Cytokines and Receptors Flashcards
WHat cells produce IL-2?
Activated CD8+ and CD4+ T cells. Naive ones do not secrete it.
What is the function of IL-2?
Stimulate T-cell proliferation and clonal expansion
What cells produce IFN-gamma?
TH1 and CD8 T cells
What is the function of ITN-gamma?
Required for macrophage and NK cell activation.
It also preps host cells for antimicrobial function (remember PEGINTERFERON?)
Lymphotoxin is abbreviated as what? It’s also sometimes called….
LT, TNF-beta
What does lymphotoxin do, and what T cells secrete it?
Stimulates the production of NO by macrophages, aiding in the bactericidal response.
Th1 and CTLs secrete it. Think intracellular response!
Which cells secrete IL-4 and what does it do?
Th2 cells. IL-4 supports growth and survival of the Th2 cell
PROMOTES CLASS SWITCHING TO IgE!!!
Other than IgE, what other Ab isotopes does IL-4 cause class switching to?
weakly opsonizing forms of IgG: IgG2, IgG4
What cytokine causes antibody class switching to IgA? What cell secretes it?
IL-5 secreted by Th2 cells
Th1 cells secrete IFN-gamma. This causes Antibody class switching to what isotopes?
Opsonizing forms of IgG: IgG1 and IgG3
Which antibody isoform is found everywhere in the body?
IgG
Which antibody isotope is found ONLY in circulation?
IgM
Which antibody isotope is found in mucosa and mucosal secretions? Where else is it found?
IgA - found in GI tract and respiratory tract (mucosa and secretions) low levels in circulation.
Where in the human body will you find IgE antibody isotopes? Why?
Epithelium underlying the skin, and in the GI tract linings and respiratory linings. IgE goes where mast cells go, because IgE exists bound to mast cells.
What receptor on mast cells binds to IgE? Why is this antibody receptor special, compared to all other antibody receptors?
FceRI receptor! Has affinity for IgE even when its cognate antigen isn’t bound.
Most antibodies must bind their cognate antigen before their Fc portions are exposed, allowing binding to Fc receptors on APCs.
What does the Poly-IG receptor do?
Binds to IgA and transports it across the epithelial linings of the git and respiratory tract, into mucosal secretions via active vesicular transport.
What receptor is responsible for the transfer of IgG from the blood to extravascular spaces AND across the placenta during pregnancy?
The Brambell receptor (FcRB/FcRn)
Which antibodies have strong NEUTRALIZATION capacity? (part of the Ab response)
IgG and IgA
What purpose does the FcgRIII receptor serve? What cell is it on? What Antibody does it bind to?
The FcgRIII receptor is on NK cells. It binds to host cells that have been opsonized with IgG1.
The host cells have been opsonized because they display intracellular pathogenic proteins on their surface.
What function do Fc receptors on macrophages serve?
Fc receptors bind the Fc regions of antibodies that have bound their cognate antigen and phagocytize them.
What id ADCC and what cell/receptor is responsible?
Antigen Dependent Cell-mediated Cytotoxicity.
IgG1 in serum binds to foreign proteins from an intracellular pathogen displayed on a host cell surface. The FcgRIII receptor on NK cells bind to the Fc regions of IgG1 and activate the NK cell.
Kills host cell the same way CTLs do.
ADCC: is it part of the acquired or innate immune response?
Acquired, because it relies on IgG1 for NK cell activation
The FceRI receptor is on which 2 main types of cells?
Mast and Eosinophils
If the body is infected with ________________, IgE will be the main antibody utilized for defense and recognition.
Parasites! Lots of eosinophils, basophils, and mast cell reactions.
MULTICELLULAR PATHOGENS. IgE
What B-cell surface receptor does EBV (Epstein Barr Virus) use to get into B-cells?
CD21 (aka… CD2… the complement receptor that binds to C3b opsonin)
What interleukin is the most responsible for fever? What about arachidonic acid derivative?
IL-6 and PGE2
TNF plays a role too.
What cells secrete IL-6?
Macrophages, phagocytic cells.
What are the 3 most important inflammatory cytokines?
TNF, IL-1, and IL-6
IL-12 helps activate what kind of effector cell?
NK cells. IL-12 is secreted by macrophages. (Il-12 does other things too though)
What 2 cytokines secreted by Th1 cells activate macrophages?
IFN-gamma and CD40L
Name all of the cytokines produced by Th1 cells and what their function is.
- IFN-gamma and CD40L - activate macrophages
- GM-CSF - stimulates macrophage differentiation in the bone marrow
- TNF- activates endothelium so more T cells are recruited to the area
- Il-2 - proliferation and clonal expansion fo T cells.
- CXCL-2 - recruits macrophages to the area
How does IL-12 cause increased activation of NK cells?
IL-12 is an up regulator of the more important cytokine, IFN-gamma. IFN-gamma causes activation of NK cells.
IL-4 secreted by Th2 cells promotes Ab class switching to what isotope?
IgE - MAST CELL RECRUITMENT
IL-5secreted by Th2 cells promotes Ab class switching to what isotope?
IgA
What is IL-7?
The cytokine secreted by stromal cells in the bone marrow in order to promote B cell maturation. (necessary signal)
If you have no IL-2, what will you no longer have?
AN ACQUIRED IMMUNE SYSTEM
You’ve have NO adaptive immunity because the differentiation and proliferation of T cells are required for both the cell-mediated response (CTLs) and humoral immunity (Helper T’s provide the 2nd signal of activation for B-cells)
No B or T cells!
What does Activation-induced cytidine deaminase do?
Class switching and affinity maturation of Antibodies.
What happens if you don’t have DC40-L?
B cells receive no secondary activation signal, so no humoral immunity. NO B CELLS. The only B cells active in your system will be B1B cells (part of innate immunity)
How is CD40 important for Macrophages?
Aids in the activation process. Th1’s CD40L binds CD40 on macrophages and increases its ability to fight intracellular pathogens. CD40 doesn’t matter really for extracellular responses cause a MAC can innately phagocyze stuff.
T/F Deficiencies in IL 2 result in NO T-cell population.
True. No proliferation of clonal expansion. Or B cell Pops.
