Expression, purification and bioactivity of a recombinant fusion protein consisting of anti-HBs single chain Fv and interleukin-2 / 解放军医学杂志

ABSTRACT

Objective To study the expression, purification and bioactivity of a recombinant fusion protein consisting of anti-HBs single chain Fv and interleukin-2. Methods The engineering bacterium M15[pQE-ScFv-IL-2] which can express the fusion protein consisting of anti-HBsAg single chain Fv and interleukin-2, was induced by IPTG, then a 43kD recombinant protein was identified by SDS-PAGE and Western-blot analysis. Results The ratio of target protein to total protein of host reached 18%. Further analysis confirmed that the recombinant protein formed inclusion body in the cytoplasm of bacteria. 95% purity could be achieved after two-step purification of ScFv-IL-2, including Ni metal chelating chromatography (the first) and ion-exchange chromatogram (the second). The bioactivity assay of the purified product showed that the antibody-cytokine fusion protein could bind to HBsAg specifically and stimulate the proliferation of CTLL-2. Conclusion These results suggest that the fusion protein retains the bioactivity of its parental molecules, and may be a potential gene-engineering targeting drug for the treatment of chronic hepatitis B and other relevant diseases.