Immunology Flashcards
(144 cards)
1
Q
What are the two components of the immune system?
A
White blood cells and soluble (humoral) factors
2
Q
What are the soluble factors involved in the immune system?
A
Antibodies, complement proteins, acute phase proteins and cytokines
3
Q
What are the two types of white blood cell involved in the immune system?
A
Lymphocytes and phagocytes
4
Q
What are the phagocytes involved in the immune system?
A
Neutrophils, monocytes/macrophages, dendritic cells
5
Q
What are the lymphocytes involved in the immune system?
A
NKC’s, B cells, T cells (cytotoxic and helper), mast cells, basophils and eosinophils
6
Q
What are the 4 different types of immunity?
A
Anti-viral, anti-helminth, anti-intracellular bacterial, anti-extracellular bacterial/fungal
7
Q
What components are involved in anti-viral response?
A
Antibodies, NKC’s, cytokines and cytotoxic T cells
8
Q
What components are involved in anti-helminth immune response?
A
Eosinophils, basophils, B-cells and antibodies and mast cells
9
Q
What components are involved in anti-intracellular bacterial immune response?
A
B-cells and antibodies, cytotoxic T-cells and NKCs
10
Q
What components are involved in anti-extracellular bacterial and fungal immune response?
A
Antibodies, neutrophils, macrophages, complement, cytotoxic T cells, NKCs
11
Q
What are some molecules which are included in the general class of ‘cytokines’?
A
Chemokines, interferons and interleukins
12
Q
What do cytokines do?
A
Modulate behaviour of cells and co-ordinate the immune system
13
Q
When are antibodies produced and how do they act?
A
In response to an antigen- they act specifically
14
Q
What produces antibodies?
A
Antigen activated B cells
15
Q
Where do complement proteins come from and what do they do before they are activated?
A
They are produced in the liver and circulate in the blood as precursor molecules
16
Q
What happens when an activated complement protein enters an inflamed or infected cell?
A
It sets off a cascade of complement activation
17
Q
What do complement proteins promote?
A
Inflammation
18
Q
What are NKCs?
A
Large granular lymphocytes
19
Q
Where are B and T cells found before the are activated?
A
Circulating in the blood as inactive molecules until they meet a pathogen
20
Q
What do B cells do?
A
Produce antibodies and defend against extra cellular pathogens
21
Q
What type of pathogen do T cells protect against?
A
Intracellular pathogens
22
Q
What do helper T cells do?
A
Regulate the immune system
23
Q
What do cytotoxic T cells do?
A
Kill virally infected cells
24
Q
Which type of pathogens do basophils, eosinophils and mast cells protect against?
A
Those which cannot be phagocytosed
25
What type of cells are eosinophils, basophils and mast cells and what do they produce?
Highly granular cells which produce histamine, heparin and cytokines
26
What do mast cells do?
Reside in tissues and protect mucosal surfaces
27
What do basophils and eosinophils do?
Circulate in blood and are recruited to the site of infection by inflammatory signals
28
What do macrophages do as well as phagocytosis?
Limit inflammation, involved in tissue repair, wound healing and antigen presentation
29
What do monocytes do?
Circulate in blood, migrate to peripheral tissues and differentiate into macrophages
30
What are monocytes, macrophages and neutrophils a source of?
Cytokines
31
What do dendritic cells have a key role in?
Antigen presentation to T cells
32
What transformation do dendritic cells undergo?
Start as immature cells in peripheral tissues and become mature as they migrate to secondary lymphoid tissues
33
What happens in primary lymphoid tissues?
Leukocyte (WBC) development
34
What are examples of primary lymphoid tissues?
Bone marrow, thymus
35
What happens in secondary lymphoid tissues?
Adaptive immune responses are initiated
36
What is found in secondary lymphoid tissues?
B cells, T cells and dendritic cells
37
What are examples of secondary lymphoid tissues?
Spleen, lymph nodes
38
What is lymphoedema?
Localised fluid retention and tissue swelling caused by a compromised lymphatic system
39
What can cause lymphoedema?
Parasitic infection, cancer treatments or it can be inherited
40
What components are involved in innate immune response?
Macrophages, mast cells, complement, neutrophils, NKCs
41
What type of response does the innate immune system produce?
Rapid (mins-hours), non-specific response
42
What type of response does the adaptive immune system produce?
Slower (days), specific response
43
What else does the adaptive immune system do?
Generates immunological memory
44
What components are involved in the adaptive immune response?
B cells, T cells
45
What has the function of switching between the innate and adaptive immune systems?
