either infected liver or infectious serum of humans or animals (e.g., chimpanzees and woodchucks) (15).…”

“…One major drawback of these tests is that they use HDAg derived from either infected liver or infectious serum of humans or animals (e.g., chimpanzees and woodchucks) (15). Thus, the potentially biohazardous nature and limited supply of these materials have been major limitations in clinical use (14,17,18). The rHDAg used in this study was expressed and harvested from E. coli, allowing for a theoretically unlimited supply of HDAg free from the potential hazards of extracting antigen from infectious materials.…”

Delta hepatitis: molecular biology and clinical and epidemiological features

“…Subsequently, human sera containing high titers of anti-HD and low titers of anti-HBc activity were labeled with horseradish peroxidase and used for the direct detection of HDAg by immunoperoxidase staining of frozen sections and paraffin-embedded sections from patients with chronic liver disease (26,82,194 (95,179). In the assay described by Shattock and Morgan (179), Tween 20 is used to release the antigen from the HBsAg envelope. Because this assay employs a dissociating agent to disrupt HDAg-anti-HD immune complexes, it was more sensitive than earlier RIA formats and was able to detect circulating HDAg for a much longer time (179).…”

“…In the assay described by Shattock and Morgan (179), Tween 20 is used to release the antigen from the HBsAg envelope. Because this assay employs a dissociating agent to disrupt HDAg-anti-HD immune complexes, it was more sensitive than earlier RIA formats and was able to detect circulating HDAg for a much longer time (179). Despite this improved HDAg detection, as the anti-HD titer continued to rise, the ability to disrupt the immune complexes that formed after release of HDAg from the HBsAg envelope resulted in the eventual inability to detect HDAg.…”

Hepatitis D

“…Delta antigen was initially detected in human liver material by direct immunofluorescence [1]. Following successful extraction of delta anti gen from human liver tissue, Rizzetto et al developed a sensitive solid-phase radioim munoassay for both delta antigen and anti delta antibody [9][10][11], Detection of delta an tigen in serum required detergent treatment of serum samples to remove the HBsAg coat and expose the antigen [5], Delta antigen and antibody has also been detected in human serum by solid-phase enzyme-linked immu noassays [12,13], These assays, although sensitive, have been unable to detect delta antigen in sera containing high titers of antidelta antibody, even though such sera arc demonstrably infectious [14], Detection of delta agent particles in the presence of anti delta antibody, by measuring delta agent RNA, may be possible in the future.…”