Immunological processes

Question 1

How does the skin provide mechanical, chemical and microbiological barriers to infection?

Answer 1

Mechanical - Epithelial calls joined by tight junctions, flow of fluid, sloughing off of skin
Chemical - sebum (fatty acids, lactic acids, lysozyme), antimicrobial peptides (defensins)
Microbiological - normal flora of the skin

Question 2

How does the GI tract provide mechanical, chemical and microbiological barriers to infection?

Answer 2

Mechanical - epithelial cells joined by tight junctions, flow of fluid, mucous, saliva
Chemical - acidity, enzymes, antimicrobial peptides (defensins)
Microbiological - normal flora of the GI tract

Question 3

How does the respiratory tract provide mechanical, chemical and microbiological barriers to infection?

Answer 3

Mechanical - epithelial cells joined by tight junctions, flow of fluid, mucous, air flow
Chemical - lysozyme in nasal secretions, antimicrobial peptides (defensins)
Microbiological - normal flora

Question 4

How does the mouth provide mechanical, chemical and microbiological barriers to infection?

Answer 4

Mechanical - oral mucosa
chemical - saliva
microbiological - normal flora of the mouth

Question 5

What is the function of the innate immunity?

Answer 5

Non-specific immunity to early infection and activates the adaptive immunity

Question 6

What is the function of macrophages?

Answer 6

Activation of endothelial cells, activation of neutrophil immigration

Question 7

What is the function of dendritic cells?

Answer 7

Present antigens to T cells and cause differential of T cells

Question 8

After establishment of a bacterial invasion, what 3 things does the innate immune response cause?

Answer 8

Complement activation, innate signally (activating macrophages), activation of DC

Question 9

Describe morphology of neutrophil?

Answer 9

Multi-lobed nucleus, highly granular

Question 10

What is the function of neutrophils?

Answer 10

Phagocytosis and activation of bacterial mechanisms

Question 11

What is the complement system?

Answer 11

A series of serum proteins

Question 12

What are the functions of the complement system?

Answer 12

Recruitment of inflammatory cells
Opsonisation of pathogens facilitating the uptake and killing by phagocytes
Perforation of pathogen cell membranes = lysis

Question 13

List the 3 pathways that activate complement system in the order they act?

Answer 13

1. Alternate pathways
2. Lectin
3. Classical pathway

Question 14

What are the main cells fo the adaptive immune response?

Answer 14

Lymphocytes

Question 15

Describe the morphology of lymphocytes?

Answer 15

Small WBC with large nucleus

Question 16

What type of cell regulates lymphocytes?

Answer 16

T lymphocytes

Question 17

What regulates the differentiation of lymphocytes?

Answer 17

Cytokines

Question 18

How are T cells mutually regulated?

Answer 18

Increase in one type may lead to suppression of another

Question 19

T cells have phenotypic plasticity, what does this mean?

Answer 19

They can change the type during infection depending on dynamics

Question 20

What is the function of:

a) TH17
b) Treg
c) TH1
d) TH2
e) TFH

Answer 20

a) re-enforcement of innate immunity
b) suppression of immune responses
c) macrophage activation
d) Mast cell/B cell activation
e) B cell activation in lymph nodes

Question 21

During a viral infection how is the innate immune response involved?

Answer 21

Production fo interferons casuistes the activation of natural killer cells which kill the infected cells

Question 22

What is the function of natural killer cells?

Answer 22

Kill virally infected cells - suppressing the expansion of the viral infection but not clearing it

Question 23

How does clearance of a viral infection occur?

Answer 23

Activation of adaptive immune response and increase in production of antigen specific T cells

Question 24

Describe the function of TFH?

Answer 24

Activates B cells in the lymph nodes
a B cell takes up and presents an antigen to TFH. The T cell then activates B cell maturation by releasing cytokines
B cell matures into antibody secreting plasma cells
The cytokine released determines what antibody the plasma cell will release

Question 25

What type of cell protects against intracellular bacteria like mycobacterium tuberculosis?

Answer 25

TH1

Question 26

Describe the function of TH1 cells

Answer 26

Intracellular bacteria invade a macrophage in an attempt to hide from immune system
Complementary TH1 cells bind to the macrophage to activate it, the provide help for the macrophage to digest the bacterium and recruit more macrophage

Question 27

What factor of the immune system do vaccines exploits?

Answer 27

Immunological memory

Question 28

Where do memory B cells develop?

Answer 28

Lymph nodes

Question 29

List 3 characteristics of memory B cells

Answer 29

Long-lived (quiescent - don’t replicate much), high affinity, class switched Ig

Question 30

List 3 major issues with vaccine in medicine

Answer 30

Important disease with no vaccine
Long term effectiveness unknown
Vaccine uptake

Question 31

What 4 things effect vaccine uptake?

Answer 31

Vaccine apathy - anti-vaxxers, misinformation
Practical issues - storage, transport
Economical issues - cost of manufacture, cost of transport
Herd immunity - if the majority of a population is not immune then the effort is pointless

Question 32

Name 2 conditons that activate the immune system due to other wise harmless antigens, define each of these terms

Answer 32

Hypersensitivity reaction = inappropriate immune response to otherwise harmless extrinsic antigens
Autoimmune response = inappropriate immune response to otherwise tolerated self antigens

Question 33

How are inappropriate immune reactions classified?

Answer 33

Type I, II, III, IV

type I is allergic reaction only

Question 34

What is the end result of inappropriate immune reactions?

Answer 34

Inflammation and tissue destruction

Question 35

What is type I reactions mediated by and what occurs?

Answer 35

Mast cells= hypersensitivity

Question 36

what cell mediated type IV reaction?

Answer 36

T cells

Question 37

What is the difference between primary and secondary immunodeficiency?

Answer 37

Primary = genetic
Secondary = acquired (chemo)

Question 38

List 3 types of immunotherapy?

Answer 38

therapeutic monoclonal antibodies
drugs
adaptive cellular immunotherapy