Application of rDNA Technology and Genetic
Engineering in the Production of Hepatitis Vaccine
The Recombivax HB (Merck) is a hepatitis B vaccine and one of the most
significant developments in recombinant DNA technology field. This vaccine
comprises of highly specific antibodies. Hepatitis causes a severe acute infection
that ulti mately results in chronic infection and permanen t liver damage. It is
caused by Hepatitis B Virus (HBV) which is an enveloped and double -stranded
DNA virus. Hepatitis B infection can be prevented with a vaccine made using
recombinant DNA technology.
In figure 3. 22, the steps followed in the production of Hepatitis B vaccine
using recombinant DNA technology are enlisted:
1) The DNA (genetic material) of the hepatitis virus is extracted. At this stage
the surface proteins incite an immune response.
2) The individual genes are analysed and identified.
3) The specific gene which directs production of surface protein is located.
4) The gene is then removed from the viral DNA and inserted into the plasmid.
5) The plasmids are accurately inserted into the corresponding yeast cells.
6) This cell is then allowed to grow via ferm entation. Thus, the cells reproduce
and generate more quanta of surface proteins.
7) After 2 days the yeast cells are ruptured to release the surface proteins.
8) The resulting mixture is processed to extract and purify the surface proteins.
9) A large amount of p ure surface proteins are obtained which provoke an
10) The resulting surface proteins are mixed with other ingredients under
optimum conditions to obtain the vaccine.
Antigenic Markers for HBV-Infection
The fol lowing three antigenic markers have been identified for the HBV
1) HBsAg: It is a surface antigen found on the viral envelope. It represents one
of the earliest marks and appears in the blood during incubation.
9) Result is a
large quantity of
that provoke an
7) After 48
6) Yeast is grown by
1) Genetic material
is extracted from
3) Gene that
4) Gene is
viral DNA and
Figure 3.21: Production of Hepatitis B Vaccine
Source: Adapted from Remington: The Science and Practice of
Pharmacy Volume I (20th ed.), by Alfonso G. (2000), (Lippincott
Williams & Wilkins).
2) HBeAg: It is obtained from the prote in capsid surrounding the DNA. It is a
marker for causing active infection.
3) HBc: It is a core antigen which does not circulate in the blood, and
stimulates the production of the primary antibodies against HBV. These
antibodies are not protective, and hence, do not provide immunity.