Cytokines and Receptors

Question 1

WHat cells produce IL-2?

Answer 1

Activated CD8+ and CD4+ T cells. Naive ones do not secrete it.

Question 2

What is the function of IL-2?

Answer 2

Stimulate T-cell proliferation and clonal expansion

Question 3

What cells produce IFN-gamma?

Answer 3

TH1 and CD8 T cells

Question 4

What is the function of ITN-gamma?

Answer 4

Required for macrophage and NK cell activation.

It also preps host cells for antimicrobial function (remember PEGINTERFERON?)

Question 5

Lymphotoxin is abbreviated as what? It’s also sometimes called….

Answer 5

LT, TNF-beta

Question 6

What does lymphotoxin do, and what T cells secrete it?

Answer 6

Stimulates the production of NO by macrophages, aiding in the bactericidal response.

Th1 and CTLs secrete it. Think intracellular response!

Question 7

Which cells secrete IL-4 and what does it do?

Answer 7

Th2 cells. IL-4 supports growth and survival of the Th2 cell

PROMOTES CLASS SWITCHING TO IgE!!!

Question 8

Other than IgE, what other Ab isotopes does IL-4 cause class switching to?

Answer 8

weakly opsonizing forms of IgG: IgG2, IgG4

Question 9

What cytokine causes antibody class switching to IgA? What cell secretes it?

Answer 9

IL-5 secreted by Th2 cells

Question 10

Th1 cells secrete IFN-gamma. This causes Antibody class switching to what isotopes?

Answer 10

Opsonizing forms of IgG: IgG1 and IgG3

Question 11

Which antibody isoform is found everywhere in the body?

Answer 11

IgG

Question 12

Which antibody isotope is found ONLY in circulation?

Answer 12

IgM

Question 13

Which antibody isotope is found in mucosa and mucosal secretions? Where else is it found?

Answer 13

IgA - found in GI tract and respiratory tract (mucosa and secretions) low levels in circulation.

Question 14

Where in the human body will you find IgE antibody isotopes? Why?

Answer 14

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.

Question 15

What receptor on mast cells binds to IgE? Why is this antibody receptor special, compared to all other antibody receptors?

Answer 15

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.

Question 16

What does the Poly-IG receptor do?

Answer 16

Binds to IgA and transports it across the epithelial linings of the git and respiratory tract, into mucosal secretions via active vesicular transport.

Question 17

What receptor is responsible for the transfer of IgG from the blood to extravascular spaces AND across the placenta during pregnancy?

Answer 17

The Brambell receptor (FcRB/FcRn)

Question 18

Which antibodies have strong NEUTRALIZATION capacity? (part of the Ab response)

Answer 18

IgG and IgA

Question 19

What purpose does the FcgRIII receptor serve? What cell is it on? What Antibody does it bind to?

Answer 19

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.

Question 20

What function do Fc receptors on macrophages serve?

Answer 20

Fc receptors bind the Fc regions of antibodies that have bound their cognate antigen and phagocytize them.

Question 21

What id ADCC and what cell/receptor is responsible?

Answer 21

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.

Question 22

ADCC: is it part of the acquired or innate immune response?

Answer 22

Acquired, because it relies on IgG1 for NK cell activation

Question 23

The FceRI receptor is on which 2 main types of cells?

Answer 23

Mast and Eosinophils

Question 24

If the body is infected with ________________, IgE will be the main antibody utilized for defense and recognition.

Answer 24

Parasites! Lots of eosinophils, basophils, and mast cell reactions.

MULTICELLULAR PATHOGENS. IgE

Question 25

What B-cell surface receptor does EBV (Epstein Barr Virus) use to get into B-cells?

Answer 25

CD21 (aka… CD2… the complement receptor that binds to C3b opsonin)

Question 26

What interleukin is the most responsible for fever? What about arachidonic acid derivative?

Answer 26

IL-6 and PGE2 TNF plays a role too.

Question 27

What cells secrete IL-6?

Answer 27

Macrophages, phagocytic cells.

Question 28

What are the 3 most important inflammatory cytokines?

Answer 28

TNF, IL-1, and IL-6

Question 29

IL-12 helps activate what kind of effector cell?

Answer 29

NK cells. IL-12 is secreted by macrophages. (Il-12 does other things too though)

Question 30

What 2 cytokines secreted by Th1 cells activate macrophages?

Answer 30

IFN-gamma and CD40L

Question 31

Name all of the cytokines produced by Th1 cells and what their function is.

Answer 31

1. IFN-gamma and CD40L - activate macrophages 2. GM-CSF - stimulates macrophage differentiation in the bone marrow 3. TNF- activates endothelium so more T cells are recruited to the area 4. Il-2 - proliferation and clonal expansion fo T cells. 5. CXCL-2 - recruits macrophages to the area

Question 32

How does IL-12 cause increased activation of NK cells?

Answer 32

IL-12 is an up regulator of the more important cytokine, IFN-gamma. IFN-gamma causes activation of NK cells.

Question 33

IL-4 secreted by Th2 cells promotes Ab class switching to what isotope?

Answer 33

IgE - MAST CELL RECRUITMENT

Question 34

IL-5secreted by Th2 cells promotes Ab class switching to what isotope?

Answer 34

IgA

Question 35

What is IL-7?

Answer 35

The cytokine secreted by stromal cells in the bone marrow in order to promote B cell maturation. (necessary signal)

Question 36

If you have no IL-2, what will you no longer have?

Answer 36

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!

Question 37

What does Activation-induced cytidine deaminase do?

Answer 37

Class switching and affinity maturation of Antibodies.

Question 38

What happens if you don't have DC40-L?

Answer 38

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)

Question 39

How is CD40 important for Macrophages?

Answer 39

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.

Question 40

T/F Deficiencies in IL 2 result in NO T-cell population.

Answer 40

True. No proliferation of clonal expansion. Or B cell Pops.