Immunology Flashcards Preview

Phase 2a Medicine - Riona > Immunology > Flashcards

Flashcards in Immunology Deck (132)
Loading flashcards...
1
Q

What is innate immunity?

A

An immune response that is present from birth

2
Q

Give 3 features of an innate immune response

A
  • ) Immediate
  • ) Non-specific
  • ) Slow
  • ) No memory
3
Q

What does PAMP stand for, and where is it found?

A

Pathogen associated molecular patterns, on microbe

4
Q

What does PRR stand for, and where is it found?

A

Pattern recognition receptors, on cells

5
Q

How is the innate immune system activated?

A

Activated by PRRs on dendritic cells recognising conserved PAMPs on microbes and triggering a response

6
Q

What does TLR stand for?

A

Toll-like receptor

7
Q

What does the complement system consist of?

A

Circulating inactive proteins synthesised by the liver that, when stimulated, trigger a proteolytic cascade

8
Q

What do TLRs and other PRRs do?

A

Drive cytokine production

9
Q

What 3 pathways is the complement system activated by?

A
  • ) Classical
  • ) Alternative
  • ) Lectin
10
Q

Which immune system is the complement system part of?

A

Innate

11
Q

What are the 4 main steps of the classical pathway?

A

1) C1q binds to Fc domains of IgG/IgM or to pathogens, activating C1r and C1s
2) C1s cleave C4 to C4a and C4b
3) C4b binds to C2 forming C4b2b complex
4) C4b2b is a C3 convertase and cleaves C3

12
Q

What is the alternative pathway activated by?

A

Bacterial cell wall

13
Q

What is the classical pathway activated by?

A

An antibody

14
Q

What are the 5 main steps of the alternative pathway?

A

1) C3 splits to form C3b and C3a
2) C3b forms a complex with factor B forming C3bB
3) Addition of factor B forms C3bBb
4) C3bBb is a C3 convertase, and catalyses the splitting of C3 (more C3b produced, positive feedback loop)
5) Rate of C3 conversion rises above rate of deactivation of convertase, pathway activates

15
Q

What is the lectin pathway activated by?

A

Mannose binding lectin that is bound to a microbe

16
Q

What are the 2 main steps of the lectin pathway?

A

1) MBL binds to mannose carbohydrate on surface of pathogen

2) Then same steps as classical

17
Q

Give 3 things complement activation results in

A
  • ) Increased vascular permeability
  • ) Chemoattraction of leucocytes
  • ) Enhanced phagocytosis
  • ) Enhanced lysis (releases pro inflammatory markers)
18
Q

What is the key step in the complement system, and why?

A

Cleavage of C3

C3b mediates opsonisation

19
Q

What is opsonisation?

A

The labelling of targets for destruction by phagocytosis

20
Q

Give the 7 steps of an inflammatory response

A

1) Bleeding stopped by coagulation
2) Acute inflammation by leukocyte recruitment
3) Killing pathogens, neutralising toxins, limiting pathogen spread
4) Clear pathogens/dead cells by phagocytosis
5) Proliferation of cells to repair the damage
6) Remove blood clot and remodel extracellular matrix
7) Re-establish normal structure/function

21
Q

Give 3 polymorphonuclear leukocytes

A
  • ) Neutrophil
  • ) Eosinophil
  • ) Basophil
22
Q

What are neutrophils involved in?

A

Innate immunity and phagocytosis

23
Q

What are eosinophils involved in?

A

Parasitic infections and allergic reactions

24
Q

What are basophils involved in?

A

Parasitic infections and allergic reactions

25
Q

Give 3 mononuclear leukocytes

A
  • ) Monocyte
  • ) T-cells
  • ) B-cells
26
Q

What are monocytes involved in? (4)

A

Innate and adaptive immunity, phagocytosis, Ag presentation

27
Q

What do monocytes differentiate into?

A

Macrophages

28
Q

What are T-cells involved in?

A

Adaptive immunity

29
Q

What do T-cells differentiate into? (3)

A

T-regs, T-helpers, cytotoxic

30
Q

What are B-cells involved in?

A

Adaptive immunity

31
Q

What do B-cells differentiate into?

A

Plasma cells

32
Q

Give 3 other cells of the immune system

A
  • ) Mast cells
  • ) Natural killer cells (NK)
  • ) Dendritic cells
  • ) Macrophages
33
Q

What are mast cells involved in?

A

Parasitic infections and allergic reactions

34
Q

What do mast cells release?

A

Histamine

35
Q

Where are mast cells found?

A

Only in tissues

36
Q

What do NK cells do?

A

Recognise and kill virus infected and tumour cells by apoptosis

37
Q

What are macrophages involved in? (4)

A

Innate and adaptive immunity, phagocytosis, Ag presentation

38
Q

What is an antibody?

A

A protein produced in respond to an antigen, can only bind to that specific antigen

39
Q

What is an antigen?

