Fusion Expression, Immunogenicity and Applications of C-terminally Truncated HCV Core Proteins

Clones expressing full-length(aa 1-191) or C-terminally truncated forms (aa 1-69 and aa 1-40) of hepatitis C virus core(HCc) protein fused to the C-terminal of glutathione S-transferase(GST) were constructed and their expressions in different strains of Escherichia coli were compared. The expressed proteins were soluble. ELISA and Western blot analyses showed that GSTC191 was poorly expressed and had poor stability, whereas GSTC69 and GSTC40 were stable and could be purified to 90% purity in a single step on glutathione-Sepharose 4B. Mice immunized with these purified proteins produced high-titre antibodies. As an application, purified GSTC69 and GSTC40 were used in a preliminary assay of anti-HCc antibodies in patients'sera, and results showed that they had high specificity in the assay.