Lecture 12 - Adaptive Immune Response (Effector Phase) Flashcards

1
Q

Which molecules on APCs present Extracellular microbes antigens to naive T cells?

A

MHC Class II

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2
Q

Which Naive T cells have extracellular antigens presented to them by MHC Class II molecules?

A

CD4+ T cells

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3
Q

What type of Immunity do activated CD4+ cells produce?

A

Humoral immunity (antibodies)

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4
Q

Which molecules on APCs present Intracellular microbes antigens to naive T cells?

A

MHC Class I molecules

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5
Q

Which Naive T cells have intracellular antigens presented to them by MHC Class I molecules?

A

CD8+ T cells

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6
Q

What type of Immunity do activated CD8+ cells produce?

A

Cell-mediated immunity (Cytotoxic T cell response)

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7
Q

Once an APC has captured a microbe where does it migrate to and what part of this area does it go to?

A

Lymphatics/lymph node

Parafollicular cortex

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8
Q

Why does an APC that’s captured a microbe migrate to the parafollicular cortex?

A

Has many T cells here so activate the maximum amount of T cells

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9
Q

Where are T and B cells produced?

A

Bone marrow

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10
Q

Where do T cells mature?

A

Thymus

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11
Q

Where do B cells mature?

A

When they come into contact with antigens in the blood

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12
Q

What is lymphadenopathy?

A

When the lymph nodes swell

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13
Q

Why can lymphadenopathy happen with infection?

A

Swell in infection due to T cells and B cells proliferating

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14
Q

What organ is absent/poorly developed in Digeorge syndrome?

A

Thymus or Spleen

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15
Q

Why is a patient with Digeorge syndrome immunocompromised?

A

No poorly developed thymus

This is where T cells mature

So very few or no mature T cells

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16
Q

What are antigen receptors on T lymphocytes called?

A

T Cell Receptors (TCR)

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17
Q

Where are the 2 extracellular regions of a T cell receptor?

A

Variable region
Constant region

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18
Q

Which region of a T cell receptor does the pathogens peptide/antigen bind to?

A

Variable region

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19
Q

What enables the variable regions of T cell receptors to be able to recognise many antigens?

A

Different segments of genes are randomly expressed generating many combinations that can recognise many different antigens

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20
Q

If T cell receptors can recognise all antigens/peptides, what limits our T cells activating against all pathogens?

A

T lymphocytes only get activated by peptides that are presented by Antigen Presenting Cells (APCs)

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21
Q

What MHC molecule must present a peptide for Helper T cells (CD4+) to recognise it?

A

MHC Class II

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22
Q

What MHC molecule must present a peptide for Cytotoxic T cells (CD8+) to recognise it?

A

MHC Class I

23
Q

What are the 3 signals on an APC that is needed to activate a T cell?

A

Signal 1 = MHC molecule with peptide
Signal 2 = B7
Signal 3 = Cytokines

24
Q

What structure does the peptide attached to the MHC molecule on the APC bind to on the T cell?

A

T cell Receptor at the variable region

25
What structure does the B7 strucutre on the APC attach to on the T cell?
CD28
26
What are some inflammatory cytokines?
IL-6 IL-1 TNF-a
27
If a pathogen that has been presented by an APC to a naive CD4+ cell is intracellular, what cytokine is the APC going to produce? What type of immunity is wanting to be achieved?
IL-12 Cell mediated immunity
28
What helper T cell (Th) is a naive CD4+ going to differentiate into once exposed to IL-12?
Th1
29
What is the function of the T helper 1 cell (Th1)?
Stimulates CD8+ T cells to become cytotoxic T cells Activates macrophages
30
If a pathogen that has been presented by an APC to a naive CD4+ cell is extracellular (like a parasite), what cytokine is the APC going to produce? What type of immunity is wanting to be achieved?
IL-4 Humoral immunity
31
What T Helper cell is formed by a naive CD4+ T cell when IL-4 is produced?
Th2
32
What is the function of the T Helper 2 cell (Th2)?
Activates B cells producing IgE and IgG The IgE attracts eosinophils which are good at killing pathogens (parasites) Mast cells drive allergies
33
What T helper cell is important in recruiting and activating Neutrophils?
Th17
34
What interleukins are produced by Antigen Presenting cells which stimulate naive CD4+ T cells to differentiate into Th17 cells (T helper 17)??
IL-1 IL-6
35
What is the function of Effector CD8+ T cells?
Cytotoxic T cells destroying infected cells
36
Why do levels of Cytotoxic T cells (Effector CD8+ cells) fall as levels of CD4+ T cells fall?
Th1 cells are differentiated types of CD4+ cells Th1 cells produce certain cytokines which trigger CD8+ cells to become Cytotoxic T cells (Effector CD8+ T cells)
37
How do cytotoxic T cells (effector CD8+ T cells) work?
MHC molecule on infected cell displays pathogens peptide Cytotoxic cell binds Produces enzymes like performing putting holes in the cells membrane Then injects granzymes inducing APOPTOSIS
38
What type of molecule is the antigen recognition receptor on a B lymphocyte?
BCR = Membrane Bound Antibody
39
What are the 2 main regions of an antibody?
Variable region (where antigen binds) Constant region
40
How does a B cell get activated?
Antigen binds and forms cross link between 2 receptors/antibodies
41
How do B cells act as APCs to T helper cells?
Display pathogens antigen on MHC molecule to T cell receptor on T helper cell Displays B7 which binds to T helper cells CD28 CD40 Displayed on B cell surface and CD40L from T helper binds to it
42
What is the function of activating CD40 on the B cell?
Stimulates the B cell to change from producing IgM to IgG
43
What is the condition called when a patients B cells have a defect in CD40?
Hyper IgM syndrome
44
What is the T helper independent antibody produced by a B cell?
IgM
45
What are the T helper DEPENDANT antibodies produced by activated B cells?
IgG IgA IgE
46
When B lymphocytes are activated, what cells do they form which last for a very long time?
Memory B cells
47
What is the antibody that responds to Thymus independent antigens which buys time for the body?
IgM
48
Why is the antibody IgM described as being a response to thymus independent antigens?
Involves no T cells
49
Where are IgA antibodies found?
Mucosal surfaces
50
What does IgM do?
Compliment activation
51
What does IgE do?
Immunity against helminths = parasitic worms Mast cell degranulation (allergies)
52
What antibody from the mother provides neonatal immunity, activates complement and neutralises toxins?
IgG
53
If there is more IgM than IgG has a patient encountered this pathogen before?
No this is the bodies first response to it
54
What serological test can be done to see if someone has encountered a disease before/
Check if they have the IgG antibody for that disease