A

A molecule that reacts with a preformed antibody and specific receptors on T cells

40
Q

What is an epitope?

A

The part of the antigen that binds to the antibody/receptor binding site

41
Q

What is affinity?

A

The measure of the binding strength between and epitope and an antibody binding site

42
Q

Give 3 features of adaptive immunity

A
  • ) Specific response
  • ) Involves memory
  • ) Cell mediated and humoral
  • ) Quicker
43
Q

What cells are against intracellular microbes?

A

T cells

44
Q

What cells are against extracellular microbes?

A

B cells

45
Q

What can T cells not recognise?

A

Antigens not bound to host cells

46
Q

How is the processed antigen presented?

A

With MHC class II antigens on the APC surface

47
Q

What does MHC stand for?

A

Major histocompatibility complex

48
Q

What does APC stand for?

A

Antigen presenting cell

49
Q

What is T cell selection?

A

T cells that recognise self are killed in the foetal thymus as they mature

50
Q

What are MHC antigens?

A

Cell surface glycoproteins

51
Q

What do class I MHCs present on?

A

All nucleated cells

52
Q

What do class II MHCs present on? (4)

A

Dendritic cells, B lymphocytes, activated T cells, macrophages (APCs)

53
Q

What do class III MHCs constituent of?

A

Early complement proteins C4 and C2

54
Q

Where do T lymphocytes mature?

A

Thymus

55
Q

What do cytotoxic CD8 T cells do?

A

Destroy infected intracellular cells

56
Q

What do memory T cells do?

A

Survive after infection to respond rapidly to recurrent infections

57
Q

What do helper T cells CD4 do? (3)

A
  • ) Activate cytotoxic T cells
  • ) Activate B cell antibody production
  • ) Secrete cytokines
58
Q

What do regulatory T cells do?

A

Negatively regulate immune response preventing autoimmunity, can suppress other T cell types

59
Q

Give the 7 steps in which Th1 activation leads to stopping viral spread

A

1) APC presents an Ag with MHC II to a naive CD4 T cell
2) Stimulation with high levels of IL-12 activate naive cells to Th1 cells
3) Th1 cells go to secondary lymphoid tissue
4) Activated
5) Clonal expansion/proliferate
6) Th1 cells recognise Ag on infected cells
7) Th1 secretes INF gamma and stops virus spread

60
Q

What type of cell is CD4?

A

Helper T cell

61
Q

What type of cell is CD8?

A

Cytotoxic T cell

62
Q

Where is the secondary lymphoid tissue?

A

Spleen, lymph nodes

63
Q

When do B cells become activated?

A

When they have bound to their specific Ag

64
Q

Where do activated B cells proliferate and differentiate?

A

Lymph nodes

65
Q

What sort of antibodies/immunoglobulin do plasma cells secrete?

A

IgM

66
Q

What is class switching?

A

IgM later turn into IgG, but have the same specificity

67
Q

What are antibodies/immunoglobulins secreted by?

A

B lymphocytes

68
Q

Where do B cells mature?

A

Bone marrow

69
Q

What are the 5 main types of Ig?

A
  • ) IgG
  • ) IgM
  • ) IgA
  • ) IgD
  • ) IgE
70
Q

What is IgG involved in?

A

Important in secondary and memory response

71
Q

Which Ig can cross the placenta?

A

IgG

72
Q

What shape is IgG?

A

Y shaped

73
Q

What is IgM involved in?

A

Important in primary response, pentamer

74
Q

Where is IgG mainly found?

A

Serum and tissues

75
Q

Where is IgM mainly found?

A

Blood

76
Q

What does IgA do?

A

Protects mucosal surfaces

77
Q

What is predominant in mucous secretions?

A

Secretory IgA

78
Q

What Ig is present as an antigen specific receptor on B cells?

A

Monomeric form mIgM

79
Q

Where is IgA mainly found?

A

Serum and secretions

80
Q

What does IgD do?

A

May have a role in respiratory infection

81
Q

What Ig is present on mature B cells?

A

Transmembrane monomeric form mIgD

82
Q

What is IgE involved in?

A

Allergic and parasitic reactions

83
Q

What 2 types of inflammatory cell have a high affinity for IgE?

A

Basophils and mast cells

84
Q

Give 3 functions of an antibody

A
  • ) Opsonisation
  • ) Activation of complements
  • ) Antibody dependent cell mediated cytotoxicity
85
Q

What is the Fab region of an antibody?

A

Variable, binds specifically to antigens

86
Q

What is the Fc region of an antibody?

A

Constant, bind to Fc receptors on cells such as phagocytes and complement proteins

87
Q

What are cytokines?

A

Proteins secreted by immune and non-immune cells

88
Q

What are the 4 main types of cytokines?

A
  • ) Inferferons
  • ) Interleukins
  • ) Colony stimulating factors
  • ) Tumour necrosis factors
89
Q

What do interferons do?

