Immunology - Memory

Question 1

What is immune memory?

Answer 1

Feature of the adaptive immune system
- Pool of antigen specific cells following infection with enhanced ability to respond to a second infection

Question 2

How does memory work?

Answer 2

Antigen presenting cells (APCs) present peptides to T lymphocytes to initiate an acquired immune response

Question 3

What are examples of antigen presenting cells?

Answer 3

• Macropahges
• B lymphocytes
• Langerhans cells
• Dendritic cells

Question 4

What is general process of memory?

Answer 4

1. Exposure to pathogen antigen(s)
2. Stimulation of specific T + B lymphocytes leads to expansion
3. Some lymphocytes become effector cells + some memory cells
4. Immunologic memory develops (long lived up to 65 years)

Question 5

What are the T memory cells?

Answer 5

• CD4
• CD8
• CD45 RO = memory T cells
• CD45 RA = naiive T cells

Question 6

What are seom general features of T memory cells?

Answer 6

• Remain for a long time following infection
• Continue to proliferate at a low rate
• Subsequent exposure = rapid + robust response, easier to activate than naiive cells
• Have idfferent cell surface markers (influences migration + adhesion & can access non lymphoid tissue - sites of microbe entry)

Question 7

What are some feature of Central T Memory Cells?

Answer 7

• Found in lymph nodes + tonsils
• Roll alonog + extravasate in high endothelial venules (HEVs)
• CCR7+ & CD62L high (allows entry/migration via HEVs to peripheral LNs)
• Produce IL2 (supports other cells)
• More central memory in CD4 population

Question 8

What are some features of Effector T Memory Cells?

Answer 8

• Found in liver + lungs + gut
• CCR7 -ve & CD62L low (not found in LNs)
• Effector so produce = perforin + IFN-gamma
• More effector memory in CD8 population

Question 9

What is the process of B cell memory?

Answer 9

• B cells stimulated by antigen
• Leads to expansion/isotope switchin (due to cytokines provided by T helper cells)
• Results in plasma cells producing antibody/memory cells

Question 10

What are some basic features of B Cell Memory?

Answer 10

• Memory cells than can differentiate into plasma cells (long lived)
• Quicker response
• More antibodies
• Higher affinity antibodies
• Produce more IgG
• Generally better antibodies than T cell memory

Question 11

What are the different types of CD4+ T cells?

Answer 11

• Th1
• Th2
• Th17

Question 12

What are some features of CD4+ Th1 T cells?

Answer 12

• Cell mediated
• Help CD8 + macrophages
• Produce: IL2, IFN-gamma, TNF

Question 13

What are some features of CD4+ Th2 T cells?

Answer 13

• Humoral response
• Helper T cells
• Produce: IL4, IL5, IL6

Question 14

What are some features of CD4+ Th17 T cells?

Answer 14

• Helps neutrophil recruitment
• Produce: IL17, IL21, IL22

Question 15

What is the mantoux test?

Answer 15

• Injection of 0.2ml of 5 tuberculin (purified protein derivative) units intradermally
• Examine arm after 48-72hrs
• +ve result indicated by induration of >= 1mm diameter = previous BCG exposure