Purification of virus-like particles of recombinant human papillomavirus type 11 major capsid protein L1 from Saccharomyces cerevisiae

Recombinant major capsid protein, L1 (M-r = 55,000), of human papillomaviru s type 11 was expressed intracellularly at high levels in a galactose-induc ible Saccharomyces cerevisiae expression system by an HPV6/11 hybrid gene. The capsid protein self-assembled into virus-like particles (VLPs) and acco unted for 15% of the total soluble protein. A purification process was deve loped that consisted of two main steps: microfiltration and cation-exchange chromatography. The purified VLPs were 98% homogeneous, and the overall pu rification yield was 10%. The final product was characterized by several an alytical methods and was highly immunogenic in mice. (C) 1999 Academic Pres s.