For subject #Ind. Micro# SHC students

1. Large scale production of
recombinant molecules
HBV vaccines
By
Mr. K.VIJAY M.Sc., TNSET, NET(LS), (Ph.D.)
Assistant Professor,
Department of Microbiology,
Sacred Heart College,
Tirupattur,TN,India.

2. •Hepatitis B is a viral infection which attacks the cells of the liver. It
can be very serious, causing chronic liver failure, liver cancer and
death
•Hepatitis B can be prevented by a vaccination, and in countries
like India where it is relatively common. A course of three (3)
vaccine injections are given with the second injection at least one
month after the first dose and the third injection given six months
after the first dose.
•Afterward an immune system antibody to HBsAg is established in
the bloodstream. The antibody is known as anti-HBsAg. This
antibody and immune system memory then provide immunity to
hepatitis B infection. The first vaccine became available in 1981.
•Hepatitis B vaccine is developed for the prevention of hepatitis
B virus infection. The vaccine contains one of the viral envelope
proteins, hepatitis B surface antigen (HBsAg). It is produced by
yeast cells, into which the genetic code for HBsAg has been
inserted.

3. Recombinant Hepatitis B Vaccine
(HBsAg)
• One of the most recent developments is the production of a
vaccine against hepatitis B using genetically modified yeast
cells.
• The Gene coding for the HBsAg is isolated and cloned into a
Vector Under the control of a strong promoter.
• The cloned gene is transferred to the Yeast Expression
system.
• The gene is allowed to express in the yeast and the
recombinant protein product of the Hepatitis is obtained.
• The protein is later purified and used for vaccination.

4. Gene encoding the 226 amino acid hepatitis B surface antigen
(HBsAg), was cloned into yeast, Saccharomyces cerevisiae.
The 5' end of the HBsAg gene was replaced with another DNA
segment so as to optimize synthesis in yeast.
High-cell-density fermentations of laboratory strains of yeast have
been developed for the production of HBsAg.
The HBsAg (lipoprotein particle) in cell lysates has been purified
to obtain homogeneity.

5. Production of Recombinant HBsAg vaccine
1. HB surface antigen coding gene is isolated from the HB virus.
2. A plasmid DNA is extracted from a bacterium and is cut with
restriction enzyme forming the plasmid vector.
3. The isolated HB surface antigen producing gene is inserted into
the bacterial plasmid vector on forming the recombinant DNA.
4. This recombinant DNA, containing the target gene, is
introduced into a yeast cell forming the recombinant yeast cell.
5. The recombinant yeast cell multiplies in the fermentation tank
and produces the HB surface antigens.
6. The HB antigens are extracted , purified and bottled. It is ready
for vaccination in humans.