allergies, autoimmunity and immunodeficiency

Question 1

central and peripheral tolerance

Answer 1

lymhoycytes that recognise self antigens are usually destroyed rapidly
occasionally B cells edit their specificity and no longer become self reactive
some CD4 T cells differentiate into regulatory T cells

Question 2

transplant rejection

Answer 2

direct and indirect recognition of alloantigens
direct is when the DC cells of the organ start getting blood and foreign antigens from the new host and direct recognition happens
indirect is when the APC or the DC start going into the organ and start messing around wiht it.
both of these lead to the activation of B and T cells
the organ will then be attacks by the CTL it will be treated as a diseased organ and the whole thing will be destroyed

Question 3

HLA typing

Answer 3

is used to match donors and patients.

when we characterise the MHC classes of our body we can come up with HLA typing.

Question 4

type 1 hypersensitivity

Answer 4

the cell that is responsible is the mast cell
IgE mediated hypersensitivity
when the allergen binds to the mast cell
and causes degranulation (releases vasoactive mediators like cytokines) this causes the runny nose and other things associates with allergies

Question 5

sequence of events in immediate type 1 hypersensitivity

Answer 5

antigens get clumped together and recognised by our immune system they are now allergens and they bind directly to the B cell.
the helper cell causes the plasma cell to release IgE. this antibody finds the mast cell and sticks to it. the second time you are expose the IgE degranulates and all the packages release the this can happen immediately.