Immunology Flashcards
(167 cards)
1
Q
What is the main function of the immune system?
A
Protects against infectious agents
2
Q
What are the two main systems of immunity?
A
Innate immunity
Adaptive immunity
3
Q
What form of immunity acts as a first line of defence? E.g. barriers, cells, soluble factors
A
Innate immunity
4
Q
What are key features of the innate immunity?
A
-present at birth
-responds rapidly
- has no specificity
- has no memory
5
Q
What are some physical barriers in innate immunity?
A
Skin, epithelial cell layer, mucosa, cilia, bronchi
6
Q
what are some chemical barriers in innate immunity?
A
-acidity in stomach
- alkaline secretions
-lysozyme in tears
7
Q
What is the main form of biological barrier in innate immunity?
A
Competition with commensal organisms
8
Q
What are examples of cells in innate immunity?
A
-phagocytes
-natural killer cells
-eosinophils
9
Q
What cells are phagocytic in nature?
A
- monocytes
- macrophages
- neutrophils
10
Q
What is the role of NK cells?
A
To kill tumour cells and virally infected cells
11
Q
What is the role of eosinophils?
A
Attack and kill parasites
12
Q
What are examples of soluble factors?
A
- lysozymes
- complement
- cytokines
- acute phase proteins
13
Q
What is the role of lysozymes?
A
Protects against bacteria, viruses and fungi
14
Q
What are cytokines?
A
Proteins that are part of the natural defences
15
Q
The innate and adaptive immune systems cooperate with one another. True or false?
A
True
16
Q
What are the two components of adaptive immunity?
A
humoral and cellular
17
Q
What are key features of adaptive immunity?
A
-slow to start
-adaptive
- highly specific
-memory
-recognition of self and non-self
18
Q
What does humoral immunity involve?
A
Antibodies (immunoglobulins)
19
Q
What produces immunoglobulins?
A
B lymphocytes
20
Q
What does cellular immunity involve?
A
Lymphocytes
21
Q
What are the two types of lymphocytes
A
B and T lymphocytes
22
Q
What are the two types of T cell?
A
Helper T cells
Cytotoxic T cells
23
Q
What is the role of helper T cells?
A
Help B cells produce antibodies, in turn aiding humoral immunity
24
Q
What is the role of cytotoxic T cells?
A
Destroy infected target cells with specific antigens, and spare uninfected cells.
25
What are effector functions?
Part of humoral response, they form an essential link between innate and adaptive immunity.
26
What are the two main roles of the immune system?
Recognition function
Effector function
27
What is recognition function?
Identifies a substance or antigen as foreign
28
What is an antigen?
Any substance which elicits an immune response
29
What part of an antigen is recognised by antibodies (humoral) and T cells ( cellular)?
The epitope/antigenic determinant
30
What is the KEY point to remember about antigens?
They are foreign
31
What are the two main roles of the cells of the immune system?
1. Migrate into tissues to detect foreign antigens
2. Accumulate in specialised organs to develop and differentiate
32
Name the five types of white blood cells
- monocytes
- eosinophils
- basophils
- lymphocytes
- neutrophils
33
What are the two different lineages of white blood cells?
- lymphoid lineage
- myeloid lineage
34
What cells are associated with the lymphoid lineage of white blood cells?
Lymphocytes
35
What cells are associated with the myeloid lineage of white blood cells?
Granulocytes and monocytes
36
Neutrophils, eosinophils and basophils are all types of what cell?
Granulocytes
37
What cell makes up 95% of circulating granulocytes?
Neutrophils
38
What cell is 10-20 micro metres in diameter?
Neutrophils
39
What type of nucleus do neutrophils have?
Multi-lobed
40
How do neutrophils enter tissues?
They adhere to endothelial cells and squeeze between them to leave the circulation and enter tissues
41
What is the main role of neutrophils?
Phagocytosis
42
What type of nucleus to eosinophils have?
Bi-lobed nucleus
43
The cells which releases toxin-containing granules upon activation in order to kill large pathogens (parasites), are known as?
Eosinophils
44
Which white blood cell is least present in the circulation?
Basophils
45
What is the difference between basophils and mast cells?
Mast cells are ONLY found in tissues, not the bloodstream.
46
What type of nucleus does a monocytes have?
Horse-shoe shaped
47
What are important features of monocytes?
Pinochet if vesicles and lysosomal granules
48
What do the lysosomes in monocytes contain?
Peroxidase and acid hydrolases
49
What is the main function if macrophages?
Phagocytosis
50
Name four types of accessory cell
- platelets
- antigen presenting cells (APC)
- mast cells
- endothelial cells
51
What role is associated with platelets
Blood clotting and inflammation
52
What role is associated with antigen presenting cells (APC)?
They present antigens to T cells and produce cytokines
53
What is the function of endothelial cells?
They control lymphocyte “traffic” and “distribution”
54
What is the role of mast cells?
