Expression of HCV genotype-4 core antigen in prokaryotic E. coli system for diagnosis of HCV infection in Egypt

Abstract

Background: Egypt has a high prevalence of hepatitis C virus (HCV) infection with 92.5% of genotype-4.

Aim: This study aimed to clone and express the core gene of HCV genotype-4 for using it to develop a highly sensitive, specific, and cost-effective diagnostic assay for detecting HCV infection.

Methods: Using synthetic HCV genotype-4 core gene, pET15b as E. coli expression vector, and 1 mM lactose as inducer, the HCV core protein (MW 17 kDa) was expressed in the form of inclusion bodies (IBs) that was purified and solubilized using 8 M guanidinium HCl. The recombinant core protein was in vitro refolded by a rapid dilution method for further purification using weak cation exchange liquid chromatography. The immunogenicity of the purified protein was tested by ELISA using 129 serum samples.

Results: The recombinant core protein was successfully expressed and purified. The results also showed that the in-house anti-HCV core assay is accurate, specific (_~96.6%), and highly sensitive (_~100%) in accordance with the commercial ELISA kit.

Conclusion: The sensitivity, specificity, and reproducibility of the developed assay were high and promising to be used as a screening assay for detecting HCV infection.

Keywords: Core protein; ELISA; HCV; Inclusion bodies; Refolding.