Expression of hepatitis B surface antigen major subtypes in Pichia pastoris and purification for in vitro diagnosis.

This study describes the expression in Pichia pastoris of hepatitis B surface antigens (HBsAg) corresponding to the S region of the four major subtypes: adr, adw2, ayr and ayw3 and to the preS2-S region of the two subtypes adr and adw2. The recombinant yeast strains have been selected amongst methanol utilization positive (Mut+) or sensitive strains (Mut s) and cultivated to high cell density in bioreactor using a short protocol. Our results prove the efficiency of P.