Principles of Immunity Flashcards
What does natural passive immunity involve?
Placental transfer of IgG
Colostral transfer of IgA - yellowish liquid secreted by mammary gland
What is human normal immunoglobulin?
Preparation of proteins from plasma
Contains antibodies of normal adult levels from several different donors
What is specific immunoglobulin?
Preparation from human plasma
Selected for high immunoglobulin count against 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
(MMR)
Define contraindications
Procedure harmful to person
Symptom/medical condition that is reason for person not to receive particular treatment/procedure as it may be harmful
What are the contraindications of vaccination?
Febrile illness - symptoms of fever
Pregnancy - cannot give live attenuated viruses
Allergy
Immunocompromised
How is attenuation of a live virus achieved?
(weakening of virus)
Repeat passage in cell culture or non-human host
Why do attenuated viruses offer lifelong immunity?
Elicit strong cellular and antibody response
What are the downsides to live attenuated viruses?
Attenuated form can revert to virulent form and cause disease
Who cannot be given attenuated viruses?
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?
Contain viruses with genetic material that has been destroyed by heat, chemicals (formaldehyde) or radiation
(Killed organisms, inactivated microbial exotoxin, purified fractions of micro-organisms)
What is the advantage/disadvantage of inactivated vaccines?
More stable and safer than live vaccines
Stimulate weaker immune response
Adjuvant often required
(ingredient in some vaccines helps create stronger immune response people receiving vaccine)
Define adjuvant
substance enhances body’s immune response to antigen
What does an acellular vaccine consist of?
Only antigenic part of organism (flagella, capsule or part of protein cell wall)
Advantages and disadvantages of acellular vaccines?
Advantages - cannot cause disease - safe for immunocompromised
Disadvantages - Don’t induce strongest immune response
When are toxoid vaccines used?
When bacterial toxin is main cause of illness
How are the bacterial toxins inactivated?
Treated with formalin (formaldehyde solution)
What is the immune response to a toxoid?
Learns how to fight off natural toxin
Produce antibodies that lock onto and block toxin
How does the BCG vaccine protect against mycobacterium tuberculosis?
Attenuated strain of mycobacterium bovis
Similar to virulent organism but does not cause serious disease
What do subunit vaccines contain?
Fragments of protein/polysaccharide from pathogen, uses epitopes
(part of antigen recognised by immune system)
What type of immune response do you get from subunit vaccines?
Strong immune response
How do conjugate vaccines work?
Link antigens or toxoids from microbe to polysaccharides - enabling 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 large immune response
Give an example of an adjuvant
Aluminium salts, causes a mild inflammatory response
What is meant by heard immunity
Vaccinated less likely to spread infection, reduces risk of unvaccinated being exposed to infection
Individuals who cannot get vaccinated will benefit
