Immune - 3rd Line Defense Flashcards
(115 cards)
1
Q
What are the main types of leukocytes?
A
Basophils, eosinophils, neutrophils, monocytes/macrophages, NK cells, B & T lymphocytes
These are types of white blood cells involved in immune responses.
2
Q
Where are basophils found in the blood and tissue?
A
In blood: basophils; in tissue: mast cells
Basophils circulate in the bloodstream, while mast cells are found in tissues.
3
Q
What substances do basophils and mast cells release?
A
Histamine, heparin
Histamine causes vasodilation and increases vessel permeability, while heparin acts as an anticoagulant.
4
Q
What is the role of histamine in the body?
A
Vasodilation and increased vessel permeability
Histamine is involved in the inflammatory response.
5
Q
What receptors do basophils express and what is their significance?
A
Receptors for IgE
This expression links basophils to allergy and hypersensitivity reactions.
6
Q
What is the primary function of eosinophils?
A
Destroy parasitic worms via phagocytosis
Eosinophils are less efficient phagocytes but have a central role in combating parasitic infections.
Play important role in inflammation, especially in asthma
7
Q
What percentage of leukocytes do neutrophils account for?
A
60%
Neutrophils are the most abundant type of leukocyte.
8
Q
What is the primary function of neutrophils? And what do they release?
A
Phagocytic cell
Lysozymes - which help digest cellular debris and pathogens.
Neutrophils are critical for engulfing and digesting debris and pathogens.
9
Q
What is the primary function of T- and B-lymphocytes in the immune system?
A
They function in adaptive (specific) immunity, learning to respond to foreign antigens.
10
Q
What do T- and B-lymphocytes possess specificity for?
A
Antigens.
11
Q
What is unique about each T- and B-lymphocyte?
A
Each is specific for a particular antigen.
12
Q
What do T- and B-lymphocytes produce in response to previously encountered antigens?
A
Immune memory.
13
Q
What is the role of immune memory in the adaptive immune response?
A
It allows for a quicker and more effective attack during subsequent encounters with the antigen.
14
Q
What is the third line of defense in the immune system?
A
The adaptive immune system.
15
Q
When is the third line of defense activated?
A
When the innate immune system fails to adequately destroy the pathogen.
16
Q
What role do cytokines play in the immune system?
A
They are the chemical messengers that mediate the connection between the innate immune system and the adaptive immune system.
17
Q
What are the effector cells of the adaptive immune system?
A
T- and B-lymphocytes.
18
Q
What happens to T- and B-lymphocytes when they encounter a foreign antigen?
A
They become activated
19
Q
True or False: The adaptive immune system acts specifically to target certain antigens.
A
True.
20
Q
Fill in the blank: The innate immune system is often sufficient to destroy invading microbes, but if it fails, the _______ is activated.
A
third line of defence / adaptive immune system
21
Q
What type of cells do cytotoxic T cells kill?
A
Virus-infected and damaged cells.
22
Q
What is the role of helper T cells?
A
Mediate the immune response by sending out cytotoxic T-cells;
Helper T-cells are the main coordinator of an immune response
23
Q
What does MHC stand for?
A
Major Histocompatibility Complex
AKA in humans … HLA (Human Leukocytic Antigens)
24
Q
What is the function of MHC I?
A
Self-antigens - recognize healthy body cells versus unhealthy or infected cells
25
What type of antigens do MHC Class II molecules present to T-cells?
Foreign antigens - on their binding groove
26
What are the two types of MHC?
* MHC class I - self (presents non-self cells) - all cells except RBC
* MHC class II - foreign - only antigen presenting cells (macrophages and b-cells)
27
Where is MHC class I located?
On all body cells, except erythrocytes
28
What happens to a body cell when it becomes cancerous or invaded by a pathogen?
It starts to produce abnormal proteins
29
What do abnormal proteins combine with in MHC-I?
MHC-I molecules
30
What does MHC-I indicate when displayed on a cell membrane?
