lecture 9 hypersensativity and autoimmunity Flashcards
can T cells undergo affinity maturation?
no
when to T cells get variation in the hypervariable loops?
during recombination (rag 1 and rag 2)
what do TdT cells do to antibodies?
add random nucleotides
what are the four mechanisms driving an abnormal immune response?
type 1 type 2 type 3 and type 4
what mediates type 1 hypersensitivity?
IgE antibodies
where do IgE antibodies bind to?(type1)
mast cells and basophils
on mast cells and basophils what do antibodies act as?(type1)
receptors for allergens
what induces cellular deregulation from mast cells?(type1)
cross linking of r or more IgE receptors
what is released during degranulation of mast cells?(type1)
histamine, leukotrienes and protoglandins
what does histamine do upon degranulation?(type1)
dilates blood vessels, increases permeability of blood vessels, increases mucus secretion and smooth muscle contraction
what do prostoglandins do upon degranulation?(type1)
contract smooth muscle and increase msucus secretion
what do leukotrienes do upon degranulation?(type1)
bronchial spasms
what happens to blood pressure during anaphylaxis?(type1)
drops
what is IgE released by?(type1)
B cells that have class switched by cytokines
on mast cells where do IgE bind to?(type1)
Fc epsilon receptors
what does mast cell activation and degranulation cause in the GI tract?(type1)
increase in peristalsis, increased fluid, vomitting and diaoreah
what happens during mast cell degranulation in the eyes, nasal cavity and airways?(type1)
increased diameter and increased musuc secretion leading to congestion and blockage of airways
mast cell activation in blood vessels causes what?(type1)
inc fluid in tissues, increased flow of lymph to lymph nodes, increased effector response in tissues and hypotension