T cells in Health and Disease- T cell subsets Flashcards
what are the functions of Effector T cells?
-remember the antigen for next time
-make different types of cytokines
-enhance innate immune system
-move to different places in the body
- different ways of killing
-support antibody production
why do immune responses differ?
Different effector responses needed to fight different pathogens
- different type of organisms
- different route of infection
- different site of infection
- different molecules
what are the different CD4+ T cells?
T helper 1 = Th1
T helper 2 = Th2
T helper 17 = Th17
T regulatory = Treg
how do cytokines work?
Antigen presenting cells produce cytokines
- cytokines activate T cells
- T cells produce cytokines
what is the effector role of cytokines?
Signalling inside the cell that help the T cells produce functional products
what is the function of chemokines?
Help attract the cell to the site or infection
what are the functional products of T cells?
More cytokines
Killing enzymes
Chemokines
Metabolic products
survival proteins
what type of T cell is always involve in an immune response?
Treg cells
what helps drive the differentiation of T cell subsets?
Polarising cytokines produced by other immune cells
Bind to receptors on naive T cell surface
Help drive differentiation into different subsets
what are the polarizing cytokines of Th1 cells?
IFNg
TNF-alpha
what are the polarizing cytokines of Th2 cells?
IL-3
IL-4
IL-5
IL-9
IL-13
what are the polarizing cytokines of Th17 cells?
IL-17
IL-21
IL-22
what are the polarizing cytokines of Treg cells?
Treg
what is the Th1 transcription factor?
T-bet
what is the structure of the IL-12 receptor?
dimer
what cytokine do Th1 cells produce?
IFNg
what type of infection is an INFg response against?
intracellular infections- virus, bacteria
how does IFNg effect macrophage?
increased phagocytosis
-enhanced bacterial killing
how does IFNg effects CD8 T cells?
kill infected cells
how does IFNg affect B cells?
make antibody to enhance phagocytosis
- the antobody acts as an opsinin
what is the transcription factor of Th2 cells?
Gata-3
what is the structure of the IL-4 receptor?
monomer
what are the cytokines produced by Th2 cells?
IL-4
IL-5
IL-13
what infection do Th2 cells fight?
Extracellular infections
- worms and parasites
how does IL-4, IL-5, and IL-13 effect mast cell eosinophils?
destroy worms
how does IL-4, 5, and 13 effect CD4 T cells?
Produce more IL-4, IL-5, and IL-13.
how does IL-4, 5, and 13 affect B cells?
make antibody to bind pathogens
- help to make antibody or antibody class switching
what is the transcription factor of Th17 cells?
RORyT
what cytokine does Th17 cells produce?
IL-17
what infection does IL-17 act against?
Extracellular infection
- fungus, bacteria
how does IL-17 act on neutrophils?
inflammation
how does IL-17 act on CD4 T cells?
IL-22
what autoimmune diseases does IL-17 act in?
MS
IBD
what are the subsets of CD8 T cells?
Tc1
Tc2
Tc17
what is T cell heterogeneity?
T cell subsets aren’t really mutually exclusive boxes
what can cause immunopathologies?
Uncontrolled effector responses
what is the role of Th1 cells?
Th1 cells secrete IFNg (proinflammatory)
Good for activating cell mediated immunity- kill infected cells, cancer cells
how do Th1 cells act in autoimmune disease?
Systemic lupus erythematosus
Type 1 diabetes
IFNg activates many inflammatory mediators and other cells
IFNg receptor on many cells in the body
Result can be tissue damage
IFNg promotes antibody class swithcing to IgG
what is the role of Th2 cells?
Th2 secrete IL-4, IL-5, IL-13
Help clear parasites- helminths
Mucus production, smooth muscle contraction, antibody class switching to IgE
what is the role of Th2 cells in autoimmunity?
Th2 cytokines are associated with allergy
e.g. asthma
how to Th2 cytokines act in asthma?
Th2 cytokine effects contribute to asthma symptoms
-airway constriction, mucus,
IgE binds to mast cells and basophils
- activation of macrophages in lungs, degranulation, release of proinflammtory modulators…. allergic inflammation
what is the function of Th17 cells?
Th17 secrete IL-17- good for immunity to extracellular bacteria
IL-17 recruits and activates neutrophils
Involved in tissue immunity; gut, skin, lungs
How does Th17 act in autoimmune disease?
Th17 can be associated with tissue specific autoimmune disease
-Il-17 is a proinflamatory cytokine
-IL-17 receptors are present on epithelial tissues
This promotes production of enzymes that can cause tissue damage
