Hypersensitivity Flashcards
What is a hypersensitivity reaction?
An immune reaction against self-antigens resulting in autoimmune disease.
Excessive undesirable reactions
How many classes of hypersensitivity reactions are there?
Type I-IV (1 to 4)
Which hypersensitivity reactions are associated with antibody action?
1 to 3
What are Type IV hypersensitivity reactions are associated with?
T-lymphocytes and cell-mediated responses
Which antibody activates complement?
IgG3
What does IgG3 complement also mediate?
Fc mediated phagocytosis
What does IgE antibody induce?
Mast cell degranulation
Which antibody region is complementary to the antigenic structures present on pathogens?
Variable regions
Which cells secrete antibodies?
Plasma cells
What is the term referred to as the clone of plasma cells secreting specific antibodies in response to a particular antigen?
Monoclonal antibodies
Describe the structure of an antibody:
2 heavy chains held together by disulfide bridges, connected by light chain via a hinge region, considered as the antigen-binding site.
How are the two heavy chains present within antibodies held together?
Disulfide bridges
Which region of the antibody is considered to be the antigen-binding site?
The hinge region
What is a type 1 hypersensitivity reaction?
Anaphylactic/immediate hypersensitivity: Provoked allergic reaction by re-exposure to a specific antigen- allergen
What is the immune mediator for type 1 hypersensitivity reactions?
IgE
Which diseases are commonly associated with type 1 hypersensitivity reactions?
Asthma, allergic rhinitis, and atopic dermatitis
What mediator is released through IgE antibodies?
Histamine
Which cells secrete histamine in response to IgE antibodies?
Mast cells and basophils