Immuno - Immune Responses (Cytokines & Cell Surface Proteins)

Question 1

What are 5 cytokines that are secreted by macrophages?

Answer 1

(1) IL-1 (2) IL-6 (3) IL-8 (4) IL-12 (5) TNF-alpha

Question 2

What kind of cytokine is IL-1? What other cytokine is like this?

Answer 2

An endogenous pyrogen; IL-6

Question 3

What 3 effects does IL-1 have?

Answer 3

(1) Causes fever, acute inflammation. (2) Activates endothelium to express adhesion molecules; (3) induces chemokine secretion to recruit leukocytes.

Question 4

What kind of cytokine is IL-6? What other cytokine is like this?

Answer 4

An endogenous pyrogen; IL-1

Question 5

What cells secrete IL-6?

Answer 5

Macrophages; Also secreted by Th2 cells.

Question 6

What effects does IL-6 have?

Answer 6

Causes fever and stimulates production of acute-phase proteins.

Question 7

What major role does IL-8 play?

Answer 7

Major chemotactic factor for neutrophils; “Think: “Clean up on aisle 8. Neutrophils are recruited by IL-8 to clear infections.”

Question 8

What cells secrete IL-12?

Answer 8

Macrophages; Also secreted by B cells.

Question 9

What effects does IL-12 have?

Answer 9

Induces differentiation of T cells into Th1 cells. Activates NK cells.

Question 10

What effects does TNF-alpha have?

Answer 10

Mediates septic shock. Activates endothelium. Causes leukocyte recruitment, vascular leak.

Question 11

What major function do IL-1, IL-2, IL-3, IL-4, IL-5, and IL-6 have?

Answer 11

IL-1: fever (hot); IL-2: stimulates T cells; IL-3: stimulates Bone marrow; IL-4: stimulates IgE production; IL-5: stimulates IgA production; IL-6: stimulates aKute-phase protein production; Think: “Hot T-Bone stEAK”

Question 12

What cytokines do all T cells secrete?

Answer 12

(1) IL-2 (2) IL-3

Question 13

What function does IL-2 have?

Answer 13

Stimulates growth of helper, cytotoxic, and regulatory T cells

Question 14

What function does IL-3 have? What other factor does it function like?

Answer 14

Supports the growth and differentiation of bone marrow stem cells. Functions like GM-CSF

Question 15

What cytokine do Th1 cells specifically secrete?

Answer 15

Interferon-gamma

Question 16

What cells secrete Interferon-gamma? What are its functions?

Answer 16

From Th1 cells; Has antiviral and antitumor properties. Activates NK cells to kill virus-infected cells, Increases MHC expression and antigen presentation in all cells.

Question 17

What cytokines do Th2 cells specifically secrete?

Answer 17

(1) IL-4 (2) IL-5 (3) IL-10

Question 18

What major 3 functions does IL-4 have?

Answer 18

Induces differentiation into Th2 cells. Promotes growth of B cells. Enhances class switching to IgE and IgG.

Question 19

What major 3 functions does IL-5 have?

Answer 19

Promotes differentiation of B cells. Enhances class switching to IgA. Stimulates the growth and differentiation of eosinophils.

Question 20

What functions does IL-10 have? What other cytokine has similar actions to IL-10, and how so?

Answer 20

Modulates inflammatory response. Inhibits actions of activated T cells and Th1; TGF-Beta has similar actions to IL-10, because it is involved in inhibiting inflammation.

Question 21

What cells secrete IL-10?

Answer 21

From Th2 cells. Also secreted by regulatory T cells.

Question 22

Which cytokines enhance class switching to the following: (1) IgA (2) IgE (3) IgG.

Answer 22

(1) IL-5 (2) IL-4 (3) IL-4

Question 23

Which cytokine suppresses Th2 cells? What other functions does it have?

Answer 23

Interferon-gamma; Activates macrophages and Th1 cells. Suppresses Th2 cells. Has antiviral and antitumor properties.

Question 24

Which cytokine promotes growth of B cells? What other functions does it have?

Answer 24

IL-4; Induces differentiation into Th2 cells. Promotes growth of B cells. Enhances class switching to IgE and IgG.

Question 25

Which cytokine modulates the inflammatory response? How does it do this?

Answer 25

IL-10; Modulates inflammatory response. Inhibits actions of activated T cells and Th1.

Question 26

What role do interferons alpha and beta play in the immune system? How do they function in general?

Answer 26

A part of innate host defense against both RNA and DNA viruses. Interferons are glycoproteins synthesized by viral-infected cells that act locally on uninfected cells, "priming them" for viral defense. (Think: "Interferon Interferes with viruses."

Question 27

What is the interferon mechanism? What is its ultimate result?

Answer 27

Interferons induce the production of a ribonuclease that inhibits viral protein synthesis by degrading viral mRNA (but not host mRNA). When a virus infects "primed" cells, viral nucleic acids activate: (1) RNAase L --> degradation of viral/host mRNA (2) Protein kinase --> inhibition of viral/host protein synthesis; Essentially results in apoptosis, thereby interrupting viral amplification

Question 28

What are the differences in function between alpha, beta, and gamma interferons? What function do they all share?

Answer 28

Alpha and Beta interferons inhibit viral protein synthesis; Gamma interferons increase MHC I and II expression and antigen presentation in all cells & Activates NK cells to kill virus-infected cells; All part of innate immune system antiviral defenses

Question 29

Which cells have MHC I?

Answer 29

All cells except mature RBCs have MHC I.

Question 30

What are the cell surface proteins that all T cells have? What is each of their purposes?

Answer 30

(1) TCR - binds antigen-MHC complex (2) CD3 - associated with TCR for signal transduction (3) CD28 - binds B7 on APC

Question 31

What cell surface proteins do helper versus cytotoxic T cells have?

Answer 31

HELPER T CELLS - CD4, CD40 ligand; CYTOTOXIC T CELLS - CD8

Question 32

What clusters of differentiation cell surface proteins do B cells have? Which is the receptor for EBV?

Answer 32

CD19, CD20, CD21 (receptor for EBV), CD40; Think: "you can drink Beer at the Bar when you're 21: B cells, Epstein-Barr virus, CD-21"

Question 33

Besides clusters of differentiation, what other 3 cell surface proteins do B cells have?

Answer 33

(1) Ig (2) MHC II (3) B7

Question 34

What clusters of differentiation cell surface proteins do macrophages have?

Answer 34

CD14, CD40

Question 35

Besides clusters of differentiation, what other 4 cell surface proteins do macrophages have?

Answer 35

(1) MHC II (2) B7 (3) Fc receptors and (4) C3b receptors (enhanced phagocytosis)

Question 36

Which cell surface proteins on macrophages promote enhanced phagocytosis?

Answer 36

Fc and C3b receptors (enhanced phagocytosis)

Question 37

What cell surface proteins do NK cells have, and what is the purpose of each?

Answer 37

(1) CD16 (binds Fc of IgG) (2) CD56 (unique marker for NK)

Question 38

What is another name for IL-1?

Answer 38

Also called osteoclast-activating factor