Question

What are recombinant DNA vaccines? Give two examples of such vaccines. Discuss their advantages.

Answer 1

A recombinant vaccine is a vaccine produced through recombinant DNA technology. This involves inserting the DNA encoding an antigen that stimulates an immune response into bacterial or mammalian cells. Recombinant DNA technology has allowed the production of antigenic polypeptides of pathogen in bacteria or yeast. Vaccines produced using this approach allow large-scale production and hence greater availability for immunisation, e.g., hepatitis B vaccine (Recombivax HB) produced from yeast. As of June 2015 one human DNA vaccine had been approved for human use, the single-dose Japanese encephalitis vaccine called IMOJEV, released in 2010 in Australia.

Advantages of recombinant DNA vaccines:

1. No risk for infection
2. Ease of development and production
3. Stability for storage and shipping
4. Cost-effectiveness
5. Expression and purification of recombinant proteins
6. Long-term persistence of immunogen
7. In vivo expression ensures protein more closely resembles normal eukaryotic structure, with accompanying post-translational modifications.