Hepatitis B vaccines prepared from yeast by recombinant DNA techniques: memorandum from a WHO meeting.

A meeting of experts was convened on 19-21 November 1984 in Geneva, Switzerland, to advise the World Health Organization on the production of hepatitis B vaccine prepared from yeast (Saccharomyces cerevisiae), using recombinant DNA technology. This vaccine development follows the advances in molecular genetics that have permitted genes coding for biologically active substances to be identified, analysed with fine precision, transferred within and between host organisms, and expressed under controlled conditions so as to obtain efficient synthesis of the product which they encode. The gene for hepatitis B surface antigen (HBsAg, the coat protein of the virus) has been cloned and inserted into several expression vectors. These recombinants have been introduced into and have been expressed in yeast cells. The meeting, which included representatives from seven manufacturers, presented preliminary guidelines for the control and testing of hepatitis B vaccine produced in yeast.