CSIM 1.27 Cell Co-operation in the Immune Response

Question 1

When macrophages are primed by a penetrated barrier, what does the macrophage do?

Answer 1

They recognise a PAMP or IFN-Ɣ, causing them to become hyperactivated, leading them to:

Act as APC for T cells:
• Upregulates MHCII
• Upregulates costimulatory molecules

Begin killing pathogens:
• Increase reactive oxygen species
• Increase lysosome number

Release cytokines:
• Starts a fever and activates other cells

Question 2

What is SIRS?

Answer 2

Systemic inflammatory response syndrome

Question 3

Describe the NK cell response to infection

Answer 3

Secrete IFN-Ɣ to activate the macrophages.

Secretes TNFα and IL-12 to activate more NK cells

Looks for antibodies bound to presented antigens

Question 4

Describe how neutrophils are recruited

Answer 4

Neutrophils free in the blood begin to ‘roll’ along the endothelium (due to selectins) OF A VEIN until they find a cell adhesion molecule, ICAM-1, which binds to it and brings it into the interstitium

NB: cytokines cause selectins to be expressed in the endothelium

Question 5

Where are naive B and T lymphocytes typically activated

Answer 5

Lymphoid organs
• Lymph nodes
• Spleen
• Lymphoid tissue

Question 6

Where do lymphocytes return to the blood?

Answer 6

The thoracic duct

Question 7

What is CD40L involved in?

Answer 7

• Class switching

* Upregulation of co-stimulatory molecules within APCs containing the same antigen as an armed effector CD4 T cell