B-VII Cyto- & chemokines

Question 1

IL-7

Answer 1

Drive the survival memory T-cells. Also released by stromal cells in bone marrow to cause proliferation in pre-B-cells to pro-B-cells

Question 2

Inflammatory cytokines

Answer 2

TNF-α, IL-1, IL-6

Question 3

IL-12

Answer 3

APC can be stimulated to produce this by IFN-γ, binding of CD40 to CD40L, or microbes binding to TLRs. Causes differentiation of naive CD4+ cells to Th1 cells. Also activates NK cells, and ILC1.

Question 4

Innate lymphoid cells

Answer 4

Tissue resident cells that turn signal cytokines into effector cytokines. They develop in the bone marrow from the lymphoid progenitor, but they dont have antigen receptors.

Question 5

ILCs Type 1

Answer 5

NK cells in this category. Reacts to intracellular microbes, viruses, tumors. Responds to IL-12, IL-15, IL-18 which activates the NK cell to release granzymes+perforin and also IFN-γ. ILC1s release TNF-α also

Question 6

ILCs type 2

Answer 6

Responds to large parasites, allergies, etc. Responds to IL-33 among others. Releases IL-4,5, 13, cause mucus production

Question 7

ILCs type 3

Answer 7

Responds to extracellular bacteria, fungi. Responds to IL-23. Releases IL-17, IL-22, which causes release of AMPs, phagocytosis, and inflammation.

Question 8

Which cytokine is important for proliferation?

Answer 8

IL-2

Question 9

Which cytokines are inhibitory?

Answer 9

TGF-β, IL-10

Question 10

How does IL-10 suppress the immune response?

Answer 10

Inhibits production of IL-12, which in turn will lower the amount IFN-γ.

Question 11

What do chemokines do?

Answer 11

Cause immune cells with the right receptors to migrate to the places with highest chemokine concentration.

Question 12

What are some places where chemokines are important?

Answer 12

In the traffic of naive cells to the lymph nodes, effector t-cells to infection sites, and to get the B and T cells to interact at the follicle edge

Question 13

CC7

Answer 13

CC7 is high in T-cell area

Question 14

CC5

Answer 14

CC5 is high in follicle area

Question 15

What is the general definition of cytokines?

Answer 15

Molecular signals that bind to receptors, modify gene expression, and cause new biological effects.

Question 16

Where do cytokines typically act? What happens if they are found in the blood?

Answer 16

Cytokines typically act near the site of production. If found in the blood, it usually indicates a severe infection.

Question 17

Briefly describe the common signaling pathway triggered by cytokine receptors.

Answer 17

Ligand binding causes receptor dimerization, leading to activation of JAK, which phosphorylates tyrosine residues on the receptor. STAT proteins bind to these phosphorylated residues, are then phosphorylated by JAK, form dimers, and travel to the nucleus to bind DNA and change gene expression.

Question 18

Name two key inflammatory cytokines and the cells that produce them during inflammation.

Answer 18

TNF-alpha and IL-1, both produced by macrophages during inflammation.

Question 19

What is a key role of IL-7?

Answer 19

Survival of naïve and memory T-cells.

Question 20

What are some functions of TNF-alpha?

Answer 20

It is an inflammatory cytokine produced by macrophages. It is also involved in leukocyte recruitment by causing endothelial cells to upregulate chemokine receptors.

Question 21

What are some functions of IL-1?

Answer 21

It induces fever during inflammation and is produced by macrophages. It also causes endothelial cells to upregulate chemokine receptors.

Question 22

What are some functions of IL-6?

Answer 22

It acts in the liver and stimulates the production of CRP, which can opsonize bacteria and activate phagocytosis.

Question 23

What is the main function of Type I interferons (alpha, beta)?

Answer 23

Antiviral activity, induced rapidly after infection.

Question 24

What is a key role of IL-12 in the early immune response?

Answer 24

Responds early to activate the adaptive immune system. It is stimulated by IFN-γ, CD40L, and microbes (via TLRs).

Question 25

What is the role of IFN-γ in the context of Th1 responses?

Answer 25

It drives the differentiation of naïve CD4+ cells into Th1 cells and is involved in macrophage activation, isotype switching to IgG2a(mouse), and increased MHC expression in APCs.

