Immunology and microbiology
Outline of the lesson
What is an immunization? Any process that develops resistance to a specific
disease. The production of immunity in an individual by
artificial means. the creation of immunity usually against a particular
disease; especially : treatment (as by vaccination) of an
organism for the purpose of making it immune to a particular pathogen
Active immunization (vaccination)
Involves the introduction of, either orally or by injection (inoculation), of specially treated bacteria, viruses or their toxins to stimulate the production of antibodies.
Active immunization is achieved by injecting( or administering orally) small amount of antigen, called the vaccine into the body of an individual.
The process is called vaccination.
If the whole organism is used as the vaccine, it is first made safe by being killed or attenuated.
The antigen stimulates the body to manufacture antibodies against the antigen.
Often a second, booster injection is given and this stimulates a much quicker production of antibody which is longer lasting and
which protects the individual from the disease for a considerable time.
Types of vaccines used
2. Killed organisms
3. Live vaccines ( attenuated organisms)
Toxins produced by tetanus and diphtheria bacteria are detoxified with formaldehyde, yet their antigen properties remain.
Therefore, vaccination with toxoids will stimulate antibody production without producing symptoms of the disease.
Some dead viruses and bacteria are able to provoke a normal antibody response and are used for immunization purpose
Example: Flu vaccine which contains dead flu virus.
Live vaccines( attenuated organism) Attenuated organism may be a mutant variety
with the same antigen but lacking the ability to cause disease.
Attenuated vaccine for the bacterial disease tuberculosis (TB), and for measles, mumps, rubella and polio are in general use.
Name of the disease Vaccine
Influenza Killed virus: must be of right strain
Mumps Living attenuated virus
Measles Living attenuated virus
Poliomyelitis Living attenuated virus given orally
Tubercuolosis living attenuated bacteria
Whooping cough Killed bacteria
Cholera Killed bacteria
Typhoid fever Polysaccharide extract from the bacterial capsule.
DPT- Diphtheria, whooping cough and tetanus.
Is induced by the injection of preformed antibodies.
What are antibiotics?
Chemotherapeutic agent usually obtained from living organism.
Metabolic product of one organism that in minute quantity inhibits the growth of other microorganism.
Wakshman 1945, chemical substances of microbial origin which in small amounts exert antimicrobial activity.
In 1929 Alexander Fleming, on agar plate inoculated S. aureus, became contaminated with a mold that mold appeared surrounded by a clear zone, indicating inhibition of bacterial growth or lysis of the bacteria.
Mold was identified as a Penicillium species. Antibiotic as penicillin.
includes penicillin, ampicillin, cephalosporin, bacitracin, streptomycin and etc.
They are used to treat various infections but tend to weaken the body’s natural defense mechanisms and can cause allergies.
Overuse of antibiotics can leads to the development of resistant strains of microorganism.
Characteristics of antibiotics
Broad spectrum Prevent development of resistant form of the
parasites. Should not produce side effects to the host. Should not eliminate the normal flora of the body.
How does antibiotic work?
Inhibits cell wall formation Disrupts cell membrane Inhibits nucleic acid synthesis. Inhibit protein synthesis. Inhibits specific enzyme system.
What are the antimicrobial action of different kinds of antibiotics?