Blood & Immune

Question 1

Major functions of immune system:

Answer 1

• Differentiate between self and nonself (foreign)

- Seeks and destroys what is nonself

Question 2

Immunological tolerance:

Answer 2

preventing immune response on particular antigen (self-antigen)

Question 3

1. Innate immunity

Answer 3

• Always deployed if pathogen
• Invariant
• Nonspecific (Use small set of receptors to identify traits shared by many pathogens)
• Doesn’t change or strengthen over time (no memory)
• Immediate

Question 4

External innate defences

Answer 4

physical/chemical barriers 
Skin (touch)
- Mucous / mucous
- membranes (breathe)
- Bodily secretions (eat)

Question 5

Internal innate defences

Answer 5

• Phagocytes (bacterial)
• Natural killer cells (viral and cancer cells)
• Defensive proteins
• Inflammatory response
• Antimicrobial substances
• Fever

Question 6

Inflammatory response

Answer 6

1) Tissue injury => chemical signals (histamine)
2) Chemotaxis
- Phagocytes, fluid with factors for healing / clotting
- Defence amplification and flooding => bleeding, redness, heat, swelling
3) Phagocytosis, cleanup and repair

Question 7

2. Adaptive immunity

Answer 7

• Activated by exposure to specific pathogens => delay

- Only in vertebrates

Question 8

components of adaptive immuity

Answer 8

• Lymphocytes - B and T cells

- Antibodies aka immunoglobulin (Ig)

Question 9

Lymphocytes - B and T cells

Answer 9

1) Exposure to specific pathogen in secondary lymphatic organs (node, spleen)
2) Specific shapes of receptors detect specific pathogens
3) Particular lymphocyte amplified/cloned
=> contributes least to first-line innate response

Question 10

Antibodies aka immunoglobulin (Ig)

Answer 10

• Proteins
• Produced by plasma cells in response to specific antigen
• Combine to neutralise, inhibit or destroy antigen
• In serum plasma

Question 11

Properties of adaptive immunity

Answer 11

1) Specificity

2) Memory

Question 12

specificity

Answer 12

Use vast array of receptors to recognise traits specific to particular pathogen

Question 13

memory

Answer 13

• Memory B cells created after response to exposure and live in nodes
• Second encounter: more rapid, vigorous/strong and long lasting secondary response (learning process not needed)
  => strengthens / adapts the longer the exposure to antigen

Question 14

antigens have

Answer 14

Several epitopes

- Multiple antigens may same epitope

Question 15

Antigen recognition =>

Answer 15

clonal expansion

Question 16

Immune evasion strategies:

Answer 16

adopted by pathogens to get around having immunogenic antigens

Question 17

antigen properties

Answer 17

• immunogenicity

- reactivity

Question 18

Immunogenicity

Answer 18

Stimulate production of specific antibodies / proliferation of specific lymphocytes
=> provoke immune response

Question 19

Reactivity

Answer 19

React specifically with antibody/cell it provoked

Question 20

origin of adaptive immunity

Answer 20

• Innate immunity evolutionarily older than adaptive

- Jawless fish ~500 mya - gene rearrangement - strong selective advantage

Question 21

Transposon:

Answer 21

aka transposable elements, jumping genes

E.g Ig and TcR gene segments/regions/loci

Question 22

Transposase:

Answer 22

operates on transposon - identify/recognise RS, cut and find places to reinsert transposon

Question 23

examples of transposases

Answer 23

recombination activation genes aka recombinase

Question 24

RAG1 and RAG2 only

Answer 24

• active/expressed in lymphocytes
• identical in all species that possess adaptive immunity
• Remnants of a primordial transposon

Question 25

Recognition sequence:

Answer 25

at ends of transposons and act as substrate for RAG-directed recombination