U4 L2 Innate Vs Adaptive Immunity

Question 1

What are the first, second and third lines of defence?

Answer 1

1st - physical and chemical barriers
2nd - innate response
3rd - adaptive response

Question 2

What are four key characteristics of innate response?

Answer 2

• rapid response
• Reacts essentially in same way in repeated exposures
• Exists at birth
• Non-specific and indiscriminate
• No immune memory

Example: Innate response includes inflammation and phagocytosis

Question 3

What are four key characteristics of adaptive response?

Answer 3

• specific to epitope/antigen on a pathogen
• Has immune memory
• Relies on mechanisms that develop as a result of infection
• Distinguishes between self and non-self

Question 4

Where do blood and immune cells originate from?

Answer 4

Hematopoietic stem cells that then differentiate into either myeloid progenitor or lymphoid progenitor cells

Question 5

What three kinds of cell originate from lymphoid progenitor cells?

Answer 5

T cells, B cells and NK (natural killer) cells

Question 6

What are the three most important phagocytosing cells?

Answer 6

Dendritic cells, neutrophils and macrophages

Question 7

What kinds of cells originate from myeloid progenitor cells?

Answer 7

Mast cells, granulocytes (e.g. neutrophils, eosinophils), dendritic cells, macrophages

Question 8

What are the two subclasses of T cells and how do they differ?

Answer 8

Helper T cells - aid in activating other immune cells e.g. B cells
Cytotoxic T cells - directly kill cells infected with viruses

Question 9

Natural killer cells are of the lymphoid progenitor lineage so why are they considered part of the immune response?

Answer 9

They have no antigen specific receptors

Question 10

What makes natural killer cells cytotoxic?

Answer 10

Their granules - contain proteins such as performing and proteases known as granzymes which can break down cells

Question 11

What is meant by the term ‘naive’ with respect to lymphocytes?

Answer 11

Have not yet encountered an antigen

Example sentence: Naive lymphocytes have not been exposed to any antigens.

Question 12

What is meant by ‘primary’ adaptive immune response?

Answer 12

Response to initial exposure of an antigen

Question 13

What happens during primary adaptive immune response?

Answer 13

• activation, proliferation and differentiation of T cells
• Generation of sub population alongside lymphocytes that become memory cells

Question 14

What is the main function of a B cell?

Answer 14

To secrete antibodies as plasma cells

Question 15

What is meant by ‘secondary’ or ‘tertiary’ adaptive immune response?

Answer 15

Secondary immune response refers to the second exposure of a particular antigen in the body, tertiary refers to third exposure etc etc

Question 16

How does each adaptive response to the same antigen differ?

Answer 16

Each subsequent response is likely quicker and more effective

Adaptive immunity does not need to be maintained through repeated exposure as original memory cells are usually long lived

Question 17

How long does adaptive immune response take

Answer 17

On average 4-7 days but an be up to 2 weeks (considerably longer than innate)

Question 18

Why are booster vaccinations sometimes necessary?

Answer 18

To enable full immunity of adaptive response to develop

Question 19

What is meant by ‘effector cells’?

Answer 19

B and T cells mature into effector cells upon activation

Question 20

What is a memory cell?

Answer 20

An antigen-specific B or T lymphocyte that immediately becomes an effector cell upon re-exposure to the same pathogen

Question 21

Why are scientists working to develop vaccines that are applied via intranasal, oral, aerosol routes?

Answer 21

Injected vaccines elicit systemic immune response, with little effect on mucosal response but many pathogens are deposited ad replicate in mucosal compartments Mucosal-administered vaccines elicit mucosal and systemic immunity

Question 22

What is meant by artificial immunity?

Answer 22

Intentional exposure to small quantities of a pathogenic antigen, giving immunity