Dendritic cells
46
What is direct biological communication?
Receptor to ligand interactions
47
What is the first part of indirect biological communication?
Injured tissue cells and activated immune cells produce cytokines which communicate with the immune system
48
What is the second part of indirect biological communication?
Virally infected cells produce interferons which puts cells into non-viral state and acts on other immune cells, particularly NKCs
49
What happens in the recognition phase of the innate immune response?
Innate immune cells recognise and respond to pathogens
50
What do pathogens express?
Pathogen Associated Molecular Patterns (PAMPs)
51
What do innate immune cells express?
Pattern Recognition Receptors (PRRs)
52
Where are PRRs found?
On the surface of the cell and intracellularly to detect intra and extra cellular pathogens
53
What happens in the activation and effector phase of the innate immune response?
Acute inflammation and pathogen killing
54
Where do macrophages reside?
Epithelial tissues at sites where pathogens are likely to invade
55
What is a major function of macrophages in innate response?
Clearance of apoptotic cells
56
What is an example of an anti-inflammatory mediator released in the innate immune response?
IL-10
57
What happens if the mechanism of apoptotic clearance fails?
Autoimmune disease
58
What is degranulation (in terms of mast cells)?
Release of pre-formed pro-inflammatory molecules
59
What is gene expression (in terms of mast cells)?
Release of new pro-inflammatory molecules
60
What happens in the acute phase response of innate response?
Changes in the plasma concentration of specific proteins in response to inflammation
61
What is the acute phase response driven by?
Cytokines
62
What do CRP, SAP and complement proteins cause?
Prevent spread of infection and act as diagnostic markers
63
What does fibrinogen do?
Coagulation and wound healing
64
What do CRP, haptoglobin, manganese superoxidase dismutase and proteinase inhibitors do?
Prevent systematic inflammation
65
What is the first branch of inflammatory mediators produced by macrophages, mast cells and NKCs?
Nitric oxide, histamine, prostaglandins and leukotrienes
66
What does the first branch of inflammatory mediators cause?
Vasodilation, increased vascular permeability, smooth muscle contraction
67
What is the second branch of inflammatory mediators released by mast cells, macrophages and NKCs?
Cytokines- TNFalpha, IL-1 and IL-6
68
What does the second group of inflammatory mediators cause?
Increased vascular permeability and endothelial cell activation
69
What is the 3rd group of inflammatory mediators released by mast cells, macrophages and NKCs?
Chemokines
70
What does the 3rd group of inflammatory mediators lead to?
Leukocyte recruitment and activation
71
What does acute inflammation cause?
Pain, heat, redness, swelling and loss of function
72
What do macrophages produce?
TNFalpha, IL-1 and NO
73
What do mast cells release?
Prostaglandins, histamine, TNFalpha, leukotrienes
74
What are the adhesion molecules that activated endothelial cells possess?
Selectins (receptors) and ICAMs (ligands)
75
Where do chemokines come from?
Macrophages and mast cells
76
What is the first stage of chemotaxis?
Neutrophils bind to selectins and roll along the endothelial surfaces
77
What is the 2nd stage of chemotaxis?
Neutrophils bind to ICAM-1/VCAM-1 ligands on the endothelium via selectins
78
What is the 3rd stage of chemotaxis?
Neutrophils change shape and migrate through the endothelial wall to the site of inflammation
79
What are two structural facts about neutrophils?
They have intracellular granules and a multi-lobed nucleus
80
What do neutrophils release to immobilise pathogens?
intracellular structures known as NETs
81
What do NETs do?
Prevent pathogens spreading and facilitate phagocytosis
82
What is pus made up of?
Neutrophils, NETs, cellular debris and dead bacteria
83
What is an accumulation of pus known as?
Abscess
84
What are used to neutralise TNFalpha?
Monoclonal antibodies
85
What are the four stages of complement function?
1) Pathogen killing
2) Opsonisation
3) Leukocyte recruitment
4) Removal of immune complexes
86
What defence is complement involved in?
Against encapsulated bacteria
87
How does complement cause pathogen killing?
C5b binds to the surface of pathogens, it then combines with C6,7,8,9 to form membrane attack complex (MAC) which is inserted into target cell walls to cause osmotic lysis
88
What does opsonisation do?
Facilitates phagocytosis
89
What complement protein is involved in opsonisation?
C3b
90
How does opsonisation facilitate phagocytosis?
Pathogens are coated with opsonsins, phagocytes have opsonin receptors
91
How do complement proteins cause leukocyte recruitment?
