019 Cellular Immunity : T cells and cytokines

Question 1

What are the main sources of:

a. IL1
b. IL2
c. IL12
d. IL4
e. IL10
f. IL17

Answer 1

a. DC and macrophages
b. T cells
c. DC and macrophages
d. Th2 cells
e. Monocytes, Th2 and Treg cells
f. Th17 cells

Question 2

What are the main functions of:

a. IL1
b. IL2
c. IL12
d. IL4
e. IL10
f. IL17

Answer 2

a. Pro-inflammatory
b. T and B cell proliferation
c. Stimulates Th1 cell differentiation
d. class switches B cells to IgE production, stimulation of Th12 cell differentiation.
e. Anti-inflammatory, B cell proliferation
f. Proinflammatory

Question 3

What are the sources and functions of:

a. IFNa
b. IFNB
c. IFN-y

Answer 3

a. all nucleated cells - limiting viral replication
b. all nucleated cells - limiting viral replication
c. Th1 cells and NK cells - limiting viral replications, activates macrophages

Question 4

What is the main role of TNFs?

Answer 4

Inflammatory cytokines showing alot of overlap with IL1 but also having some anti-tumor effects

Question 5

What is the main role of growth factors and colony-stimulating factors?

Answer 5

Promoting maturation of various white blood cells in the bone marrow

Question 6

What cytokine treatment can be used for chronic hep C infection?

Answer 6

INFa treatment

Question 7

What cytokine treatment can be used for renal cell carcinoma and metastic melanoma?

Answer 7

IL2 treatment

Question 8

What can G-CSF and GM-CSF be used for therapeutically?

Answer 8

Reverse neutropaenia

Question 9

Which cytokines are often associated with autoimmune diseases?

Answer 9

IL1, TNFa, IL6

Question 10

What is the main role of Th1 cells?

Answer 10

Activating macrophages by releasing INFy when bound to antigen.

Question 11

How can Th1 cells help cytotoxic T cells?

Answer 11

It can sensitize or license the dendritic cell to cytotoxic t-cell recognition. When Th1 sees MHC class II on DC, the CD80/CD86 and CD40 on the DC will interact with the CD28 and CD40L respectively. They then produce IL2 to stimulate T and B cell proliferation. CD8 cells will be licensed because costimulatory molecules are now upregulated on dendritic cells. DC also releases IL12 to stimulate Th1 differentiation.

Question 12

What is the main role of Th2 cells?

Answer 12

This is used against helminth infections. It produces IL5, and IL4 which stimulates the production of eosinophils. IL4 also supports B antibody class switching to IgE.

Question 13

What is the main role of IL17?

Answer 13

Attacking extraceullar pathogens and functions by releasing IL17 and IL22. It is normally found on exposed surfaces e.g. GI tract and it stimulates cells like fibroblasts, epithelial cells and keratynocytes. It produces many inflammatory cytokines e.g. IL6 and chemokines which recruite neutrophils.

Question 14

What is the main role of Tfh cells?

Answer 14

Follicular helper t cells ar especialised to provide help for B cells to produce high affinity antibodies in lymphoid follicles.

Question 15

What are the 2 different ways that cytotoxic T cells are able to stimulate apoptosis?

Answer 15

1. It produces perforin which acts like a MAC of complement. It punches a perforin channel in the infected cell which allowws granules that contain granzymes to enter and activate caspase enzymes that are able to mediate aptosis.
2. The FasL ligand on the T-cell directly interacts with the Fas receptor on the infected cell that leads to aptosis.

Question 16

Which cytokines do cytotoxic T cells produce and what are their functions?

Answer 16

IFNy - inhibiting viral replication and activating innate immune responses
LT-a (lymphotoxin) - activates macrophages, inhibits B cells and cytotoxic to some cells
TNF - induction of apoptosis and inflammation