To release histamine (usually in an allergic reaction)
55
Lymphocytes are involved in both cellular and humoral immunity. True or false?
True
56
Where are lymphocytes found?
In blood, lymph and specialised tissue
57
Where do lymphocytes originate?
In bone marrow from pluripotent cells
58
Where are B cells produced?
Bone marrow
59
Where are T cells produced?
Thymus
60
What are monoclonal antibodies used for?
As cell markers, they are highly specific and used to study cell surfaces
61
When does activation of lymphocytes occur?
Only on binding of antigen by antigen receptor
62
Where are antibodies (immunoglobulins) produced?
Plasma cells ( activated B cells)
63
What is clonal expansion a result of?
Binding of antigen to lymphocyte receptor
64
What does clonal expansion produce?
More activated and memory cells
65
A more rapid and effective response of lymphocytes to foreign antigens is a result of?
Clonal expansion
66
Tissues where immune response occurs are usually rich in what?
Macrophages
67
What is required for an immune response to occur?
Cooperation of cells, cell to cell contact and secretion of cytokines
68
What is another word for immunoglobulin?
Antibody
69
What are activated B cells called?
Plasma cells
70
What are the five classes of immunoglobulins ( IgG)?
IgG
IgM
IgA
IgD
IgE
71
What shape do immunoglobulins have?
Y shape
72
What are three important regions on an immunoglobulin?
Fab region
Fc region
Hinge
73
What are the two chains of immunoglobulin structure?
Heavy chain and light chain
74
What is the “hinge” region of the immunoglobulin?
Disulphide bridge
75
What is the recognition function of antibodies?
The Fab arms bind to antigens
76
What is the effector function of antibodies?
Interaction of Fc region on antibody with effector molecules (this is a clearance mechanism to get rid of foreign bodies)
77
What are the two types of light chains on antibodies?
1. Lambda
2. Kappa
78
What two globular domains will light chains on antibodies fold up into?
VL and CL
79
What determines the class of antibody?
Heavy chains
80
How many domains will heavy chains on antibodies fold up into and what are they?
4 (or 5) domains
VH,CH1,CH2,CH3 (and CH4)
81
What are found in V domains?
Complementary determining regions (CDR’s)
82
What are key in determining which antigen will bind?
Complementary determining regions (CDR’s)
83
What forms the antigen binding site?
Complementary determining regions (CDR’s)
84
Where are antigen binding sites found on immunoglobulins?
At the tip of the Fab arms
85
What type of immunoglobulin is most abundant in plasma?
IgG
86
How many subclasses does IgG have and what are they?
4 subclasses
IgG1, IgG2, IgG3, IgG4
87
What is the role of IgG
Triggers complement and phagocytosis
88
What immunoglobulin class is the only one to cross the placenta from mother to foetus?
IgG
89
What antibody is only in plasma and secretions, not tissues and why?
IgM, its too large to enter tissues
90
What immunoglobulin is predominant in the secondary antibody response?
IgG
91
What immunoglobulin has a special feature known as a ‘J joining chain’ ?
IgM
92
What is the shape and number of binding sites of IgM?
Five Y-shaped units with 10 binding sites (FAB arms) for antigen
93
What is the function of IgM?
Activates complement
94
Which antibody is predominant in the first antibody response?
IgM
95
What antibody is largely associated with seromucous secretions ( e.g. saliva)?
IgA
96
What are the two subclassses of IgA?
IgA1 and IgA2
97
What is IgE’s effector function?
It interacts with high affinity receptor: Fc£R1
98
Where is the high affinity receptor, Fc£RI expressed?
On mast cells and basophils (it is associated with the allergic response)
99
Which immunoglobulin is important against parasitic infections?
IgE
100
What immunoglobulin is found on the surface of lymphocytes?
IgD
101
Which region of an antibody is recognition associated with?
Fab arms
102
Which region of an antibody is effector function associated with?
Fc region
103
Define complement
A system of plasma proteins, protects the host from infection through a cascade of reactions that occurs on the surface of pathogens, recruiting and enhancing phagocytosis and leading to Lysis of cells.
104
Where precursors trigger proteolytic enzymes to go on and trigger other precursors. What is this known as?
Enzyme cascade
105
What are the three pathways involved in complement?
- classical
- Lectin
- alternative
106
Deficiency in what inhibitor will result in recurrent bacterial infections?
C3 inhibitor
107
Which of the three complement pathways is the first major line of defence against systemic infection?
Alternative pathway
108
Define lysis
Break down of cell
109
Define opsonisation
Attracts phagocytosis
110
What is released from mast cells in responses to anaphylaxis?
Histamine
111
What is the function of chemotaxis?
Causes phagocytes to migrate to infection site
112
What inhibitor deficiency will cause inappropriate activation of complement system?
C1 inhibitor
113
What can deficiencies in the classical complement pathway be associated with?
