immunity 1 Flashcards

1
Q

innate immune cells (8)

A

macrophage, natural killer, dendritic, neutrophil, eosinophil, basophil, t, natural killer t

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2
Q

adaptive immune cells (5)

A

B, T, CD4+ t, CD8+ t, Natural killer t

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3
Q

other components of innate immunity (5)

A

interferons, complement, chemokines, defensins, lysozymes

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4
Q

other components of adaptive immunity (3)

A

interferons, interleukins, chemokines

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5
Q

what does innate immunity respond to

A

chronic inflammation as a result of bacteria or virus

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6
Q

what do interferons do

A

block virus replication

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7
Q

what do defensins and lysozymes do

A

break down bacterial cell walls

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8
Q

what does compliment do

A

actively lyses bacteria

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9
Q

how long does the innate immune response take

A

6-12 hrs

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10
Q

how long does adaptive immunity take

A

10-14 days in primary response

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11
Q

pros of adaptive

A

very effective as it develops memory

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12
Q

soluble factors of adaptive

A

antibodies and interferons

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13
Q

soluble factors of innate

A

lysozyme, complement, acute phase proteins

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14
Q

con of innate immune system

A

no memory

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15
Q

complement summary

A

its a cascade of proteins which results in the activation of another complement component

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16
Q

complement and opsonisation

A

some complement proteins bind covalently to bacteria to opsonise them for them to be engulfed by phagocytes with complement receptors

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17
Q

complement proteins as chemoattractants

A

small fragments of complement proteins act as chemoattractants to recruit phagocytes so complement can be activated

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18
Q

what do terminal complement components do

A

damage some bacteria by creating pores in the bacterial cell membrane - membrane attack complex (MAC)

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19
Q

how does the complement cascade work

A

each component cleaves the next e.g. C1 cleaves C2

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20
Q

3 ways that complement is activated

A

classical pathway, mannan binding lectin (MBL), Alternative pathway

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21
Q

what happens when complement is activated

A

proteolytic cascade (C1-C5) is triggered which leads to the formation of the MAC (C6-C9) on the surface of the closest cell. this pore destabilises the membrane causing lysis of the cell

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22
Q

what does the MAC do (membrane attack complex)

A

punches holes in the cell causing osmotic shock, swelling, lysis and death

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23
Q

NK cells

A

large granular lymphocyte like cells, dont have antigen specific, programmed to kill all the time - when going around the body they are told not to kill by receptors by normal cells.

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24
Q

what receptors do NK cells recognise

A

major histocompatibility complex (MHC)

25
Q

what do viruses do to MHC

A

down regulate it or switch it off, making NK cells target them as there are no more inhibitory receptors

26
Q

how are NK cells regulated

A

balance between activating and inhibitory receptors stops them becoming activated.

27
Q

what is known as the ‘self’ molecule

A

MHC

28
Q

tumour cells and MHC regulation

A

they evolve to down regulate MHC and so they are not recognised by immune cells but they maintain just enough MHC to turn NK cells off

29
Q

what are macrophages and what do they do

A

phagocytic cells that recognise common patterns on many pathogens (PAMPS) which are recognised by receptors on innate cells and stimulate a response like cytokine production and killing

30
Q

what are PAMPS

A

pathogen associated molecular patterns

31
Q

4 postulates of the clonal selection theory

A
  1. each lymphocyte has a specific receptor
  2. lymphocytes are activated when their receptor binds to a foreign molecule with high affinity
  3. differentiated cells from the lymphocytes will have the same receptors as their parents
  4. lymphocytes are negatively selected for things that do not recognise us
32
Q

2 types of lymphocytes

A

B cell and T cell

33
Q

similarities of B and T cells

A

both have antigen receptors

34
Q

differences of B and T cells

A

B cells have surface immunoglobulins and 2 identical antigen recognition sites, T cells have 1 recognition site and no surface immunoglobulins

35
Q

what do surface immunoglobulins do

A

recognise antigens

36
Q

what are the 2 components of t cell receptors

A

alpha and beta chains

37
Q

what do some variants of B cell receptors have that allow it to bind to plasma membranes

A

transmembrane domains

38
Q

what does T cell activation result in

A

production of cytokines and cell division for amplified response

39
Q

where are B cells produced

A

bone marrow

40
Q

where are T cells produced

A

Thymus

41
Q

where do circulating lymphocytes encounter antigens

A

peripheral lymphoid tissue

42
Q

what is an epitope

A

the specific region of an antigen that the receptor binds to

43
Q

what are naïve lymphocytes

A

when they have not encountered an antigen

44
Q

where is the only place where a naïve lymphocyte is activated

A

lymph nodes, NOT at site of infection

45
Q

what two signals are required for B cell activation

A

Signal 1 - antigen receptor binding and Signal 2 - activation of B cell by T cell

46
Q

what cells provide signal 2 for T cells

A

macrophages and dendritic cells

47
Q

what do B cells make

A

antibodies, different B cells make different antibodies

48
Q

antibody structure

A

2 chains - heavy and light, each made of a variable region and constant regions

49
Q

antibodies: light chain structure

A

one variable region and one constant region

50
Q

antibodies: heavy chain structure

A

1 variable region and 3 constant regions (hinge between Ch1 and Ch2)

51
Q

what are antibody isotypes

A

different types of antibodies that are produced - they have different properties

52
Q

When does a B cell change the class of the isotype of the antibody

A

when it encounters the antigen again

53
Q

What are the different isotypes of antibodies

A

IgA, IgM, IgG, IgD, IgE

54
Q

which isotypes of antibody are multimeric

A

IgA and IgM

55
Q

what is the J chain

A

in IgA, it links 2 constant regions together, it has a receptor that assists delivery to mucosal surfaces

56
Q

what does neutralisation do

A

prevent infection

57
Q

what does opsonisation do

A

clears the antigen

58
Q

what does complement activation do

A

kills directly