Overview of the adaptive immune system

Question 1

What is the adaptive immune system?

Answer 1

= part of the immune system that has enhanced rapidity, potency or specificity as a consequence of previous events (exposure or vaccination)

Anamnestic response - memory is the key element

Question 2

What is the purpose of the adaptive immune system?

Answer 2

Protection from and defence against pathogens

• Opportunity to have effectors ready which are specific and potent
• Some pathogens stick around and need controlling - ‘latency’ - controlled by effectors

Role in malignancy surveillance

Liked to damage healing and repair

Question 3

How do we spot pathogens?

Answer 3

Generic recognisable features - PAMPs

Presence is associated with damage

• Damage-associated molecular pattern molecules (DAMP)
• There is co-stimulation of CD28 to confirm the pathogen

Previous exposure

Autoimmunity - self vs non-self (it shouldn’t be there)

Question 4

What are examples of innate and adaptive cells invovled?

Answer 4

Question 5

How can you describe lymphocytes?

Answer 5

• White cell, small with large nucleus
• T and B cells
• Can either be:
  
  • naive/memory
  • immature/mature or differentiated
• They: helper, cytotoxic, regulatory and antibody-producing
• Surface markers they express: cd4, cd8 cd28
• Type of receptor: Ig class for B cells/ ab vs yg for T cells
• What they produce: TH1 or TH2

Question 6

How is clonal selection used in adaptive immunity?

Answer 6

One clone - one specificity

• B-cells - one cell, one antibody
  
  • Defined by their antibody
  • May class switch/undergo affinity maturation but always Ig
• T-cells - one cell, one T cell receptor
  
  • Selection and expansion of that clone with or without differentiation
  • Retention in memory of clonal progeny
• Continued protection
  
  • Continued production of antibody (B cells and plasma cells)
  • More rapid specific secondary responses (B and T cells)

Question 7

What happens in the primary and secondary response in B cells?

Answer 7

Question 8

How do the lymphocytes have different receptors?

Answer 8

Question 9

What is the B cell repertoire selection?

Answer 9

• Positive selection
• Receptor editing
• Negative selection to make sure they’re not recognised in cell
• Antigen recognition leads to proliferation to differentiation
• Activated B cells transform into plasma cells