C3a and C5a (anaphylatoxins) promote inflammation by acting directly on blood vessels
92
Where are T and B cells produced?
Bone marrow
93
What are the antigen receptors for T cells?
Membrane bound protein heterodimers
94
What are the antigen receptors for B cells?
Membrane bound antibodies (IgM/IgD)
95
Where are antibodies found?
Expressed on the surface of B cells and secreted as soluble proteins into extra cellular fluid
96
What type of polypeptide chains are antibodies made of?
2 Ig heavy and 1 Ig light polypeptide chains
97
What do they polypeptide chains that make up antibodies contain?
A variable region and a constant domain
98
What holds the polypeptide chains in antibodies together?
Disulphide bonds
99
What is the part of the antibody structure that changes with the different types?
Different Ig heavy chain constant regions
100
What forms the antigen binding site?
Hypervariable regions of the Ig heavy and light chains
101
Where does adaptive immune response take place?
Secondary lymphoid tissues
102
Where do mature, antigen specific B and T cells circulate between?
Blood, secondary lymphoid tissues and lymph nodes
103
What is trapped in secondary lymphoid tissues?
jDendritic cells, pathogens, antigens and debris
104
What is another name for MHC proteins?
HLA
105
Where are class I MHC proteins found?
All uncleared cells
106
What do class I MHC proteins do?
Present peptide antigens to CD8+ T cells
107
Where are class II MHC proteins found?
Only on professional antigen presenting cells
108
What do class II MHC proteins do?
Present peptide antigens to CD4+ T cells
109
What is the differentiation process of forming antibodies?
B cells, plasma cells, antibodies
110
What do short lived plasma cells do?
Churn out lots of antibodies
111
What do long-lived plasma cells do?
Reside in bone marrow for low level secretion of specific antibodies (immunological memory)
112
What role does the variable region of antibodies play?
Involved in recognition function
113
What role do heavy chain constant regions play?
Involved in effector function, contact region interacts with effector molecules (Fc receptors and complement)
114
What is an early role of IgM and what does this mean?
B-cell activation therefore it is the first Ig type produced in an immune response
115
What is the structure of IgM?
Pentamer
116
Where is IgM found and why?
Only in tissue fluid as it is too big to cross the membrane
117
What are the other 2 functions of IgM?
Agglutination and complement system activation
118
What is agglutination?
Immune complex formation (cross linking multiple antigens to produce clumps of antigens) to increase efficacy of phagocytosis
119
What is agglutination mediated by?
Specific antigen binding
120
When is IgM produced?
Innate immune response
121
What is IgG?
The most abundant antibody in human serum, dominant type produced during a secondary response and the best as it has many functions
122
What are the functions of IgG?
Agglutination, complement system activation, foetal immune protection, neutralisation, opsonisation and NKC activation
123
How is IgG transported to the foetus?
Directly across the placenta into the foetal blood supply
124
What does neutralisation prevent?
Pathogens from infecting host cells and microbial toxins disrupting normal cell function
125
What is opsonisation initiated and mediated by?
Initiated by antigen binding and mediated by Fc receptors binding to the constant region of the heavy chain
126
What is the function of IgD?
B cell antigen receptor (B cell activation)
127
Where is IgD found?
Extremely low concentrations in the blood
128
How abundant is IgA?
Second most abundant form
129
Where is IgA found?
Monomeric form in serum, dimeric form in secretory fluid
130
What are the functions of IgA?
Neutralisation and neonatal immune protection
131
How does IgA protect neonates?
Transported in the colostrum and breast milk to protect the GI tract of neonates
132
How are false readings of neonatal antibodies common?
Shows maternal ones
133
What is the function of IgE?
Triggers allergic responses
134
What do CD4+ T cells secrete?
IL-2
135
What does IL-2 cause?
Growth factor production and promotes mitosis in T cells
136
What response are TH1 cells involved in?
Bacteria
137
What response are TH2 cells involved in?
Helminth and Protozoa
138
What do T helper cells help activate?
B cells and macrophages
139
What cells does immunological memory involve?
Memory CD4+ and CD8+ T cells, memory B cells and long lived plasma cells
140
Describe antibody concentrations in primary response?
IgM first until concentrations of IgG take over
141
Describe antibody concentrations in secondary response?
Immediate secretion of IgM and IgG but IgG at higher concentrations
142
What are some examples of opsonins and what do they do?
CRP, IgG antibodies and C3b- mediate opsonisation
143
What is a key mediator of complement and why?
C3 as it is activated by all 3 pathways
144
Where is CRP produced?
Liver cells
