Immune system and adaptive immune system: Antigen recognition

Question 1

Define concepts of specificity and memory as they apply to immunity

Answer 1

specificity - Immune system able to recognise specific virus or bacteria and respond in a specific way.
Memory - Remembers previous encounters. Future response will be faster, stronger and longer lasting (and produce more antibodies)

Question 2

Define innate immunity

Answer 2

system which gives non specific resistance, response to pathogen will be the same each time

Question 3

list events of the inflammatory response

Question 4

Adaptive immunity

Answer 4

response to pathogen improves each time when exposed to it. Due to specificity and memory

Question 5

Key cells in innate immunity

Answer 5

Monocyte
Macrophage
Natural Killer cells
Dendritic cells
Neutrophils
Mast cells
Eosinophils
Basophils
T Killer cells

Question 6

Innate immunity examples of non specific responses

Answer 6

Physical barriers
Chemical mediators
leukocytes
inflammatory response

Question 7

Key cells in adaptive immunity

Answer 7

B cells
T cells
T killer cells

Question 8

Examples of Physical barriers

Answer 8

Skin - Keratinized cells
Sweat and secretion lowers pH
Mouth - salivary glands - lysozyme
Stomach- Low pH
Mucosal epithelia (lined with cilia)- GI tract, respiratory tract, nose (traps and removes)
Tears, saliva and urine wash substances from body surfaces

Question 9

complement chemical mediators

Answer 9

> 20 proteins in plasma
normally inactive
activated in a series, activates next one (complement cascade)
Contribute to both adaptive and innate

Innate: “alternate pathway” of complement activation

Molecules bind to cell membrane of pathogen, label, opsonization.
Act as chemotactic agents to attract phagocytic cells to site of inflammation
Form damaging pores in plasma membrane of pathogens

Question 10

Cytokines

Answer 10

Small signalling molecules released to trigger immune response e.g. interleukins, chemokines, interferons

Interferons:

Viruses - Induce cells to produce viral nucleic acids and proteins. Infected cells secrete interferons. Signals adjacent cells to make antiviral proteins. Inhibit production of new viral nucleic acids.

Question 11

Cytokines

Answer 11

Small signalling molecules released to trigger immune response e.g. interleukins, chemokines, interferons

Interferons:

Viruses - Induce cells to produce viral nucleic acids and proteins. Infected cells secrete interferons. Signals adjacent cells to make antiviral proteins. Inhibit production of new viral nucleic acids.

Question 12

Other chemical mediators

Answer 12

Histamine
Prostaglandins
Leukotrienes

They increase vasodilation, vascular permeability and stimulate phagocytosis

Question 13

White blood cells in innate immunity

Answer 13

produced in red bone marrow
Leave blood supply and enter tissues
Chemicals released from pathogens and damaged tissue attract WBCs

Neutrophils - Normally first to arrive at site
Release signals that call other immune cells and begin to phagocytose then dies

Macrophages (monocytes that leave blood) - Later in stage of infection, phagocytose dead neutrophils and other cellular debris

Question 14

Basophils

Answer 14

Mobile cells

Question 15

Mast cells

Answer 15

non mobile cells in connective tissue

Question 16

Eosinophils

Answer 16

Allergic response

Question 17

What causes inflammatory response

Answer 17

activation and degranulation of WBCs to release histamine and leukotrienes

Question 18

Natural killer cells

Answer 18

kill virus infected cells
kill target cells using chemicals to damage cell membranes –> cells lyse

Question 19

Inflammatory response

Answer 19

Hallmark of innate immune system
- Tissue injury
- Mast cells basophils degranulate
- Stimulate release and activation of chemical mediators
- Lead to vasodilation of local blood supply = more blood supply + WBCs = more phagocytosis

-Histamine = increased vascular permeability = more swelling and leakage= more complement in tissue, phagocytes and clotting factors e.g. fibrinogen

• Leukotrienes and complement recruit phagocytes (neutrophils followed by macrophages). Pyrogens increase body temp and help protect against pathogens

Question 20

Local inflammatory response

Answer 20

redness, heat, swelling and pain

Question 21

Systemic inflammatory response

Answer 21

More widespread
more neutrophils
pyrogens–> fever
can cause sepsis and death

Question 22

where are antigens transported to in the inflammatory response?

Answer 22

lymph nodes - important for adaptive immune response

Question 23

What are antigens?

Answer 23

substances that bind to receptors on lymphocytes - stim adaptive immune response

Question 24

Antibody mediated response

Answer 24

B lymphocyte differentiated to plasma cells that produce antibodies

Question 25

Cell - mediated response

Answer 25

T lymphocytes (helper and cytotoxic)

Question 26

Where do B and T cells mature

Answer 26

B in bone marrow
T travel to Thymus

Question 27

T and B cells receptor response to antigen

Answer 27

very specific and complementary

Question 28

Antigen recognition by lymphocytes

Answer 28

when receptor is recognised and binds to antigen, lymphocyte is activated and proliferates, clonal expansion