That the cell is non-self or abnormal
31
Which type of leukocytes primarily respond to MHC-I signals?
Cytotoxic T-cells (CD8 cells)
32
Fill in the blank: MHC-I allows leukocytes to determine healthy body cells from _______.
abnormal / infected cells
33
What is displayed on the binding groove of MHC molecules?
A protein produced by the cell (self-antigen)
34
What does Class II MHC facilitate?
Antigen presentation
## Footnote
Class II MHC is crucial for communication between antigen presenting cells and T-helper cells.
35
Where are MHC-II molecules located?
Cell membrane of antigen presenting cells
## Footnote
Antigen presenting cells include macrophages and B-lymphocytes.
36
What do MHC-II molecules display?
Foreign antigens on their binding groove
## Footnote
MHC-II molecules present antigens to T-helper cells.
37
Which cells utilize MHC-II for communication?
T-helper cells
## Footnote
MHC-II is vital for antigen presentation.
38
What type of cells associate with Class I MHC molecules?
All nucleated body cells (no RBC bc no nucleus)
## Footnote
This includes infected cells presenting antigens.
39
What do cytotoxic T cells recognize?
Class I MHC molecules with antigen fragments
## Footnote
Cytotoxic T cells are involved in killing infected cells.
40
True or False: Class II MHC molecules present antigens to cytotoxic T cells.
False
## Footnote
Class II MHC molecules primarily interact with T-helper cells.
41
What is the primary role of T-lymphocytes?
Cell-mediated immunity
## Footnote
T-lymphocytes, or T-cells, are crucial for the immune response against pathogens.
42
What is unique about each T-lymphocyte?
Each has a unique T-cell receptor (TCR) that recognises a specific antigen
## Footnote
This diversity allows the immune system to respond to a wide range of antigens.
43
Where are T-lymphocytes produced and matured?
Produced in bone marrow and mature in the thymus
## Footnote
The maturation in the thymus is essential for their functionality.
44
What types of T-cells are there?
Helper T-cells
Cytotoxic T-cells
Memory T-cells
Regulatory T-cells
## Footnote
T-helper cells assist other immune cells, while cytotoxic T-cells kill infected cells.
45
What are T-helper cells also known as?
CD4 cells
## Footnote
They express the CD4 protein on their surface.
46
What are cytotoxic T-cells also referred to as?
CD8 cells
## Footnote
They express the CD8 protein on their surface.
47
What two traits must T-cells have to function properly?
Self-recognition and self-tolerance - they’re tested against thymus epithelial cells
## Footnote
These traits prevent the immune system from attacking the body’s own cells.
Only 1-5% survive the process. They rest - undergo apoptosis.
48
What happens if T-cells lose self-tolerance?
It leads to autoimmunity
## Footnote
Autoimmunity occurs when the immune system mistakenly attacks the body's own tissues.
49
What percentage of T-cells typically survive the selection process in the thymus?
1-5%
## Footnote
This low percentage highlights the rigorous selection process for functional T-cells.
50
What similar process do B-cells undergo?
A screening process in the bone marrow
## Footnote
Similar to T-cells, B-cells must also recognize self-antigens to function properly.
51
Fill in the blank: T-lymphocytes mature in the _______.
thymus
52
True or False: Most T-cells arise after puberty.
False
## Footnote
Most T-cells arise before puberty but continue to mature throughout life.
53
What is adaptive immunity?
The ability of the body to defend itself against SPECIFIC agents
## Footnote
Characterised by specificity for particular foreign antigens and the production of immune memory
54
What are the two types of adaptive immunity?
* Cell-mediated immunity
* Antibody-mediated immunity
55
Which lymphocytes are involved in cell-mediated immunity?
T-lymphocytes
56
Which lymphocytes are involved in antibody-mediated immunity?
B-lymphocytes
57
What do cytotoxic T-cells do?
Directly attack invading antigens (the FBI field agents)
58
What do B-cells transform into?
