Case Study: Hepatitis B vaccines: a product of rDNA techniques

This chapter discusses the use of recombinant DNA technology to produce a vaccine, that is, a protection against infection. Hepatitis B virus (HBV) is the major infective agent of liver and it can cause either acute or chronic viral hepatitis. In acute hepatitis, the virus can be cleared, leading to recovery. In chronic hepatitis B, the virus persists and may lead to progressive liver disease, cirrhosis, and primary hepatocellular carcinoma. The virus is maintained in the population primarily via maternal transmission. In the developed countries, infection is also transmitted by exposure to contaminated needles or instruments, by blood transfusion, or by sexual contact. The main steps in the production of hepatitis vaccine (HB-Vax) are yeast fermentation, culture harvest, cell rupture and extraction, absorption onto silica, butyl agarose adsorption, thiocyanate treatment, sterile filtration, formaldehyde treatment, adsorption onto alum, and filling and packaging. One of the key properties associated with the immunogenicity of a vaccine is the availability of epitopes (antigenic determinants) capable of eliciting the production of specific antibodies.