Type II and III hypersensitivity Flashcards
What is the pathogenesis of goodpasture’s syndrome?
Ab binds to type IV collagen in glomeruli causing complement act. and phagocyte recruitment > glomeruli damage
What hormone is mimicked in grave’s disease?
TSH
How can self reactive ab form when there is a tolerance mechanism in place in the primary lymphoid tissue?
Self ab’s sneak through the system!
Which type of hypersensitivity involved immune complexes?
III
What is targeted in goodpasture’s syndrome?
A variant of collagen IV - particularly on glomeruli
What are the two possible outcomes ab binding to host ag in type II hypersensitivity?
- Complement activation > Inflammation > Damage
- Ab binding to proteins or receptors interfering with their function - can stimulate or inhibit
After which pregnancy (in a single mother) does haemolytic disease occur in newborns?
The 2nd pregnancy (if both children are Rh+)
Which hormone is overproduced in grave’s disease?
Thyroid hormones
Which organs are commonly affected in systemic lupus erythematosis?
Kidney
Skin
How can some drugs initiate a type II hypersensitivity response?
Drug bind to RBCs or platelets > anti-drug ab’s target the RBC/platelet+drug > damage
What happens to receptors in myasthenia gravis?
Aberrant self ab bind to them, blocking ligands from binding and causing them to be internalised
What is characteristic of immune complexes that are most effectively cleared?
They act complement well
They ab is high affinity
Their makeup is relatively high in ab’s
T/F Immune complexes in type III HS have self ag only
False, they can have self or foreign ag’s
What type of hypersensitivity occurs when blood transfusions are mismatched?
Type II
Which type of hypersensitivity II or III, targets cell bound or extracellular matrix protein?
II
What is an example of a type II HS disease where there is activation by the aberant ab
Grave’s disease
Are self ab’s generally high or low affinity to their ag
Low affinity
What must the ag status of the mother and baby be for haemolytic disease of newborns to occur?
Mother: Rh-
Baby: Rh+
Which blood groups is the universal donor?
O
Which receptors are targeted in myasthenia gravis?
Acetylcholine receptors
Are small or large complexes better cleared?
Large
Which blood group is the universal acceptor?
AB
Where are immune complexes deposited in farmer’s lung?
Alveolar air spaces - leads to fibrosis and scarring
What is example of a type II HS disease where there is inactivation by the aberrant ab
Myasthenia gravis
What mediates type II hypersensitivity?
Antibody (particularly IgG and IgM)
Describe the classical pathway for complement activation
Ab bound to a cell’s surface
C1 > C4 > C2 = C3 Convertase
C3 Convertase cleave C3 in C3a and C3b
What are some examples of disease mediated by type III HS?
Farmers lung
Serum sickness
Glomerulonephritis
Rheumatic fever
Endocarditis
Arthritis
How can you prevent haemolytic disease of newborns?
Give anti-Rh ab to the mother right after birth so she can’t develop an immune response to that ag.
When do complexes in type III HS becomes probematic?
When are they overproduced or not effectively cleared and complement is activated and a strong inflammatory response is attracted in small vessels
Which ag mediates haemolytic disease in newborns?
Rh (Rhesus)
What do you find in kidneys in SLE?
Immune complexes and anti-DNA ab’s
When do maternal antibodies against Rh form in haemolytic disease of newborns?
During the first pregnancy, the fetal blood enters the mother and the mother mounts an immune response to it
What is the name of the bacteria in farmer’s lung?
Actinomyces