Plasma cells - that synthesis and secrete specific anti-bodies (Ig)
59
What type of pathogens does cell-mediated immunity primarily defend against?
Intra-cellular pathogens (within a cell)
60
What type of pathogens does antibody-mediated immunity primarily defend against?
Extra-cellular pathogens
61
What must happen for an immune response to occur?
T-cells must recognise that a foreign antigen is present
62
What do T-cells recognise?
Protein fragments (antigens) that are processed and presented in a certain way from the antigens presenting cells (macrophages and b-cells)
63
Where are antigen-presenting cells strategically located?
In places where antigens are likely to penetrate the body, then they migrate into lymphatic tissue where they present the antigen to the T-helper cells. ANTIGEN PRESENTATION .
64
What do antigen-presenting cells combine foreign antigens with?
MHC-II complexes on their cell membrane
65
What happens to antigen-presenting cells after they process antigens?
They migrate into lymphatic tissue to present the antigen to T-helper cells - ANTIGEN PRESENTATION.
66
How do macrophages process antigens?
Through phagocytosis, using lysozymes to break down the antigen into fragments.
## Footnote
Some fragments are combined with MHC molecules for presentation.
67
What happens when an antigen fragment binds with a T-helper cell?
The T-helper cell secretes a cytokine called interleukin-2 (IL-2).
## Footnote
This binding is crucial for the activation of T-lymphocytes.
68
What is the role of interleukin-2 in T-lymphocyte activation?
It causes the T-helper cell to undergo 'clonal selection'.
## Footnote
Interleukin-2 is the prime trigger for activated T-cell proliferation and division.
69
What additional function does interleukin-2 serve in the immune response?
It stimulates clonal selection of B-lymphocytes.
## Footnote
This is critical for the adaptive immune response.
70
Define 'clonal selection'.
The process to create a response to an antigen.
## Footnote
Produces:
Cytotoxic T-cells
Memory T-cells
Helper T-cells (which controls both T & B sides)
Memory B-cells
Plasma cells (antibodies)
71
What type of cells undergo clonal selection after antigen presentation?
T-helper cells and B-cells.
## Footnote
Clonal selection ensures that the immune system produces an adequate response to the specific pathogen.
72
Fill in the blank: Interleukin-2 is the prime trigger for T-lymphocyte _______.
proliferation and division.
73
True or False: Memory T-cells are formed during the clonal selection process.
True.
74
What binds to receptors on the cell membrane of the T-helper cell that secreted it?
Interleukin-2
## Footnote
Interleukin-2 is a cytokine that plays a crucial role in the immune response.
75
What does Interleukin-2 stimulate in T-cells?
Division and proliferation
## Footnote
This process is essential for the immune response to effectively target pathogens.
76
What do Cytotoxic T-lymphocytes use to destroy target cells?
Granzymes and PERFORIN
## Footnote
Granzymes are protein-digesting enzymes that help in the destruction of infected or cancerous cells.
77
What is the role of Memory T-lymphocytes?
Recognize the antigen in future contacts
## Footnote
Memory T-lymphocytes provide long-term immunity by remembering pathogens.
78
What do Helper T-lymphocytes release to increase the activity of immune cells?
Cytokines
## Footnote
Cytokines are signaling molecules that mediate and regulate immunity and inflammation.
79
What was the former name of Regulatory T-cells and what do they deactivate?
Formerly called - Suppressor T-cells
Deactivate - Immune cells such as T-helper, B-cells and macrophages - this deactivation is important for preventing overactive immune responses.
## Footnote
This name reflects their function in suppressing immune responses.
80
What do Regulatory T-cells maintain in the immune system?
Homeostasis and tolerance to self-antigens
## Footnote
This function is crucial to prevent autoimmune diseases.
81
What happens without Regulatory T-cells?
The body would keep fighting off diseases that no longer exist
## Footnote
This could lead to autoimmune reactions where the body attacks its own cells.
82
What do antigens do once inside a B-cell?
