immunology Flashcards
What is hypersensitivity?
An overreaction and undersirable response of the immune system to an antigen
What is the classification system used for hypersensitivity and how many classes are there?
Coombs and gells
4 classes
Describe T1 hypersensitivity
anaphylaxis
IgE mediated
IgE crosslinks with mast cell/ basophill causing degranulation and release of histamine
What are the effects of histamine
vasodilator
bronchoconstrictor
pruitis
flushing
what are the main cells involved with t1 hypersensitivity
mast cell and basophil
Give examples of t1 hypersensitivity
anaphylaxis, asthma, hay fever, ezema (atopy)
What is the main Ig associated with t1 hypersensitivity
IgE
Describe T2 hypersensitivity
Cell bound antibody antigen complex
IgG/IgM binds to cell surface antigen
causes cell destruction of the cell with the pathogen via MAC - membrane attack complexes
Give examples of t2 hypersensitivity
goodpastures syndrome, autoimmune haemolytic anaemia, pernicious anaemia, rhuematic fever
What are the main Ig associated with t2 hypersensitivity
IgG and IgM
What are examples of t3 hypersensitivity
IgA nephropathy
SLE nephropathy
Describe t3 hypersensitivity
Binding of IgG/ IgA on soluble (circulating) antigens
this causes complexes which are deposited in organs eg kidneys
this triggers complement reaction, phagocytosis as a response
Describe t4 hypersensitivity
T-helper cell mediated
they are activated by antigen presenting cells to stimulate a response
delayed hypersensitivity 24-72hrs
Give examples of t4 hypersensitivity
TB
multiple sclerosis
guillian barre syndrome
