2. We will talk about :
ďś Definitions:
ďś History of vaccine discovery :
ďś Properties of ideal vaccines :
ďś Types of vaccines :
1- Character
2- Preparation
3- Exampels
ďś Combined immunization
3. Active Immunization
Stimulates the hostâs immune system to
produce specific antibodies or cellular
immune responses or both which would
protect against or eliminate a disease.
Passive Immunization
preparation of antibodies that neutralizes a
pathogen and is administered before or
around the time of known or potential
exposure
4. Vaccines
Provide an antigenic stimulus that does not
cause disease but can produce long lasting,
protective immunity.
5. HISTORY
ď The word vaccine derived from
the word vaca, meaning a cow
in Spanish.
ď Edward Jenner discovered a
vaccination for smallpox
disease in 1796.
ď Jenner scratched some pus
from a Cowpox sore into the
arm of a boy James Phipps
to see whether exposure to
the virus protect the child from
the smallpox virus.
6. ď Louis Pasteur performed first experiment in immunology in
July 6,1885.
ď Louis Pasteur treated a boy against rabies by injecting
spinal cord fluid of a rabid dog. The spinal cord fluid
stimulated the production of antibodies against the rabies
virus
7. ďś Golden age of vaccine technology from 1950-
1970.
ďś During this period, vaccines for polio, measles,
mumps and rubella was developed.
8. Properties of an ideal vaccine
ď Should provide long lasting immunity.
ď Should induce both humoral and cell mediated
immunity.
ď Should not induce autoimmunity or
hypersensitivity reactions.
ď Should be inexpensive to produce, easy to store
and administer.
ď Should be safe and effective
9. Types of vaccines
1- Killed vaccine :
Virulent bacteria or viruss used to prepare these vaccines
may be killed by heat (60 °C) or by chemicals (formalin,
phenol or merthiolate).
10. Characters :
ďś Do not stimulate local immunity
ďś Short lasting
ďś Do not stimulate cytotoxic T cell response in contrast to
live attenuated vaccines
ďś safe can be given to pregnant woman and
immunocompromised host
ďś It is heat stable
examples:
a-TAB vaccine against entric fever (heat)
b-Salk vaccine against poliomylitis (formaline)
c-Semples vaccine against rabies (phenol)
d-pertussis vaccine against whooping cough (merthiolate)
11. 2-live attenuated vaccines:
- living m.o lost its virulence so do not produce disease but
produce immunity.
It is prepared by:
a-repeated subculture in unsuitabl condition
e.g BCG vaccine against T.B.
b-growing at high temp. (above optimum temp)
e.g Pasteur anthrax vaccine
c-selection of mutant strains of low virulence
e.g Sabin vaccine against poliomylitis.
12. Characters :
ďś stimulate both humoral and cell mediated immunity,
local and systemic.
ďś not given to pregnant women and immunocompromised
hosts (may cause diseases)
ďś heat unstable
13. 3- Toxoids
ďś It is prepared by detoxifying bacterial toxins.
ďś bacterial exotoxins treated by formalin to destroy
toxicity and retain antigenicity
ďś e.g.diphtheria and tetanus toxoid.
14. 4- Subunit vaccines
use only those antigenic fragments of a microorganism
that best stimulate an immune response.
5-recombinant vaccines
Subunit vaccines that are produced by genetic modification
techniques, meaning that other microbes are programmed
to produce the desired antigenic fraction.
Example:
the vaccine against the hepatitis B virus consists of a portion
of the viral protein coat that is produced by a genetically
modified yeast.
15. Example:
the vaccine against the hepatitis B virus consists of a
portion of the viral protein coat that is produced by a
genetically modified yeast.
16. 6-Conjugated vaccines
have been developed in recent years to deal with the
poor immune response of children to vaccines based on
capsular polysaccharides.
17. Combined immunization (Vaccination)
Immunization against diseases is recommended in
combination (for young children) as :
ďś diphtheria, tetanus (lockjaw), and pertussis (whooping
cough), given together (DTP).
ďś measles, mumps, and rubella, give together as MMR
ďś Haemophilus influenzae b (Hib) with DTP
ďś influenzae b (Hib) with inactivated poliomyelitis vaccine
(IPV)
ďś influenza; and Neisseria meningitidis (meningococcal
meningitis).