Broken down into fragments and expressed on MHC II
83
What role do Helper T-cells play in B-cell activation?
Recognize antigen complex and stimulate B-cells by releasing interleukin-2
84
What is the primary function of plasma cells?
Secrete antibodies into the blood
85
How many types of antibodies do plasma cells produce?
Only one type of antibody
86
What do plasma cells do a few days after antigen exposure?
Secrete hundreds of millions of antibodies each day until they die
87
What is the lifespan of plasma cells?
Short-lived
88
What is the characteristic of memory B-cells?
Long-lived
Inactive until needed
Remember antigen for next time
89
Fill in the blank: Memory B-cells remember _______ for the next time.
a specific antigen
90
True or False: Plasma cells are responsible for long-term immunity.
False
91
What triggers B-cell clonal selection?
Release of interleukin-2 by Helper T-cells
92
What is the role of cytokines in B-cell activation?
Stimulate B-cells during clonal selection
93
What are antibodies also known as?
Immunoglobulins (Ig)
## Footnote
Antibodies belong to a group of glycoproteins called globulins.
94
What is the region varies for each kind of antibody?
Variable region
## Footnote
This region allows antibodies to bind specifically to different antigens.
95
How many antigen-binding sites do antibodies generally have?
Two antigen-binding sites
96
What do antibodies form when they combine with antigens?
Antibody-antigen immune complexes
97
What is the mechanism by which antibodies bind to antigens described as?
Lock and key
98
List the ways antibodies can inactivate antigens.
* Neutralising
* Immobilising
* Agglutinating (clumping) and precipitating
* Activating complement
* Enhancing phagocytosis
99
What is the neutralising action of antibodies?
Neutralise bacterial toxins or prevent viral attachment to cells.
100
What does the immobilising action of antibodies involve?
Binding to antigens on bacterial cilia or flagellae
101
What is agglutination?
Clumping together of cells
102
How do antigen-antibody complexes activate the complement system?
By activating the complement cascade
103
What role do antibodies play in enhancing phagocytosis?
Act as a flag to attract phagocytes and aid phagocytosis
104
What is the third line of defence in the immune system?
Antibodies
## Footnote
Antibodies play a crucial role in the immune response by identifying and neutralizing pathogens.
105
What type of antibody is IgG?
Most abundant (80% of blood antibodies)
## Footnote
IgG is the primary antibody class found in the bloodstream
Protects against bacteria and viruses
Involved in food intolerances
Crucial for long-term immunity
106
Where is IgG primarily located?
Blood, lymph and intestines
## Footnote
IgG is distributed throughout the body's fluids.
107
What type of antibody is IgA?
Localized protection of mucous membranes
## Footnote
IgA is important for immune defense on mucosal surfaces.
A= first letter of alphabet, first line of defense
108
Where is IgA found?
Sweat, tears, saliva, breast milk
## Footnote
IgA is secreted in various body fluids to protect mucosal areas.
109
What is the function of IgM?
Main class of antibody in early immune response - first on the scene
## Footnote
IgM is the first antibody produced during an infection.
110
What percentage of blood antibodies does IgM constitute?
10%
## Footnote
IgM is significant but less prevalent compared to IgG.
111
What is the primary role of IgE?
Involved in allergic reactions - thus not seen on normal blood test unless there’s a current reaction.
binds to mast cells
## Footnote
IgE antibodies react to allergens and trigger histamine and heparin release, when needed.
112
What is the prevalence of IgE in blood?
<0.1%
## Footnote
Despite its low concentration, IgE plays a major role in allergy and asthma.
113
What does IgG do that no other antibody class does?
Crosses the placenta
## Footnote
This allows maternal antibodies to provide immunity to the fetus.
114
What happens to IgA levels during stress?
Decreases with stress
## Footnote
Stress can negatively impact mucosal immunity.
115
Fill in the blank: IgE binds to _______.
mast cells
## Footnote
Mast cells release histamine and other mediators during allergic responses.
