Cytokines

Question 1

Describe the 6 different families of cytokine receptors and give an example of one ligand for each

Answer 1

• immunoglobin super familly–loops, Il-1
• Il-17, most recent, prinflamatory
• Class I–>Hematopoetin, WSXWS motif, Il 2
• Class II–> interferon, IFN-alpha, first to be discovered. Viraly infected cells, APC produce type 1 , the rest 2
• TNF, 4 units on top of each other, TNF-alpha, activation, proliferation and death of cells
• Chemokine receptor= interloop and G protein,MCAF

Question 2

Which interleukin is the most studied, Give its two names and what are its 3 subunits and affinities?

Answer 2

Il-2 or CD25
expressed by Tcells for proliferation
units are alpha, beta and gamma

High affinity and Low affinity for CD4+ and CD8+ cells and B cells and Med affinity NK cells and resting T cells

Question 3

What is the role of Interferon and what does IFN-gamma do that is unique?

Answer 3

block viral replication, IFN -gamma also plays an immunoregulatory role

Question 4

Describe the figure that lays out the signalling pathway of cytokines using the terms Jak/Stat/dimers/phosphorelation/gene activation

Answer 4

yea

Question 5

Name 4 ways that Viruses can combat cytokines

Answer 5

• homologs (mimic host)
• cytokine binding proteins
• homologs of receptors
• interference with intracellular pathways

Question 6

Differentiate between TH1 and TH2 t helper cells with respect to function.

Answer 6

TH1 activate Tc, produce opsonins and promote IgG

Th2 activate eosinophils, B cells, IGM, IGE, support allergic reaction

Question 7

How can looking at different levels of TH1 and TH2 help diagnose diseases?

Answer 7

growth in one causes inhibition of the other

Question 8

What is leprosy caused by and give the 2 different kinds.

Answer 8

Caused by mycobacterium lepral, survives in the phagosome

1) High TH1 called Tubercoid, progresses slowly, patients usually survive, forms GRANULOMAS which are macrophages that wall off foreign substances but are unable to eliminate them (they are stuck there) so most get destroyed.
2) High TH2 called lepromatus, the mycobacterium is widely distributed in the macrophage, not just in the phagosome, excessive nerve and tissue damage

Question 9

Differentiate between bacterial septic shock and bacterial toxic shock.

Answer 9

• Septic shock: gram -, drop in BP, fever, clotting. Cytokine imbalances lead to overproduction of IL-1 and TNF-alpha, can lead to organ failure. Bind to TLR’s on APCs, treated by blocking TNF-alpha
• Toxic shock: Superantigens, Bind to both MHCII and TCRs and cause Tcell activation despite specificity of antigen. Tampons and contact lenses can cause this

Question 10

What is Chaga’s disease?

Answer 10

caused by tryponasoma cruzi/protosomic disease, causes reduced Il-2 receptor.

Question 11

What are the challanges of cytokine therapy?

Answer 11

dosage, short half life, unpredictable side effects

Question 12

Pleiotropy
Redundency
syngerism
antagonism
cascade induction

Answer 12

P:Il 4 , interaction of one cytokine can lead to different
R: any leads to same, Il 2 or 4 or 5 
S: working together, Il4 5
A: inhibiting Il4 by Inf gamma
C: cascading