About Vaccines

3. ABDUL LATIF UNI ERSITY
KHAI PUR
Presentation Topic: Biotechnology applications for the discovery of vaccines
Presented By: Abdul-Rahman, Ali Gohar, Ayaz
Ahmad, Aamir Khoso & Ghulam Mustafa

4. Presented to: Respected Sir
Muhammad Saleem Lashari

5. Introduction to Vaccines
A biological preparation, which evokes an immune response when administered
into the body, is termed as vaccines. This usually consists of parts of pathogen
in its weakened state or its products. This triggers an immune response from the
body to the particular disease without actually causing the disease.
Vaccines are preparation, containing weakened or dead microbes of the kind
that cause disease, administered to stimulate the immune system to produce
antibodies against the disease. Vaccine was used by British Physician Edward
Jenner at the end of 18th century in the terms “vaccine disease” means at that
time the Sore of other disease is inoculated to immunize the person.

6. Our discussion is about the applications of Biotechnology for production of
Vaccines. So now a days so-many vaccines are developed by applying the
biotech methods.
Recombinant vaccines:
Biotechnology sector has also played its part in developing vaccines against
certain diseases. Such vaccine which makes use of recombinant DNA
technology is known as recombinant vaccines. It is also known as subunit
vaccines.
Recombinant vaccines can be broadly grouped into two kinds:
(i) Recombinant protein vaccines: This is based on production of recombinant
DNA which is expressed to release the specific protein used in vaccine.

7. preparation.
(ii) DNA vaccines: Here the gene encoding for immunogenic protein is isolated
and used to produce recombinant DNA which acts as vaccine to be injected into
the individual.
Steps involved:
Production of recombinant vaccines involves the following steps:
1. First and foremost, it is important that the protein which is crucial to the
growth and development of the causative organism be identified.
The corresponding gene is then isolated applying various techniques. Further to
this, an extensive study of the gene explains the gene expression pattern

8. 1. involved in the production of corresponding protein.
2. This gene is then integrated into a suitable expression vector to produce a
recombinant DNA.
3. This rDNA is used as vaccines or is introduce into another host organism to
produce immunogenic proteins which acts as vaccines.
Recombinant protein vaccines:
A pathogen upon infection produces proteins, vital for its functions, which elicit
an immune response from the infected body. The gene encoding such a protein
is isolated from the causative organism and used to develop a recombinant
DNA.

9. This DNA is expressed in another host organism, like genetically engineered
microbes; animal cells; plant cells; insect larvae etc, resulting in the release of
the appropriate proteins which are then isolated and purified. These when
injected into the body, causes immunogenic response to be active against the
corresponding disease providing immunity against future attack of the pathogen.
Based on the proteins involved in evoking immune response recombinant
protein vaccines are of two types:
Whole protein vaccines: The whole immunogenic protein is produced in
another host organism which is isolated and purified to act as vaccines.

10. Polypeptide vaccines: It is known that in the immunogenic protein produced,
the actual immunogenic property is limited to one or two polypeptides forming
the protein. The other parts of the protein may be successful in evoking an
immune response but do not actually cause the disease. For e.g. in the case of
cholera caused by Vibrio cholera, consists of three polypeptide chains like A1,
A2, and B. The A polypeptides are toxic while B is non-toxic. Thus while
producing vaccines, the polypeptide B is produced by rDNA technology and
used for vaccination.

11. DNA vaccines:
It refers to the recombinant vaccines in which the DNA is used as a vaccine.
The gene responsible for the immunogenic protein is identified, isolated and
cloned with corresponding expression vector. Upon introduction into the
individuals to be immunized, it produces a recombinant DNA. This DNA
when expressed triggers an immune response and the person becomes
successfully vaccinated.
The mode of delivery of DNA vaccines include: direct injection into muscle;
use of vectors like adenovirus, retrovirus etc; in vitro transfer of the gene into
autologous cells and re-implantation of the same and particle gun delivery of
the DNA.

12. In certain cases, the responsible gene is integrated into live vectors which are
introduced into individuals as vaccines. This is known as live recombinant
vaccines. E.g. vaccinia virus. Live vaccinia virus vaccine (VV vaccine) with
genes corresponding to several diseases, when introduced into the body elicit
an immune response but does not actually cause the diseases.
Advantages:
(i) Since it does not involve actual pathogen, recombinant vaccines is
considered to be safe than the conventional vaccines.
(ii) It induces both humoral and cellular immune response resulting in effective
vaccination.

