Questions from immunology overview

Question 0

Which interleukin promotes a common lymphoid progenitor to develop into a NK cell in the bone marrow?

Answer 0

IL-13

Question 1

Which interleukin promotes a common lymphoid progenitor to develop into a T cell in the bone marrow?

Answer 1

IL-7

Question 2

What 2 processes do common lymphoid progenitor cells undergo before development into either Naive T or B cells?

Answer 2

1) (random) Antigen receptor VDR rearrangement
2) negative selection (to detect inappropriate self binding –> autoimmunity, to detect for affinity to individual HLA for T cells, can bind but not too strongly)

Question 3

What is the role of AIRE?

Answer 3

Autoimmune Regulator
Genes which allow the expression of peripheral proteins in the thymus–> developing T cells are exposed and therefore reduces chances of autoimmunity eg small amounts of insulin are made in the thymus!

Question 4

Where can you find T cells expressing both CD4 and CD8 receptors?

Answer 4

Thymus

Question 5

Which cells function as antigen presenting cells (APCs)?

Answer 5

Dendritic cells
Macrophages
B cells

Question 6

What is the role of dendritic cells in the immune system?

Answer 6

Recognise foreign antigen
Phagocytose
Break down into peptides
Travel to lymphoid tissue to present peptide on MHC
Also up regulate costimulatory molecules

Question 7

What costimulatory mechanism is important for CD4 T cell interactivation with APC ( acting with the TCR - MHC Class II interaction )?

Answer 7

CD 28 on the T cell with B 7 on the APC

Question 8

Which interleukin (secreted by activated T cells) promotes T cell proliferation?

Answer 8

IL-2

Question 9

Which cytokines promote the development of Th17 cells?

Answer 9

TGF beta
IL-6
IL-1

Question 10

Which cytokines promote the development of Th2 cells?

Answer 10

IL-4

Question 11

Which cytokines promote the development of Th1 cells?

Answer 11

IL-12

Question 12

Which cytokines promote the development of Treg cells?

Answer 12

TGF beta

IL-10

Question 13

What costimulatory mechanism is important for CD4 T cell interactivation with B cell ( acting with the TCR - MHC Class II interaction )?

Answer 13

CD 40 on the B cell

CD 40 ligand on the T cell

Question 14

What happens in the germinal centres?

Answer 14

Activated naive B cels travel here (to the lymph node)
Purpose is to randomly generate a better fit antibody for the antigen (affinity maturation)
And produce that antigen (isotype switching)- IgG has a higher affinity for antigen than IgM
Generate memory B cells and plasma cells (generally migrate to the marrow)

Question 15

What are the 3 pathways to activate the complement cascade?

Answer 15

Lectin- mannose binding lectin acts as a kind of “universal antibody” and activates the cascade
Alternate- complement recognition of a surface as foreign –> coating
Classical- immunoglobulin coating of a pathogen noticed and activated by C1q

Question 16

What is the common point in all 3 pathways of the complement cascade?

Answer 16

C3–> C3b

Results in opsonisation OR induces C5-C9 (MAC)

Question 17

Which cytokines are secreted by Th2 cells in response to antigen presentation, and what is the cellular response to the signals?

Answer 17

IL-4 and IL-13 activate B cells to produce IgE

IL-5 secreted to activate eosinophils (recognize the IgE on a pathogen)

Question 18

What is thought to be the evolutionary purpose of the Th2- eosinophilic interaction?

Answer 18

Fight helminth infections- eosinophils are designed to fight pathogens that are not able to be phagocytosed

Question 19

Which cytokines are particularly involved in inducing a systemic inflammatory response?

Answer 19

IL-1
IL-6
TNF

Question 20

What is the role of Th2 cells in the allergic response?

Answer 20

Th2 detects antigen (from an allergen) presented by an APC
Induces production of IgE to the allergen by B epsilon cells/plasma cells (secretion of IL-4, IL-13)
IgE on the allergen surface is the detected by the mast cells and results in
1) stored mediator release (eg histamine)
2) manufacture of mediators (eg leukotrienes)
3) release of chemokines and cytokines to induce a late phase response by monocytes, neutrophils, T cells and eosinophils

Question 21

Which cytokines secreted by Th17 cells promote chemokines to be secreted by somatic cells?

Answer 21

IL-17

IL-22

Question 22

How do NK cells induce antibody-mediated cell-independant cytotoxicity?

Answer 22

Viral antigen expressed on the cell membrane
Targeted by IgG
FcgammaR on NK cell recognises antigen
Induces a lethal hit (perforin, granzyme, Fas, TNF)

Question 23

How do NK cells induce antibody-mediated cell-dependant cytotoxicity?

Answer 23

Virus/tumour down regulates MHC expression
MHC inhibitory signal not received by NK cell, activatory co-signal recieved
–> Lethal hit

Question 24

How do CTLs induce cytotoxicity due to cell processing of internal antigen, ie monitor the intracellular environment?

Answer 24

All somatic cells are processing both internal pathogenic and self-proteins constantly and present on the cell surface on MHC1 for CTL detection
CTL approaches MHC1 with TCR, if protein foreign or indicates need for apoptosis
–> Lethal hit

Question 25

Which cytokine is most responsible for fever?

Answer 25

IL-1

Question 26

Which cytokines are released by cells undergoing apoptosis?

Answer 26

IFN-alpha

IFN-beta

Question 27

Which cells mediate the activity of cytotoxic T lymphocytes?

Answer 27

Treg cells