Hypersensitivity Flashcards
What is hypersensitivity?
It is when molecules of the immune system work together to eliminate antigens by different mechanisms
Hypersensitivity reactions may be due to either a humoral or cell mediated immune response, categorised into what?
Immediate hypersensitivity and delayed hypersensitivity
What initiates immediate hypersensitivity reaction?
Antibody or antigen antibody complexes
How long does it take for symptoms to occur in immediate hypersensitivity reaction
minutes/Hours
How long does it take for delayed hypersensitivity symptoms to show
days after exposure
What does hypersensitivity reactions differ in
The immune response and the effector molecules generated in the reaction
What antibodies are apart of hypersensitivity reactions
IgE, IgG and IgM
Delayed hypersensitivity are due to what cell mediated immune reactions
TH and TC
What is an allergen
A type of antigen that induces a humoral response
What do IgE antibodies with high affinity bind to?
Fc receptors on the surface of mast cells/blood basophils
What is involved in type 1 reactions
IgE
Someone who recieves an allergy genetically is called what?
Atopic
What do atopic individuals allow
They allow non parasitic antigens to stimulate inappropriate IgE production.
When are the symptoms of type I reactions released
During mast cell/basophil degranulation
Where do mast cells and basophils act on?
They act on local tissues along with secondary effector cells
Name a primary effect
Histamine
Name a secondary effect
Leukotriens
What happens when histamine is released from mast cells
Histamine binds to specific receptors on target cells
when are Leukotriens formed?
They are formed when mast cells are degranulated and phospholipids are broken down
How long are the effects of leukotrienes
longer and more pronounced than histamine
What are the steps of the contraction of the human bronchial?
its initially mediated by histamine and then mediated by the leukotrienes and prostaglandins
What are cytokines released from?
mast cells and eosinophils
What is systematic type I reactions
Systematic anaphylaxis, a shock like and often fatal state
What are some triggers of systematic anaphylaxis?
Venom from bees, seafood and nuts
What is localised type I reactions
A reaction limited to the target tissue/ organ
What is atopy typically associated with?
a heightened immune response to common allergens like food