A

Induce a state of antiviral resistance in uninfected cells and limit the spread of viral infection

90
Q

What can interleukins be?

A

Pro or anti-inflammatory

91
Q

What do interleukins do?

A

Cause cells to divide, differentiate or secrete factors

92
Q

What do colony stimulating factors involved in?

A

Directing the diversion and differentiation of bone marrow stem cells

93
Q

What are colony stimulating factors the precursors of?

A

Leukocytes

94
Q

What do tumour necrosis factors do?

A

Mediate inflammation and cytotoxic reaction

95
Q

What are chemokines?

A

Chemotaxic cytokines

96
Q

What do chemokines do?

A

Direct the movement of leukocytes and other cells from the blood stream into tissues or lymph organs by binding to specific receptors on cells

97
Q

What is autoimmunity?

A

A system of immune responses of an organism against its own cells and tissues

98
Q

Give 2 causes of autoimmune disease

A
  • ) Tissue damage

- ) Disturbed functions from autoimmunity

99
Q

What does organ specific autoimmune disease usually affect?

A

Endocrine glands

100
Q

Give 2 environmental triggers for autoimmune diseases

A
  • ) Hormones
  • ) Infection
  • ) Drugs
  • ) UV radiation
101
Q

What is the recognition and elimination of cancer cells mediated by? (2)

A

T cells and NK cells

102
Q

What is cancer immunosurveillance?

A

The system that can recognise and destroy new cells

103
Q

What is cancer immunoediting?

A

When changes in the immunogenicity of tumours due to the anti-tumour response of the immune results in immune resistant variants

104
Q

What are over expressed on cancer cells?

A

Tumour associated antigens

105
Q

Where are tumour associated antigens found?

A

Normal and tumour cells

106
Q

Where are tumour specific antigens found?

A

Tumour cells

107
Q

How can tumours change immune responses?

A

By promoting immune suppressor cells, so they can be seen as self

108
Q

What are transplants crossmatched to detect?

A

Anti HLA antibodies

109
Q

What does HLA stand for?

A

Human leukocyte antigen

110
Q

What is the HLA complex?

A

A gene complex encoding the MHC proteins in humans

111
Q

What immunological cell plays a central role in rejection of a transplant?

A

CD4 T helper cells recognise the donor MHC and recruit effector cells

112
Q

Give 2 ways in which we can prevent transplant rejection

A
  • ) Tissue typing
  • ) Cross matching
  • ) Immunosuppression
113
Q

What is an allergy?

A

An abnormal response to harmful foreign material, usually involving IgE

114
Q

Give 3 clinical indications for an allergy

A
  • ) Eczema
  • ) Itching
  • ) Mucous
  • ) Airway constriction
  • ) Anaphylaxis
  • ) Vomiting
  • ) Diarrhoea
115
Q

Give 3 cells that are involved in an allergic response

A
  • ) Mast cells
  • ) Eosinophils
  • ) Lymphocytes
  • ) Macrophages
  • ) Cytokines
116
Q

What are the 4 main types of hypersensitivity reactions?

A
Type I - allergic and immediate
Type II - cytotoxic, antibody to cell bound antigen
Type III - immune complex
Type IV - delayed type
ACID
117
Q

What Ig does type I hypersensitivity involve?

A

IgE

EGGT

118
Q

What Ig does type II hypersensitivity involve?

A

IgG

EGGT

119
Q

What Ig does type III hypersensitivity involve?

A

IgG

EGGT

120
Q

What cell does type IV hypersensitivity involve?

A

T cells

EGGT

121
Q

Give an example of a type I hypersensitivity reaction

A

Peanut allergy, latex, bee venom, antibiotics

122
Q

How does type I hypersensitivity occur?

A

Binding of antigen by IgE on mast cells/basophils releases preformed mediators

123
Q

Give an example of a type II hypersensitivity reaction

A

Drugs, haemolytic anaemia

124
Q

How does type II hypersensitivity occur?

A

Cell destruction caused by activation of complement system and promotion of phagocytosis, body’s own cells attacked

125
Q

Give an example of a type III hypersensitivity reaction

A

RA, glomerulonephritis, Goodpasture’s

126
Q

How does type III hypersensitivity occur?

A

Deposition of IgG containing immune complexes, especially in joints and kidneys

127
Q

Give an example of a type IV hypersensitivity reaction

A

DM, MS, Crohn’s, contact dermatitis

128
Q

How does type IV hypersensitivity occur?

A

Local inflammation occurs after days, granulation tissues delay response

129
Q

What does immunodeficiency present as?

A

Serious persistent, unusual or recurrent infections

130
Q

How do we treat immunodeficiency?

A

Bone marrow transplant

131
Q

Give 3 causes of immunodeficiency

A
  • ) Antibody deficiency
  • ) Cellular immunity deficient
  • ) Phagocytic/complement defects
  • ) Genetic (primary)
132
Q

What does C3b go on to form?

A

Membrane attack complex