Autoimmune disorders
114
What is the specificity of lymphocytes achieved by?
Antigen receptors on cell surface
115
What is the antigen receptor on B cells?
Cell-surface antibody
116
What is the antigen receptor of T cells?
T cell receptor (TCR)
117
What do B cells synthesise and secrete?
Immunoglobulins
118
How do B cells produce immunoglobulins?
They are activated by binding antigens, then they differentiate into plasma cells which actively produce immunoglobulins
119
What is the initial immunoglobulin produced by B cells?
IgM
120
What immunoglobulins are produced by memory B cells?
IgG, IgA and IgE
121
What immunoglobulin do T cell independent antigens produce In small amounts?
IgM
122
What is a T cell receptor (TCR)?
A structure on T cell surface that recognises antigen
123
What are the two classes of T cells?
- helper T cell ( Th)
- cytotoxic T cell ( Tc)
124
What important cell surface protein do helper T cells express?
CD4
125
What important cell surface protein do cytotoxic T cells present?
CD8
126
What are the cell surface proteins, CD4 and CD8, required for?
For an effective response to antigen
127
What is the role of antigen presenting cells ( APC)?
Phagocytose foreign bodies
128
What do helper T cells secrete after binding to antigen? And what is their importance?
Cytokines, which control immune response
129
What are the two main functions of cytokines in controlling immune response?
- favour macrophage activation and cell mediated responses
- stimulate B cells to produce antibodies
130
An exaggerated, inappropriate adaptive immune response is known as?
Hypersensitivity
131
What can be the result of hypersensitivity?
Inflammatory reactions and tissue damage
132
When does hypersensitivity manifest, on the first contact or second contact?
Second contact
133
How many classifications of hypersensitivity are there?
4
134
Which hypersensitivity classifications are antibody mediated?
Class I, II and III
135
Which type of hypersensitivity classification is mediated by T cells and macrophages?
Class IV
136
Describe type I hypersensitivity
IgE response to non-harmful environmental antigens
137
What high affinity receptor on mast cells does IgE bind to?
Fc£R1
138
What does the second encounter to an antigen trigger?
The release of inflammatory mediators such as histamine
139
What are severe type I hypersensitivity reactions with systemic symptoms known as?
Anaphylactic shock
140
What chemical must be sued to treat anaphylaxis?
Adrenaline
141
Which class of hypersensitivity is antibody- dependent cytotoxic?
Type II
142
Does type II hypersensitivity occur slower or faster than type I?
Slower ( within 18-24hrs)
143
What classification of hypersensitivity is mediated by the persistence and deposition of antibody-antigen immune complexes?
Type III
144
What does deposition of immune complexes cause?
Inflammation
145
What class of hypersensitivity is delayed, occurring within 48-72 hrs post antigen exposure?
Type IV
146
What are the three types of type IV hypersensitivity?
1. Contact
2. Tuberculin
3. Granulomatous
147
What are the two phases of type IV hypersensitivity?
1. Sensitisation
2. Elicitation (inflammation)
148
What class of hypersensitivity can sometimes be seen as a reaction to dental materials e.g. amalgam, gold, mercury and resin-based materials?
Type IV
149
What is the most key step of adaptive immunity?
Lymphocytes must recognise antigen
150
Which cells only recognise parts of antigens expressed on cell surfaces?
T cells
151
What are major histocompatibility complex (MHC) molecules also referred to as?
Human leukocyte antigens (HLA)
152
What are the two MHC families?
Class I and Class II
153
What are the three members of the Class I MHC family?
HLA-A, HLA-B, HLA-C
154
What are the three members of the Class II MHC family?
HLA-DP, HLA-DQ, HLA-DR
155
What MHC class is expressed on all nucleated cells?
Class I
156
Which MHC class is expressed only on leukocytes which present antigen T cells? e.g. monocytes
Class II
157
What are the three clinical implications of MHC?
1. Tissue grafting
2. Certain HLA types exposed to certain disease
3. Forensic medicine
158
Which MHC class has a structure where the peptide-binding cleft is more open?
Class I
159
What do MHC molecules present to cells?
Antigenic peptides
160
what type of T cell does MHC class I present peptides to?
Cytotoxic T cell
161
what type of T cell does MHC class II present peptides to?
Helper T cell
162
Define the breakdown of self-tolerant mechanisms in the immune system
Autoimmunity
163
What antibodies develop in autoimmunity and what do they recognise?
Auto reactive antibodies that recognise self antigens
164
What are the two classes of autoimmune disease?
Organ-specific and Non organ-specific
165
what reactions can organ-specific autoimmunity bring about?
Type II hypersensitivity and cell mediated reactions
166
Define the chronic autoimmune disease of mucosal membranes and/or skin
Cicatrical Pemphigoid
167
What are oral indicators of Sjogren’s disease?
- oral candida
- dental caries
- dry lips
- dry and lobulated tongue
