Immune system 2 Flashcards

1
Q

What are interferons?

A

Cytokines that inhibit viral replication within cells

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2
Q

Describe how interferons are activated and their effects

A

Activated macrophages release IL-12 which stimulates IFNgamma by natural killer cells and lymphocytes

IFNgamma leads to further macrophages activation in feedback loop amplifying innate immune response
Increases phagocytosis and iNOS expression

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3
Q

Which cytokines induce endothelial cells to express adhesion molecules allowing neutrophils and monocytes to bind and leave the blood stream

A

IL-1

TNFAlpha

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4
Q

What is the role of IL-8?

A

Potent neutrophil chemoattractant and activates macrophages

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5
Q

What 3 things act on the endothelium to increase permeability?

A

TNFAlpha
Platelet Activating Factor
PG

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6
Q

PAF causes what in relation to platelets?

A

Causes platelets to release histamine also increases vascular endothelial permeability

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7
Q

Define complement

A

A group of plasma and cell membrane proteins that leads to the formation of a membrane attack complex and inflammation

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8
Q

What is the role of complements?

A

Directly recognises pathogen, insert into membrane results in membrane attack eg holes in the surface
think cell lysis

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9
Q

Which cell is part of the humoural response?

A

B-cell

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10
Q

Which cells are part of the cellular immune response

A

CD4+ T cell

CD8+ T cell

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11
Q

Where are T lymphocytes derived from?

A

Thymus

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12
Q

Where are B lymphocytes derived from?

A

Bursa of Fabricus in mammals the bone marrow

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13
Q

What do B lymphocytes produce?

A

AB antibodies known as immunoglobins

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14
Q

Describe the humoral response

A

B cells have B cell receptor, a surface bound antibody
Antibodies are opsonins that bind proteins,sugars and rarely lipids
Facilitate uptake of AG as Ab-Ag complex binds Fc receptors on phagocytic cells

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15
Q

Describe the structure of an antibody

A
Y shaped
2 heavy chains - 50-75kDa
2 light chains-25kDa
Chains linked by disulphide bonds
Hinge region
Fab and Fc portions
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16
Q

What is the role of the hinge region on an antibody?

What is it made out of?

A

Gives the molecule flexibility

Made from prolines breaking the alpha heliex

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17
Q

What did antibodies evolve from?

A

Primordial gene encoding a polypeptide of about 110 amino acids

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18
Q

What part of the antibody gives specificity?

A

N terminal of the Fab portion

19
Q

Which region of an antibody is constant?

A

The Fc domain

20
Q

What does an antibody bind to?

A

The epitope- part of an antigen

21
Q

How many amino acids long are epitopes?

22
Q

Define affinity in relation to the antibody-antigen binding

A

The strength of the interaction between an antibody and antigen

23
Q

Define avidity

A

The binding of a whole antibody

24
Q

Name the 2 types of antibodies

A

Monoclonal antibody

Polyclonal antibody

25
Where so monoclonal antibodies come from? | And how many epitopes does it have?
Comes from a single B cell and has a single epitope
26
Where so polyclonal antibodies come from? | And how many epitopes does it have?
Produced by the different B cells and recognises different epitopes
27
Name 3 uses of antibodies in biotechnology
Detection of neutralising antibodies in a patient Detection of antigens in a virus or a cell Therapeutics- monoclonal only
28
How many classes of antibody are there?
5
29
Name the 5 Ab classes of antibody. How are these determined?
``` IgM IgG IgA IgE IgD ``` Determined by the structure of the Fc domain
30
Which antibody class is the most abundant?
IgG Accounts for 70%
31
The specificity is not related to its class What does this mean?
Different classes of antibody raised to a target have the same specificity
32
What are the 6 roles of antibodies?
``` Neutralisation Agglutination Opsonisation Complement Activation Trigger mast cell degranulation Activate B lymphocytes ```
33
Describe how antibodies cause neutralisation
Ab binds to toxins released by the bacteria Ab can block viral binding proteins Block the adherence of bacteria to host cells
34
What is opsonisation?
When a pathogen is marked for phagocytosis
35
Describe how a B cell is activated and what it produces
Naive B cell is actiavted and divides into memory cells or plasma cells
36
What is the difference between Memory cells and plasma/effector cells?
Memory cells have a long life span and have the same BCR as parent cells Plasma cells lived a few days but secrete antibodies
37
Describe clonal expansion/ clonal selection
Antigen binding the particular B cell bound antibody molecules inniates clonal expansion Produced large number of specific B cells Antibodies of higher affinity evolve selecting B cells expressing antibodies with high affinity
38
Which antibody is first secreted in clonal selection?
IgM then later class switching
39
What are the roles of the CD4+ T cells?
Immunity against intracellular bacteria and parasites Provide help to CD8 Tcells Promotes humoural immune response
40
What are the roles of the CD8+ T cells?
Cytotoxic when activated Kill virally infected cells Kill tumour cells
41
Where do all blood borne immune cells originate from?
Hematopoietic stem cells
42
What is haematopoiesis?
formation of blood cells
43
Where does haematopoiesis occur in the 3rd to 7th month of gesteration?
Fetal liver then spleen