Truncated L1 protein of human papillomavirus type 11

A method for producing a N-terminally truncated HPV11 L1 protein consisting of SEQ ID NO.:

• 2, comprising:
• a) expressing a HPV L1 gene encoding the N-terminally truncated HPV L1 protein in an E. coli expression system;
• b) disrupting the E. coli, which has expressed the N-terminally truncated HPV L1 protein, in a solution at a salt concentration of from 100 mM to 600 mM, and isolating the supernatant;
• c) 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 a precipitate;
• and
• d) redissolving the precipitation of c) in a solution at a salt concentration of from 150 mM to 2500 mM, adding a reductant to it, and then isolating the resultant solution, wherein the solution contains the N-terminally truncated HPV L1 protein with a purity of at least 50%.