13. Risks involved:
(i) High cost of production.
(ii) Have to be stored at low temperature since heat destabilizes protein. Hence
storage and transportation is tedious.
(iii) Individuals with immunodeficiency may elicit poor immune response.

14. Steps of Production of New Vaccine
Generation of the antigen
The first step in order to produce a vaccine is generating the antigen
that will trigger the immune response. For this purpose the
pathogen’s proteins or DNA need to be grown and harvested using
the following mechanisms:
 Viruses are grown on primary cells such as cells from chicken
embryos or using fertilised eggs (e.g. influenza vaccine) or cell
lines that reproduce repeatedly (e.g. hepatitis A)

15.  Bacteria are grown in bioreactors which are devices that use a
particular growth medium that optimizes the production of the
antigens
 Recombinant proteins derived from the pathogen can be
generated either in yeast, bacteria or cell cultures.
Release and isolation of the antigen
The aim of this second step is to release as much virus or bacteria as
possible. To achieve this, the antigen will be separated from the cells
and isolated from the proteins and other parts of the growth medium

16. that are still present.
Purification
In a third step the antigen will need to be purified in order to
produce a high purity/quality product.
This will be accomplished using different techniques for protein
purification. For this purpose several separation steps will be
carried out using the differences in for instance protein size,
physio-chemical properties, binding affinity or biological activity.

17. Addition of other components
The fourth step may include the addition of an adjuvant, which is a
material that enhances the recipient’s immune response to a
supplied antigen. The vaccine is then formulated by adding
stabilizers to prolong the storage life or preservatives to allow multi-
dose vials to be used safely as needed. Due to potential
incompatibilities and interactions between antigens and other
ingredients, combination vaccines will be more challenging to
develop. Finally, all components that constitute the final vaccine are
combined and mixed uniformly in a single vial or syringe.

18. Packaging
Once the vaccine is put in recipient vessel (either a vial or a syringe),
it is sealed with sterile stoppers. All the processes described above
will have to comply with the standards defined for Good
Manufacturing Practices that will involve several quality controls and
an adequate infrastructure and separation of activities to avoid cross-
contamination, as shown in the diagram below. Finally, the vaccine is
labelled and distributed worldwide.

20. Restriction for the discovery of New Vaccines
According to the Vaccination point of view the various species cause
different diseases such as HIV (Human immune deficiency Virus),
Influenza virus which causes the Cold, Hepatitis-C are not
vaccinated because there is no vaccine for these diseases.
Researchers have made so many struggles to produce a vaccine for
these type of diseases but they have to face the restrictions i.e. about
200 species of influenza virus have been detected. So how many
types of vaccines will be prepared for the influenza virus.

21. Different vaccines are produced in different periods of time and
estimated time for the production is given by the researchers. It had
taken 105 years after the discovery of the typhoid bacterium to
develop a vaccine for typhoid. For whooping cough (pertussis) it had
taken 89 years; for polio and measles 47 and 42 years respectively.
But the time lag was getting shorter. It had only taken 16 years from
the discovery of the hepatitis B virus to the development of a
vaccine.

22. The biotechnology era has experienced significant changes in the
number of companies involved in vaccine manufacturing as well as in
the production systems they use. Nevertheless, challenges in this area
are multiple. In the current vaccine-manufacturing environment, time
to market and cost effectiveness are key issues that need to be
addressed.
One important difference between the production of vaccines and
other biopharmaceuticals is the risk-safety consideration related to
working with pathogens and pathogenic antigens. As with all

23. biomolecules purified from crude biological material, the removal
of contaminants (e.g., derivatives from host cell such as DNA,
protein, or leachable), must be documented. However, the removal
or inactivation of adventitious viruses remains a unique challenge.

24. Conclusion
In simple words, Biotechnology play a major role in the production
of new vaccines, which will be Tested, Measured, cheaper and
Nanotechnology based Vaccines. The Multiple vaccines of Tetanus,
Typhoid, Hepatitis and Tuberculosis.
Vaccinology has been very effective in preventing infectious
diseases. However, in several cases, the conventional approach to
identify protective antigens, based on biochemical, immunological
and microbiological methods, has failed to deliver successful vaccine

25. candidates against major bacterial pathogens. The recent
development of powerful biotechnological tools applied to
genome-based approaches has revolutionized vaccine development,
biological research and clinical diagnostics. The availability of a
genome provides an inclusive virtual catalogue of all the potential
antigens from which it is possible to select the molecules that are
likely to be more effective.