Mapping novel linear B-cell epitopes target Hepatitis C virus envelope proteins E1 and E2 by monoclonal antibodies for increasing the sensitive detection sites.

Since there is no protective vaccine against Hepatitis C, timely diagnosis and treatment at an early stage of viral infection is crucial to prevent and control hepatitis C virus (HCV) from causing chronic infection. E1 and E2 proteins of HCV can produce neutralizing antibodies and are often used to screen potential epitopes. In this study, human embryonic kidney 293 (HEK293F) cells were used to generate highly active HCV E1 and E2 proteins, which were then used as antigen for producing mouse monoclonal antibodies (mAbs). Novel B cell epitopes of E1 and E2 were disclosed using monoclonal antibodies for the first time. Based on the epitopes, three multi-epitope (MEP) antigens were designed and prepared including non-structural proteins and novel identified B cell epitopes in E1 and E2 in HCV 1b, 2a, 3a, 6a subtypes. Double antigen sandwich enzyme immunoassay was established based on the MEPs to detect HCV serum antibodies, showing potential diagnostic application. This study suggests that B-cell epitopes of E1 and E2 could contribute to the development of diagnostic reagents, provides an important reference value and theoretical support for the optimization of diagnostic reagents for HCV.