natural killer cells
innate lymphocytes with germ-line receptors
germ-line receptor
1) Recognize MHC class I and self -turns on the brakes
2)recognize stress ligands (viral infection, DNA damage, tumors
activation of NK cells
perforin, death receptors and release of cytokines
Basophils
rare (0-1%), activated by cytokines and IgE crosslinking
activated basophils
releaase histamine, heparin (vasodilation), cytokines (IL-4), and encourage the Th2 immunity anf IgE response (does more signalling then destruction
eosinophil
rare (1-4%) pink granules with toxic substances, recruited by T-cells ti deal with parasites too big to phagocytose, they release granules
eosinophil realease of cytokines that
encourage tissue remodeling, fibrosis, B-cell class switch (more IgE, more eosinophils (more destruction than signalling
Mast cell
long lived, tissue resident myeloid
where are mast cells stationed
at barrier sites (skin, airways, GI tract)
mast cells guard against
parasites, venom, physical wounds
mast cells are activated by
IgE cross-linking, complement (C3a, C5b), physical injury, venomes
mast cells effects
degranulate (histamine, heparin, tryptase)
-type I hypersensitivity, anaphylaxis
