Lecture 7

Question 1

What are the main myeloid cells that are involved in “Innate immunity”?

Answer 1

• neutrophils, mast cells, eosinophils, basophils - macrophages - Dendritic cells

Question 2

What are the main cells that are involved in “adaptive immunity”?

Answer 2

B cells -

T cells - CD4+ helper (Th)

CD8+ killers

(Tcyt) - regulators

Question 3

Where do all of the T-cells found in the tissues and the blood derive from?

Answer 3

• These all derive from the bone marrow

Question 4

What is special about the development of T-cells?

Answer 4

• They are unique in the sense that they mature in the thymus

Question 5

What is the “central dogma”?

Answer 5

All immune cells need to be activated to be able become effector cells

Question 6

Briefly describe how the activation of innate immune cells occurs:

Answer 6

1.Occurs in tissues by conserved microbial components shared by many pathogens (PAMP-pathogen associated molecular patterns, DAMP - danger associated molecular patterns) 2. Bind to Pattern Recognition Receptors (RRR) expressed on all myeloid cells (e.g. Toll-Like-Receptors-TLR)

Question 7

Name the following components in the diagram below:

Answer 7

1. LPS
2. TLR4
3. Inflammasome
4. Cytokines
5. Phagocytosis

Question 8

Explain how the inflammasome works:

Answer 8

1. Activated intracellularly by PAMP binding to PRR
2. Activates Caspase-1
3. Converts pro-IL-1- beta to active IL-1-beta
4. IL-1-beta then amplifies acute imflammation

Question 9

Where are naiive lymphocytes activated?

Answer 9

1. Naive T cells and B cells are activated by an antigen in the lymph

Question 10

What is the function of MHC Class 1 and where is it found?

Answer 10

MHC Class 1 is found intracellularly and it is found within all cells

Question 11

What is MHC Class II found and what is its function?

Answer 11

These process extracellular antigens. They are only found on specialised antigen presenting cells (APC) for example dendritic cells

Question 12

What is the context in which CD8+ T-cells are able to bind to the antigen?

Answer 12

• CD8+ T-cells can only bind to antigen in context of MHC Class One
• CD8 and TCR molecules bind to the antigen fragments bound to the groove of the MHC Class 1 Molecule
• Activated CD8+ T-cells gain a cytotoxic function
• CTL cells can then kill every virally infected cell in body that expresses the MHC Class 1

Question 13

In what context are the CD4 cells able to bind to the antigen ?

Answer 13

1. CD4 cell are only able to recognise the antigen in the context of MHC Class II Molecules on surface of APC
2. The APC is able to process proteins into short peptide fragements (epitopes) these then combine with the grooves in MHC Class II
3. The CD4 molecule and the TCR bind to the antigen/MHC Class II complex
4. APC provides other signals (signal 2) that allows for co-stimulation of the T-cell
5. Activated CD4 + T-cells help B cells to make anitbody and amplify CTL responses