Truncated L1 protein of human papillomavirus type 6

A method for obtaining a virus-like particles (VLP) of a human papillomavirus (HPV) 6 L1 protein, the method consisting of:

• a) expressing a HPV L1 gene encoding the HPV6 L1 protein in an E. coli expression system;
• b) disrupting the E. coli, which has expressed the HPV6 L1 protein, in a salt solution having a salt concentration of from 200 mM to 600 mM, centrifuging the solution comprising the disrupted E. coli, and isolating the supernatant without using chromatography;
• c) precipitating the HPV L1 protein from the supernatant of b) by decreasing the salt concentration of the supernatant of b) to from 100 mM to 0, inclusive, by using water or a low salt solution, and collecting the resultant precipitate;
• d) redissolving the precipitate of c) in a salt solution having a salt concentration of from 150 mM to 2500 mM, adding a reductant to it, and then centrifuging the resultant solution, and isolating the supernatant without using chromatography, wherein the supernatant contains the HPV6 L1protein with a purity of at least 50%;
• e) further purifying the HPV 6 L1 protein with a purity of at least 50% obtained in step d) by chromatography;
• and
• f) removing the reductant from the HPV 6L1 protein obtained in step e).