Oral presentation on

Vaccine as immunotheraputic agent

Microbiology departmentBenha faculty of medicine

We will talk about :

Definitions: History of vaccine discovery : Properties of ideal vaccines : Types of vaccines : 1- Character 2- Preparation

3- Exampels Combined immunization

Active Immunization Stimulates the host’s 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

VaccinesProvide an antigenic stimulus that does not cause disease but can produce long lasting, protective immunity.

HISTORYThe word vaccine derived

from the word vaca, meaning a cow in Spanish. 

Edward Jenner discovered a vaccination for smallpox disease in 1796.

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.  

Louis Pasteur performed first experiment in immunology in July 6,1885.

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

Golden age of vaccine technology from 1950-1970.

During this period, vaccines for polio, measles, mumps and rubella was developed.

Properties of an ideal vaccine Should provide long lasting immunity.

Should induce both humoral and cell mediated immunity.

Should not induce autoimmunity or hypersensitivity reactions.

Should be inexpensive to produce, easy to store and administer.

Should be safe and effective

Types of vaccines1- 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).

Characters : Do not stimulate local immunity Short lasting Do not stimulate cytotoxic T cell response in

contrast to live attenuated vaccines safe can be given to pregnant woman and immunocompromised host 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)

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.

Characters : stimulate both humoral and cell mediated

immunity, local and systemic. not given to pregnant women and

immunocompromised hosts (may cause diseases) heat unstable

3- Toxoids It is prepared by detoxifying bacterial

toxins. bacterial exotoxins treated by formalin to

destroy toxicity and retain antigenicity e.g.diphtheria and tetanus toxoid.

4- Subunit vaccines use only those antigenic fragments of a

microorganism that best stimulate an immune response.

5-recombinant vaccinesSubunit 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.

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.

6-Conjugated vaccines have been developed in recent years to deal with

the poor immune response of children to vaccines based on capsular polysaccharides.

Combined immunization (Vaccination)

Immunization against diseases is recommended in combination (for young children) as :

diphtheria, tetanus (lockjaw), and pertussis (whooping cough), given together (DTP).

measles, mumps, and rubella, give together as MMR

Haemophilus influenzae b (Hib) with DTP

influenzae b (Hib) with inactivated poliomyelitis vaccine (IPV)

influenza; and Neisseria meningitidis (meningococcal meningitis).

ahmed hamza