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Cross-Reactivity of Hbe Antigen-Specific Polyclonal Antibody With Hbc Antigen Publisher Pubmed



Hojatizadeh M1 ; Amiri MM1 ; Mobini M1 ; Makoui MH1 ; Ghaedi M1 ; Ghotloo S1, 2 ; Peyghami K1 ; Jedditehrani M3 ; Golsazshirazi F1 ; Shokri F1, 3
Authors
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Authors Affiliations
  1. 1. Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
  2. 2. Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Kashan University of Medical Sciences, Kashan, Iran
  3. 3. Monoclonal Antibody Research Center, Avicenna Research Institute, ACER, Tehran, Iran

Source: Viral Immunology Published:2023


Abstract

Hepatitis B virus (HBV) infection is a major health problem worldwide and causes almost one million deaths annually. The HBV core gene codes for two related antigens, known as core antigen (HBcAg) and e-antigen (HBeAg), sharing 149 residues but having different amino- and carboxy-terminals. HBeAg is a soluble variant of HBcAg and a clinical marker for determining the disease severity and patients’ screening. Currently available HBeAg assays have a shortcoming of showing cross-reactivity with HBcAg. In this study, for the first time, we evaluated whether HBcAg-adsorbed anti-HBe polyclonal antibodies could specifically recognize HBeAg or still show cross-reactivity with HBcAg. Recombinant HBeAg was cloned in pCold1 vector and successfully expressed in Escherichia coli and after purification by Ni-NTA resin was used to generate polyclonal anti-HBe antibodies in rabbit. Purified HBeAg was further characterized by assessing its reactivity with anti-HBe in the sera of chronically infected patients and HBeAg-immunized rabbit. Sera from patients with chronic HBV infection, containing anti-HBe, specifically reacted with recombinant HBeAg, implying antigenic similarity between the prokaryotic and native HBeAg in the serum of HBV-infected patients. In addition, the designed enzyme-linked immunosorbent assay (ELISA) with rabbit anti-HBe polyclonal antibodies could detect recombinant HBeAg with high sensitivity, while high cross-reactivity with HBcAg was observed. It is noteworthy that HBcAg-adsorbed anti-HBe polyclonal antibodies still showed high cross-reactivity with HBcAg, implying that due to the presence of highly similar epitopes in both antigens, HBcAg-adsorbed polyclonal antibodies cannot differentiate between the two antigens. © Mary Ann Liebert, Inc.