[Expression of HPV16 E6 recombinant protein and preparation of its rabbit polyclonal antibody]

Objective To express E6 protein of human papillomavirus (HPV) type 16 in prokaryotic expression system and prepare its polyclonal antibody. Methods HPV16 E6 gene was obtained from Siha cells by PCR and cloned into pET21a(+) vector to construct the recombinant plasmid pET21a(+)/HPV16 E6 that was confirmed by sequencing. The recombinant plasmid pET21a(+)/HPV16 E6 was transformed into E. coli BL21 (DE3). The HPV16 E6-His tag recombinant protein was expressed after the induction of isopropyl beta-D-1-thiogalactopyranoside (IPTG), purified by Ni-NTA affinity chromatography, and then analyzed by Western blot analysis. The purified HPV16 E6 recombinant protein was used to immunize Japanese white rabbits to prepare polyclonal antibody. The titer of the serum polyclonal antibody was determined by ELISA. The specificity of the polyclonal antibody was analyzed by Western blotting and immunofluorescence. Results The recombinant plasmid pET21a(+)/HPV16 E6 was successfully constructed and confirmed by sequencing. After the recombinant plasmid pET21a(+)/HPV16 E6 was transformed into E. coli BL21 (DE3), the recombinant HPV16 E6 protein was expressed and purified by affinity chromatography. The polyclonal antibody at a titer of 1:40 000 was obtained by immunizing Japanese big-ear white rabbit with the purified recombinant HPV16 E6 protein, and its specificity was confirmed by Western blotting and immunofluorescence assay. Conclusion HPV16 E6 recombinant protein was successfully expressed and the rabbit polyclonal antibody against HPV16 E6 recombinant protein was prepared.