Immunology Flashcards

1
Q

There exists an evolutionary arms race between pathogen and host. What does this mean?

A

Pathogen exploits flaws in the defensive barriers of its host
The host evolves to correct those flaws
Pathogen replicates and evolves to evade corrections to exploit other flaws
Pathogen has ability to replicate much faster than the host; host relies on flexible and rapid immune response to combat

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2
Q

Some features of skin that contribute to barring infection include…

A

Tightly packed keratinised cells undergo renewal constantly; limits colonisation
Low pH kills pathogens
Sebaceous glands secrete oils and enzymes to destroy bacterial cell walls

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3
Q

The innate immune system has a ___ response and is ____ to micro-organisms

A

Fast, non-specific

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4
Q

The adaptive immune system has a ___ response and is ____ to micro-organisms

A

Slow, specific

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5
Q

The 5 types of leukocytes (WBCs)?

A

Neutrophils, Monocytes, Lymphocytes, Eosinophils, Basophils + Mast cells

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6
Q

Primary lymphoid tissue?

A

Bone marrow, thymus

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7
Q

Secondary lymphoid tissue?

A

Spleen, tonsils (any sites of AIS activation)

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8
Q

List the leukocyte components of the innate immune system

A

Macrophages, neutrophils, dendritic cells, basophils, mast cells, eosinophils, NK cells

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9
Q

List the protein components of the innate immune system

A

Complement, acute phase, cytokines

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10
Q

Basophils and mast cells mature in bone marrow. True/false?

A

False

Basophils mature in bone marrow; mast cells mature once in tissue

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11
Q

Basophils and mast cells are mainly involved in ____. They secrete ____, leading to _____…

A

Allergic reactions

Secrete histamine and inflammatory mediators, leading to increased vascular permeability and smooth muscle contraction

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12
Q

The main function of phagocytes is?

A

“Eat” cells by ingesting them and mopping up debris

Neutrophils, macrophages and dendritic cells mainly involved in phagocytosis

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13
Q

PRRs recognise what on bacteria/viruses?

A

PAMPs

Not expressed by human cells

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14
Q

Opsonins enhance…

A

Phagocytosis

Act as a bridge between pathogen and phagocyte receptors

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15
Q

Major opsonins include…

A

C3b, collectins, Fc of IgG, CRP

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16
Q

Oxidative killing requires which crucial enzyme?

A

NADPH oxidase complex

Converts oxygen into reactive free radicals

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17
Q

Acute phase proteins are produced by…

A

The liver

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18
Q

CRP greater than 200mg/l indicates…

A

Severe bacterial/fungal infection

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19
Q

The function of cytokines is to…

A

Modulate the behaviour of cells, locally and systemically

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20
Q

Interferons are important in…

A

Limiting viral infections

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21
Q

Interleukins are important in…

A

Directing cells to divide/differentiate

Mainly produced by T cells (IL-2 important for T cell activation)

22
Q

Chemokines are important in…

A

Establishing a concn gradient to direct movement of cells (tell leukocytes where to go)

23
Q

Complement involves enzymatically activating proteins in a…

A

Biological cascade, resulting in a rapid response

24
Q

Classical pathway is activated by…

A

Antibodies (so B cells need to have been activated for this)

IgG/IgM cause conformational change in C1, activating cascade

25
In the classical pathway, first C1 is activated, then...
C4, C2, C3
26
Lectin pathway is activated by...
Mannose-binding lectin binding to carbohydrates | This mimics binding of C1 to immune complexes, so there is no need for antibodies
27
Alternate pathway is activated by...
Spontaneous hydrolysis of C3 and its direct binding to bacterial cell walls
28
Membrane attack complex is assembled by which complement proteins?
C5-C9
29
Functions of C3a and C5a
Inflammatory mediators - recruit phagocytes
30
Examples of complement inhibitors
C1, Factor I, Factor H, C4 binding protein, CD59
31
List the leukocyte components of the adaptive immune system
B lymphocytes, T lymphocytes
32
List the protein components of the adaptive immune system
Antibodies, cytokines
33
Antibodies act as opsonins. True/False?
True
34
Antibodies are Y shaped glycoproteins made up of...
Two heavy chains and two light chains | Heavy chains have variable regions; light chains have constant regions
35
List the immunoglobulins found in the blood, from most to least abundant
IgG, IgA, IgM, IgD, IgE
36
Main function of IgG
Provides antibody-mediated immunity to developing foetus and neonates
37
Main function of IgA
Secretory; found in breast milk, saliva, tears | Defence at mucosal surfaces
38
Main function of IgM
Found in blood; first Ig produced during infection
39
Main function of IgD
Unknown; protection against URT infections
40
Main function of IgE
Activates mast cells (causes degranulation)
41
T cell antigen receptors can recognise free antigens. True/False?
False | Need to be presented as a complex with MHC molecules
42
MHC I presents to?
CD8+ T cells | Expressed on all nucleated cells
43
MHC II presents to?
CD4+ T cells | Expressed only on antigen presenting cells (dendritic cells, B cells, macrophages)
44
T cell activation requires...
MHC binding to T-cell receptor | B7 binding to CD28
45
B cell activation requires...
Antigen binding to B-cell receptor PRRs recognising PAMPs Optional co-stimulation by CD4+ cells through CD40L
46
Function of IL-2
Activates CD8+ cells
47
Function of IL-4, IL-5 and IFNy
Activate B cells; increase killing
48
3 different types of memory cells
Helper T-cells B-cells Cytotoxic T-cells
49
Name some pro-inflammatory cytokines
IL-1 IL-6 TNF
50
What effect do pro-inflammatory cytokines such as IL-6 have on the liver?
Stimulate release of acute phase proteins (CRP, C3...)