L12: Overview of Innate Immunity II Flashcards
What Ig molecule is bound to mast cells under mucosal surfaces?
predominantly IgE
Which growth factors are necessary for maintenance of memory cells?
IL-7 and IL-15.
Do differentiated effector T cells need B7 activation signaling to perform their function?
no. They only require and MHC:antigen complex signal
What would happen if L-selectin was defective? Think about naive T cells.
Naive T cells use L-selectin to bind to CD34 on HEV (high epithelial venules) to help them pass through into secondary lymphoid tissues
Why would you not want L-selectin on CD8+ cells?
you don’t want a cell that kills anything presenting its MHC class I - antigen complex to wander into a secondary lymphoid tissue full of B and helper T cells presenting those antigens
What are the adhesion molecules Effector CD8+ T cells upregulate after activation?
VLA-4 which binds to VCAM-1 on endothelium. This allows effector cells to enter inflammatory sites.
Which T helper cell would express VLA-4?
Think about what VLA-4 does. It lets cells move into inflammatory sites. TH1 cells have a role in inflammatory sites, so they upregulate surface VLA-4.
What type of cell expresses Fas ligand?
CTLs (CD8+ killer cells). They use this to kill virus infected cells.
What do TH1 cells do?
produce cytokines, express CD40 to activate macrophages, produce IFN-gamma to activate macrophages. Also can produce cytokines to activate and class switch B cells. Promote production of IgG1, which is good for intracellular infections. Cytokines: IFN-gamma, GM-CSF, TNF-alpha, LT, IL-3
What do TH2 cells do?
Express CD40 to actiavte B cells, produce cytokines to activate and drive class switching of B cells. Cytokines: IL-4, IL-5, IL-10, IL-13, TGF-beta
Which T cell types produce IL-10?
TH2
Which T cell types produce TNF-alpha
TH1
Which T cell types produce LT?
TH1 and Cytotoxic T cells
Which T cell types produce TGF-beta?
TH2
Which T cell types produce GM-CSF?
TH1
Which T cell types produce IL-4 and IL-5?
TH2
Which T cell types produce IFN-gamma?
CD8 T cells and TH1
What will IL-4 and IL-5 promote TH0 cells to differentiate to? What type of infection is this good for?
TH2. Extracellular infections (they activate B cells to make antibodies)
What will IL-2 and IFN-gamma promote TH0 cells to differentiate into? What type of infection is this good for?
TH1. Good for intracellular infection. (promote B-cell activation and production of opsonizing antibodies such as IgG1)
Which T helper cell type assist in extracellular bacterial infections and upregulate neutrophils?
TH17 cells.
A patient is showing signs of several different autoimmune diseases, all related to T cells. What type of cell would you expect a defect in?
Treg cells. They downregulate T cell responses. Without them, patients suffer from an unholy autoimmune disease
Which T cell type would activate fibroblasts?
TH17 cells
What will IL-12 promote TH0 cells to differentiate into? What type of infection is this good for?
IL-12 promotes production of IFN-gamma. Both of these promote TH1 cell production, which are good for intracellular infections because of the IgG1 the promote
What type of infection would you expect IL-4 to be upregulated?
extracellular. IL-4 will promote TH2 cell differentiation.
How do TH2 cells downregulate TH1 production?
IL-10 and TGF-beta, the cytokines that Treg cells produce. They dont produce nearly as much though.
What happens when macrophages are unable to kill the bacteria they take up?
they tend to form granulomas.
What is IgM’s main function?
activation of the complement system
What is IgE’s main function?
Sensitization of mast cells
Which IgG molecules activate compliment system?
IgG3 predominantly
Which Ig molecule is the primary opsonization immunoglobin?
IgG1. Very important for intracellular infections.
Which Ig molecule type helps transport pathogens out of mucosal cells and into gut lumen for excretion?
IgA
What Ig molecule helps with ADCC? What cell type carries the kill out? What receptor do they use?
IgG1, IgG3, IgA.
NK cells, using their Fc-gamma-3 receptors.
What Ig do mast cells ‘hijack’ and use as antigen receptors?
IgE
What complement component can degranulate mast cells?
C5a (attack complex)
