Lecture 10: Adaptive Immunity and Immune Recognition

Question 1

Outline the general features and components of adaptive immunity.

Answer 1

Question 2

Mention and describe the phases of adaptive immunity.

Answer 2

• Priming phase: the first time the adaptive immune system encounters an antigen
• Effector phase: activates adaptive cells differentiate into effector cells to fight infection and eliminate the pathogen
• Contraction phase: most effector cells die following clearance of the pathogen
• Memory phase: some long-lived memory cells remain to ensure that the immune system can respond faster and stronger upon reencountering that pathogen

Question 3

Recall the cells of adaptive immunity.

Answer 3

Question 4

Recall the characteristic of adaptive immunity.

Answer 4

Question 5

_______________ comprises the cells of the adaptive immune system.

Answer 5

The lymphoid lineage

Question 6

Describe B cells.

Answer 6

• Derived from lymphoid progenitor
• Mature in the bone marrow
• CD19 positive (surface biomarker)
• Each B cell has around 100,000 BCRs, all with the same specificity
  
  • BCR engagement leads to proliferation and transition into plasma cells (‘effector B cells’)
• Plasma cells secrete soluble BCR (-antibodies) that have same specificity as surface receptor

Question 7

Describe T cells.

Answer 7

• derived from lymphoid progenitor in the bone marrow
• develop and become educated in the thymus
• express co-receptors: either CD4 (MHC class II restricted) or CD8 (MHC class I restricted)
• recognise antigen via distinct cell surface receptors (α/ß T cell receptor) with high degree of specificity
  
  • requires processing of antigen by the APC and presentation on MHC
• T cells need to be activated to exert function
  
  • activated T cells can leave the blood and survey the periphery
  • CD4+ Helper T cells: regulators of immune responses
  • CD8+ Cytotoxic T cells: cytotoxic (perforin, granzymes)

Question 8

Recall the functional polarization of helper T cells.

Answer 8

Question 9

Recall the unique receptors on lymphocytes.

Answer 9

Question 10

Recall the anatomy of a lymph node.

Answer 10

Question 11

Recall how antigens are encountered by lymphocytes in the body.

Answer 11

Question 12

What are antigens and epitopes?

Answer 12

Question 13

What are eptiopes?

Answer 13

Question 14

What are immunogens? What are the factors affecting immunogenicity?

Answer 14

Question 15

What are hapten-carrier complexes?

Answer 15

Question 16

Recall the effect of hapten carrier complexes in immunogenicity.

Answer 16

Question 17

Recall the innate vs adaptive immune recognition

Answer 17

Question 18

Recall the receptor characteristics of innate vs adaptive immune recognition.

Answer 18

Question 19

Describe the basics of T cell receptor recognition.

Answer 19

• T cell receptors antigen in the form of a complex of a foreign peptide bound to an MHC molecule.
• Peptides must be processed to be presented, peptides are stably bound to MHC molecules, serving to stabilise the MHC molecule on the cell surface.

Question 20

Recall the two type of T cell receptor recognition (CD4 and CD8)

Answer 20

Question 21

Recall the mechanism behind immunoglobulin recognition.

Answer 21

Immunoglobulins bin antigen via contacts in their variable regions that are complementary to the size and the shape of antigen. Majority of BCR epitopes are conformational (discontinuous)

Immunoglobulins (BCR/Abs) bind to conformational shapes on the surfaces of antigens using a variety of non-covalent forces.

Question 22

Immunoglobulins (BCR/Abs) bind to conformational shapes on the surfaces of antigens using a variety of _______________.

Answer 22

non-covalent forces.