Question 26

What is the role of IL-4

Answer 26

It drives the differentiation of naïve CD4+ cells into Th2 cells and inhibits differentiation into Th1 cells. It also promotes isotype switching to IgE and IgG1/IgG4.

Question 27

What is a key role of IL-17?

Answer 27

It is mostly found in the intestinal tract and can be involved in autoimmune responses. Causes production of chemokines , which in turn causes inflammation and neutrophil response. Produced by Th17 subset

Question 28

What are chemokines and what are some of the cell types that produce them?

Answer 28

Chemokines are a class of signaling molecules involved in cell migration. They are produced by leukocytes, endothelial cells, epithelial cells, and fibroblasts.

Question 29

What is the primary function of chemokines?

Answer 29

To direct cell migration (chemotaxis) by creating a chemical gradient that guides cells towards higher concentrations of the chemokine. They also affect the surface of endothelial cells to facilitate leukocyte binding and transmigration.

Question 30

True or false. Cytokines are exclusively produced by immune cells.

Answer 30

False; endothelial cells are another group of cells that might produce cytokines

Question 31

True or false. Interleukins (ILs) are cytokines that act between leukocytes.

Answer 31

True

Question 32

True or false. Cytokines typically act over long distances in the body, similar to hormones.

Answer 32

False; in fact, a high concentration of cytokines in the blood indicate severe infections

Question 33

True or false. When a cytokine binds to its receptor, it always leads to the immediate secretion of another type of cytokine.

Answer 33

False; cytokine might cause other biological effects, such as isotype switching.

Question 34

True or false. JAK and STAT proteins are key components of a common signaling pathway utilized by many cytokine receptors.

Answer 34

True

Question 35

True or false. IL-7 is primarily involved in activating macrophages during inflammation.

Answer 35

False. IL-7 is primarily involved in survival of memory and naive T-cells.

Question 36

True or false. IL-12 primarily functions to inhibit the adaptive immune system.

Answer 36

False; IL-12 triggers the adaptive immune system, favoring Th1 responses.

Question 37

True or false. IL-10 promotes the production of IFN-gamma.

Answer 37

False; IL-10 inhibits the production of IL-12, which in turn inhibits the production of IFN-gamma.

Question 38

True or false. TGF-β, secreted by Treg cells, enhances the proliferation of effector T-cells.

Answer 38

False; It inhibits the proliferation

Question 39

True or false. IFN-γ is a key cytokine in Th2 responses, promoting isotype switching to IgE.

Answer 39

False; IFN-gamma is associated with Th1 responses. IL-4 promotes IgE

Question 40

True or false. Chemokines bind to receptors that belong to the GPCR family.

Answer 40

True

Question 41

True or false. Chemotaxis is the movement of cells directed by a chemical gradient

Answer 41

True

Question 42

Which cytokines are produced by macrophages?

Answer 42

IL-1, IL-6, TNF-alpha, IL-12

Question 43

IL-2

Answer 43

Proliferation signal, which is released by activated T-cells and bind to other activated T-cells, causing clonal expansion

Question 44

IL-1

Answer 44

Inflammatory cytokine. Activates production of IL-6 and activates lymphocytes

Question 45

IL-6

Answer 45

Inflammatory cytokine. Activates lymphocytes, and triggers Th17. Stimulates production of CRP. Mainly acts in liver

Question 46

TNF-α

Answer 46

Inflammatory cytokine, leads to increased vascular permeability so that IgG and complement protein can more easily enter tissue. Released by macrophages, ILC1

Question 47

IFN-γ

Answer 47

Cause Th1 differentiation of helper T-cells. Released by Th1 cells, ILC1, NK cells. A signal to macrophages to kill the thing they have phagocytised. Cause isotype switching in B-cells

Question 48

IL-33

Answer 48

Stimulate ILC2 and Th2

Question 49

IL-4

Answer 49

Stimulate Th2. Released by Th2 and ILC2, causes class switching to IgE and IgG1 (mouse).

Question 50

IL-5

Answer 50

Released by Th2 and ILC2. Recruits Eosinophils

Question 51

IL-23

Answer 51

Triggers ILC3 and Th17

Question 52

IL-17

Answer 52

Released by ILC3 and Th17. Results in production of chemokines.

Question 53

IL-22

Answer 53

Released by ILC3 and Th17. Triggers endothelial cells to produce AMPs

Question 54

TGF-β

Answer 54

Inhibitory cytokine.