Expression of the PreS1 peptide of hepatitis B virus and preparation of its polyclonal antibody.

PreS1 is a hypothetical candidate domain of L protein for hepatitis B virus (HBV) to adhere to and invade host hepatic cells. This report deals with the expression and purification of recombinant adw2 subtype of the preS1 peptide of hepatitis B virus surface antigen in Escherichia coli. The DNA fragments of the full-length or N/C terminal sequence of preS1 synthesized by PCR were inserted into the prokaryotic expression vector pGST-MOLUC, respectively. Reconstitute plasmids (named pGST-preS1, pGST-preS1N, and pGST-preS1C) were confirmed by sequencing analysis and transferred into Escherichia coli BL21(DE3). Recombinant full-length and N/C terminal of preS1 with GST tag were expressed at high levels in soluble form after induction with IPTG. The recombinant proteins were purified by a single-step affinity chromatography method. The immune reactivity of recombinant preS1 was confirmed by Western blot and virus capture assay. Furthermore, when the purified recombinant protein was used to immunize rabbit, the specific antibody titer can reach 10(-7). Thus, our successful expression system and achievement of purified recombinant preS1 protein and its polyclonal antibody lay the foundation for better understanding of the mechanism of HBV PreS1 protein in virus endocytosis and are helpful in seeking the PreS1-related protein.