Simple One-step Purification of Hepatitis B Core Antigen in Escherichia coli

Hepatitis B core antigen (HBcAg) is one of the most important diagnostic reagents in hepatitis B virus (HBV) infection. The purification of HBcAg using conventional methods, such as sucrose density gradient ultracentrifugation, is time and cost consuming. To overcome this difficulty, we aimed at developing an efficient method for producing a soluble form of HBcAg for diagnostic application. The HBcAg construct was secreted into periplasm space of E. coli, which facilitates purification by selective disruption of the outer membrane. The His-tagged HBcAg was purified from prepared periplasmic fraction using Ni-NTA affinity chromatography with an average yield of 20 mg/L culture. The results of competitive ELISA indicated that the antigenicity of periplasmic HBcAg is comparable with commercial E. coli-derived antigen. These results demonstrate the periplasmic system is suitable for the rapid and simple purification of bioactive and soluble HBcAg.