lecture 32 - innate immunity Flashcards

1
Q

What type of immune responses is the inflammatory response?

A

Innate

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2
Q

What is the overall process of the inflammatory response?

A

Chemical signals from tissue attract more cells, mature neutrophils enter blood from marrow, blood vessels dilate so neutrophils can squeeze through to injury

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3
Q

Where do mature neutrophils for the inflammatory response originate?

A

Bone marrow

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4
Q

What are the overall steps in phagocytosis?

A

Phagocyte adheres to pathogen, forms pseudopod that engulfs particle and forms a phagosome, phagosome fuses with lysosome to form phagolysosome to break down pathogen.

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5
Q

What component of a phagocyte initially engulf particles at the cell surface, and what do they form?

A

Pseudopods on the cell surface form phagosomes/phagocytic vesicles inside the cell.

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6
Q

How are phagolysosomes formed?

A

A lysosome fuses with a phagocytic vesicle/phagosome.

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7
Q

How do phagolysosomes destroy pathogens?

A

By using toxic compounds, an acidic environment and lysosomal enzymes

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8
Q

What toxic compounds do phagolysosomes use to destroy pathogens?

A

Reactive oxygen (hydrogen peroxide) and reactive nitrogen (nitric oxide)

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9
Q

What form of reactive oxygen is found in phagolysosomes?

A

Hydrogen peroxide

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10
Q

What form of reactive nitrogen is found in phagolysosomes?

A

Nitric oxide

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11
Q

Is the pH high or low in a phagolysosome?

A

Low (acidic)

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12
Q

What are the 3 classes of enzymes found in phagolysosomes?

A

Proteases, lipases, nucleases

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13
Q

What are proteases?

A

Enzymes that break down proteins

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14
Q

What type of enzyme breaks down proteins?

A

Proteases

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15
Q

What are lipases?

A

Enzymes that break down fats/lipids

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16
Q

What class of enzyme breaks down lipids/fats?

A

Lipases

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17
Q

What are nucleases?

A

Enzymes that break down nucleic acids (e.g. DNA)

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18
Q

What is the Complement cascade?

A

A component of the immune system that enhances the ability of anti-bodies and phagocytic cells to clear microbes and damaged cells.

19
Q

What is complement?

A

Proteins that act in sequence to clear pathogens in the immune response.

20
Q

How many major complement proteins are there?

A

9 - (C1-C9)

21
Q

What are the 3 key roles of the complement system/cascade?

A

Opsonisation, chemotaxis, lysis

22
Q

What is opsonisation, in terms of the complement system?

A

the binding and labelling of complement proteins to pathogens/antigens so they can be recognised by complement receptors on phagocytes.

23
Q

What is the term for binding labelling proteins to phagocytes, in the complement system?

A

Opsonisation

24
Q

What is chemotaxis?

A

A role of the complement system, which involves the recruitment and migration of phagocytes to the site of injury/inflammation

25
Q

What is the term for the recruitment of phagocytes to injury site, in the complement system?

A

Chemotaxis

26
Q

What is lysis?

A

The destruction of pathogen cells by rupturing the cell wall

27
Q

What is the term for the rupturing of pathogen cell walls, in the complement system?

A

Lysis

28
Q

What are the 3 complement pathways?

A

Classical, alternative, lectin

29
Q

What is the classical complement pathway?

A

A pathway that triggers the complement cascade by binding a pathogen-bound antibody to complement.

30
Q

What is the alternative complement pathway?

A

Pathogen binds complement to surface/pathogen component

31
Q

What is the lectin complement pathway?

A

Carbohydrate components of microbes bind to complement.

32
Q

What are the 3 complement pathways amplified by?

A

enzyme complex - C3 convertase

33
Q

What are microbes coated with during opsonisation/labelling, and what does this enable?

A

Antibody or complement fragment C3b - allows them to be attracted to phagocytes for destruction

34
Q

What is the process of destruction in the complement pathway of innate immunity?

A

Microbes coated with complement fragment c3b are phagocytised. Complement protein C9 allows for the assembly of membrane attack (MAC) complex creates pores that lead to lysis.

35
Q

What is the process of recruitment in the complement pathway?

A

Phagocytes are attracted into the site of injury/infection. Mast cells are degranulated by complement proteins C3a and C5a, releasing inflammatory mediators that tract phagocytes.

36
Q

What proteins degranulate mast cells in recruitment of the complement pathway?

A

C3a and C5a

37
Q

What are inflammatory mediators?

A

Substances released during the degranulation of mast cells.

38
Q

How does recruitment lead to the attraction of phagocytes to a site of infection?

A

Inflammatory mediators released from mast cells include proteins that attract phagocytes.

39
Q

What is the term given for the clinging of neutrophils to capillary walls in an innate reaction to a peripheral site of early infection/inflammation?

A

Margination

40
Q

What is the name given to the process in which mature neutrophils are released from bone marrow to facilitate an immune response?

A

leukocytosis

41
Q

What is diapedesis?

A

When neutrophils travelling to an inflammatory response squeeze through capillary walls to exit blood stream

42
Q

What complement protein leads to “destruction” via the creation of a MAC?

A

C9

43
Q

What is the function of C3 convertase enzyme?

A

Breaks C3 complement protein into C3a and C3b