Principles of Immunity Flashcards
What does natural passive immunity involve?
Placental transfer of IgG
Colostral transfer of IgA - yellowish liquid secreted by the mammary gland
What is human normal immunoglobulin?
A preparation of the proteins from the plasma contains anitbodies of normal adult levels from several different donors.
What is specific immunoglobulin?
A preparation from the human plasma that is selected for its particularly high immunoglobulin count against a specific pathogen.
What can immunoglobulins be used for?
Post - exposure prophylaxis
Give an example of Human Normal Immunoglobulin
Hepatits A, Measles, Rubella
Give an example of a human specific immuhnoglobulin
Hep B
Rabies
Tetanus
What are the advantages and disadvantages of passive immunity?
Advantages - Immediate protection
Disadvantages - Short term effect - no immunological memory
Serum Sickness - body recognises antibody as foreign - anaphylaxis
What is natural and artificial active immunisation?
Natural - exposure / infection
Artificial - Vaccination
What immunoglobulin is responsible for the primary response to infection?
IgM next is IgG
What are common diseases we vaccinate against?
Measles, mumps and rubella
Define contraindications
Procedure harmful to the person
What are the contraindications of vaccination?
Febrile illness - displaying symptoms of fever
Pregnancy - cannot be given live attenuated viruses
Allergy
Immunocompromised
How is attenuation of a live virus achieved?
Repeat passage in cell culture or a non-human host.
Why do attenuated viruses offer lifelong immunity?
They elicit a strong cellular and antibody response
What are the downsides to live attenuated viruses?
Remote possibility that the attenuated form can revert to a virulent form and cause disease
Who cannot be given attenuated viruses?
People who have a damaged or weak immune system
Which microorganism allows easy/difficult formation of an attenuated vaccine?
Easy for viruses
Difficult for bacteria
How are inactivated vaccines created?
Killing the disease causing microbe with chemicals (formaldehyde), heat or radiation
They are killed organisms, inactivated microbial exotoxin or purified fractions of the micro-organisms
What is the advantage/disadvantage of inactivated vaccines?
More stable and safer than live vaccines
Stimulate weaker immune response
Adjuvant often required
Define adjuvant
A substance that enhances the body’s immune response to an antigen
What does an acellular vaccine consist of?
Only the antigenic part of the organism (flagella, capsule or part of the protein cell wall)
Advantages and disadvantages of acellular vaccines?
Advantages - cannot cause disease - safe for immunocompromised
Disadvantages - Don’t induce the strongest immune response
When are toxoid vaccines used?
When a bacterial toxin is the main cause of the illness
How are the bacterial toxins inactivated?
They are treated with formalin
What is the immune response to a toxoid?
Learns how to fight off the natural toxin
Antibodies produced that lock onto and block the toxin
How does the BCG vaccine protect against mycobacterium tuberculosis?
It uses an attenuated strain of mycobacterium bovis - similar to virulent organism but does not cause serious disease
What do subunit vaccines contain?
Antigens that best stimulate the immune system - use epitopes
What type of immune response do you get from subunit vaccines?
Strong immune response
How do conjugate vaccines work?
Link antigens or toxoids from the microbe to the polysaccharides - enabling the immature immune system to react to polysaccharide coatings
Young children can’t respond to antigens disguised by polysaccharide coatings
What are DNA vaccines?
DNA sequence coding for antigen is incorporated into some body cells, causes a large immune response
Give an example of an adjuvant
Aluminium salts, causes a mild inflammatory response
What is meant by heard immunity
Those who are vaccinated are less likely to be the ones spreading an infection, reduces risk of unvaccinated individuals being exposed to infection
Individuals who cannot get vaccinated will benefit
