Hepatitis B vaccine produced in yeast

Area of Science:

• Biotechnology
• Virology
• Immunology

Background:

• Hepatitis B virus (HBV) poses a significant global health challenge.
• Effective vaccines are crucial for preventing HBV infection.
• Recombinant DNA technology offers a pathway for producing viral antigens.

Purpose of the Study:

• To develop a yeast-based expression system for hepatitis B surface antigen (HBsAg).
• To characterize the structure and immunogenicity of yeast-derived HBsAg.
• To assess the potential of yeast-produced HBsAg as a vaccine candidate.

Main Methods:

• Cloning the HBsAg gene into Saccharomyces cerevisiae.
• Optimizing gene expression using a synthetic DNA segment.
• High-cell-density fermentation for antigen production.
• Purification and characterization of HBsAg particles.
• Immunization of chimpanzees and viral challenge studies.

Main Results:

• Successful high-level production of HBsAg in yeast.
• Yeast-derived HBsAg forms 22 nm lipoprotein particles, similar to human plasma HBsAg.
• Yeast HBsAg exhibits identical reactivity to human HBsAg with monoclonal antibodies.
• Purified HBsAg formulated with alum adjuvant conferred immunity in chimpanzees against HBV challenge.

Conclusions:

• Saccharomyces cerevisiae is a viable host for producing functional HBsAg.
• Yeast-derived HBsAg is structurally and antigenically similar to human HBsAg.
• This recombinant HBsAg holds promise as a safe and effective vaccine component against hepatitis B.