Defense against extracellular pathogens Flashcards

1
Q

How many different isotopes of immunoglobulin are there

A

9

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2
Q

What are the two regions on immunoglobulin

A

Fab

Fc

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3
Q

Which region on immunoglobulin binds to the antigen

Which region points away from the antigen

A

Fab

Fc

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4
Q

Which isotopes trigger complement proteins

A

IgM

IgG

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5
Q

Which isotopes trigger phagocyte binding

A

IgG

IgA

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6
Q

Which isotopes trigger mast cell binding

A

IgE

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7
Q

What is the advantage of having different isotopes

A

Different types of defensive processes activated because of different antibodies

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8
Q

When are complement proteins active

A

Activated in presence of infeciton

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9
Q

What active complement proteins does C3 (inactive complement protein) make

A

C3a + C3b

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10
Q

Reaction to show inactive C3 and what it becomes

A

C3—-> C3a+ C3b

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11
Q

What enzyme activates C3 into active complement proteins

A

C3 convertase

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12
Q

Names of the 3 reactions that produce C3 convertase

A
  • Classical pathway
  • Mb Lectin pathway
  • Alternative pathway
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13
Q

What happens in the classical pathway

A

1) Immunoglobulin (IgG) binds to antigen and the Fc region points away from it
2) Binding of C1q triggers activation of C1s and C1r which causes them to be split into fragments
3) Split into C4 and C2
4) C4 forms C4a and C4b, C2 forms C2a and C2b
5) C4b and C2a combine to form C4b2a
6) C4b2a is C3 convertase

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14
Q

What happens in the Mb lectin pathway

A

1) Manose binding lectin binds to manose residues in microbial carbs
2) Activation of MASP 1 & MASP2 (which are bits attached to the top of mans binding lectin0
3) MASP1 & MASP2 activate C4 and C2
4) C4 and C2 split into C4a, C4b, C2a, and C2b
5) C4b and C2a combine to form C4b2a which is C3 convertase

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15
Q

What is the Alternative pathway

A

1) C3b binds to microbial surfaces
2) Bb binds to it
3) P protein also binds to it
4) this all makes- C3bBbP (which is C3 convertase)

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16
Q

How to make C5 convertase

A

C3 convertase+ C3b

17
Q

Reaction to show what C5 is activated to using C5 convertase

A

C5—–> C5a+C5b

18
Q

What do C3a and C5a do

A
  • activate mast cells

- Recruit neutrophils

19
Q

What does C5b take part in

A

Membrane attack pathway which using membrane attack complex (causes cell lysis)

20
Q

Whats the membrane attack complex and pathway

A

1) C5b sticks to lipid membranes of microbes
2) C6 and C7 bind to C5b
3) C8 inserts into lipid membrane
4) Lots of C9 make their way over
5) hole formed in lipid membrane

21
Q

What are opsonins

A

Bind to microbes and encourages binding of microbe to phagocyte

22
Q

How are opsonins made

A

1) bacteria induce macrophages which produce IL-6
2) IL6 goes to liver
3) Liver releases active phase proteins such as C reactive protein and Maman-binding lectin
4) These act as opsonins which bind to microbes and encourages binding of microbe to phagocyte

23
Q

Two types of opsonins

A

C reactive protein

Maman-binding lectin

24
Q

What are other types of opsonins and how do these work

A

1) Microbe bound to antibody
2) Complement proteins also bound to microbe
3) FC receptors on phagocyte binds to Fc on antibody
4) CR binds to the C3b (complement protein on microbe)

25
Q

What granulocyte digests extracellularly

A

Eosinophil

26
Q

What does eosinophil have that binds to the complement proteins and antibodies bound on foreign objects

A

Fc receptors and CR proteins

27
Q

What do mast cells release

A

Inflammatory mediators

28
Q

How can mast cells be activated to release inflammatory mediators

A
  • Mast cells sit on tissues
  • Soak up IgE on surface
  • Gain antigen specificity of that particular IgE so can bind to the antigen that the IgE was specific to
  • If antigen binds to two antibodies , then mast cell activated
29
Q

What complement proteins can activate mast cells

A

C3a, C5a

30
Q

What do inflammatory mediators cause

A
  • Relaxing of smooth muscle around blood vessels (vasodilation)
  • Cause endothelial ells to produce adhesion molecules which bind to leucocytes
  • Cause endothelial cells to move apart from eachother which increases permeability
  • movement through endothelial (chemotaxis) to get to site of infection
31
Q

What does the vasodilation cause

A

Slower movement of leucocyte

32
Q

What adhesion molecules do the endothelial cells make

A

Integrins and selectins

33
Q

Whats the name of the acute phase response

A

systematic inflammatory response

34
Q

What effect do cytokines cause

A

‘flu’ like symptoms

35
Q

What do cytokines do to hypothalamus

A

-Act on it to raise temp

36
Q

What do cytokines do to bone marrow

A

-Act on it to increase leucocytosis

37
Q

What do cytokines do to liver

A

-Act on liver to release acute phase proteins (C-reactive protein)