Foundations in Immunology 1 Flashcards Preview

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Flashcards in Foundations in Immunology 1 Deck (70)
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1
Q

Tolerance

A

Immunological unresponsiveness to an antigen

2
Q

How is self-tolerance maintained?

A
  • The elimination of lymphocytes which react to self-antigens in their early stages of development
  • Allowing lymphocytes to encounter self antigens in a setting which leads to their destruction if they react to self-antigens
3
Q

What does the body’s immune defences not usually attack?

A

Tissues that carry a self marker.

4
Q

Pathogen

A

Any organism that cause harm

5
Q

What organisms can cause harm?

A
  • Viruses
  • Protozoa
  • Bacteria
  • Fungi
  • Parasite
6
Q

What physical barriers do our bodies have?

A
  • Skin

- Reproductory, respiratory and digestive tracts

7
Q

What is the main barrier to infection?

A

Mucous membranes

8
Q

What does mucus prevent?

A

The attachment of pathogens and any pathogens that are trapped are repeatedly sloughed off

9
Q

What produces mucus?

A

Goblet cells

10
Q

What does mucus contain?

A

Antimicrobial enzymes such as growth inhibitors, enzyme inhibitors, lysins and immunoglobulins.

11
Q

What do lysins do?

A

Kill invading pathogens

12
Q

What do immunoglobulins do/

A

Help destroy pathogens

13
Q

What are the two divisions in the immune system?

A
  • The innate immune system

- The adaptive immune system

14
Q

What are the characteristics of the innate immune system?

A
  • Non-specific
  • First to come into play
  • Will produce the same response time and again=no memory
15
Q

What are the characteristics of the adaptive immune system?

A
  • Highly specific
  • Immunological memory
  • Antibody production
16
Q

What immune system do we have when we are born?

A

The innate immune system

17
Q

Describe the process when you receive a wound that gets infected with bacteria.

A
  • Area around wound gets red and swollen

- Influx of macrophages to the area

18
Q

What cells are professional phagocytes?

A
  • Monocytes
  • Macrophages
  • Granulocytes
  • Dendritic cells
19
Q

Describe the process of phagocytosis.

A
  • Chemotaxis and adherence of microbe phagocyte
  • Ingestion of microbe by phagocyte
  • Formation of phagosome
  • Fusion of the phagosome with a lysosome to form a phagolysosome
  • Digestion of ingested microbe by enzymes
  • Formation of residual body containing indigestible material
  • Discharges of waste materials
20
Q

Describe how macrophages descend from self-renewing stem cells.

A

One of the daughter cells goes back to being a stem cell and the other goes through a number of choices to end up being one of a number of blood cells

21
Q

Where are macrophages made?

A

Bone marrow

22
Q

What are monocytes?

A

Immature macrophages that divide and differentiate to become macrophages

23
Q

What causes redness in injury?

A

Macrophages give off chemicals that restrict blood flow away from the site of injury

24
Q

What causes swelling in injury?

A

Contraction of endothelial cells

25
Q

What do macrophages produce?

A

Cytokines to alert other cells to the danger and induce them to travel to the site of injury

26
Q

What is the most abundant WBC?

A

Neutrophils

27
Q

How do macrophages and neutrophils differ?

A

Neutrophils aren’t APCs they just eat pathogens

28
Q

When do neutrophils become active?

A

When the enter the tissues from the blood

29
Q

When do neutrophils migrate to the tissues?

A

In the acute phase of inflammation

30
Q

What infections are eosinophils found in?

A

Parasitic

31
Q

What are eosinophils involved in

A

Allergy and asthma

32
Q

What do granules of eosinophils contain?

A

Many enzymes such as:

  • Peroxidase
  • RNase
  • DNase
  • Lipase
  • Plasminogen
  • major basic protein
33
Q

What are mediator released by eosinophils toxic to?

A

Host and parasites

34
Q

Where are eosinophils found?

A
  • Thymus
  • Lower GIT
  • Ovary
  • Uterus
  • Spleen
  • Lymph nodes
35
Q

Where are eosinophils not found?

A
  • Lung
  • Skin
  • Oesophagus
36
Q

What is the cause of anaphylactic shock?

A

Mast cell degranulation

37
Q

What do mast cells protect against?

A

Parasites

38
Q

What do mast cells contain?

