immunology 4

Principle of Immunization

Immunization
In medicine : the fact or process of becoming immune, as against a disease, usually as a result of activation of immune system

In finance : method of protection against flactuation in investing rate

How does the body become immune against a disease?
Passive immunization
Active immunization
Following clinical infection
Following subclinical infection
Following vaccination
Following administration of
Immunoglobulin or antiserum

Transfer of maternal

Antibodies Through milk


Transfer of maternal
Antibodies Through placenta

natural

acquired

Immunization

Active immunization
Resistance developed in response to stimulus by an antigen (infecting agent or vaccine) and is characterized by the production of antibodies by the host.

Passive immunization

Immunity conferred by an antibody produced in another host. It may be acquired naturally or artificially (through an antibody-containing preparation).

Immunizing agents

Immunizing agents
antisera
immunuglobulins
vaccines


Immunoglobulins: Passive immunization
There are 5 major classes: IgM, IgA, IgG, IgE, IgD.
Two types of immunoglobulin preparations are available for passive immunization:
Normal human immunoglobulin
Specific (hyper-immune) human immunoglobulin

Immunoglobulins: indications.......

Used when there is a high risk of infection and insufficient time for the body to develop its own immune response,

Or when people cannot synthesize antibodies, and when they have been exposed to a disease that they do not have immunity against.

Igs usually given IV or s.c

Usually temporary, lasting from few weeks to 3-4 months

Always risk of hypersensitivity reaction

Antisera or antitoxins: Passive immunization
These are blood serum containig polyclonal antibodies , or antibodies against specific toxin prepared in animals or non human sources such as horses.

Immunoglobulin and antiserum: examples

Human normal immunoglobulin
Human specific immunoglobulin
Non human Ig (antisera)
Hepatitis A
Measles
Rabies
Tetanus
Mumps
Hepatitis B
Varicella
Diphtheria
Diphtheria
Tetanus
Gas gangrene
Botulism
Rabies


Vaccination: Active immunization
Vaccination is a method of giving antigen to stimulate the immune response through active immunization.

A vaccine is an immuno-biological substance designed to produce specific protection against a given disease.
A vaccine is antigenic or immunogic but not “pathogenic”.

Types of vaccines

Live vaccines
Attenuated live vaccines
Inactivated (killed vaccines)
Toxoids
Polysaccharide and polypeptide (cellular fraction) vaccines
Surface antigen (recombinant) vaccines.

Live vaccines

Live vaccines are made from live infectious agents without any amendment.
The only live vaccine is “Variola” small pox vaccine, made of live vaccinia cow-pox virus (not variola virus) which is not pathogenic but antigenic, giving cross immunity for variola.

Live attenuated (avirulent) vaccines

Virulent pathogenic organisms are treated to become attenuated and avirulent but antigenic.


Live attenuated vaccines should not be administered to persons with suppressed immune response :
Leukemia and lymphoma
Other malignancies
Receiving corticosteroids and anti-metabolic agents
Radiation
pregnancy

Inactivated (killed) vaccines

Organisms are killed or inactivated by heat or chemicals but remain antigenic. They are usually safe but less effective than live attenuated vaccines. The only absolute contraindication to their administration is a severe local or general reaction to a previous dose.

Toxoids: detoxyfied toxin

They are prepared by detoxifying the exotoxins of some bacteria rendering them antigenic but not pathogenic.

The antibodies produces in the body as a consequence of toxoid administration neutralize the toxic moiety produced during infection rather than act upon the organism itself. In general toxoids are highly efficacious and safe immunizing agents.

Polysaccharide and polypeptide (cellular fraction) vaccines

They are prepared from extracted cellular fractions e.g. meningococcal vaccine from the polysaccharide antigen of the cell wall, the pneumococcal vaccine from the polysaccharide contained in the capsule of the organism, and hepatitis B polypeptide vaccine.

Their efficacy and safety appear to be high.

Surface antigen (recombinant) vaccines.
It is prepared by cloning HBsAg gene in yeast cells where it is expressed. HBsAg produced is then used for vaccine preparations.


Their efficacy and safety also appear to be high.

Types of vaccines

Live
vaccines
Live
Attenuated vaccines
Killed
Inactivated vaccines
Toxoids
Cellular fraction vaccines
Recombinant vaccines
Small pox variola vaccine
BCG
Typhoid oral
Plague
Oral polio
Yellow fever
Measles
Mumps
Rubella
Intranasal
Influenza
Typhus
Typhoid
Cholera
Pertussis
Plague
Rabies
Salk polio
Intra-muscular influenza
Japanise encephalitis
Diphtheria
Tetanus
Meningococcal polysaccharide vaccine
Pneumococcal polysaccharide vaccine
Hepatitis B polypeptide vaccine
Hepatitis B vaccine


Routes of administration
Oral route (Polio vaccine, oral BCG vaccine

Intradermal route (BCG vaccine)

Deep subcutaneous or intramuscular route (most vaccines

Scarification (small pox vaccine)

Intranasal route (live attenuated influenza vaccine)

Differences among Intradermal, S.C and IM injections

Periods of maintained immunity due to vaccines

Short period (months): cholera vaccine
Two years: TAB vaccine
Three to five years: DPT vaccine
Five or more years: BCG vaccine
Ten years: yellow fever vaccine
Solid immunity: measles, mumps, and rubella vaccines.


Immunization Schedule In Iraq
* First 24hr : hepatitis B vacc .(HBV)
* 72 hr. : BCG , OPV.
* 2m. : DPT , OPV , HBV , Hib , Rota virus vacc .
* 4m. : DPT , Hib , OPV , Rota virus vacc .
* 6m. : DPT , HBV , Hib , Opv , Rota virus vacc.
* 9m. : Measles vacc. , + Vitamine A 100,000 I.u.
* 15m. : MMR
* 18m. : DPT , Hib , Opv , Vitamine A 200.000 I.u.
* 4 – 6 y. : DPT , Opv , MMR .

Complications of vaccination

• . local skin reaction .
• . Fever.
• . Renal complications.
• . Neurological complications.
• . Paralytic complications.
• . Encephalitic complication .
• . Joint involvement .
• . Lymphadenopathy .
• . Teratogenic effect .
• .Skeletal complications.
• . Hematological complication .