ELISA for IgG-class antibody to hepatitis E virus based on a highly conserved, conformational epitope expressed in Eschericia coli

In assays based on most recombinant hepatitis E virus (HEV) antigens, the I gG antibody responses to HEV are observed commonly to wane or disappear aft er the acute phase of infection. Such IgG assays have therefore been used f or the diagnosis of acute HEV infection, but they have limited usefulness i n seroepidemiological studies. Using western immunoblotting, it was shown p reviously that the open reading frame (ORF) 2.1 antigen, representing the c arboxy-terminal 267 amino acids (aa) of the capsid protein, exposes a confo rmational epitope which allows optimal detection of convalescent antibody c ompared to other proteins expressed in Escherichia coli. This conformationa l epitope is shown to be highly conserved between divergent human HEV isola tes, and the development of a sensitive and highly specific enzyme immunoas say (ELISA) based on this recombinant antigen is described. The ORF2.1 ELIS A allows the detection and quantitation of both acute- and convalescent pha se HEV-specific IgG, and will help to define better the antibody responses to the virus and the prevalence of HEV infection worldwide. (C) 1999 Elsevi er Science B.V. All rights reserved.