[W2] Introduction to Innate and Adaptive Immunity

Question 1

What are the four main tasks of the immune system?

Answer 1

Recognition, effector function, regulation, and memory.

Question 2

What are the three lines of defence in the immune system?

Answer 2

1) Physical barriers, 2) Innate immunity, 3) Adaptive immunity.

Question 3

Name three components of the first line of defence.

Answer 3

Skin, mucous membranes, normal microbiota.

Question 4

How fast is the innate immune response?

Answer 4

Rapid – minutes to hours.

Question 5

Is the innate response specific or non-specific?

Answer 5

Non-specific.

Question 6

What are the main innate phagocytic cells?

Answer 6

Macrophages, neutrophils, dendritic cells.

Question 7

What is the role of macrophages?

Answer 7

Recognise and phagocytose pathogens, remove debris, signal other immune cells.

Question 8

Name a tissue-specific macrophage in the liver.

Answer 8

Kupffer cells.

Question 9

What is the lifespan of a neutrophil?

Answer 9

2–3 days.

Question 10

What type of nucleus do neutrophils have?

Answer 10

Multilobed (polymorphonuclear).

Question 11

What is the primary role of dendritic cells?

Answer 11

Activate T helper cells via antigen presentation.

Question 12

From which precursor are dendritic cells derived?

Answer 12

Monocytes.

Question 13

What does PAMP stand for?

Answer 13

Pathogen-Associated Molecular Pattern.

Question 14

Which receptors recognise PAMPs?

Answer 14

Toll-like receptors (TLRs).

Question 15

What is TLR4 also known as?

Answer 15

CD284 – binds LPS from gram-negative bacteria.

Question 16

What cytokines are involved in triggering inflammation?

Answer 16

IL-1, IL-6, TNF-α.

Question 17

What do mast cells release during inflammation?

Answer 17

Histamine.

Question 18

What causes the symptoms of inflammation?

Answer 18

Vasodilation, permeability, cytokine signalling, and fluid leakage.

Question 19

What activates the inflammasome?

Answer 19

Detection of PAMPs or DAMPs.

Question 20

What does caspase-1 do once activated?

Answer 20

Cleaves pro-IL-1β into its active form.

Question 21

What type of interferons are part of innate immunity?

Answer 21

Type I – IFN-α and IFN-β.

Question 22

What triggers IFN-α/β production?

Answer 22

Detection of intracellular dsRNA by TLR3.

Question 23

What do interferons do?

Answer 23

Induce antiviral states in neighbouring cells.

Question 24

What is the main difference in specificity between innate and adaptive immunity?

Answer 24

Innate is non-specific; adaptive is highly specific.

Question 25

What types of cells are involved in adaptive immunity?

Answer 25

B cells and T cells (lymphocytes).

Question 26

What receptor do B cells use to recognise antigens?

Answer 26

B cell receptor (BCR), a membrane-bound antibody.

Question 27

What do plasma cells do?

Answer 27

Secrete large quantities of antigen-specific antibodies.

Question 28

What is the role of memory B cells?

Answer 28

Provide rapid secondary responses upon re-exposure to antigen.

Question 29

Name four antibody types.

Answer 29

IgM, IgG, IgA, IgE.

Question 30

What are some functions of antibodies?

Answer 30

Neutralisation, blocking entry, complement activation, opsonisation.

Question 31

What does the T cell receptor (TCR) recognise?

Answer 31

Peptides bound to MHC molecules.

Question 32

Which MHC class presents to CD8+ T cells?

Answer 32

MHC Class I.

Question 33

Which MHC class presents to CD4+ T helper cells?

Answer 33

MHC Class II.

Question 34

Where are MHC I molecules expressed?

Answer 34

On all nucleated cells.

Question 35

Where are MHC II molecules expressed?

Answer 35

On professional APCs (macrophages, dendritic cells).

Question 36

What triggers clonal expansion of T cells?

Answer 36

Antigen presentation via MHC molecules.

Question 37

What happens after infection clearance?

Answer 37

T cell numbers contract; memory cells persist.

Question 38

Do innate and adaptive systems work independently?

Answer 38

No – they are highly interlinked and support each other.