Vaccines work by stimulating the immune system to recognize and destroy microorganisms like bacteria and viruses. There are several types of vaccines including those made from killed or weakened pathogens, toxoids that treat toxins, and surface molecules. DNA vaccines are a newer approach that use only the DNA from pathogens to produce antigenic proteins in the body and stimulate both antibody and T cell immune responses. They provide long-term immunity without refrigeration but more research is needed to address potential risks like genetic toxicity. Overall, vaccination is considered the most effective way to prevent infectious diseases.

1. Supervised by
Prof.Dr.Amina Al.Thwani

2. A vaccine si a biological preparation that improves
immunity to a particular disease. A vaccine typically
contains an agent that resembles a disease-causing
microorganism, and is often made from weakened or
killed forms of the microbe, its toxins or one of its
surface proteins. The agent stimulates the body's
immune system to recognize the agent as foreign,
destroy it, and "remember" it, so that the immune
system can more easily recognize and destroy any of
these microorganisms that it later encounters.
Vaccines

3. Vaccines can be prophylactic (example: to prevent or ameliorate the
effects of a future infection by any natural or "wild" pathogen, or
therapeutic(
(e.g. vaccines against cancer ).

4. Kinds of vacines
1. Killed whole organisms
In this relatively crude approach, the vaccine is made from the
entire organism, killed to make it harmless. The typhoid and
cholera vaccines are examples.
2. Attenuated organisms
Here, the organism has been cultured so as to reduce its
pathogenicity, but still retain some of the antigens of the virulent
form. The Bacillus Calmette-Guérin (BCG) is a weakened
version of the bacterium that causes tuberculosis in cows.

5. 3. Toxoids
In some diseases, diphtheria and tetanus are notorious
examples, it is not the growth of the bacterium that is
dangerous, but the protein toxin that is liberated by it.
Treating the toxin with, for example, formaldehyde,
denatures the protein so that it is no longer dangerous,
but retains some epitopes on the molecule that will elicit
protective antibodies.
4. Surface molecules
Antibodies are most likely to be protective if they bind to
the surface of the invading pathogen triggering its
destruction. Several vaccines employ purified surface
molecules:

6. 5. Inactivated virus
Like killed bacterial vaccines, these vaccines contain whole virus
particles that have been treated (again, often with formaldehyde)
so that they cannot infect the host's cells but still retain some
unaltered epitopes. The Salk vaccine for polio (IPV) is an
example.
•Influenza vaccine contains purified hemagglutinins from the viruses
currently in circulation around the world.

7. 6. Attenuated virus
In these vaccines, the virus can still infect but has been
so weakened that it is no longer dangerous. The measles,
mumps, and rubella ("German measles") vaccines are
examples. The Sabin oral polio vaccine (OPV) is another
example. It has advantages over the Salk vaccine in that
eparation that improves immunity to a particular
disease.

8. is the administration of antigenic material (a vaccine)
to stimulate the immune system of an individual to
develop adaptive immunity to a disease. Vaccines can
prevent or ameliorate the effects of infection by many
pathogens. The efficacy of vaccination has been
widely studied and verified; for example, the
influenza vaccine, the HPV vaccine, and the chicken
pox vaccine among others.
Vaccination

9. In general, vaccination is considered to be the most
effective method of preventing infectious diseases.
Toxoids are produced for the immunization against
toxin-based diseases, such as the modification of
tetanospasmin toxin of tetanus to remove its toxic
effect but retain its immunogenic effect.

10. DNA vaccine is DNA sequence used as a vaccine.
This DNA Sequence code for antigenic protein of
pathogen.
As this DNA inserted into cells it is translated to form
antigenic protein. As this protein is foreign to cells , so
immune response raised against this protein.
In this way ,DNA vaccine provide immunity against
that pathogen.
DNA VACCINATION

11. DNA vaccines Vs Traditional vaccines
 Uses only the DNA from
infectious organisms.
 Avoid the risk of using
actual infectious organism.
 Provide both Humoral &
Cell mediated immunity
 Refrigeration is not
required
 Uses weakened or killed
form of infectious
organism.
 Create possible risk of the
vaccine being fatal.
 Provide primarily
Humoral immunity
 Usually requires
Refrigeration.
DNA vaccines Traditional vaccines

12. HOW DNA VACCINE IS MADE
Viral gene
Expression
plasmid
Plasmid with foreign gene
Recombinant DNA
Technology

13. Bacterial cell
Transform into
bacterial cell
Plasmid
DNA

14. Plasmid DNA get
Amplified

15. Plasmid DNA
Purified
Ready to use

16. METHODS OF DELIVERY
Syringe delivery:-
Either intramuscularly or
Intradermally
Gene gun delivery:-

17. HOW DNA VACCINE WORKS
BY TWO PATHWAYS
ENDOGENOUS :- Antigenic Protein is presented by
cell in which it is produced.
EXOGENOUS :- Antigenic Protein is formed in
one cell but presented by
different cell.

18. ENDOGENOUS PATHWAY
mRNA
Antigenic
Protein
Antigenic
Peptides
MHC-I
Plasmid
DNA
Nucleus

19. Memory T cells
T- Helper Cell

20. EXOGENOUS PATHWAY
Antigenic Protein come outside

21. Memory
Antibodies
Antigen Presenting Cell
Antigenic Peptides
T- Helper Cell
Cytokines
Activated B-Cell Memory B-Cell
Plasma B-Cell
MHC-II

22. WHEN VIRUS ENTER IN THE BODY
Viral Protein
Memory T-Cell
Antibodies

23. ADVANTAGES
Elicit both Humoral & cell mediated
immunity
Focused on Antigen of interest
Long term immunity
Refrigeration is not required
Stable for storage

24. DISADVANTAGES
 Limited to protein immunogen only,
 Extended immunostimulation leads to chronic
inflammation
 Some antigen require processing which sometime
does not occur
 Genetic Toxicity integration of DNA vaccine into host
Genome lead to
 Insertional mutagenesis
 Chromosome instability
 Turn on oncogenes
 Turn off Tumor suppressor genes

25. DISADVANTAGES
 Over Expression of DNA vaccine that lead to:
 Acute or chronic inflammatory responses
 Destruction of normal tissues
 Generation of Autoimmune diseases
 Anti DNAAntibodies
 Anti DNAAntibodies
 Autoimmune Myositis
 Antibiotic Resistance lead to
 Plasmid used is resistance to antibiotics for
selection
 Raise the resistance to same antibiotic in the host