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Flashcards in immunology Deck (23)
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function of C3a, C3b, C5a and C5b

C3a and C5a - mediators of inflammation and phagocyte recruitment
C3b - opsonization and removal of immune complexes
C5b - formation of MAC, lysis


what is type 2 hypersensitivity

IgM and IgG mediated immune response against cell bound or cell associated antigens


what is type 3 hypersensitivty

IgM and IgG mediated immune complex deposition (they cant be cleared efficiently and get stuck in things where they cause damage


two outcomes of Type 2 hypersensitivity

- injury due to activation of effector mechanisms (C', recruitment of inflammatory cells, activation via Fc R)
- abnormal physiological response by either binding to receptors or proteins interfering with function or by activation/inhibtion


unwanted immune mediated response against foreign ABO blood group antigens is an example of

type 2 hypersenstivity responses


why do some people produce antibodies against some drugs

because the drug becomes bound to RBCs or platelets which are then the target of anti-drug antibodies


type 2 hypersenstivity involving RBCs leads to

haemolytic anaemia or thrombocytopaenia


what is haemolytic disease of the newbord

Pregnant mother is Rh positive and foetus is negative. Some RBCs of the foetus will enter the mothers circulation --> mother produces anti-Rh antibodies. With second pregnancy, if foetus if Rh positive --> maternal antibodies will cross the placenta and lyse RBCs of the foetus --> anaemia of the foetus


how do you prevent haemolytic disease of the newborn

give mum injection of specific Rh antibody during delivery so that if any foetal RBCs enter maternal circulation, an immune response will be made against them so the mother cant make Ab against Rh


what causes goodpastures syndrome

antibodies are made against a variant of collagen type 4 (major component of BM) -> specifically in the kidneys --> complement and phagocyte activation leading to glomerular disease


what are the examples of Type 2 hypersensitivity leading to stimulating and inhibitory Ab

stimulatory - graves disease
inhibitory - Myaesthenia gravis


what causes graves disease

Abs bind to TSH R on thyroid cells --> stimulates the thymus to produce thyroid hormones --> hyperthyroidism


what causes myaesthenia gravis

Ab block the ability of ACh to bind to the R on muscles and therefore no contraction --> atrophy and wasting


when does hype 3 hypersensitivity occur

when complexes are excessively produced and inefficiently cleared


how are immune complexes normally cleared

by the spleens resident macrophages


what are some reasons that immune complexes can be inefficiently cleared

Ag excess
low affinity Ab
inefficient C' activation


how do the immune complexes trigger damage

initiate C' activation --> C3a and C5a inflammatory activation


common outcomes of Type 3 hypersensitivity



what causes farmers lung

actinomyces in mouldy hay inhaled --> stimulates production of IgG --> alveolitis


what is diagnostic of SLE

anti-DNA autoantibodies and immune complex deposition in the kidney


what are the 2 forms of immunological tolerance

central tolerance
peripheral tolerace


where and what is central tolerance

occurs during development in primary lymphoid organs.
removes self-reactive lymphocytes during development


where and what is peripheral tolerance

occurs in the periphery
controls self reactive lymphocytes