Flashcards in 12.2 - Antibodies and immunity Deck (29):
What are antibodies?
Soluble glycoprotein molecules
Where are antibodies produced?
Plasma cells (B lymphocytes)
What region is different in all antibodies?
What are antibodies made up of?
4 polypeptide chains
Chain of sugar molecules attached to constant region
Antigen binding sites
Receptor binding site
What methods are used by antibodies to destroy pathogens?
Precipitation of soluble antigens
Lysis --> antibodies bind and attract complement
Neutralisation of toxins
How does agglutination work?
Pathogens are immobilised when clumped together so prevents them from entering cells, making phagocytosis easier
What are complement?
A collection of proteins in the plasma which destroy the cell
Why may a blood test be carried out?
To establish if antibodies are present in the blood for several conditions
To establish if the patient has become infected
What test is done before giving a TB vaccine?
What is a mantoux test?
Skin test for TB (tuberculin injection)
What do the results of a mantoux test indicate?
If inflammation occurs, they don't need the TB vaccine because they are already immune
What 2 types of HIV tests are there in the UK?
Point of care test
What do HIV tests look for?
What is a point of care test?
Finger-prick test or mouth swab sample
What is a disadvantage of a point of care test?
There are issues with the sensitivity
What is the second method of detecting HIV?
What is an advantage of taking a blood sample?
Less false positives/negatives
What is an advantage of a point of care test?
Find out the result almost immediately
What is a disadvantage of taking a blood sample?
Have to wait longer to find out the results
What is natural active immunity?
Immune response activates antibody production and memory cell production
What is artificial active immunity?
Vaccine of dead pathogen triggers immune response and encourages the production of antigens
What is natural passive immunity?
No antibody production by the person themselves
e.g. antibodies cross the placenta to the fetus
What is artificial passive immunity?
Antibodies are injected from another source
e.g. Tetanus immunoglobulin injections
What are allergens?
Antigens which trigger an (inflammatory) allergic reaction
Give examples of allergens
Outline the stages of an allergic reaction
1) Initial contact with the allergen
2) Primary immune response triggered
3) IgE antibodies produced
4) Antibodies bind to receptors on mast cells
5) On the next encounter with allergen, allergen molecules bind to the IgE antibodies attached to the mast cell
6) Mast cell releases histamine
7) Inflammatory response is triggered
What is a mast cell?
A cell involved in the inflammatory response that releases histamine
What is a hypersensitive reaction?
Any undesirable reaction produced by the immune system