A

Granules containing pharmacologically active chemicals including histamine

39
Q

What do mast cells do on encountering a parasite?

A

Dumps all of its contents onto the parasite to kill it

40
Q

What happens to some people on first exposure to an allergen?

A
  • They make lots of IgE antibodies against the allergen.

- The mast cells have receptors which can bind to the Fc region of the IgE antibodies.

41
Q

What happens to some people on second exposure to an allergen?

A
  • The IgE antibdoies which are bound to the mast cell can also bind to the allergen.
  • The mast cell receptors are dragged together and a signal is sent to release the cells chemicals
42
Q

What is the result of mast cell chemical release?

A

Increase in capillary permeability allows fluid to escape the blood vessel resulting in classic allergy symptoms

43
Q

How does allergy become anaphylaxis?

A
  • If the toxins released by mast cells spread throughout the body a massive mast cell degranulation is triggered.
  • Blood volume is reduced causing cardiac arrest
  • Histamine causes airway constriction
44
Q

When are basophils often seen?

A

In parasitic infection

45
Q

Describe the structure of basophils.

A
  • Contains nucleus with two lobes

- Contains cytoplasmic granules which contain histamine

46
Q

When is histamine released from basophils?

A

When the cell is stimulated

47
Q

What are examples of non-specific humoral factors?

A
  • Growth inhibitors
  • Enzyme inhibitors
  • Lysins
  • Complement proteins
48
Q

What does the complement system do?

A

Bridges a gap between the adaptive and innate immunity

49
Q

What does the complement system consist of?

A

Serum and cell surface proteins

50
Q

What is the outcome of the complement system?

A

Lysis of the target cell and/or opsonisation of pathogens

51
Q

What are the 3 pathways of the complement system?

A
  • Classical
  • Alternative
  • Lectin
52
Q

How does the complement system kill pathogens?

A
  • Proteins act together in an enzyme cascade to form a membrane attack complex making a hole in the pathogen
  • This disrupts the pathogens homeostasis and it dies
53
Q

What are lectins?

A

Sugar binding proteins that are specific for their sugar moieties

54
Q

What is the central event in complement activation?

A

The proteolysis of complement protein C3

55
Q

What pathways are effector mechanisms of the innate immune system?

A
  • Alternative

- Lectin

56
Q

What pathway is the effect mechanism of the adaptive immune system?

A

Classical

57
Q

What is the end product of all 3 pathways?

A

C5 convertase

58
Q

When does the membrane attack complex become active?

A

Once the final protein C9 is bound

59
Q

What mechanisms are in place to ensure the complement doesn’t attack our cells.

A
  • Decay acceleration factor is found on the surface of our cells and accelerates the breakdown of C3bBb
  • C3b can be made inactive by proteins in the blood
60
Q

What are the other functions of the complement system?

A
  • Opsonisation of invaders
  • C3a and C5a serve as chemoattractants
  • Induce lysis of microbes
  • Promote phagocytosis of microbes
  • Stimulate inflammation
  • Stimulate activation of B cells and Ab production
61
Q

What can NK cells kill?

A
  • Tumour cells
  • Virus infected cells
  • Bacteria
  • Parasites
  • Fungi
62
Q

How do NK cells kill?

A
  • They can bore holes in target cells be secreting perforin and forming a MAC.They can then secrete enzymes in via the pore and the cells commit suicide
  • They contain protein FasL which interacts with Fas on the target cell surface. When they connect a signal is given and the target cell commits suicide
63
Q

How can NK cells be activated?

A

By IFN-a and B given off by cells under viral attack

64
Q

What are cytokines?

A

Chemicals used by cells to communicate with other cells

65
Q

What signals can shift macrophages and NK cells to a higher state of activation?

A

LPS

66
Q

What accelerators do macrophages produce?

A

IL-12 and TNF

67
Q

What do NK cells produce in response to IL-12 and TNF?

A

-IFN-y

68
Q

What is the inflammatory response?

A

The battle that macrophages, neutrophils and other immune system cells wage against an invader

69
Q

What is acute inflammation?

A

The initial response of the body to harmful stimuli

70
Q

What is chronic inflammation?

A

It leads to a progressive shift in the type of cells present at the site of inflammation and is characterised by simultaneous destruction and healing of the tissue from the inflammatory response.