Session 5-Adaptive Immune Response

Question 1

What are the strategic locations of antigen presenting cells?

Answer 1

• skin
• mucous membranes (GALT, NALT=nasal, BALT, GUALT)
• lymphoid organs (nodes and spleen)
• blood circulation

Question 2

What are the two methods of pathogen capture by antigen presenting cells?

Answer 2

• phagocytosis (whole microbe)

- macropinocytosis (soluble particles)

Question 3

Explain the diversity in pathogen sensors in antigen presenting cells

Answer 3

• extracellular pathogens (bacteria)

- intracellular pathogens (viruses)

Question 4

What are the different types of antigen-presenting cells?

Answer 4

• dendritic cells
• Langerhans’ cells
• macrophages
• B cells

Question 5

Where are dendritic cells present?

Answer 5

Lymph nodes
Mucous membranes
Blood

Question 6

What do dendritic cells present to?

Answer 6

Naive T cells (T cells that haven’t encountered pathogen)

Question 7

Where are Langerhans’ cels found?

Answer 7

Skin

Question 8

What do Langerhans’ cells present to?

Answer 8

Naive T cells

Question 9

What do macrophages present to?

Answer 9

Effector T cells

Question 10

Where are B cells found?

Answer 10

Lymphoid tissues

Question 11

What do B cells present to?

Answer 11

Effector and naive T cells

Question 12

What is the human version of the major histocompatibility complex (MHC)?

Answer 12

Human leukocyte antigen (HLA)

Question 13

What are the two different classes of MHC/HLA?

Answer 13

1) Class I molecules - found on all nucleated cells

2) Class II molecules - found on dendritic cells, macrophages, B cells

Question 14

What are the key features of MHC Class I and Class II molecules?

Answer 14

1) co-dominant expression: both parental genes expressed -> increased number of different MHC molecules
2) polymorphic genes: different alleles among different individuals -> increased presentation of different antigens/microbes

Question 15

What is the main function of MHC class I molecules?

Answer 15

Present peptides from intracellular microbes

Question 16

What is the main function of MHC class II molecules?

Answer 16

Present peptides from extracellular microbes

Question 17

Describe the structure of MHC class I and class II molecules

Answer 17

1) peptide binding cleft: variable region with highly polymorphic residues
2) broad specificity: many peptides presented by same MHC molecule
3) responsive T cells

Question 18

Which T cell recognises MHC class I molecules?

Answer 18

CD8+ T cells

Question 19

Which T cells recognise MHC Class II molecules?

Answer 19

CD4+ T cells

Question 20

What a does susceptibility to infections depend on?

Answer 20

Types of MHC molecules

Question 21

What are the clinical problems with MHC molecules?

Answer 21

• organ transplant rejection

- HLA association and autoimmune disease

Question 22

Which type of immunity does the activation of CD4+ T cells lead to in response to extracellular microbes?

Answer 22

Humoral immunity (antibodies and complement)

Question 23

Which type of immunity does CD4+ T cells lead to in response to intracellular microbes?

Answer 23

Cell-dependent immunity

Question 24

Which cells are activated in response to CD8+ T cells?

Answer 24

Cytotoxic T cells

Question 25

Why are costimulatory signals needed?

Answer 25

For T cell activation

Question 26

What role does eosinophils have against extracellular microbes?

Answer 26

Killing of parasites

Question 27

What are the roles of B cells against extracellular microbes?

Answer 27

Phagocytosis

Complement

Question 28

What are the roles of mast cells against extracellular microbes?

Answer 28

Local inflammation

Allergies

Question 29

What is the immune function of IgG?

Answer 29

Toxin/virus neutralisation